akasan

TV

2008-11-23T23:35:00.001-08:00

Television is a widely used telecomunication medium for sending (broadcasting) and receiving moving images, either black and white”) or color , usually accompanied by sound. “Television” may also refer specifically to a television set, television programming or television transmission. The word is derived from mixed latin and greek roots, meaning “far sight”. Since late 1930, the television set has become a common communications receiver in homes, businesses and institutions, particularly as a source of entertainment and news. Since the 1970s, recordings on video cassette, and later, digital media such as DVD, have resulted in the television frequently being used for viewing recorded as well as broadcast material.

A standard television set comprises multiple internal electronic circuits, including those for tuning and decoding broadcast signals. A display device which lacks these internal circuits is therefore properly called a monitor, rather than a television. A television set may be designed to handle other than traditional broadcast or recorded signals and formats, such as closed circuit television (CCTV), digital television (DTV) and high definition television (HDTV).

Around the globe, broadcast television is financed by either government, advertising, licensing (a form of tax), subscription or any combination of these. To protect revenues, subscription TV channels are usually encrypted to ensure that only subscription payers receive the decryption codes to see the signal. Non-encrypted channels are known as free to air.

DVD

2008-11-23T23:34:00.001-08:00

Digital Versatile Disk/DVD is a popular optical disc storage media format. Its main uses are video and data storage. Most DVDs are of the same dimensions as compact discs but store more than six times as much data.

The basic types of DVD are referred to by a rough approximation of their capacity in gigabytes.

The 12 cm type is a standard DVD, and the 8 cm variety is known as a mini DVD. These are the same sizes as a standard CD and a mini CD, respectively. The capacity by surface (MiB/cm²)differs from 6.92MiB/cm² in the DVD-1 to 18.0 MiB/cm² in the DVD-18

DVD uses 650nm wavelength laser diode light as opposed to 780 nm for CD or 405 nm for HD-DVD or Blu-ray Disc. This permits a smaller pit to be etched on the media surface (1.32 µm for DVD versus 1.6 µm for CD) compared to CDs.

Writing speeds for DVD were 1×, that is 1350 kB/s (1318 KIB/s), in the first drives and media models. More recent models at 18× or 20× have 18 or 20 times that speed. Note that for CD drives, 1× means 150 KIB/s (153.6 kB/s), approximately 9 times slower.

DVD recordable discs supporting this technology are backward compatible with some existing DVD players and DVD-ROM drives^.Many current DVD recorders support dual-layer technology, and the price is now comparable to that of single-layer drives, though the blank media remains more expensive. The recording speeds reached by dual-layer media are still well below those of single-layer media.

There are two modes for dual layer orientation. With parallel track path (PTP), used on DVD-ROM, both layers start at the inside diameter (ID) and end at the outside diameter (OD) with the lead-out. With opposite track path (OTP), used on DVD-Video, the lower layer starts at the ID and the upper layer starts at the OD, where the other layer ends, they share one lead-in and one lead-out

MP3

2008-11-23T23:32:00.000-08:00

MPEG-1 Audio Layer 3 more commonly referred to as MP3,is a digital audio encoding format using a form of lossy data compression. It is a common audio format for consumer audio storage, as well as a de facto standard encoding for the transfer and playback of music on digital audio players. MP3 is an audio-specific format that was designed by the Motion Pictures Expert Group. A group formed by several teams of engineers at Fraunhofer in Erlangen,Germany, AT&T Bell Lab in Murray Hill, NJ, USA, Thomson-Brandt, and CCETT as well as others. It was approved as an ISO standard in 1991.

The use in MP3 of a lossy compression algorithm is designed to greatly reduce the amount of data required to represent the audio recording and still sound like a faithful reproduction of the original uncompressed audio for most listeners, but is not considered high fidelity audio by audiophiles. An MP3 file that is created using the mid-range bit rate setting of 128 kbit/s will result in a file that is typically about 1/10th the size of the CD file created from the original audio source. An MP3 file can also be constructed at higher or lower bit rates, with higher or lower resulting quality. The compression works by reducing accuracy of certain parts of sound that are deemed beyond the auditory resolution ability of most people. This method is commonly referred to as perceptual coding. It internally provides a representation of sound within a short term time/frequency analysis window, by using pscyoacoustic models to discard or reduce precision of components less audible to human hearing, and recording the remaining information in an efficient manner. This is relatively similar to the principles used by JPEG, an image compression format.

DC and AC Motor

2008-11-12T19:21:00.000-08:00

A DC motor is designed to run on DC electric power. Two examples of pure DC designs are Michael Faraday's homopolar motor(which is uncommon), and the ball bearing motor , which is (so far) a novelty. By far the most common DC motor types are the brushed and brushless types, which use internal and external commutation respectively to create an oscillating AC current from the DC source -- so they are not purely DC machines in a strict sense.

In 1882, Nikola Tesla invented the rotating magnetic field, and pioneered the use of a rotary field of force to operate machines. He exploited the principle to design a unique two-phase induction motor in 1883. In 1885, Galileo Ferraris independently researched the concept. In 1888, Ferraris published his research in a paper to the Royal Academy of Sciences in Turin.

Introduction of Tesla's motor from 1888 onwards initiated what is sometimes referred to as the Second Industrial Revolution, making possible the efficient generation and long distance distribution of electrical energy using the alternating current transmission system, also of Tesla's invention (1888). Before the invention of the rotating magnetic field, motors operated by continually passing a conductor through a stationary magnetic field (as in homopolar motors).

Tesla had suggested that the commutators from a machine could be removed and the device could operate on a rotary field of force. Professor Poeschel, his teacher, stated that would be akin to building a perpetual motion machine.

Universal Motor

2008-11-12T19:16:00.000-08:00

A variant of the wound field DC motor is the universal motor. The name derives from the fact that it may use AC or DC supply current, although in practice they are nearly always used with AC supplies. The principle is that in a wound field DC motor the current in both the field and the armature(and hence the resultant magnetic fields) will alternate (reverse polarity) at the same time, and hence the mechanical force generated is always in the same direction. In practice, the motor must be specially designed to cope with the AC (impedance must be taken into account, as must the pulsating force), and the resultant motor is generally less efficient than an equivalent pure DC motor.

Operating at normal power line frequencies, the maximum output of universal motors is limited and motors exceeding one kilowatt (about 1.3Horse power) are rare. But universal motors also form the basis of the traditional railway traction motor in electric railways . In this application, to keep their electrical efficiency high, they were operated from very low frequency AC supplies, with 25 and 16.7 hertz (Hz) operation being common. Because they are universal motors, locomotives using this design were also commonly capable of operating from a third rail powered by DC.

The advantage of the universal motor is that AC supplies may be used on motors which have the typical characteristics of DC motors, specifically high starting torque and very compact design if high running speeds are used. The negative aspect is the maintenance and short life problems caused by the commutator. As a result such motors are usually used in AC devices such as food mixers and power tools which are used only intermittently. Continuous speed control of a universal motor running on AC is easily obtained by use of a thyristor circuit, while stepped speed control can be accomplished using multiple taps on the field coil. Household blenders that advertise many speeds frequently combine a field coil with several taps and a diode that can be inserted in series with the motor (causing the motor to run on half-wave rectified AC).

Universal motors generally run at high speeds, making them useful for appliances such as blenders, vacuum cleaners and hair dryerswhere high RPM operation is desirable. They are also commonly used in portable power tools, such as drills, circular and jig saws, where the motor's characteristics work well. Many vacuum cleaner and weed trimmer motors exceed 10,000 RPM, while Dremel and other similar miniature grinders will often exceed 30,000 RPM.

Motor damage may occur due to overspeeding (running at an RPM in excess of design limits) if the unit is operated with no significant load. On larger motors, sudden loss of load is to be avoided, and the possibility of such an occurrence is incorporated into the motor's protection and control schemes. In smaller applications, a fan blade attached to the shaft often acts as an artificial load to limit the motor speed to a safe value, as well as a means to circulate cooling airflow over the armature and field windings.

With the very low cost of semicobductor rectifiers, some applications that would have previously used a universal motor now use a pure DC motor, sometimes with a permanent magnet

Torque Capacity of Motor types

2008-11-12T19:13:00.000-08:00

When optimally designed for a given active current (i.e., torque current), voltage, pole-pair number, excitation frequency (i.e., synchronous speed), and core flux density, all categories of electric motors or generators will exhibit virtually the same maximum continuous shaft torque (i.e., operating torque) within a given physical size of electromagnetic core. Some applications require bursts of torque beyond the maximum operating torque, such as short bursts of torque to accelerate an electric vehicle from standstill. Always limited by magnetic core saturation or safe operating temperature rise and voltage, the capacity for torque bursts beyond the maximum operating torque differs significantly between categories of electric motors or generators.

