The process of manufacturing plastic components varies according to the type of part being made. Most parts of this sort are made by a technique known as plastic injection molding. Quality production depends on understanding this process and how it can be adjusted to create components which possess the desired features for their application.
Many items are produced using this approach, including containers, automotive parts, bottles, electronic casings, and much more. It is considered to be highly efficient as large quantities of products can be manufactured at once, it has low labor costs, high precision, a wide selection of compatible materials, and little waste of resources.
Plastic polymers suitable for molding, mostly fall into one of the following groups; thermosets, elastomers, and thermoplastics. The chemical composition of each polymer blend has different properties which give the manufacturer a large selection. Polymer types are matched to the strength required and intended use of the product.
Standard molding equipment consists of molds, and a press, or injection molding machine. Molds are hollow forms in the shape of the objects being molded, they can be made out of any of several types of metal. The press is a comprised of a hopper, plunger, and heating unit which function together as a system to produce the finished product. Presses are rated by the tons of clamping force they are capable of exerting to keep the molds closed while in use.
The molding cycle begins with solid plastic being introduced into the hopper, where it is moved along by the plunger to be heated to the point of melting and then squeezed into a nozzle and injected into the gate of the mold. The hot, liquid plastic sets under a constant pressure and temperature, then it is allowed to cool, and is ejected. Carefully planning the design of each mold in a way that minimizes physical stress placed on the parts will generally yield fewer manufacturing defects.
The gates are the openings on the mold through which the molten polymers are injected into the cavity. These gates can differ in size, location, and design. In general, larger parts require larger gates. Another point to consider, is the thickness of the walls of the molded object; thinner walls will help reduce the length of the cooling cycle and also save materials.
If something other than a smooth surface is desired for a molded object, a process known as texturing is implemented. Patterns are added to the surface of the part to give it a particular appearance. Besides serving an aesthetic purpose, this technique can also be useful in a practical sense for disguising minor flaws and to minimize the effects of friction over time.
Many items are produced using this approach, including containers, automotive parts, bottles, electronic casings, and much more. It is considered to be highly efficient as large quantities of products can be manufactured at once, it has low labor costs, high precision, a wide selection of compatible materials, and little waste of resources.
Plastic polymers suitable for molding, mostly fall into one of the following groups; thermosets, elastomers, and thermoplastics. The chemical composition of each polymer blend has different properties which give the manufacturer a large selection. Polymer types are matched to the strength required and intended use of the product.
Standard molding equipment consists of molds, and a press, or injection molding machine. Molds are hollow forms in the shape of the objects being molded, they can be made out of any of several types of metal. The press is a comprised of a hopper, plunger, and heating unit which function together as a system to produce the finished product. Presses are rated by the tons of clamping force they are capable of exerting to keep the molds closed while in use.
The molding cycle begins with solid plastic being introduced into the hopper, where it is moved along by the plunger to be heated to the point of melting and then squeezed into a nozzle and injected into the gate of the mold. The hot, liquid plastic sets under a constant pressure and temperature, then it is allowed to cool, and is ejected. Carefully planning the design of each mold in a way that minimizes physical stress placed on the parts will generally yield fewer manufacturing defects.
The gates are the openings on the mold through which the molten polymers are injected into the cavity. These gates can differ in size, location, and design. In general, larger parts require larger gates. Another point to consider, is the thickness of the walls of the molded object; thinner walls will help reduce the length of the cooling cycle and also save materials.
If something other than a smooth surface is desired for a molded object, a process known as texturing is implemented. Patterns are added to the surface of the part to give it a particular appearance. Besides serving an aesthetic purpose, this technique can also be useful in a practical sense for disguising minor flaws and to minimize the effects of friction over time.
About the Author:
Genevive B. Mata has taught plastics molding techniques for over 15 years. He specializes in injection molding and thermoforming. If you are interested in learning more about recycle plastic pallets then he recommends you visit his friends at PTM: Custom Plastics Injection Molding Company.
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