What Is a Molding Machine?

An injection molding machine, also called an infill machine, is a device for producing plastic objects by the simple injection molding technique. It consists of two major components, an inlet unit and a clamping device. The two parts are connected by means of a vacuum source, a die head, and a pressure arm. Depending on the model, one or more of the equipment components may also be controlled electronically.

In general, you can find two kinds of plastic injection molder/injector combinations. The first type, called the solid-state plastic injection molding machine (SSI), has all the components located in the same chamber. This kind of molding machine is designed to create parts with consistent measurements and consistency.

On the other hand, the semi-automatic injection molded part maker (SMA) has two separate machines - a cupping machine and an infilling machine. The first type of machine is usually used to manufacture a few parts at a time. Meanwhile, the other type has the capacity to mold hundreds of parts at a time. Both types of molding press operate using the identical principles, such as clamping and pressing. However, the SMA machines feature automated feeding system and high-speed die cutting equipment.

Molding machines with injection feed mold technology use a large continuous cycle gas-fueled mold feed system to feed plastic materials (polymer) through a large number of chambers. As the material passes along, the plastic gets pressed and compressed, and the mold-feed mechanism automatically clamps the two halves of the mold together. Molded parts are then manually pressed or cranked into position. The two types of molding machine also differ in their mold complexity, from simple polymer molds up to full-scale auto-action polyethylene molds.

The most commonly used types of machines are found in small shops. However, some large industrial companies with vast molding machine resources also make use of automated machines for their plastic injection molding machines. Large companies usually employ the use of full-scale factory machines to manufacture polyethylene, because these machines have greater capacity for fast plastic injection molding operations. However, smaller shops can also purchase small-scale, manual machines for their smaller-scale plastic injection molding machines.

Hydraulic machines are generally used in larger molding shops. A hydraulic press is able to provide greater access to various areas inside the large molding machines. Some of the common hydraulic press found in plastic injection molding machines are: wet presses, dry presses, disc benders, rotary and screw pump hydraulic presses, and water-powered and electric powered hydraulic presses. Each of these has its own advantages and disadvantages, and it's important to know your shop's or manufacturer's specifications before making a purchase decision.