Note: Capacity for bursts of torque should not be confused with Field Weakening capability inherent in fully electromagnetic electric machines (Permanent Magnet (PM) electric machine are excluded). Field Weakening, which is not readily available with PM electric machines, allows an electric machine to operate beyond the designed frequency of excitation without electrical damage.

Electric machines without a transformer circuit topology, such as Field-Wound (i.e., electromagnet) or Permanent Magnet (PM) Synchronous electric machines cannot realize bursts of torque higher than the maximum designed torque without saturating the magnetic core and rendering any increase in current (i.e., torque) as useless. Furthermore, the permanent magnet assembly of PM synchronous electric machines can be irreparably damaged, if bursts of torque exceeding the maximum operating torque rating are attempted.

Electric machines with a transformer circuit topology, such Induction (i.e., asynchronous) electric machines, Induction Doubly-Fed electric machines, and Induction or Synchronous Wound-Rotor Doubly-Fed (WRDF) electric machines, exhibit very high bursts of torque because the active current (i.e., Magneto-Motive-Force or the product of current and winding-turns) induced on either side of the transformer oppose each other and as a result, the active current contributes nothing to the transformer coupled magnetic core flux density, which would otherwise lead to core saturation.

Electric machines that rely on Induction or Asynchronous principles short-circuit one port of the transformer circuit and as a result, the reactive impedance of the transformer circuit becomes dominant as slip increases, which limits the magnitude of active (i.e., real) current. Still, bursts of torque that are two to three times higher than the maximum design torque are realizable.

The Synchronous WRDF electric machine is the only electric machine with a truly dual ported transformer circuit topology (i.e., both ports independently excited with no short-circuited port). The dual ported transformer circuit topology is known to be unstable and requires a multiphase slip-ring-brush assembly to propagate limited power to the rotor winding set. If a precision means were available to instantaneously control torque angle and slip for synchronous operation during motoring or generating while simultaneously providing brushless power to the rotor winding set (see brushless wound-rotor doubly-fed electric machine ), the active current of the Synchronous WRDF electric machine would be independent of the reactive impedance of the transformer circuit and bursts of torque significantly higher than the maximum operating torque and far beyond the practical capability of any other type of electric machine would be realizable. Torque bursts greater than eight times operating torque have been calculated.

Electric Motor

2008-11-12T19:03:00.000-08:00

An electric motor uses electrical energy to produce mechanical energy. The reverse process, that of using mechanical energy to produce electrical energy, is accomplished by a generator or dynamo. Traction motor used on locomotives and some electric and hybrid automobiles often perform both tasks if the vehicle is equipped with dynamic brakes. Electric motors are found in household appliances such as fans, refrigerators, washing machines, pool pumps, floor vacuums, and fan-forced ovens. They are also found in many other devices such as computer equipment, in its disk drives, printers, and fans; and in some sound and video playing and recording equipment as DVD/CD players and recorders, tape players and recorders, and record players. Electric motors are also found in several kinds of toys such as some kinds of vehicles and robotic toys.

Cutting

2008-11-12T18:52:00.000-08:00

Cutting is the separation of a physical object, or a portion of a physical object, into two portions, through the application of an acutely directed force. An implement commonly used for cutting is the knife or in medical cases the scalpel. However, any sufficiently sharp object is capable of cutting if it has a hardness sufficiently larger than the object being cut, and if it is applied with sufficient force. Cutting also describes the action of a saw which removes material in the process of cutting.

Cutting is a compressive and shearing phenomenon, and occurs only when the total stress generated by the cutting implement exceeds the ultimate strength of the material of the object being cut. The simplest applicable equation is stress = force/area: The stress generated by a cutting implement is directly proportional to the force with which it is applied, and inversely proportional to the area of contact. Hence, the smaller the area (i.e., the sharper the cutting implement), the less force is needed to cut something.

When referring to propagating plants, cutting is one of the methods that can be used. It involves cutting a part of the plant typically a healthy shoot, with sharp and sterile scissors or any other cutting device, and then placing the removed part in water. Some cuttings do not require water. Certain shoots when cut are able to grow when placed in vermiculite or potting soil. However, the former is the easiest to do as most shoots when cut from the main plant need time to grow roots, and then they are able to be transferred to potting soil.

Boiler

2008-11-11T23:10:00.000-08:00

A Boiler is a closed vessel in which water or other fluidis heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications.Boilers have many applications. They can be used in stationary applications to provide heat, hot water, or steam for domestic use, or in generators and they can be used in mobile applications to provide steam for locomotion in applications such as trains, ships, and boats. Using a boiler is a way to transfer stored energy from the fuel source to the water in the boiler, and then finally to the point of end use.
The source of heat for a boiler is combustion of any of several fuels, such as wood, coal, oil,or natural gas. Electric steam boilers use resistance or immersion type heating elements. Nuclear fission is also used as a heat source for generating steam. Heat recovery steam generators (HRSGs) use the heat rejected from other processes such as gas turbines.

Cooling Tower

2008-11-11T22:52:00.000-08:00

Cooling towers can generally be classified by use into either HVAC or Industrial duty.ndustrial cooling towers can be used to remove heat from various sources such as machinery or heated process material. The primary use of large, industrial cooling towers is to remove the heat absorbed in the circulating cooling water systems used in power plants,petroleum rafineries,petrochemical plants, natural gas processing plants, food processing plants, semi-conductor plants, and other industrial facilities.

With respect to the heat transfer mechanism employed, the main types are:

Wet cooling towers or simply cooling towers operate on the principle of evaporation. The working fluid and the evaporated fluid (usually H₂O) are one and the same.
Dry coolers operate by heat transfer through a surface that separates the working fluid from ambient air, such as in a heat exchanger, utilizing convective heat transfer. They do not use evaporation.
Fluid coolers are hybrids that pass the working fluid through a tube bundle, upon which clean water is sprayed and a fan-induced draft applied. The resulting heat transfer performance is much closer to that of a wet cooling tower, with the advantage provided by a dry cooler of protecting the working fluid from environmental exposure.

In a wet cooling tower, the warm water can be cooled to a temperature lower than the ambient air dry-bulb temperature, if the air is relatively dry. (see:dew point and psychrometrics). As ambient air is drawn past a flow of water, evaporation occurs. Evaporation results in saturated air conditions, lowering the temperature of the water to the wet bulb air temperature, which is lower than the ambient dry bulb air temperature, the difference determined by the humidity of the ambient air.

To achieve better performance (more cooling), a medium called fill is used to increase the surface area between the air and water flows. Splash fill consists of material placed to interrupt the water flow causing splashing. Film fill is composed of thin sheets of material upon which the water flows. Both methods create increased surface area.

Selection the right Heat Exchanger

2008-11-11T22:30:00.000-08:00

Due to the many variables involved, selecting optimal heat exchangers is challenging. Hand calculations are possible, but many iterations are typically needed. As such, heat exchangers are most often selected via computer programs, either by system designers, who are typically engineers or by equipment vendors.

In order to select an appropriate heat exchanger, the system designers (or equipment vendors) would firstly consider the design limitations for each heat exchanger type. Although cost is often the first criterion evaluated, there other several other important selection criteria which include:

High/ Low pressure limits
Thermal Performance
Temperature ranges
Product Mix (liquid/liquid, particulates or high-solids liquid)
Pressure Drops across the exchanger
Fluid flow capacity
Cleanability, maintenance and repair
Materials required for construction
Ability and ease of future expansion

Choosing the right heat exchanger (HX) requires some knowledge of the different heat exchanger types, as well as the environment in which the unit must operate. Typically in the manufacturing industry, several differing types of heat exchangers are used for just the one process or system to derive the final product. For example, a kettle HX for pre-heating, a double pipe HX for the ‘carrier’ fluid and a plate and frame HX for final cooling. With sufficient knowledge of heat exchanger types and operating requirements, an appropriate selection can be made to optimise the process

Heat Exchangers

2008-11-11T22:26:00.000-08:00

Heat exchangers may be classified according to their flow arrangement. In parallel-flow heat exchangers, the two fluids enter the exchanger at the same end, and travel in parallel to one another to the other side. In counter flow heat exchangers the fluids enter the exchanger from opposite ends. The counter current design is most efficient, in that it can transfer the most heat. See countercurrent Exchange. In a cross flow heat exchanger, the fluids travel roughly perpendicular to one another through the exchanger.

For efficiency, heat exchangers are designed to maximize the surface area of the wall between the two fluids, while minimizing resistance to fluid flow through the exchanger. The exchanger's performance can also be affected by the addition of fins or corrugations in one or both directions, which increase surface area and may channel fluid flow or induce turbulence.

