Reaction Injection Mold Release

Approximately 30% of all plastic products are produced using an injection molding process. Of this 30%, a large amount of these products are produced reaction by using custom injection molding technology. Six steps are involved in the injection molding process, after the prototype has been made and approved. The first step to the injection molding process is the clamping of the mold. This clamping unit is one of three standard parts of the injection machine. They are the mold, the clamping unit and the injection unit. The clamp is what actually holds the mold while the melted plastic is being injected, the mold is held under pressure while the injected plastic injection is cooling. Next is the actual injection of the melted plastic. The plastic usually begins this process as pellets that are put into a large hopper. The pellets are then fed to a cylinder; here they are heated until they become molten plastic that is easily forced into the mold. The plastic stays in the mold, where it is being clamped under pressure until it cools. The next couple of steps consist of the dwelling phase, which is basically making sure that all of the cavities of the mold are filled with the melted plastic. After the dwelling phase, the cooling process begins and continues until the plastic becomes solid mold inside the form. Finally, the mold is opened and the newly formed plastic part is ejected from its mold. The part is cleaned of any extra plastic from the mold.

The 2-shot injection molding process creates the first plastic component, and the material molded round it, using a single mold and a 2-shot injection molding machine. 2-shot machines have two-barrels (one for each material) and they have the ability to rotate the mold. The machine injects the first shot material into cavities on one side of the mold, rotates the mold 180 degrees, and then injects the second shot material onto the first shot. The first and second shots occur at the same time. When the mold opens, it ejects the completed parts from the second shot cavities and it rotates the mold to position the first shot for the second shot. This is accomplished in a machine running in an automatic cycle. Because the 2-shot injection molding process is fast and highly repeatable, the shrinkage of the first shot is very consistent and two materials can be molded together with virtually no flash. 2-shot molding is the process of choice when molded-in graphics or other fine details are required. The elimination of the shrinkage variable allows 2-shot molding to produce details impossible to achieve with over-mold injection molding.

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 release 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.

Injection molding is a relatively new way to manufacture parts. It is a fast process and is used to produce large numbers of identical items from high precision engineering components to disposable consumer goods. Injection molding is often used in mass-production and prototyping. It produces such small products as bottle tops, sink plugs, children's toys, containers, model kits, disposable razors and parts of cameras. The process can even mould such large items as dingy hulls and kit car body shell parts. The advantages of injection molding are: high tolerances are repeatable, wide range of materials can be used, low labor costs, minimal scrap losses, little need to finish parts after molding. The disadvantages of injection molding are: expensive equipment investment, running costs may be high, parts must be designed with specific molding consideration.

The corporation specializes in plastic injection molding, injection molding plastics design, custom injection molded plastics manufacturing in China and Taiwan at their manufacturing facilities. CAD plastic injection molding designer services are performed in Taiwan assisted by their engineers in the US. Rapid prototyping capabilities also compliment their plastic injection molding in China capabilities for customers in need of SLS prototypes quickly, for modeling and proof of design or concept. Their rapid prototyping, SLS and custom molding and plastics machining capabilities can get your new designs in solid form in a short amount of time.