What is the definition of "injection molding"?
A type of molding process in which resin is heated in a barrel and then injected into a mold by a reciprocating screw.

Learn more about injection molding in the class Overview of Plastic Materials 115 below.


Materials Training


Class Information
Tooling U classes are offered at the beginner, intermediate, and advanced levels. The typical class consists of 12 to 25 lessons and will take approximately one hour to complete.
Class Name:Overview of Plastic Materials 115
Description:This class describes the different types of plastics and their characteristics.
Prerequisites: none
Difficulty:Beginner
Number of Lessons:17
Language:English, Spanish

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Below are all the competencies and job programs that contain the class Overview of Plastic Materials 115. Job programs are our traditional class lists organized according to common job functions. Competencies are our latest job-specific curricula that help tie online learning to practical, hands-on tasks.

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Competencies


Class Outline
  • Objectives
  • The Advantages of Plastics
  • The Structure of Polymers
  • Types of Polymers
  • Thermoplastics
  • Polycarbonates
  • Acrylic
  • Acetal
  • Nylon
  • Polyvinyl Chloride
  • Polyethylene
  • ABS
  • Thermosets
  • Phenolics
  • Polyester
  • Polyurethane
  • Summary
  
Class Objectives
  • Describe the advantages of plastic.
  • Describe the molecular structure of polymers.
  • Identify the main types of polymers.
  • Describe thermoplastics.
  • Describe polycarbonates.
  • Describe acrylics.
  • Describe acetals.
  • Describe nylon.
  • Describe polyvinyl chloride.
  • Describe polyethylene.
  • Describe ABS.
  • Describe thermosets.
  • Describe phenolics.
  • Describe polyester.
  • Describe polyurethane.