The driving temperature across the heat transfer surface varies with position, but an appropriate mean temperature can be defined. In most simple systems this is the Log Mean Temperature Difference (LMTD). Sometimes direct knowledge of the LMTD is not available and the NTU Method is used.

Cooling tower

2008-11-11T22:09:00.000-08:00

All thermal power plants produce waste heat as a byproduct of the useful electrical energy produced. Natural draft wet cooling tower at nuclear power plants and at some large thermal power plants are large hyperbolic chimney like structures (as seen in the image at the left) that release the waste heat to the ambient atmosphere by the evaporation of water (lower left image).However, the mechanical induced-draft or forced-draft wet cooling towers (as seen in the image to the right) in many large thermal power plants, petroleum rafineries,petrochemical plants,geothermal,Biomass, and waste to energy plants use fans to provide air movement upward through downcoming water and are not hyperbolic chimney-like structures. The induced or forced-draft cooling towers are rectangular, box-like structures filled with a material that enhances the contacting of the upflowing air and the downflowing water.

In desert areas a dry cooling tower or radiator may be necessary, since the cost of make-up water for evaporative cooling would be prohibitive. These have lower efficiency and higher energy consumption in fans than a wet, evaporative cooling tower.

Where economically and environmentally possible, electric companies prefer to use cooling water from the ocean, or a lake or river, or a cooling pond, instead of a cooling tower. This type of cooling can save the cost of a cooling tower and may have lower energy costs for pumping cooling water through the plant's heat exchangers. However, the waste heat can cause the temperature of the water to rise detectably. Power plants usingnatural bodies of water for cooling must be designed to prevent intake of organisms into the cooling cycle. A further environmental impact would be organisms that adapt to the warmer plant water and may be injured if the plant shuts down in cold weather. In recent years, recycled wastewater, or grey water, has been used in cooling towers.

Integrated Circuit

2008-11-11T20:03:00.000-08:00

Integrated circuits were made possible by experimental discoveries which showed that semiconductor devices could perform the functions of vacuum tubes and by mid-20th-century technology advancements in semiconductor device fabrication. The integration of large numbers of tiny transistors into a small chip was an enormous improvement over the manual assembly of circuits using discrete electronic components.The integrated circuit's mass production capability, reliability, and building-block approach to circuit design ensured the rapid adoption of standardized ICs in place of designs using discrete transistors.

There are two main advantages of ICs over discrete circuits: cost and performance. Cost is low because the chips, with all their components, are printed as a unit by photolithography and not constructed one transistor at a time. Furthermore, much less material is used to construct a circuit as a packaged IC die than as a discrete circuit. Performance is high since the components switch quickly and consume little power (compared to their discrete counterparts), because the components are small and close together. As of 2006, chip areas range from a few square mm to around 350 mm², with up to 1 million transistors per mm².

Metal working lathe

2008-11-11T19:50:00.000-08:00

Metal is removed from the workpiece using a hardened cutting tool, which is usually fixed to a solid moveable mounting called the "toolpost", which is then moved against the workpiece using handwheels and/or computer controlled motors. The toolpost is operated by leadscrews that can accurately position the tool in a variety of planes. The toolpost may be driven manually or automatically to produce the roughing and finishing cuts required to turn the workpiece to the desired shape and dimensions, or for cutting threads, worm gear,etc. Cutting fluid may also be pumped to the cutting site to provide cooling, lubrication and clearing of swarf. from the workpiece. Some lathes may be operated under control of a computer for mass production (Computer Numerical Control ).Metalworking lathes are commonly provided with a variable ratio gear train to drive the main leadscrew. This enables different pitches of threads to be cut. Some older gear trains are changed manually by using interchangeable gears with various numbers of teeth, while more modern or elaborate lathes have a quick change box to provide commonly used ratios by the operation of a lever.

Drilling process in Manufacturing

2008-11-11T19:40:00.000-08:00

Hole making is one of the most important machining operations in the manufacturing process. Holes serve a variety of functions including but not limited to: fasteners for assembly, weight reduction, ventilation, access to other parts, or simply for aesthetics. Hole making or drilling is used in the production of almost any part conceivable and those that aren't drilled are made with machines that have been drilled. On most workpieces it is vitally important that the hole be drilled precisely in reference to the x, y, z-axes. When possible drilled holes should be located perpendicular to the workpiece surface. This is due to the large length-to-diameter ratio which causes the drill bit to be easily deflected which can cause the hole to be misplaced, or the drill bit to break or fatigue. Because there are so many types of production operations that involve making a variety of holes in countless different materials, there are many methods for hole making.
The most common type of drill is a standard-point twist drill. This type of drill is versatile and can be used on a variety of materials such as wood, plastic, masonry, ceramic, and metal. These drill bits have two spiral grooves running the length of the drill. These grooves aid in transporting cutting fluid to the drill tip and in removing the chips from the hole. These types of drill bits are held in chucks or collets on machines that are either hand-held or automated. This type of drilling can often cause burrs at both the entrance and the exit of the hole and parts will often need a subsequent deburring operation to smooth out the holes.

Welding

2008-11-11T18:58:00.002-08:00

Welding is a fabrication or scultural process hat joins materials, usually metalls or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes used in conjunction with heat, or by itself, to produce the weld. This is in contrast with soldering and brazing, which involve melting a lower-melting-point material between the workpieces to form a bond between them, without melting the workpieces.

Many different energy sources can be used for welding, including a gas flame, an electric arc, a laser, an electron beam, friction, and ultrasound. While often an industrial process, welding can be done in many different environments, including open air, underwater and in outer space. Regardless of location, however, welding remains dangerous, and precautions must be taken to avoid burns,electric shock, eye damage, poisonous fumes, and overexposure to ultra violet. Until the end of the 19th century, the only welding process was forge welding which blacksmiths had used for centuries to join metals by heating and pounding them. Arc welding and oxyfuel welding were among the first processes to develop late in the century, and resistance welding followed soon after. Welding technology advanced quickly during the early 20th century as world war 1 and world war 2 drove the demand for reliable and inexpensive joining methods. Following the wars, several modern welding techniques were developed, including manual methods like shielded metal arc welding now one of the most popular welding methods, as well as semi-automatic and automatic processes such as gas metal arc welding, submerged arc welding, flux scored welding and electroslag welding. Developments continued with the invention of laser beam welding and electron beam welding in the latter half of the century. Today, the science continues to advance. Robot welding is becoming more commonplace in industrial settings, and researchers continue to develop new welding methods and gain greater understanding of weld quality and properties.

Setting the torque

2008-11-11T18:52:00.000-08:00

Engineered joints require the torque to be accurately set. Setting the torque for cap screws is commonly achieved using a torque wrench. The required torque value for a particular screw application may be quoted in the published standard document or defined by the manufacturer.

The clamp load produced during tightening is higher than 75% of the fastener's proof load. To achieve the benefits of the pre-loading, the clamping force in the screw must be higher than the joint separation load. For some joints a number of screws are required to secure the joint, these are all hand tightened before the final torque is applied to ensure an even joint seating.

The torque value is dependent on the friction between the threads and beneath the bolt or nut head, this friction can be affected by the application of a lubricant or any plating (e.g. cadmium or zinc) applied to the screw threads. The screw standard will define whether the torque value is for a dry or lubricated screw thread. If a screw is torqued rather than the nut then the torque value should be increased to compensate for the additional friction - screws should only be torqued if they are fitted in clearance holes.

Lubrication can reduce the torque value by 15 – 25%, so lubricating a screw designed to be torqued dry could over tighten it. Over tightening may cause the bolt to fail, it could damage the screw thread or stretch the bolt. A bolt stretched beyond its elastic limit may no longer adequately clamp the joint.

Torque wrenches do not give a direct measurement of the clamping force in the screw - much of the force applied is lost in overcoming friction. Factors affecting the tightening friction: dirt, surface finish, lubrication, etc. can result in a deviation in the clamping force.

More accuratemethods for setting the screw clamping force rely on defining or measuring the bolt extension. The screw extension can be defined by measuring the angular rotation of the screw (turn of the nut method) which gives a screw extension based on thread pitch. Measuring the screw extension directly allows the clamping force to be very accurately calculated. This can be achieved using a dial test indicator, reading deflection at the bolt tail, using a strain gauge or ultrasonic length measurement.

Bolted Joint

2008-11-11T18:45:00.000-08:00

Bolted joints are one of the most common elements in construction and machine design. They consist of cap screws or studs that capture and join other parts, and are secured with the mating of screw threads.

There are two main types of bolted joint designs. In one method the bolt is tightened to a calculated clamp load, usually by applying a measured torque load. The joint will be designed such that the clamp load is never overcome by the forces acting on the joint (and therefore the joined parts see no relative motion).

