Injection Molding

In the industrial designers and engineers to design good mold after the injection mold manufacturing business of metal (typically steel or aluminum) in the next action precision instrument manufacturing mold desired traits.

Injection molds can produce tens of thousands of the same size, character and texture of parts, mold design and therefore must follow extremely strict manufacturing procedures.

Molten plastic under high pressure is injected into the mold, when the mold is cooled, liquid plastic cured, plastic parts to be produced. After the mold is opened, part ejected. When the mold is closed after the next injection can be produced.

Injection Moulding

Injection molding is a thermoplastic or thermosetting plastic molded in plastics to uniformly heat the cylinder, and then pushed by a plunger or screw to a method for moving a mold cavity in the closed molding.


Injection molding is suitable for almost all thermoplastics. In recent years, it is also successfully used for the injection molding of certain thermosetting plastics molding. Injection molding of molding cycle is short (seconds to minutes), the quality of the molded article by a few grams to several kilograms, can be a complex shape forming precise size, with a metal or non-metal insert moldings. Thus, the method adaptable, high production efficiency.

Injection molding injection machine is divided into a plunger-type injection molding machine and screw injection machine into two categories, the injection system, and the mold clamping system has three major components; the molding can be divided into:

(1) Vent type injection molding - Vent type injection molding applications vent type injection machine, in the central cylinder has an exhaust port, is also connected to the vacuum system, when the plasticizing, the vacuum pump may close some moisture in the plastic monomer, volatilization substances and air pumped through the exhaust port; raw material does not have to pre-drying, thereby enhancing production efficiency, improve product quality. Especially suitable for polycarbonate, nylon, glass, cellulose and other hygroscopic material molding.

(2) Flow injection molding - Flow injection molding can be an ordinary mobile screw injection machine. Namely the continuous plastics and plastic squeeze a certain temperature, the mold cavity, the cavity filled plastic back, stop turning the screw, the screw thrust by the inner mold material to maintain an appropriate time under pressure, and then cooling stereotypes. Flow injection molding equipment to overcome the limitations of the production of large products, parts quality can exceed the maximum injection volume injection machine. It features plasticized object is not stored in the barrel, but continue to squeeze into the mold, so it is a method of extrusion and injection combination.

(3) Co-injection molding - Co-injection molding is the use of having two or more injection units injection machine, the different species or a different color of plastic, simultaneously or successively injected into a mold within. This method can produce a variety of colors and (or) a variety of plastic composite products, representative of co-injection molding is injection-color and multi-color injection.

(4) No runner injection molding - Runner mold is not provided, and the injection machine nozzle extends directly to the molten material is dispensed into each mold cavity molding method. In the injection process, the plastic melt flow path within the flow state is maintained, does not emerge together with the article during demolding, and therefore there is no article runner residue. This molding method not only saves raw materials, lower costs, and reduce the process, can be achieved fully automated production.

(5) Reaction injection molding - After the reaction principle of the reaction injection molding was measured by the measuring device material pumped into the mixing head, impingement mixing in the mixing head and then injected into the high-speed closed mold, fast curing, release, remove products. It is suitable for some of the processing of thermosetting plastics and elastomers polyurethane, epoxy resin, unsaturated polyester resin, silicone resin, alkyd resin and the like. Currently mainly used for processing polyurethane.

(6) Injection molding of thermosetting plastics - Granular or slug thermosetting plastics, in the strict control of the temperature of the barrel, by the action of the screw, the plasticizing a viscoplastic state at higher injection pressure, the material into the crosslinking die within a certain temperature range. Thermosetting plastics injection molding in addition to outer physical state, as well as chemical changes. So with thermoplastic injection molding ratio on molding equipment and processing technology is very different there.