I have been in the field of Custom Plastic Injection Molding for about 21 years now as of the writing of this article.
Plastic injection molding, by definition, is the practice of injecting plastic into a mold (or mould in Western circles), cooling the plastic, ejecting it in the mold, and packaging the final product available to the customer. This seems simple and in it’s basic form it’s, but the process involved with creating all this happen is actually rather complex.
There are lots of varied types of injection molding and so many different types of plastic injection molding machines to go with it. Some of the more common types of plastic molding are conventional mold injection, insert molding, plastic extrusion, blow molding, multi-color or cloth molding, pile molding, and rotary molding simply to mention a few. Precision Injection mold There are custom plastics as well, from common every day plastic resins to the more exotic engineering grade resins used in most automobiles today. There are injection molding grade”alloys” being experimented with and utilized nowadays.
There are many types of injection molding machines all made for specific functions. You will find the standard horizontal injection molding machines which range in size from a couple of heaps all the way up to 9000 tons and more. You could drive car between the platens of a press that large. Vertical injection molding machines are often used for insert molding (though this may also be accomplished horizontally) and share a common cover using two ejection halves of the mold. This allows for de-molding and loading of inserts in 1 half, whereas the other half is producing the following shot of components. There are also two and three shot injection molding machines for creating multi-color or multi-material components such as lenses for tail lights and gear shift knobs with hard plastic inner core and a soft vinyl out covering. The most recent machines have been”all electric versions” which stray from the standard hydraulic injection machines utilized now for ages. These injection molding machines are much more effective and repeatable then their hydraulic cousins are. Common injection molding machine manufacturers are Toshiba, Husky, Cincinnati, DeMaag, Engel, Nissei, UBE, Arburg and Boy, simply to mention a couple.
The fundamental steps to producing a plastic injection molded part on a stand injection molding machine would be:
Heat the plastic resin into the required range of this product being used.
Creating the shot size through use of a reciprocating screw which communicates the melted plastic to the front of the screw.