The other type of bolted joint does not have a designed clamp load but relies on the shear sthrength of the bolt shaft. This may include clevis linkages, joints that can move, and joints that rely on locking mechanism (like lock washers, thread adhesives, and lock nuts).

Chain Conveyor

2008-11-11T18:31:00.000-08:00

Chain conveyors utilise a powered continuous chain arrangement, carrying a series of single pendants. The chain arrangement is driven by a motor, and the material suspended on the pendants are conveyed.

Many industry sectors use chain conveyor technology in their production lines. The automotive industry commonly use chain conveyor systems to convey car parts through paint plants. Chain conveyors also have widespread use in the white and brown goods, metal finishing and distribution industries.

Vibrating Conveyor System

2008-11-11T18:26:00.000-08:00

A Vibrating Conveyor is a machine with a solid conveying surface which is turned up on the side to form a trough. They are used extensively in food grade applications where sanitation, washdown, and low maintenance are essential. Vibrating conveyors are also suitable for harsh, very hot, dirty, or corrosive environments. They can be used to convey newly cast metal parts which may reach upwards of 820 °C. Due to the fixed nature of the conveying pans vibrating conveyors can also perform tasks such as sorting, screening, classifying and orienting parts. Vibrating conveyors have been built to convey material at angles exceeding 45° from horizontal using special pan shapes. Flat pans will convey most materials at a 5° Incline from horizontal line.

Conveyer

2008-11-11T18:17:00.000-08:00

A belt conveyor consists of two or more pulleys with a continuous loop of material - the conveyor belt - that rotates about them. One or both of the pulleys are powered, moving the belt and the material on the belt forward. The powered pulley is called the drive pulley while the unpowered pulley is called the idler. There are two main industrial classes of belt conveyors; Those in general material handling such as those moving boxes along inside a factory and bulk material handling such as those used to transport industrial and agricultural materials, such as grain, coal, ores, etc. generally in outdoor locations. The belt consists of one or more layers of material they can be made out of rubber. Many belts in general material handling have two layers. An under layer of material to provide linear strength and shape called a carcass and an over layer called the cover. The carcass is often a cotton or plastic web or mesh. The cover is often various rubber or plastic compounds specified by use of the belt. Covers can be made from more exotic materials for unusual applications such as silicone for heat or gum rubber when traction is essential.Belt Conveyors are used in self-unloading bulk freighters and in live bottom trucks. Conveyor technology is also used in conveyor transport such as moving sidewalks or escalator as well as on many manufacturing assembly lines.

Grease

2008-11-11T18:00:00.000-08:00

Greases are used where a mechanism can only be lubricated infrequently and where a lubricating oil would not stay in position. They also act as valuable sealants to prevent ingress of water and dust. Grease-lubricated bearings have greater frictional characteristics due to their high viscosity. Under shear, the viscosity drops to give the effect of an oil-lubricated bearing of approximately the same viscosity as the base oil used in the grease. Lithium-based greases are the most commonly used; sodium and lithium based greases have higher melting point (dropping point) than calcium-based greases but are not resistant to the action of water. Lithium based grease has a dropping point at 190 °C to 220 °C (350 °F to 400 °F). However the maximum usable temperature for Lithium-based grease is 120 °C.
Grease used for axles are composed of a compound of fatty oils to which tar,graphite or mica is added to increase the durability of the grease and give it a better surface.
A true grease consists of an oil and/or other fluid lubricant that is mixed with another thickener substance, a soap, to form a solid. The term soap is used in the chemical sense sense, meaning a metallic salt of a fatty acid which forms an emulsion with the oil. Greases are a type of shear-thinning or pseudo plastic fluid, which means that the viscosity of the fluid is reduced under shear.After sufficient force to shear the grease has been applied, the viscosity drops and approaches that of the base lubricant, such as the mineral oil. This sudden drop in shear force means that grease is considered a plastic fluid and the reduction of shear force with time makes it thixotropic. It is often applied using a grease gun which applies the grease to the part being lubricated under pressure, forcing the solid grease into the spaces in the part.

Vibration

2008-11-10T23:13:00.000-08:00

Vibration refers to mechanical oscillation about an equilibrium point. The oscillations may be periodic such as the motion of a pendulum or random such as the movement of a tire on a gravel road. Vibration is occasionally "desirable". For example the motion of a tuning fork,the reed in the woodwind instrument or harmonica or the cone of the loudspeaker is desirable vibration, necessary for the correct functioning of the various devices. More often, vibration is undesirable, wasting energy and creating unwanted sound.For example, the vibrational motions of Engine, electrical Motor or mechanical device in operation are typically unwanted. Such vibrations can be caused by imbalances in the rotating parts, uneven friction the meshing of gear teeth, etc. Careful designs usually minimize unwanted vibrations. Types of vibration:free and forced Vibration.

Vibration testing is accomplished by introducing a forcing function into a structure, usually with some type of shaker. Generally, one or more points on the structure are kept at a specified vibration level. Two typical types of vibration tests performed are random- and sine test. Sine tests are performed to survey the structural response of the device under test (DUT). A random test is generally conducted to more closely replicate a real world environment.

Most vibration testing is conducted in the vertical axis. Some may be conducted horizontally, in multiple axes, or rotationally.

Cold Forming

2008-11-10T22:46:00.000-08:00

In the case of cold forming, an aluminum-based laminate film is simply pressed into a mold by means of a stamp. The aluminum will be elongated and maintain the formed shape. In the industry these blisters are called cold form foil (CFF) blisters. The principal advantage of cold form foil blisters is that the use of aluminum is offering a near complete barrier for water and oxygen, allowing an extended product expiry date. The principal disadvantages of cold form foil blisters are: the slower speed of production compared to thermoforming; the lack of transparency of the package (a therapy compliance disadvantage); and the larger size of the blister card (aluminum can not be formed with near 90 degree angles).

Blow Molding

2008-11-10T22:37:00.000-08:00

Blow Molding is a manufacturing process by which hollow plastic parts are formed. In general, there are three main types of blow molding: extrusion blow molding, injection blow molding, and stretch blow molding. The blow molding process begins with melting down the plastic and forming it into a parison or preform. The parison is a tube-like piece of plastic with a hole in one end in which compressed air can pass through. The parison is then clamped into a mold and air is pumped into it. the air pressure then pushes the plastic out to match the mold. Once the plastic has cooled and hardened the mold opens up and the part is ejected.
There has been evidence found suggesting that Egyptians and Babylonians blew plastic materials, but Enoch Ferngren and William Kopitke were the first verified people who used the Blow Molding Process. The process principle comes from the idea of blowing glass. Ferngren and Kopitke produced a blow molding machine and sold it to Hartford Empire Company in 1937. This was the beginning of the commercial blow molding process. During the 1940s the variety and amount of products were still very limited and therefore blow molding did not take off until later. Once the variety and production rates went up the amount of products created followed soon there after. In the United States soft drink industry the amount of plastic containers went from zero in 1977 to ten Billion in 1999. Today even a greater amount of products are blown and it is expected to keep increasing.

Injection Process

2008-11-10T22:23:00.000-08:00

For the injection molding cycle to begin, four criteria must be met: mold open, ejector pins retracted, shot built, and carriage forward. When these criteria are met, the cycle begins with the mold closing. This is typically done as fast as possible with a slow down near the end of travel. Mold safety is low speed and low pressure mold closing. It usually begins just before the leader pins of the mold and must be set properly to prevent accidental mold damage. When the mold halves touch clamp tonnage is built. Next, molten plastic material is injected into the mold. The material travels into the mold via the sprue bushing, then the runner system delivers the material to the gate. The gate directs the material into the mold cavity to form the desired part. This injection usually occurs under velocity control.When the part is nearly full, injection control is switched from velocity control to pressure control. This is referred to as the pack/hold phase of the cycle. Pressure must be maintained on the material until the gate solidifies to prevent material from flowing back out of the cavity. Cooling time is dependent primarily on the wall thickness of the part. During the cooling portion of the cycle after the gate has solidified, plastication takes place. Plastication is the process of melting material and preparing the next shot. The material begins in the hopper and enters the barrel through the feed throat. The feed throat must be cooled to prevent plastic pellets from fusing together from the barrel heat. The barrel contains a screw that primarily uses shear to melt the pellets and consists of three sections. The first section is the feed section which conveys the pellets forward and allows barrel heat to soften the pellets. The flight depth is uniform and deepest in this section. The next section is the transition section and is responsible for melting the material through shear. The flight depth continuously decreases in this section, compressing the material. The final section is the metering section which features a shallow flight depth, improves the melt quality and color dispersion. At the front of the screw is the non-return valve which allows the screw to act as both an extruder and a plunger.When the screwis moving backwards to build a shot, the non-return assembly allows material to flow in front of the screw creating a melt pool or shot. During injection, the non-return assembly prevents the shot from flowing back into the screw sections. Once the shot has been built and the cooling time has timed out, the mold opens. Mold opening must occur slow-fast-slow. The mold must be opened slowly to release the vacuum that is caused by the injection molding process and prevent the part from staying on the stationary mold half. This is undesirable because the ejection system is on the moving mold half. Then the mold is opened as far as needed, if robots are not being used, the mold only has to open far enough for the part to be removed. A slowdown near the end of travel must be utilized to compensate for the momentum of the mold. Without slowing down the machine cannot maintain accurate positions and may slam to a stop damaging the machine. Once the mold is open, the ejector pins are moved forward, ejecting the part. When the ejector pins retract, all criteria for a molding cycle have been met and the next cycle can begin.

