anyone here has a solution for this ?
When thermoforming ABS, a line appears through the plastic where the mold first touched the plastic. See attached picture.
We are using a Vacuum box or draw box from above to pre-stretch the sheet upward, then the male mold lifts in the sheet from below.
I tried more/less heat on the mold, more/less heat on the sheets, teflon mold release, with no luck.