Premix manufactures Sheet Molding Compounds (SMC) that are primarily used in compression molding. Premix offers SMC's that are suitable for molding a wide range of parts from very small to very large, from flat panel to very complex shapes. Through our Engineered Solutions, SMC's are tailored to specific customer needs providing part performance as well as manufacturing efficiency. The pliable sheet allows enough body for handling and cutting but enough rigidity for manual charge building or automation.
This molding process utilizes a pre-staged charge of material that is created by manually or automatically cutting, stacking, arranging and weighing the individual SMC or TMC pieces. This charge is either manually or automatically loaded into the open mold. Once the charge is placed, the mold is closed with a fast closing speed followed by a controlled final closure speed once the thermoset compound begins to flow. As the compound flows in the mold, it reaches a telescoping shear edge zone at the perimeter of the cavity that enables air to escape. The major advantages of compression molding:
·Very large parts (>250 lbs) can be produced with minimal fiberglass degradation, yielding the strongest parts of all molding processes.
·Material can be placed in the cavity to achieve optimum fiber orientation in critical strength locations – the process is not limited by gate locations.
·Dissimilar materials can be placed in the mold, such as glass mat or uni-directional glass to improve part strength.
·An economical choice for small (<1,000) to very large volumes using single or multiple cavity tooling.