Machining

2008-11-10T22:15:00.000-08:00

Molds are built through two main methods: standard machining and EDM. Standard Machining in its conventional form, has historically been the method of building injection molds. With technological development, CNC Machining became the predominant means of making more complex molds with more accurate mold details in less time than traditional methods.
The Electrical Discharge Machining (EDM) or spark erosion process has become widely used in mold making. As well as allowing the formation of shapes which are difficult to machine, the process allows pre-hardened molds to be shaped so that no heat treatment is required. Changes to a hardened mold by conventional drilling and milling normally require annealing to soften the steel, followed by heat treatment to harden it again. EDM is a simple process in which a shaped electrode, usually made of copper or graphite, is very slowly lowered onto the mold surface (over a period of many hours), which is immersed in paraffin oil. A voltage applied between tool and mold causes spark erosion of the mold surface in the inverse shape of the electrode.
The cost of manufacturing molds depends on a very large set of factors ranging from number of cavities, size of the parts (and therefore the mold), complexity of the pieces, expected tool longevity, surface finishes and many others. The initial cost is great, however the piece part cost is low, so with greater quantities the overall price decreases.

Injection Moulding

2008-11-10T20:32:00.000-08:00

Injection Moulding is a manufacturing process for producing from both thermoplastic and thermosettingplastic materials. Molten plastic is injected at highpressure into a mould, which is the inverse of the product's shape. After a product is designed, usually by an industrial designer, molds are made by a mould maker. from metal, usually either steel or aluminium and precision-machined to form the features of the desired part. Injection molding is widely used for manufacturing a variety of parts, from the smallest component to entire body panels of cars.Injection molding is the most common method of production, with some commonly made items including bottle caps and outdoor furniture. Injection molding typically is capable of tolerances equivalent to an IT Grade of about 9–14.
Injection molding machines, also known as presses, hold the molds in which the components are shaped. Presses are rated by tonnage, which expresses the amount of clamping force that the machine can exert. This force keeps the mold closed during the injection process. Tonnage can vary from less than 5 tons to 6000 tons, with the higher figures used in comparatively few manufacturing operations. The required force is determined by the material used and the size of the part, larger parts require higher clamping force.

Vacuum Forming

2008-11-10T20:21:00.001-08:00

Vacuumforming is simplified of thermoforming whereby a sheet of plastic is heated to a forming temperature, stretched onto or into a single surface mold, and held against the mold by applying vacuum between the mold surface and the sheet.
Normally,draft angle must be present in the design on the mold (a recommended minimum of 3°), otherwise release of the formed plastic and the mold is very difficult.Vacuum forming is usually – but not always – restricted to forming plastic parts that are rather shallow in depth. A thin sheet is formed into rigid cavities for unit doses of pharmaceuticals and for loose objects that are carded or presented as point-of-purchase items. Thick sheet is formed into permanent objects such as turnpike signs and protective covers.
Relatively deep parts can be formed if the form-able sheet is mechanically or pneumatically stretched prior to bringing it in contact with the mold surface and before vacuum is applied.
Suitable materials for use in vacuum forming are conventionally thermoplastics , the most common and easiest being High Impact polystrene sheetingThis is molded around a wood, structural foam or cast/machined aluminum mold and can form to almost any shape. Vacuum forming is also appropriate for transparent materials such as acrylic which are widely used in applications for aerospace such as PCW (passenger cabin windows) canopies for military fixed wing aircraft and "bubbles" for rotary wing aircraft.

Thermoforming Engineering

2008-11-10T20:15:00.000-08:00

Thermoforming has benefited from applications of engineering technology,although the basic forming process is very similar to what was invented many years ago. Microprocessor and computer controls on more modern machinery allows for greatly increased process control and repeatability of same-job setups from one production run to the next, usually with the ability to save oven heater and process timing settings between jobs. The ability to place formed sheet into an inline trim station for more precise trim registration has been hugely improved due to the common use of electric servo motors for chain indexing versus air cylinders, gear racks, and clutches on older machines. Electric servo motors are also used on some modern and more sophisticated forming machines for actuation of the machine platens where form and trim tooling are mounted, rather than air cylinders which have traditionally been the industry standard, giving more precise control over closing and opening speeds and timing of the tooling. Quartz and radiant-panel oven heaters generally provide more precise and thorough sheet heating over older cal-rod type heaters, and better allow for zoning of ovens into areas of adjustable heat.
The more than USD10 billion North American market has traditionally been ¾ thin gauge and ¼ heavy gauge. In 2003 there were about 150 thin gauge thermoformers in North America. Sixty percent formed proprietary products. Thirty percent were custom formers and 10 percent were OEMs with in-house forming capability. There were nearly a dozen thin-gauge formers having annual sales of at least USD100 million. The largest had annual sales in excess of USD1,000 million. There were about 250 heavy gauge formers in North America. Nearly all were custom formers. Only two or three heavy gauge formers had annual sales of more than USD100million. The largest had annual sales of about USD140 million

Thin and thick gauge Thermoforming

2008-11-10T20:03:00.000-08:00

There are two general thermoforming process categories. Sheet thickness less than 1.5 mm is usually delivered to the thermoforming machine from rolls or from a sheet extruder. Thin-gauge roll-fed or inline extruded thermoforming applications are dominated by rigid or semi-rigid disposable packaging. Sheet thicknesses greater than 3 mm is usually delivered to the forming machine by hand or an auto-feed method already cut to final dimensions. Heavy, or thick-gauge, cut sheet thermoforming applications are primarily used as permanent structural components. There is a small but growing medium gauge market that forms sheet 1.5 mm to 3 mm in thickness.

Heavy-gauge forming utilizes the same basic process as continuous thin-gauge sheet forming, typically draping the heated plastic sheet over a mold. Many heavy-gauge forming applications use vacuum only in the form process, although some use two halves of mating form tooling and include air pressure to help form. Aircraft windscreens and machine gun turret windows spurred the advance of heavy-gauge forming technology during WWII. Heavy gauge parts are used as cosmetic surfaces on permanent structures such as automobiles, refrigerators, spas, and shower enclosures, and electrical and electronic equipment. Unlike most thin-gauge thermoformed parts, heavy-gauge parts are often hand-worked after forming for trimming to final shape or for additional drilling, cutting, or finishing, depending on the product.

Thermoforming

2008-11-10T19:14:00.000-08:00

Thermoforming is a manufacturing process for thermoplastic sheet or film. Specifically, it is more of a converting process, where plastic sheet or film is converted into a formed, finished part. The sheet or film is heated in an oven in an oven to its forming temperature, then streched into or onto a mold and cooled.Early generation thermoforming machines usually incorporated cal rod type of heater.similar to heating elements found in conventional electric kitchen ovens. These are still used, but more modern equipment frequently uses quartz heaters or radiant-panel heaters for more efficient sheet heating and ease of zone control. Cast or machined aluminum is the most common mold material, although epoxy, wood and structural foam are sometimes used for prototypes, samples, and low volume production runs. Aluminum molds are normally water-cooled by a cooling tower or chiller system for faster production capabilities. Thermoforming differs from blow moulding, injection moulding,and other forms of processing plastics, and is primarily used in the manufacture of disposable cups, containers, lids, trays, blisters, clamshells, and other products. A thermoform machine can utilize vacuum only, or vacuum combined with air pressure, in the forming process. It can be as small and simple as a table-top sample former where small cut sheets of material are placed into a clamp and heated and formed, or as large and complex as a complete inline extrusion, thermoforming, trimming, granulating, and material handling system for continuous high-speed production. Many thermoforming companies do not extrude their own plastic sheet, but rather purchase it in roll-wound form for running on their forming equipment. Others purchase plastic resin in bulk pellet form and extrude the sheet for use on roll-fed or inline forming machines.

