Vibration

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.