Plastic Injection Molding Machine

Cast kirksite cavities from SLA models can provide excellent rapid tools for prototype and bridge to production injection molding parts. Parts can be molded in two to three weeks in any thermoplastic production resin, this technology has been around for many years, but with the growth of stereolithography and the need for rapid turnaround of plastic parts in the correct production material, the kirksite approach has re-emerged. More complex parts can be made using handloads. Injection molding tapers are important and are best incorporated in the master file. One of the advantages of kirksite aluminum/zinc alloy moulds is the ease of making geometry modifications by either welding or adding inserts. Another main benefit is the ability to mold most materials.

Injection Molding is the most advanced typical method of molding rubber products. Injection molding produces the most consistent results by automating all aspects of how the rubber gets into the mold. In injection molding, the rubber is worked and warmed and then squirted into the mold at controlled speeds, pressures and temperatures. Advantages of Injection Molding are: Provides the maximum product consistency, Allows the most control of flash, Because the rubber is warmed before going into the mold, fastest cycle times, Disadvantages of Injection Molding.

The details of the design in a large part determines the cycle time of the machine. The cycle time is the amount of time it takes from the time a part is ejected from the machine to the time the next part ejects. Smaller parts require less "fill time", the time it takes for the machine to push the melted resin into the mold, and thinner part walls cool faster reducing the "hold time". The customer is charged a set up fee which pays for installing the mold into the injection molding machine, and getting it ready to mold parts. Typically it runs a couple of hundred dollars and depends on things like how big the mold is and which accessories will be needed etc.

Reaction Injection Molding (RIM) produces parts with intricate detail that are dimensionally stable, chemically resistant, physically tough, and wear resistant. This process is an excellent choice for larger plastic parts produced in short run or low volume production quantities. Considerable design freedom is possible, including thick and thin wall sections that are not good for injection molding, due to the uniform shrink characteristics. Foamed polyurethanes are natural thermal and acoustic insulators. Excellent flowability allows for the encapsulation of a variety of inserts.