Injection molded plastics manufacturers including plastic injection molding, plastic injection mold, plastic gears, injection molded plastics, plastic injection molders, and molded plastics.  

Plastic Molding Types and Terms

Types of Plastic Molding

• Double-shot molding is a two-step process in which either the color or the material is injected first. Upon the hardening of the material, a second color or material is injected into or around the first shape.
  
• Gas-assisted injection molding is a process in which inert gas, such as nitrogen, is forced into the melt while it is entering the mold, packing the plastic into the cavities. Gas-assisted injection molding reduces cycle time, part weight, warpage and stress to the cooled parts, as well as minimizing other problems.
  
• Injection blow molding (http://www.blowmoldedplastic.com) is the process in which plastic is injected into a mold to form a plastic tube. The tube is then blown into a cavity mold to form a hollow part.
  
• Injection molding is a process by which plastics parts and products are formed.
  
• Molded plastic pieces are parts that are formed by pouring heated plastic into molds.
  
• Plastic injection molding is a process by which plastic is heated into a malleable form and pressed into molds.
  
• Plastic insert molding is an injection molding process in which plastic gets injected into a cavity surrounding an insert piece just prior to molding. Plastic insert molding results in a single piece encapsulated by the plastic.
  
• Plastic manufacturers make a variety of plastic goods.
  
• Plastic molders are the tools and dies used to mold molten plastic.
  
• Push-pull molding is a process that involves multiple layers with different orientations, providing more uniform properties to the parts than if they were molded from a single direction
  

Plastic Molding Terms

Backing Plate – A plate that provides support for the mold cavity block, guide pins, bushings and so forth.
 
Cavity – The space inside a mold into which the material is injected.
 
Charge – The amount of material needed to fill a mold during a single cycle.
 
Cooling Channels – Channel through which a cooling medium flows to control the temperature of the surface of the mold. Cooling channels are located within the body of the mold.
 
High Density Polyethylene (HDPE) – Plastic used to package products with short shelf lives, such as bottles for milk, juice, water and laundry products. Unpigmented HDPE bottles are translucent and have good stiffness.
 
Hydraulic Units – Devices that use the force of fluids to move the mold in the injection molding process.
 
Linear Low Density Polyethylene (LLDPE) – A plastic that is used predominantly in film applications due to its toughness and flexibility. LLDPE is the preferred resin for injection molding because of its superior toughness and is used in items such as grocery bags, garbage bags and landfill liners.
 
Mold – A series of steel plates, which contain cavities into which plastic resin is injected to form a part.
 
Monomer – A relatively simple compound that can react to form a polymer.
 
Melt Index – A test that measures the ability of molten plastic to flow.
 
Melting Point (Tm) – The temperature at which crystalline portions of polymers melt. A material becomes soft and completely amorphous once it reaches the Tm.
 
Melt Viscosity – A term that refers to the measure of resistance to flow. For all materials, the viscosity decreases as the temperature increases.
 
Polymer – A term that means many units. These units are linked together to form chain-like structures that give polymers unique properties.
 
Polypropylene (PP) – A very strong substance that has the lowest density of the plastics used in packaging. PP has a high melting point, making it ideal for hot-fill liquids.
 
Polystyrene (PS) – A very versatile plastic that can be rigid or foamed and has a relatively low melting point. General purpose polystyrene is clear, hard and brittle.
 
Resin – Any of a class of solid or semi-solid organic products of natural or synthetic origin, generally of high molecular weight with no definite melting point. Most resins are polymers.
 
Thermoplastics – Materials that can be melted by heating and then re-solidified by cooling. Blends of thermoplastics can be prepared by melt-mixing.
 
Thermosets – Materials that “cure” to form solids when heated. Unlike thermoplastics, solid thermosets do not melt when heated, so they are very useful for high heat applications.
 
Toggle Unit – Device that uses mechanical links to move the mold during the formation of injection molded plastics.