What are some of applications of the thermoset molding process? Isn’t that some kind of outdated plastic molding process from the days of dial telephones or something?
The thermoset molding of electrical connectors, oil field electrical connectors, automotive electrical parts, these are just a few of the applications for thermosetting plastics. Many thermoset plastic parts are insert molded and have very specific applications.
In the past, thermosetting plastics were compression molded, which resulted in less accurate finished parts. Compression molding also is more labor intensive. Higher melt temperatures, higher molding pressures, more abrasive molding operations, and higher mold temperatures are just a few of the unique aspects.
The thermoset molding of plastics has dramatically changed with the introduction of injection molding to the process. This has produced many new applications and enabled designers to develop highly complex product designs. This is readily apparent in the photo below.
A high level of experience is required to effectively use this process. Though the injection molding process is similar to thermoplastics, it is, on the other hand quite different.
Advantages of thermoset plastic molding
- Excellent dimensional stability. This is due to the chemical change that occurs during molding. When heated, the part maintains it’s size and shape.
- Great electrical insulators.
- Excellent dielectrics.
- Good structural strength. This can be enhanced by using fiber fillers.
- Chemically resistant. Common chemicals have little effect, but some reducing agents and strong oxidizers can attack it.
- Excellent for Insert molding. Once the insert is molded in place, it is nearly impossible to extract it.
- Fire retardant. Very difficult to burn most thermosetting plastics.
- Extremely rigid. This is due to the cross-linking chemical change that takes place in molding.
- Excellent for sound absorption. Might even drown out your teenagers hip-hop music!
For plastic molding companies who wish to branch out into other areas, thermoset molding offers a somewhat ignored market.
Disadvantages of thermoset plastic molding
Probably the biggest drawback to thermoset molding is that these plastics are not recyclable. The runners and scrap cannot be reground and used again.
Another disadvantage is that not so many shops are skilled at molding these plastics. Neither are they equipped with the special presses or auxiliary equipment. There are many difficult obstacles to overcome and experience is the only good teacher.
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