Injection Molding is a process by which we take small pellets of plastic, then melt it to the point that will inject under moderate pressure. The mold is made of two separate halves that will open after the plastic has cooled for the product to be removed.
Injection Molding Machines are used to run the molds that make the actual products. The machines are rated in tons, which is the amount of clamp pressure that the machine will apply on the mold. Also, the barrel size is a factor of what an injection molding machine will produce in the amount of plastic it will inject into a mold. Reliable Injection Molding machines range from a 75 Ton - 450 Ton, and will produce parts up to 60 ounces.
The Injection Mold is two separate halves that are machined from steel to the exact dimension of what product will be produced. The molds can be sometimes very expensive in that it takes weeks to produce a mold within thousands of an inch. The key to successfully producing quality parts that are in tolerance is the mold. The molds are made to many different requirements depending on the amount of production that it will be expected to produce. A mold that will only need to produce 500 - 1000 pieces, would make one part per shot out of steel, but a high production mold would probably produce many of the same parts per shot and be made from hardened steel.
Thermoplastic resin is used to make molded plastic parts, because it will melt under certain temperatures and hardened when it is cooled off. The proper plastic depends on the part requirements. This is just a general overview of injection molding process, to give you an idea of the process. Contact Reliable Plastic Injection representatives about any further information or assistance.