How do you decide which type of plastic molding is best for your product or prototype? Regardless of the molding method, molding compound or type of molding equipment, one thing remains consistent: the end objective. The end objective is to produce sound moldings that are capable of meeting all appropriate specifications, at an economical rate.
The key factor in attaining this objective is to carefully monitor and control the molding parameters directly affecting the filling and packing of the mold cavity during the molding cycle. When done correctly, both compression and injection molding are capable of producing consistent, detailed parts. Below is an overview of the two molding processes and capabilities.
|Compression Molding||Injection Molding|
|An overall slower process but enables better dimensional stability.||The injection molding process is designed for speed.|
|Capable of processing nearly all thermoset compounds, especially long fiber compounds, allowing for stronger structural parts.||Can process a variety of thermoset short fiber materials, as well as commodity and engineered thermoplastics grades.|
|Capable of utilizing insert moldings to incorporate metal threads and bushings.||Also capable of utilized insert molding but may need more complex mold design or handling equipment to ensure mold safety and repeatability.|
|In most cases, the tooling cost between compression and injection molding is similar.||In most cases, the tooling cost between compression and injection molding is similar.|
|The process allows for simple hand load prototype molds that are cost effective at the development state.||Lower cost options for prototyping and low volume parts using Master Unit Die inserts with hand loads.|
|Allows for heavier cross sections, ranging from .030″ to 1.0″ or more. However, this leads to long cycle times.||Typical wall thicknesses are taken down to a minimum to improve efficiency and speed.|