Plastic

2008-11-10T18:57:00.000-08:00

Plastic is the general common term for a wide range of synthetic or semisynthetic organic solid materials suitable for the manufacture of industrial products. Plastics are typically polymers of high molecular weight and may contain other substances to improve performance and/or reduce costs.
The common word "plastic" should not be confused with the technical adjective "plastic", which is applied to any material which undergoes a permanent change of shape (a "plastic deformation") when strained beyond a certain point. Aluminum, for instance, is "plastic" in this sense, but not "a plastic" in the common sense; while some plastics, in their finished forms, will break before deforming — and therefore are not "plastic" in the technical sense. It refers to their malleability, or plasticity during manufacture, that allows them to be cast,pressed or extruded into an enormous variety of shapes—such as films, fibers plates, tubes, bottles, boxes, and much more.The common word "plastic" should not be confused with the technical adjective "plastic", which is applied to any material which undergoes a permanent change of shape (a "plastic deformation") when strained beyond a certain point. Aluminum, for instance, is "plastic" in this sense, but not "a plastic" in the common sense; while some plastics, in their finished forms, will break before deforming — and therefore are not "plastic" in the technical sense.

Types of Airsoft Gun

2008-11-10T18:42:00.000-08:00

Spring-powered airsoft guns are single-shot devices that use potential energy stored in a spring to compress air to launch an airsoft pellet down the barrel of the gun. The user must cock a spring gun prior to each shot. This is typically achieved by pulling back the slide (pistols), bolt (rifles), or the grip on a shotgun, which in turn compresses the spring and makes the gun ready to fire.Because of this, these guns are by definition incapable of automatic or semi-automatic fire. Spring powered airsoft guns are generally not as powerful as gas and electric models, although this can vary by cost.While most electric guns also use springs for propulsion of the airsoft pellet, they are not considered to be in the same category as the single-shot spring-powered guns. Low-end spring guns tend to be much cheaper than their electric-powered equivalents due to their simplicity and lack of electrical components (spring assembly, electric motor, battery, and battery charger) and thus are widely available. These guns are less suited for competition because they are at a disadvantage against automatic guns in close combat and do not provide enough accuracy and power for long-range use. There are some exceptions, however, as higher-end spring-powered airsoft rifles can be quite expensive; these guns are typically suited for "marksman" applications in airsoft matches and provide competitive muzzle velocities. Additionally, pump shotguns are sometimes used, especially in CQB (Close Quarters Battle). In colder weather, spring pistols are more reliable than gas-powered pistols. This represents one of the major advantages of spring powered airsoft gun, as it can be fired in any situation, without reliance on an external source of power, such as batteries or gas. The lack of reliance on external power sources causes some players to favor spring powered guns. Spring guns are also less susceptible to the effects of water, where a battery-powered gun could malfunction when wet. The other major advantage that spring weapons hold over other powered airsoft guns is price. True AEGs can range from $200-$550 and high-end gas pistols generally cost from $80-$200 both of which also require extra equipment; gas, batteries etc. Spring guns tend to not exceed $50, except in cases of high end "sniping" rifles which average out to be around $103-$370 in price. Most players start with a spring pistol as their first airsoft weapon, which will usually cost about $10-$30. They are also more readily available in most department stores. Because of their price, spring guns tend to act as "training guns" to bring new players to airsoft games and are considered the primary weapon of "backyard skirmishes." Almost all airsoft players at some point owned a spring weapon, whether for its actual use in the sport or for the replica value since some airsoft weapons are only available as spring versions.

Airsoft Gun

2008-11-10T18:30:00.000-08:00

An airsoft gun is a type of gun used for recreational purposes, and firing nonlethal projectiles.

There are three types of airsoft gun: spring, gas, and electric . All work on the same principle of compressed gas expanding to force a pellet down the gun's barrel and each type has its own advantages and disadvantages. In 1970 Japan it was illegal to possess firearms, but there was a large interest in them. Because of this interest, manufacturers started to produce spring-powered guns that looked like the real firearms in the 1970s. These guns fired several calibers of plastic or rubber BBs, but were eventually standardized into 6mm and 8mm sizes. The early spring powered weapons then morphed into gas powered ones, using a variety of systems. The hobby then migrated to North America in the mid 1990s.then low powered spring guns transformed into classic airsoft.About ten years after this time, Japan hit a recession just as AEGs, or automatic electric guns, hit the market, so many old manufacturers were lost, leaving Tokyo Marui, inventor of the AEG, as the primary manufacturer. Marui then invented an improved Hop up system, further improving the accuracy and range of the weapons. In the early 2000s, Classic Army of Hong Kong entered the scene and gradually improved its quality of guns until it now rivals Tokyo Marui. A few years later countless Chinese brands have flooded the market with cheap entry level weapons.

Motorcycle

2008-11-10T18:08:00.000-08:00

Motorcycle construction is the engineering, manufacturing, and assembly of components and systems for a motorcycle which results in performance, cost and aesthetics desired by the designer. With some exceptions, construction of modern mass-produced motorcycles has standardised on a steel or aluminium frame holding the front wheel and disk brake. A gasoline powered typically consisting of between one and four cylinders (and less commonly, up to eight cylinders) coupled to a manual five- or six-speed sequentiell transmission drives the swingarm mounted rear wheel by a chain, driveshaft and belt. Motorcycle fuel economy benefits from the relatively small mass of the vehicle. This, of course, relates to how the motorcycle is used. One person on a small motorcycle travelling a short distance is generally very economical. However a large motorcycle generally has bad aerodynamics compared with a typical car, poor aerodynamics of exposed passengers and engines designed for goals other than fuel economy can work to reduce these benefits. Riding style has a large effect on fuel economy. Fuel economy varies greatly with engine displacement and riding style. Different types of motorcycles have different dynamics and these play a role in how a motorcycle performs in given conditions. For example, a shorter wheelbase would generally make a bike lean faster and would be quicker around corners compared to a longer wheelbase.Longer wheelbase on the other hand provides more stability in a straight line. Motorcycles must be leaned in order to make turns. This lean is induced by the method known as counterstreering, in which the rider presses on the handlebars on the side of the desired direction of turn, but 'steering' the bars in the opposite direction. Because it is counter-intuitive this practice is often very confusing to novices—and even to many experienced motorcyclists

Car / Automobile

2008-11-10T17:51:00.000-08:00

Car/ Automobile is one of the transport vehicle in now a days world and consider the most important one. Most definitions of the term specify that automobiles are designed to run primarily on roads, to have seating for one to eight people, to typically have four wheels, and to be constructed principally for the transport.However, the term is far from precise because there are many types of vehicles that do similar tasks. In 1879 Benz was granted a patent for his first engine, which had been designed in 1878. Many of his other inventions made the use of the internal combustion engine feasible for powering a vehicle.His first motorwagon was built in 1885 and he was awarded the patent for its invention as of his application on January 29, 1886. Benz began promotion of the vehicle on July 3, 1886 and approximately 25 Benz vehicles were sold between 1888 and 1893, when his first four-wheeler was introduced along with a model intended for affordability. They also were powered with four-stroke engines of his own design. France industrial Emile Roger already producing Benz engines under license, now added the Benz automobile to his line of products. Because France was more open to the early automobiles, initially more were built and sold in France through Roger than Benz sold in Germany.

Permeation

2008-11-09T23:03:00.000-08:00

The Permeation of films and membranes can be measured with any gas or liquid. The method uses a central module which is separated by the test film: the testing gas is fed on the one side of the cell and the permeated gas is carried to the detector by a sweep gas. The testing medium (liquid or gas) is situated in the inner white pipe and the permeate is collected in the space between the pipe and the glass wall. It is transported by a sweep gas (connected to the upper and lower joint) to an analyzing device.
Permeation in daily Life, example in
* Packaging the permeability of the package (materials, seals, closures, etc) needs to be matched with the sensitivity of the package contents and the specified shelf life. Some packages must have nearly hermetic Seals while other can (and sometimes must) be selectively permeable. Knowledge about the exact permeation rates is therefore essential.
* Tire Air pressure in tyres should decrease as slowly as possible. Therefore it is good to know which gas permeates least through the rubber wall.
* Insulating material: Water vapour permeation of insulating material is important as well as for submarine cables to protect the conductor from corrosion.
* Fuel System To meet legal regulations, it is essential to use barrier materials for fuel hoses and tanks.

