Trying to melt thin sheets of HDPE (3mm thick_)

Polymer Craft Research about plastic
1

Hi all,

so I am trying to melt shredded HDPE plastic into thin sheets of about 3mm which I then plan to mill with a CNC machine.  I have had a couple of goes at it and the end result isn’t great.

I made a frame out of MDF that was 3mm thick.  I pressed the plastic into the frame using a heat press.  After the plastic had melted I pressed the plastic and frame between other bits of wood held together with clamps until it had completely cooled.  When I removed the clamps I found that the plastic sheet warped/bent.  I have tried a couple of times with the same result.

Has anyone got any suggestions how I can stop the plastic from bending/warping.  For it to work in the CNC Machine I need the plastic to be a flat sheet.

0

2

yup, pressing stuff together that way just won’t distribute mass evenly over space. you could try 2 rollers just like in the pasta maker machines – I’ve seen good success that way.

3

3 mm is pretty thin. I wonder if you could set up a straightening pair of platens that heats it up below melting and cools uniformly on both sides.