Class Vocabulary

Vocabulary TermDefinition
acetal A semi-crystalline thermoplastic that can withstand a wide temperature range. Acetals, however, cannot be exposed to ultraviolet light or they will degrade.
acrylic An amorphous thermoplastic that is resistant to weather and ultraviolet light. Acrylics are often used for optical products because they are transparent.
acrylonitrile-butadiene-styrene ABS. An amorphous, thermoplastic polymer that is often injection molded because it has good heat and impact resistance.
additive Any substance that is added to a plastic during manufacturing in order to improve its properties.
air inhibition An undesirable quality that can occur when uncured resin is exposed to air. Air inhibition slows the curing process, causing the resin to become soft and tacky.
alkali A soluble substance directly opposite acid on the pH scale. Certain polymers, like acetal, are unable to resist strong alkalies.
amorphous region A region in a plastic in which the molecules are unorganized. Amporphous regions are hard and brittle.
amorphous thermoplastic A thermoplastic with a molecular structure that lacks a definite repeating form, shape, or structure. Amorphous thermoplastic materials form clear plastic parts.
carbon black A soot-like residue that is used as a colorant and/or a protector against UV radiation in polymers. Carbon black is often applied to various acetals.
cold drawing The process of stretching a nylon fiber until it will no longer stretch. When cold drawn, fibers also become thinner and stronger.
continuous service temperature The highest temperature at which a material can function for an extended period of time without failing. ABS, for example, has low continuous service temperature.
creep resistance A polymer's ability to resist any kind of distortion when under a load over an extended period of time.
cross-linking The development of primary bonds that form between polymer molecules. Thermosets are heavily cross-linked, while thermoplastics are not cross-linked.
cure To cross-link molecules permanently by heating them. Curing occurs in thermosets when they are heated to mold.
cutting fluid A fluid used during cutting operations to reduce heat and friction between the cutting tool and the workpiece.
elastomer A formation of a thermoplastic or thermoset that can stretch and then return to its original shape without permanent deformation. Elastomers are only slightly cross-linked.
fatigue endurance A material's ability to withstand cycles of external stress over and over again.
flame retardant The ability to resist catching fire. Some polymers offer improved flame-retardant properties through the use of additives.
heat resistance The ability to resist degradation when under extreme heat. Heat resistance is important for plastics that will be exposed to heat on a regular basis.
high-density polyethylene HDPE. A type of polyethylene that is popularly used in the United States. HDPE's polymer chains are packed tightly together, forming semi-crystalline structures.
impact strength The ability of a plastic to withstand high energy impact without fracturing or breaking.
injection molding A type of molding process in which resin is heated in a barrel and then injected into a mold by a reciprocating screw.
low-density polyethylene LDPE. A type of polyethylene that is very flexible and translucent. LDPE is often used to make plastic bags.
lubricant Any substance added to a resin that reduces friction and aids in the injection of the resin into the mold and facilitates the removal of the part from the mold.
macromolecule An incredibly large molecule that consists of repeating molecular units. Polymers consist of long chains of multiple macromolecules.
mer The basic molecular unit that chemically bonds into long, repeating chains to form a macromolecule.
mold release agent Any chemical that is used to help release the molded part from the mold cavity.
molecule The smallest unit into which a material can be divided without changing its properties. A molecule consists of a group of atoms held together by strong primary bonds.
nylon A type of thermoplastic that was developed as a substitute for silk. Nylon is cold drawn to make its fibers very strong.
organic chemical Chemicals that are found in nature. Some plastics are resistant to organic chemicals.
organic polymer Polymers that occur naturally. Organic polymers are not synthesized by humans.
oxidizing agent A substance that adds oxygen to a polymer, resulting in the break-down of that polymer.
phenolic A type of thermoset that is rigid and relatively inexpensive. Phenolics are often used in the manufacturing of plywood.
plastic The common name for commercial polymers consisting of macomolecules and engineered to exhibit specific properties.
polycarbonate A type of thermoplastic that is used for items that require high heat resistance such as coffee pots, hair dryers, and appliance housings.
polyester A type of thermoset that is highly compatible with additives or other chemicals that will give it desired characteristics. Polyester is also used to manufacture artificial limbs.
polyethylene A thermoplastic that is highly resistant to electricity and heat. Polyethylene is often used to manufacture tough plastic bags.
polymer A material made of very large molecules that generally does not have a crystalline structure. Polymers are more commonly referred to as plastics.
polymerization The chemical process of forcing small molecules to bond together, forming long macromolecule chains.
polyurethane A thermoset that was first developed as a replacement for rubber. Polyurethane is used in the manufacturing of many medical devices, like surgical drains, artificial hearts, feeding tubes, and wound dressings.
polyvinyl chloride PVC. A type of thermoplastic that is used in the manufacturing of many everyday products. PVC is a controversial material because of its toxic effect on the environment.
resin A raw polymer, usually in the form of beads or pellets, that is not yet formed into its final molded shape.
self-extinguishing The inability to support flame after the source of the flame is withdrawn. Certain plastics are self-extinguishing.
semi-crystalline region A region in a plastic in which the molecule arrangement is ordered and structured. Semi-crystalline regions increase the melting point of the plastic because more heat is needed to encourage molecular movement.
semi-crystalline thermoplastic A thermoplastic that contains areas of crystalline molecular structure, but contains amorphous regions as well. Semi-crystalline thermoplastics are often stronger and more resistant to gas diffusion than amorphous thermoplastics.
solvent resistance A polymer's ability to resist chemicals or solvents that would otherwise degrade the polymer.
stiffness The ability of a material to resist bending or stretching.
stress cracking The cracking of a material after it has been subjected to a force that attempts to deform it.
synthetic polymer A polymer that is chemically manufactured from separate materials. The formation of synthetic polymers requires human intervention.
temperature limit The upper and lower temperature range in which a plastic may effectively function. Outside of their temperature limit, plastics will fail to function properly.
terpolymer A new polymer made from the connection between three different polymers. ABS is an example of a terpolymer.
thermal stabilizer A material that helps polymers endure the effects of increased heat.
thermoplastic A group of plastics that can be softened by heat, hardened by cooling, and then softened again by heat. This cycle can occur over and over again.
thermoset A group of plastics that is permanently hardened by cooling. If heated after it has been initially cooled, the thermoset will char or burn.
UL94 A flammability standard written by the Underwriters Laboratories. The UL94 gives specifications on characteristics such as the rate flame spreads through a material.
ultraviolet light A wavelength that is above violet in the color spectrum. Ultraviolet light will damage certain plastics.
unsaturated acid A chemical that can be added to a resin to increase cross-linking and produce a final material that is harder and stiffer. Unsaturated acid is often added to polyester.
viscoelastic Having both viscous and elastic qualities. Plastics are an example of a viscoelastic material.
viscosity A fluid's resistance to flow. As temperature increases, viscosity decreases.