LASER

2008-11-09T22:10:00.000-08:00

The Word LASER is an acronym for light amplification by stimulated emission of radiation. LASER consist of a gain Medium inside a highly reflective optical cavity.as well as a means to supply energy to the gain medium. The gain medium is a material with properties that allow it to amplify light by stimulated emission. In its simplest form, a cavity consists of two mirrors arranged such that light bounces back and forth, each time passing through the gain medium. Typically one of the two mirrors, the output coupler partially transparent. The output laser beam is emitted through this mirror.Light of a specific wavelength that passes through the gain medium is increased in power the surrounding mirrors ensure that most of the light makes many passes through the gain medium, being amplified repeatedly. Part of the light that is between the mirrors (that is, within the cavity) passes through the partially transparent mirror and escapes as a beam of light. The process of supplying the energy required for the amplification is called pumping. The energy is typically supplied as an electrical current or as light at a different wavelength. Such light may be provided by a flash lamp.or perhaps another laser. Most practical lasers contain additional elements that affect properties such as the wavelength of the emitted light and the shape of the beam.
The types of LASER :
* Gas LASER using gases, e.g. He Ne, Carbon dioxide, Argon ion LASER
* Chemical LASER are powered by a chemical reaction, and can achieve high powers in continuous operation. For example, in the Hydrogen Flouride LASER
* Solid-state LASER, Solid state LASER Materials are commonly made by "doping" a crystalline solid host with ions that provide the required energy states. E.g. Ruby LASER

Absorption

2008-11-09T20:47:00.000-08:00

Absorption in chemistry is a physical or chemical process in which atoms, ions or moleculs enter some bulk phase-gas, liquid,solid material.In many technologically important processes, the chemical absorption is used in place of the physical process, e.g. absorption of carbon dioxide by sodium hydroxide - such processes do not follow the Nernst partition law. In the case of gas absorption, one may calculate its concentration by using e.g. the ideal gas law. Alternatively one may use partial pressure instead of concentration. This is a different process from adsoption since the molecules are taken up by the volume, not by surface.

Cavitation

2008-11-09T20:21:00.000-08:00

The word cavitation refers to the formation of vapor bubbles in regions of low pressure within the flow field of a liquid. In some respects, cavitation is similar to boiling, except that the latter is generally considered to occur as a result of an increase of temperature rather than a decrease of pressure. This difference in the direction of the state change in the phase diagram is more significant than might, at first sight, be imagined. It is virtually impossible to cause any rapid uniform change in temperature throughout a finite volume of liquid. Rather, temperature change most often occurs by heat transfer through a solid boundary. Hence, the details of the boiling process generally embrace the detailed interaction of vapor bubbles with a solid surface, and the thermal boundary layer on that surface. On the other hand, a rapid, uniform change in pressure in a liquid is commonplace and, therefore, the details of the cavitation process may differ considerably from those that occur in boiling. Cavitation can cause damage to the material surfaces close to the area where the bubbles collapse when they are convected into regions of higher pressure. Cavitation damage can be very expensive, and very difficult to eliminate. As the result of the cavitation can damage the surface of the blade of pump and can influence the performance of the pump.

Engine

2008-11-09T18:19:00.000-08:00

Engine is mechanical device that converted force into motion. In most cases the work is supplied by exerting the torque, which is used to operate other machinery, generate electricity, pump water or compressed gases. Types of internal combustion engine include reciprocating engine, gas turbine, jet engine, turbo propeller engine, pulse jet, pulse detonation engine ,hot bulb engine, diesel engine, gasoline engine. Internal Combustion Engine is air breathing engine that use the oxygen in atmospheric air to burn the fuel carried rather than carrying an oxidiser as in rocket. Theoretically, this should result in a better spesific impulse than for rocket engine.

Lubricant

2008-11-06T22:41:00.000-08:00

Lubrication is the process employed to reduce wear of one or both surfaces in close proximity and moving relative to each other by interposing a substance called Lubricant between the surfaces to carry the load between the opposing surfaces. The interposed Lubricant film can be solid, a solid/liquid dispersion, liquid-liquid dispersion

In the most common case the applied is carried by the pressure generated between the fluid due to the frictional viscous resistance to motion of the lubricating fluid between the surfaces.

Lubrication can also describe the phenomenon such reduction of wear occurs without human intervention

When we talk about lubrication smooth continuous equipment operation is assumed, with only mild wear, and without excessive stresses within the lubricated conjunctions to cause seizure at the conjunction, or break of any part of the equipment, and when such a catastrophic event does occur it means that the lubrication has broken down.

Coordinate Measuring Machine

2008-11-06T20:21:00.000-08:00

A Coordinate Measuring Machine is a device for measuring physical geometrical of characteristic of an object. This Machine may be manually controlled by an operator or it may be computer controlled Measurement are defined by a probe attached to third moving axis of this machine. This probe touch the part of interest and allows collecting discrete points on the object surface's. The typical CMM is composed on three axes X,Y, and Z. These axes is orthogonal to each other in typical three dimensional coordinate system. Each Axis has a very accurate scale system that indicates the Location of that Axis. All three Axes are digital Display readout. The Probe is used to touch different spot of the part being measured. The Machine then uses the X,Y,Z coordinates of each these points to determine size and position. The next generation of scanning, known as laser scanning. This Method use laser beams that are projected against the surface of the part. Many thousand of points can be taken and used to not only to check the size and position, but also to create a 3D image of the part as well. This point cloud of Data can then be transffered to CAD Software to create a working 3D Model of the part.

Metrology

2008-11-06T19:22:00.000-08:00

Metrology is a scientific study of measurement. The act of Measuring always involves a measuring instrument. Measurement always have errors and uncertainties. A core concept of Metrology is traceability defined as the property of result of a measurement or the value of a standard whereby it can be related to stated references usually national or international standards,through an unbroken chain of comparison all having stated uncertainties. The level of traceability establishes the level of comparibilty of the measurement whether the result of a mesurement can be compared to the previous one, a measurement result a year ago or to the result of a measurement performed anywhere else in the world. The traceability is most often obtained by calibration, establishing the relation between the indication of a mesuring instrument and the value of measurement standard. These Standard are usually coordinated by national laboratories e.g. like National Institute of Standards and Technology(USA)

Types of Bearing

2008-11-06T18:42:00.000-08:00

The a different types of Bearing in industrial Usage, E.g.
* Fluid Bearing, can fail quickly due to the grit or dust or other contaminants. Maintenance free in continious use
* Magnetic Bearing often needs considerable power, maintenance free
* Plain Bearing, simplest type of Bearing, widely used, relatively high friction
* Rolling Element Bearing, mainly used for higher loads
* Jewel Bearing usually mainly used in low load, high precision work such as clock
* Flexure Bearing: Limited range of movement, backlash, extremly smooth motion

Pump

2008-11-06T17:50:00.000-08:00

A pump is a device to move gases, liquids, slurries. A pump moves liquids or gases from lower pressure to higher pressure and overcomes this differences in pressure by adding energy to the system (E.g. such as water to the system). The service liquid has the task of compressing the gas to be conveyed, sealing off the various discharge chambers from each other, lubricating the shaft seals and absorbing the compression energy as heat. A gas pump is normally called compressor, except in very low pressure application, like heating, ventillating, or air conditioning where the operative equipment consists of fans or blowers.
Pumps works by using mechanical forces to pushthe material, either by physically lifting or by force of compression

Problemsolving in Lamination problems

2008-11-06T01:06:00.000-08:00

Problem Bubbles in Lamination
Possible causes
* Low nip pressure preventing proper wetting of secondary web (Action: Increase nip pressure)
* Too soft a nip roll (Action: Solid rubber back up roll is preffered over sleeve system )
* Too much agitation of adhesive resulting in foam (Action: Slow pump down)
* Improper mixing of adhesive which may allow for more carbon dioxide gas formation resulting in out gassing. Especially on two high barrier films(Action: make sure scale is accurate)
* No smoothing bar(Action: Keep smoothing bar clean)

Galvanic deposit on the cylinder

2008-11-06T00:39:00.000-08:00

After degreasing and nickel plating, the cylinder is ready for copper plating
Electrolytic process
* It is the electric charge transfer from a positive pole (anode) to the negative one (cathode) using a liquid solution bath as a conductor
Bath Solution composition
* Copper sulphate melted in demineralized water
* Sulfuracid
Elements influencing the crystalline of the copper deposit
* Copper quality
* Bath Temperature
* Electricity intensity (amp/dm square)
* Electrolytic Components Stability
* Hardness additive
The galvanic deposit must guarantee:
* Crsyalline Structure
* Constant hardness on the width of the cylinder
* Ductility

Ink Structure

2008-11-06T00:21:00.000-08:00

Ink contain Pigment and Medium; Pigment can be Organic, Inorganic, Organomettalic (dye stuff) and Medium can be PP Based, Acrylic based,PU based, Vinyl based.
Usually the pigment is dispersedin the diluted medium (with certain kind of solvent).
Where color comes from inorganic?
For inorganic; metal oxide, generally from the metal in transition group in periodic table
Each oxidation state can give different color, for example FeO(reddish), Fe2O3 (yellowish)
Orbital d from the electron structure has empty orbital state, resulting electron movement from one orbital to another orbital. This movement results certain color according to the formula E=h x f (certain frequency give certain color)

