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Plastics Engineering
Plastics engineering encompasses the processing, design, development, and manufacture of plastics products. A plastic is a polymeric material that is in a semi-liquid state, having the property of plasticity and exhibiting flow. Plastics engineering encompasses plastics material and plastic machinery. Plastic machinery is the general term for all types of machinery and devices used in the plastics processing industry. The nature of plastic materials poses unique challenges to an engineer. Mechanical properties of plastics are often difficult to quantify, and the plastics engineer has to design a product that meets certain specifications while keeping costs to a minimum. Other properties that the plastics engineer has to address include: outdoor weatherability, thermal properties such as upper use temperature, electrical properties, barrier properties, and resistance to chemical attack. In plastics engineering, as in most engineering disciplines, the economics of a product plays an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptability, plus a wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to its widespread use. Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum; however, recent industrial methods use variants made from renewable materials, such as corn or cotton derivatives. 9.2 billion tonnes of plastic are estimated to have been made between 1950 and 2017. More than half this plastic has been produced since 2004. In 2020, 400 million tonnes of plastic were produced. If global trends on plastic demand continue, it is estimated that by 2050 annual global plastic production will reach over 1, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stretch-blow Molding
Blow molding (or moulding) is a manufacturing process for forming hollow plastic parts. It is also used for forming glass bottles or other hollow shapes. In general, there are three main types of blow molding: extrusion blow molding, injection blow molding, and injection stretch blow molding. The blow molding process begins with softening plastic by heating a preform or parison. The parison is a tube-like piece of plastic with a hole in one end through which compressed air can enter. The plastic workpiece is then clamped into a mold and air is blown into it. The air pressure inflates the plastic which conforms to the mold. Once the plastic has cooled and hardened the mold opens and the part is ejected. Water channels within the mold assist cooling. History The process principle comes from the idea of glassblowing. Enoch Ferngren and William Kopitke produced a blow molding machine and sold it to Hartford Empire Company in 1938. This was the beginning of the commercial blow mol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Economics Of Plastics Processing
The economics of plastics processing is determined by the type of process. Plastics can be processed with the following methods: machining, compression molding, transfer molding, injection molding, extrusion, rotational molding, blow molding, thermoforming, casting, forging, and foam molding. Processing methods are selected based on equipment cost, production rate, tooling cost, and build volume. High equipment and tooling cost methods are typically used for large production volumes whereas low - medium equipment cost and tooling cost methods are used for low production volumes. Compression molding, transfer molding, injection molding, forging, and foam molding have high equipment and tooling cost. Lower cost processes are machining, extruding, rotational molding, blow molding, thermoforming, and casting. A summary of each process and its cost is displayed in figure 1. Aspects of plastic processing Degradable plastics Oxo-degradable plastics: these are petroleum-based plastic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Design Of Plastic Components
Injection molding has been one of the most popular ways for fabricating plastic parts for a very long time. They are used in automotive interior parts, electronic housings, housewares, medical equipment, compact disc The compact disc (CD) is a Digital media, digital optical disc data storage format that was co-developed by Philips and Sony to store and play digital audio recordings. In August 1982, the first compact disc was manufactured. It was then rele ...s, and even doghouses. Below are certain rule based standard guidelines which can be referred to while designing parts for injection molding considering manufacturability in mind. Geometric considerations The most common guidelines refer to the specification of various relationships between geometric parameters which result in easier or better manufacturability. Some of these are as follows: Wall Thickness Non-uniform wall sections can contribute to warpage and stresses in molded parts. Sections which are too th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrasonic Welding
Ultrasonic welding is an industrial process whereby high-frequency ultrasonic acoustic vibrations are locally applied to work pieces being held together under pressure to create a solid-state weld. It is commonly used for plastics and metals, and especially for joining dissimilar materials. In ultrasonic welding, there are no connective bolts, nails, soldering materials, or adhesives necessary to bind the materials together. When used to join metals, the temperature stays well below the melting point of the involved materials, preventing any unwanted properties which may arise from high temperature exposure of the metal. History Practical application of ultrasonic welding for rigid plastics was completed in the 1960s. At this point only hard plastics could be welded. The patent for the ultrasonic method for welding rigid thermoplastic parts was awarded to Robert Soloff and Seymour Linsley in 1965. Soloff, the founder of Sonics & Materials Inc., was a lab manager at Branson Instr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotational Molding
Rotational molding (BrE: moulding) involves a heated mold which is filled with a charge or shot weight of material. It is then slowly rotated (usually around two perpendicular axes), causing the softened material to disperse and stick to the walls of the mold forming a hollow part. In order to form an even thickness throughout the part, the mold rotates at all times during the heating phase, and then continues to rotate during the cooling phase to avoid sagging or deformation. The process was applied to plastics in the 1950s but in the early years was little used because it was a slow process restricted to a small number of plastics. Over time, improvements in process control and developments with plastic powders have resulted in increased use. Rotocasting (also known as rotacasting), by comparison, uses self-curing or UV-curable resins (as opposed to thermoplastics) in an unheated mould, but shares slow rotational speeds in common with rotational molding. This kind of rotocas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuum Forming
