Rotary Injection Molding Machines

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.

About 2 years ago I purchased a tool set. It came with a wonderful set of tools, but a really low end, thin and hollow plastic injection molding case that belies the namesake and tradition. Needless to say, the case finally gave up the ghost this past week. I began shopping for a replacement tool box for the old set that has since grown to over 200 pieces. Wanting some level of organization that is needed on the trail while off roading, the plastic tool box intrigued me due to its thick plastic construction and it's similarity to a larger tool chest with extendable drawers. Its size and depth allowed me to place it in the same spot as where I held the old plastic injection molding case in my truck.

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.

Injection molding is a common method of producing intricate plastic components in high volume. Injection molds are made from hardened tool steel, although aluminum may be used for some low volume applications of injection molding. Injection molds can vary from simple open-shut injection molds, single cavity injection molds to complex multi-cavity injection molds with moving cores, stepped shut-offs, unscrewing devices. Due to the tonnage used in this high pressure process, proper materials, supports, parting line locks etc. must used to ensure the life of the mold. Cavities may be polished or textured to achieve a desired finish on the injection molded part.

High volume injection molding capabilities and precision tool makers in their China Factory allow us to provide quick-turn service on medium to high volume orders, where they build dedicated long-run production molds. The company specializes in high volume plastics injection molding custom plastics jobs. High-end second-op machining is also available. Their PVC and plastic injection molding factories in China manufacture very high quality products that are extremely cost effective. Their warehousing and distribution facility in Austin, Texas also allows them to service custom injection molding projects in Dallas, Houston, San Antonio and other cities across the country very easily.