Vacuum forming

I am new to vacuum forming and I am hoping to get some advice before I ruin a few sheets of ABS, I built a 4 x 8 foot vacuum forming machine , it uses 8 oven burners divided into 4 sections with 4 heat controllers. The parts I want to form are approx. 8 to 10 inches tall and I am concerned about the corners not forming correctly, the ABS is 1/8 of an inch thick.

Best Answer

  • edited January 30 Answer ✓
    Here's a handy table that may help:

    Plastic Processing Temperatures
    In Degrees F
    MaterialSpecific GravityMold Surface & DemoldsLower ProcessingOrientationUpper Temp
    Polyethersulfone, glass filled 20%1.51410535560720
    Polyethelene, high density0.99180260270430
    Polypropylene, glass filled1.05195265280450
    Vinyl, rigid1.47150220245310
    Vinyl, rigid foam0.70160240260350

    You can learn more here:

    The challenge is determining the core temperature of your plastic based on surface temperature and material thickness.



  • If you are worried about webbing happening on the bottom edges of your parts,  you can elevate them off the platin using small blocks, or design them a bit taller and cut off the bottom portion.

    With new parts, there can be a bit of trial and error as you figure out the spacing between parts, if they need to be elevated, and how much to let the plastic sag before dropping and pulling the vacuum.

    For taller parts, you'll want the plastic to sag a bit more before dropping it.

  • Thank you for the reply, I did leave an extra inch on the bottom to accommodate for any deformities, I was worried about the extra material I may get on the corners, kind of like when you are wrapping a gift and you have to fold over the corners. The extra sag makes sense, what is the max temp you can go to with ABS.  
  • Thank you this is very helpful
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