Two Component Systems

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Handling :
* Preheating of Adhesive usually not necessary
* Meter/Mix/Dispense equipment is required
* Mix ratio should be monitored
* Excellent
*Clean-up of machine areas
Advantages :
* Wide performance range
* Chemical cure
* Mix ratio adjustment
*Chemistry reduces tendencytoward anti-sealing of PE Laminates
* Reduced curl of finished laminates

Single Component Systems Adhesive

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Handling :
* Need to heat containers
* Heated delivery system and application rollers
* Moisturization at the nip

Precautions :
* Viscosity will build if the adhesiveis overheated
* Misting good tension control
* Corona treatment of some films
* Careful, immediate clean up of hot rollers
* possible loss of metallization

Polyether- and Polyester based Adhesives

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This leads to a different polarity of the backbone. The Polyether-structure is unpolar, the polyesther-structure is polar. This has some basic consequences:
The polar Polyesther - structure adheres better to metal surfaces (aluminiumfoil and metallized films).
The unpolar Polyether-structure is more able to absorb slip additives. This means that there may be better bonds and a" slip drop"

Principle of Phase-Doppler Anemometry

2008-11-05T19:53:00.000-08:00

The principle of phase-Doppler anemometry (PDA) relies on the Doppler difference method used for conventional laser-Dopler anemometry and was first introduced by Durst and Zare (1975). By using an extended receiving optical System with two or more photo detectors it is possible to measure simultaneously size and velocity of spherical particles. For obtaining the particle size the phase shift of the light scattered by reflection or refraction from the two intersecting laser beams is used.

Electronic Engraving

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The advantages of Electronic engraving
* Use of whole offset tonal scale from 1 to 100 %
* Constant repetition
* Little ink used
* Quicker start-up on printing machines due to optimized cylinders physical chracteristics
* Nowadays technology allows to work directly from digital information received, to the Helioklischograph with an electronic managing system, by-passing photographic phases and obtaining better engraving quality

Application Structures in Flexible Packaging

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* Liquid, Chemicals, Hot Filled Liquid, Retorted Meals, Pasteurized, Oily Products
PET/Ink/Adh/Nylon/Adh/LLDPE
PET/Ink/Adh/ALU-F/Adh/LLDPE
PET/Ink/Adh/MET-OPP/Adh/LLDPE
Nylon/Ink/Adh/LLDPE
PET/Ink/Adh/MET-OPP/Adh/LLDPE
* Dry Foods
PET/Ink/Adh/VMCPP
OPP/Ink/Adh/VMCPP
PET/Ink/Adh/ MET-PET/Adh/CPP

Lamination Problem

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During the Laminating process normally we face with a lot kind of problem e.g.
* Bubbles in Lamination
* Low Bonds
* Tunneling
* Telescoping
* Haze in Laminations
* Poor Heat and Chemical Resistance
* Fish eyes

Printing Proof

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To let the customer assess directly the quality level of the manufacturing process, together with the finished cylinder, also a complete printing proof should be delivered. To quarantee the final result maximum fidelity, the colour sample is the Cromalin proof approved by the customer. The colour sample on the printing proof are read with a spectrometer interfaced with a computer containing "formulation ink" software. Therefore it is possible to have automatically the formulation to mix colour recipe with a computer-aided mixing station that prints the colour recipe. This recipe is supplied to the customer attached to the cylinder's printing proof, so that in printing start-up a better speed in control and correct valuation and preparation of colours is made sure.

How the Helioklischograph works

2008-11-05T17:31:00.000-08:00

The direct electronic engraving is a fully digitalized process. The 'engraving originals' are download from a directory (released) shared in line with the digital page-up department, where sigle images (digital files) are processed to obtain, with Step & Repeat, the final page-up with all the register marks(cross, autotron,slitting line,buttons,etc) following the customer's specifications. This is to obtain a complete digital printing(cromalin) for final control before engraving. In this part of the process a set of Job Tickets( files containing all the engraving parameters necessaryfor the Helioklischograph) will be coupled with the job single colours.
After the acquisition of the file, the machine will execute automatically a set of Test Cut, then (when the requested engraving parameters are obtained) will proceed directly with the definitive engraving of bthe images.

The chemistry of ink

2008-11-04T23:58:00.000-08:00

Generally there are two kinds of ink
*Inorganic e.g.: TiO2(white), FeO(red)
* Organic e.g.Phthalocyanine blue
Advantage and disadvantage
Inorganic:* color strength not good, Longer life time, Processability not good
Organic :*good color strength, Shorter Life Time, Better Processability

Base Cylinder

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The base cylinder is a steel unwelded tube, 12 to 20 mm thick (for practical use 6-10 mm is common)
* It is grinded outside
* It is turned inside
* It is balanced statically or dynamically
There are two categories of cylinder
*Shaftless
*Shafted
The Cylinder dimensions are
*Width=horizontal length
* Develop=circumference ( n replicate)
Shaftless cylinders are mounted to the printing machine with a set of cones with 10 cone angle and 90 mm diameter

The Colour Sequence

2008-11-04T23:43:00.000-08:00

When materials have to be printed inside, the colour sequence has to start from the darkest colour to the lightest one
*Black
*Cyan
*Magente
*Yellow
This technique is used to keep the chromatic result at the end of the process close to the original
For outside printing, colour starts from the lightest to the darkest one
* Yellow
* Magente
* Cyan
*Black

UV STABILIZERS

2008-11-04T23:11:00.000-08:00

3 Clases of Light Stabilizers-HALS (Hindered Amine Light Stabilizers); Absorbers(UVA) e.g. benzophenones and benzotriazoles;Quenchers e.g. Ni(Energy transfer)
HALS chemically scavenge free radicals and decompose peroxides;usually more effective.
UVA's need high concentrations and thick polymer governed by Beer Lambert Law
[Absorbance=Ext'n Coeff x Path Length x Concentration]

Homopolymers and Copolymers

2008-11-04T22:57:00.000-08:00

Polymers made solely from one kind of monomer are called homopolymers
Polymers made from two monomers (or co-monomers) are called copolymers
Ethylene only=homopolymer
LDPE,HDPE
Ethylene & octene = copolymer
LLDPE
Ethylene & Vinyl acetate = copolymer
EVA,EAA

Fundamentals of Polyethylene

2008-11-04T22:45:00.000-08:00

Types of Polyethylene
Polyethylene is composed of only carbon and hydrogen(with some exceptions) which can be combined in number of ways to make many different polyethylenes including:
LDPE, Low Density Polyethylene
EVA, Ethylene Acrylic Acid Copolymers
HDPE, High Density Polyethylene
LLDPE,Linear Low Density Polyethylene
ULDPE,Ultra Low Density Polyethylene(a.k.a. very low Density PE, VLDPE)
Single-site polyethylenes

Laminating Process

2008-11-04T20:02:00.000-08:00

Normally during laminating process two or more layers of materials will be laminated together using adhesive. They are different types of Adhesives, example solventbased Adhesive, solventfree Adhesive and also waterbased Adhesives. Each typed of Adhesives have their advantage and disadvantage, depends on Usage and Application. For economically and health issue nowadays food Industry prefer to use waterbased Adhesives or solventfree Adhesives. The Laminating Process is simple, in which Unwinder A will unwind the Material A through the transferring rolls and the then through the coater and then drying chamber at the same time the Unwinder B will also unwind Material B, normally the position of Unwinder B are at behind of the Laminating Maschine. Then the both Material A+B will go through Niprolls, so that both Material can be laminated together. At the same time the Rewinder will rewind the laminated Material as finish goods. After that the laminated rolls will be stored inside Agingroom for certain time so that Adhesive can really be cured perfectly, especially Adhesives with solventbased.

Flexible Packaging Process

2008-11-04T17:40:00.000-08:00

In this modern & dynamic world everybody expect instant product. So the food industry must work together with packaging company to solve this problem especially in flexible packaging. The packaging company must make a breakthrough with innovation. I would like to share with everybody how this process from beginning until finish product. First from choosing the right material suitable to pack the food and the design the customer want. It's quite complex. First the material must be printed as customer's wish. For that the designer must prepare the rolls for printing department. The rolls must be engrave first like the customer's design. Then will test print be done for to see if the design already suitable like customer's wish. If so, then the mass production can be done. Printing technology normally be use is rotogravure. After printed, then will go to laminating process. After that go to slitting process as finish product and then can deliver to customer.