Compression molding

A molding method in which preheated thermoplastic and thermoset raw materials are usually placed in an open heated mold cavity. The mold is then closed, pressure and heat are applied to force the material to contact all areas of the mold, and the heat and pressure are maintained until the molding material is cured. The advantage of compression molding is that it can form large and quite complex parts. Although this technology cannot fully achieve the production speed of plastic injection molding, compression molding does provide more geometric shapes than typical laminated composite materials. Compared to plastic injection molding, it also allows longer fibers, which makes the material stronger. Therefore, compression molding can be seen as a middle ground between plastic injection molding and laminated composite manufacturing.
Compression molding is suitable for forming complex high-strength glass fiber reinforced materials, and can produce parts with different lengths, thicknesses and complexity. Due to the use of advanced composite materials, these materials tend to be stronger, harder, lighter and more resistant to corrosion than metal parts, resulting in objects with better performance.
Compression molding steps
First install the mold in the press and heat it, put the calculated weight of the material into the cavity, and then apply the pressure required for molding to the mold, usually in the range of 800psi to 2000psi (depending on the thickness of the part and the type of material used ), after releasing the pressure, eject the part from the mold and take out the product to remove the waste left in the mold.
Compression molding has the ability to manufacture complex parts in a variety of applications, while putting the cost and molding time of the parts in the first place, so for manufacturers in many industries, compression molding is a favorable process. In compression molding, engineers should keep in mind six important considerations:
  Determine the appropriate amount of raw materials.
  Determine the minimum energy required to heat the material.
  Determine the minimum time required to heat the material.
  Determine the appropriate heating technology.
  Predict the pressure required to ensure adequate filling of the cavity.
  Good heating circuit design