Guys, as posted on the hardware forum, I’ve discovered that the reason I was getting bad initial layers with my prints was that the PEI sheet was lifting and affecting the first few layers. Essentially it would cause small bubbles in between the layers, then over time these bubbles were growing, and joining together with the result that when the bed was hot, the PEI was essentially detached from the glass. After I replaced the bed, I out of curiosity lifted the corner of the PEI sheet on the removed bed, and it came off completely with virtually no effort.
Further investigation with a brand new bed shows that after just three prints with ABS, the adhesive layer between the PEI and the borosilicate glass bed is already bubbling and lifting. The ABS I’m using (Protopasta ABS) recommends a bed temperature of 110 degrees, which is clearly affecting the adhesive. I tried printing at 90 degrees, and ended up printing bananas as the prints lifted at the edges.
As I don’t want to have to keep replacing beds after 20 prints, I need to find an alternative media to print with, one that will give a good percentage of the toughness of ABS but without the bed degradation. Clearly this means a lower temperature bed requirement.
Do you have any suggestions as to what would be a suitable alternative?