Vacuum forming is a simplified version of thermoforming, where a sheet of plastic (in various forms HIPS (High impact polystyrene) for low impact products, or for Bathroom shower trays ABS, and exterior vehicle parts HDPE, plus various other types of vacuum formable materials) is heated to a forming temperature, stretched onto a single-surface mould, and forced against the mould by a vacuum. This process can be used to form plastic into permanent objects such as turnpike signs and protective covers. Normally draft angles are present in the design of the mould (a recommended minimum of 3°) to ease removal of the formed plastic part from the mould. Relatively deep parts can be formed if the formable sheet is mechanically or pneumatically stretched prior to bringing it into contact with the mold surface and applying the vacuum. Suitable materials for use in vacuum forming are conventionally thermoplastics. The most common and easiest to use thermoplastic is ''high impact polys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filament Winding
Filament winding is a fabrication technique mainly used for manufacturing open (cylinders) or closed end structures (pressure vessels or tanks). This process involves winding filaments under tension over a rotating mandrel. The mandrel rotates around the spindle (Axis 1 or X: Spindle) while a delivery eye on a carriage (Axis 2 or Y: Horizontal) traverses horizontally in line with the axis of the rotating mandrel, laying down fibers in the desired pattern or angle to the rotational axis. The most common filaments are glass or carbon and are impregnated with resin by passing through a bath as they are wound onto the mandrel. Once the mandrel is completely covered to the desired thickness, the resin is cured. Depending on the resin system and its cure characteristics, often the mandrel is autoclaved or heated in an oven or rotated under radiant heaters until the part is cured. Once the resin has cured, the mandrel is removed or extracted, leaving the hollow final product. For some prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pultrusion
Pultrusion is a continuous process for manufacture of fibre-reinforced plastics with constant cross-section. The term is a portmanteau word, combining "pull" and "extrusion". As opposed to extrusion, which pushes the material, pultrusion pulls the material. A very early pultrusions type patent was filed by J.H. Watson in 1944. This was followed by M.J. Meek's filing of 1950. The first commercial pultrusions were provided by Glastic Company of Cleveland, Ohio under the patent filed in 1952 by Rodger B. White. The patent issued to W. B. Goldsworthy in 1959 helped initiate the promotion and knowledge spread within the industry. W. Brandt Goldsworthy is widely regarded as the inventor of pultrusion. Parallel to the work of Goldsworthy, who concentrated his work on unsaturated polyester resins, Ernst Kühne in Germany developed a quite similar process in 1954 based on epoxy resin. Invention, development and the issuance of patents continue in the pultrusion field through today. A la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiberglass Molding
Fiberglass molding is a process in which fiberglass reinforced resin plastics are formed into useful shapes. The process usually involves first making a mold and then using the mold to make the fiberglass component. Mold making The fiberglass mold process begins with an object known as the plug or buck. This is an exact representation of the object to be made. The plug can be made from a variety of materials, usually certain types of foam. After the plug has been formed, it is sprayed with a mold release agent. The release agent will allow the mold to be separated from the plug once it is finished. The mold release agent is a special wax, and/or PVA (Polyvinyl alcohol). Polyvinyl alcohol, however, is said to have negative effects on the final mold's surface finish. Once the plug has its release agent applied, gelcoat is applied with a roller, brush or specially-designed spray gun. The gelcoat is pigmented resin, and gives the mold surface a harder, more durable finish. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laminating
Lamination is the technique/process of manufacturing a Raw material, material in multiple layers, so that the composite material achieves improved strength of materials, strength, stability, sound insulation, visual appearance, appearance, or other properties from the use of the differing materials, such as plastic. A laminate is a permanently assembled object created using thermal energy, heat, pressure, welding, or adhesives. Various coating machines, machine presses and calendering equipment are used. Materials There are different lamination processes, depending primarily on the type or types of materials to be laminated. The materials used in laminates can be identical or different, depending on the process and the object to be laminated. Textile Laminated fabric are widely used in different fields of human activity, including medical and military. Woven fabrics (organic and inorganic based) are usually laminated by different chemical polymers to give them useful proper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transfer Molding
Transfer molding (BrE: transfer moulding) is a manufacturing process in which casting material is forced into a mold. Transfer molding is different from compression molding in that the mold is enclosed rather than open to the fill plunger resulting in higher dimensional tolerances and less environmental impact. Compared to injection molding, transfer molding uses higher pressures to uniformly fill the mold cavity. This allows thicker reinforcing fiber matrices to be more completely saturated by resin. Furthermore, unlike injection molding the transfer mold casting material may start the process as a solid. This can reduce equipment costs and time dependency. The transfer process may have a slower fill rate than an equivalent injection molding process. Process The mold interior surfaces may be gel-coated. If desired, the mold is first pre-loaded with a reinforcing fiber matrix or preform. Fiber content of a transfer molded composite can be as high as 60% by volume. The fill m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
