Compression Mold Making

What Type of Parts are Good Candidates for Compression Mold Making

The mold consists of two primary components, the injection mold and the ejector mold. Plastic resin enters the mold through a spur in the injection mold the spur bushing is to seal tightly against the nozzle of the injection barrel of the molding machine and to allow molten plastic to flow from the barrel into the mold, also known as the cavity. The spur bushing directs the molten plastic to the cavity images through channels that are machined into the faces of the A and B plates. These channels allow plastic to run along them, so they are referred to as runners. The molten plastic flows through the runner and enters one or more specialized gates and into the cavity geometry to form the desired part.

Designing Parts for Compression Mold Making

Compression mold making is mostly used in the baking industry. They mold and then shape cookies and cakes into different shapes.  The molds are mostly made up of masses of granulates. They also can be made of metal fibers. In compression molding, the molding material is generally preheated than placed in an open, heated mold container. The mold is closed with a top force, pressure is applied to force the material into contact with all mold areas, and heat and pressure are maintained until the molding material has settled. The process employs thermosetting resins in a partially cured stage, either in the form of granules or putty-like masses. Compression molding is a high-volume, high-pressure method suitable for molding complex, high-strength fiberglass reinforcements. The advantage of compression molding is its ability to mold large, fairly intricate parts. Compression molding produces fewer knit lines and less fiber-length degradation than injection molding.

Sourcing Compression Mold Making

The cost of manufacturing molds depends on a very large set of factors ranging from number of cavities, size of the parts, complexity of the pieces, surface finishes and many other things. The initial cost is great; however the piece part cost is low, so with greater quantities the overall price decreases. There are several important molding variations including Co-injection (sandwich) molding, Fusible (lost, soluble) core injection molding, Gas-assisted injection molding, In-mold decoration and in mold lamination, Injection-compression molding, Insert and outset molding, Lamellar (micro layer) injection molding, Low-pressure injection molding, Metal injection molding, Microinjection molding, Microcellular molding, multi component injection molding, Multiple live-feed injection molding, Powder injection molding and much more! Obviously, the mold must be cooled in order for the production to take place. Because of the heat capacity, low cost, and availability of water, water is used as the primary cooling agent. To cool the mold, water can be channeled through the mold to account for quick cooling times. Usually a colder mold is more efficient because this allows for faster cycle times. However, this is not always true because crystalline materials require the opposite: a warmer mold and lengthier cycle time.