Compression Molding is a plastic molding process where preheated thermoset materials such as Phenolics or BMC’s, among other composites, are placed directly into the heated mold cavities. The mold is then closed, forcing the material into the cavity detail to produce the part. Heat and pressure are maintained until the molding material has cured. This process yields exceptional dimensional stability, thick and thin cross sections and the use of insert molding in the correct application. While compression molding has some unique benefits, it also has some limitations.
If you are producing simple, mostly flat, large parts, then compression molding is often the most cost-effective molding method. A few curves or pockets in the part design are acceptable, but extreme angles can be challenging to achieve. Due to the lower pressures, tooling costs are affordable, and molds typically last a long time without warping or needing to be replaced. To offset the cost associated with compression molding’s long cycle times, a mold with multiple cavities can be used to produce multiple parts in the same cycle.
Produces Strong Parts
Compression molding produces parts that have exceptional dimensional stability, thick and thin cross sections and can also allow the use of insert molding. Compression molding is also used to manufacture parts using composite materials, which means that durable, corrosion-resistant parts and products can be produced easily through this method.
Flexibility in Design
Compression molding allows for low-cost prototyping. This is a great manufacturing too for engineers and product developers.
Compression molding has a large number of applications and industries. Here are just a few examples:
- Home Appliances
- Automotive & Transportation
- Medical Device Parts
- Electrical Components
While there are many benefits to using compression molding, it does have its limitations. Compression molding doesn’t work well for molding complex parts, such as those with harsh slanted angles or small details. The cycle time, which can be several minutes long, is slow in comparison to high-volume molding methods. Injection molding, for example, often has cycle times of just seconds.
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