Plastics engineering
Encyclopedia
Plastics engineering encompasses the processing, design, development, and manufacture of plastic
s products. A plastic is a polymer
ic material that is in a semi-liquid state, having the property of plasticity
and exhibiting flow. 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 important role. The cost of plastic materials ranges from the cheapest commodity plastics
used in mass produced consumer products to the very expensive, specialty plastics. The cost of a plastic product is measured in different ways, and the absolute cost of a plastic material is difficult to ascertain. Cost is often measured in price per pound of material, or price per unit volume of material. In many cases however, it is important for a product to meet certain specifications, and cost could then be measured in price per unit of a property. Price with respect to processibility is often important, as some materials need to be processed at very high temperatures, increasing the amount of cooling time a part needs. In a large production run cooling time is very expensive.
Some plastics are manufactured from re-cycled materials but their use in engineering tends to be limited because the consistency of formulation and their physical properties tend to be less consistent. Electrical and electronic equipment and motor vehicle markets together accounted for 58 percent of engineered plastics demand in 2003.http://mdmr.net/onesource/catalog/Engineered-Plastics-p-517.html Engineered plastics demand in the US was estimated at $9,702 million in 2007.
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
s products. A plastic is a polymer
Polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
ic material that is in a semi-liquid state, having the property of plasticity
Plasticity (physics)
In physics and materials science, plasticity describes the deformation of a material undergoing non-reversible changes of shape in response to applied forces. For example, a solid piece of metal being bent or pounded into a new shape displays plasticity as permanent changes occur within the...
and exhibiting flow. 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
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
disciplines, the economics
Economics
Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...
of a product plays an important role. The cost of plastic materials ranges from the cheapest commodity plastics
Commodity plastics
Commodity plastics are plastics that are used in high volume and wide range of applications, such as film for packaging, photographic and magnetic tape, beverage and trash containers and a variety of household products where mechanical properties and service environments are not critical. Such...
used in mass produced consumer products to the very expensive, specialty plastics. The cost of a plastic product is measured in different ways, and the absolute cost of a plastic material is difficult to ascertain. Cost is often measured in price per pound of material, or price per unit volume of material. In many cases however, it is important for a product to meet certain specifications, and cost could then be measured in price per unit of a property. Price with respect to processibility is often important, as some materials need to be processed at very high temperatures, increasing the amount of cooling time a part needs. In a large production run cooling time is very expensive.
Some plastics are manufactured from re-cycled materials but their use in engineering tends to be limited because the consistency of formulation and their physical properties tend to be less consistent. Electrical and electronic equipment and motor vehicle markets together accounted for 58 percent of engineered plastics demand in 2003.http://mdmr.net/onesource/catalog/Engineered-Plastics-p-517.html Engineered plastics demand in the US was estimated at $9,702 million in 2007.
Plastics engineering specialties
- Consumer Plastics
- Medical plastics
- Automotive plastics
- Recycled or recyclable plastics
- Biodegradable plastics
- ElastomerElastomerAn elastomer is a polymer with the property of viscoelasticity , generally having notably low Young's modulus and high yield strain compared with other materials. The term, which is derived from elastic polymer, is often used interchangeably with the term rubber, although the latter is preferred...
s / RubberRubberNatural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined... - EpoxyEpoxyEpoxy, also known as polyepoxide, is a thermosetting polymer formed from reaction of an epoxide "resin" with polyamine "hardener". Epoxy has a wide range of applications, including fiber-reinforced plastic materials and general purpose adhesives....
s - Plastics processing: Injection mouldingInjection mouldingInjection molding is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials. Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the cavity...
, Plastics extrusionPlastics extrusionPlastics extrusion is a high volume manufacturing process in which raw plastic material is melted and formed into a continuous profile. Extrusion produces items such as pipe/tubing, weather stripping, fence, deck railing, window frames, adhesive tape and wire insulation.-Process:In the extrusion of...
, Stretch-blow molding, ThermoformingThermoformingThermoforming is a manufacturing process where a plastic sheet is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product...
, Compression moldingCompression moldingCompression molding is a method of molding in which the molding material, generally preheated, is first placed in an open, heated mold cavity. The mold is closed with a top force or plug member, pressure is applied to force the material into contact with all mold areas, while heat and pressure are...
, CalenderingCalenderingCalendering is a finishing process used on cloth where fabric is folded in half and passed under rollers at high temperatures and pressures. Calendering is used on fabrics such as moire to produce its watered effect and also on cambric and some types of sateens.In preparation for calendering, the...
, Transfer moldingTransfer moldingTransfer molding, like compression molding, is a process where the amount of molding material is measured and inserted before the molding takes place. The molding material is preheated and loaded into a chamber known as the pot...
, Laminating, Fiberglass moldingFiberglass moldingFiberglass molding is a process in which fiberglass reinforced resin plastics are formed into useful shapes.-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, and can be made from a variety of different...
, PultrusionPultrusionPultrusion is a continuous process for manufacture of composite materials with constant cross-section. Reinforced fibers are pulled through a resin, possibly followed by a separate preforming system, and into a heated die, where the resin undergoes polymerization...
, Filament windingFilament windingFilament winding is a fabrication technique for manufacturing composite material, usually in the form of cylindrical structures. The process involves winding filaments under varying amounts of tension over a male mould or mandrel. The mandrel rotates while a carriage moves horizontally, laying...
, Vacuum formingVacuum formingVacuum forming, commonly known as vacuuforming, is a simplified version 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.The vacuum... - Ultrasonic weldingUltrasonic weldingUltrasonic welding is an industrial technique whereby high-frequency ultrasonic acoustic vibrations are locally applied to workpieces being held together under pressure to create a solid-state weld. It is commonly used for plastics, and especially for joining dissimilar materials...
See also
- PlasticPlasticA plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
- Polymer chemistryPolymer chemistryPolymer chemistry or macromolecular chemistry is a multidisciplinary science that deals with the chemical synthesis and chemical properties of polymers or macromolecules. According to IUPAC recommendations, macromolecules refer to the individual molecular chains and are the domain of chemistry...
- Fields of engineering
- Engineering plasticEngineering plasticEngineering plastics are a group of plastic materials that exhibit superior mechanical and thermal properties in a wide range of conditions over and above more commonly used commodity plastics. The term usually refers to thermoplastic materials rather than thermosetting ones...
- Medical grade siliconeMedical grade siliconeMedical grade silicones are silicones tested for biocompatibility and are appropriate to be used for medical applications. In the United States, the Food and Drug Administration regulates materials implanted into the body. Medical grade silicones are generally grouped into three categories: non...
External links
- University of Wisconsin - Stout - Plastics Engineering
- Umass Lowell Plastics Department Website
- Ferris State University Plastics Engineering Technology Department
- Society of Plastics Engineers
- Pittsburg State University Plastics Engineering Technology Website
- Penn State Behrend Plastics Engineering Technology Website
- Pennsylvania College of Technology Plastics and Polymer Engineering Technology Website
- Western Washington Univeristy Plastics Engineering Website