Printing PLA on PEX surface - is heated bed needed?

Question

I have a WhamBam build system on order. A magnet attaches (glues down I think) to the Aluminium printing bed (or add a glass sheet? Separate question), then PEX material on flexible steel sheet gets slapped down for the print surface.

I have been printing PLA on a cold PEI sheet from Vertex, using 4 binder clips to hold it in place vs peeling the backing off and sticking it down. The print job wants to keep heating the bed to 60 °C, I turn it down, a couple minutes into a job it cranks it back to 60 °C and I turn it down again. A few times I missed the second turn on, and the PEI has been kinda warped now (or maybe it's just the plastic over the sticky backing), and has also peeled off some surface chunks in the middle, so we've been trying to print around the damaged section. The warping has now made the PEI unusable, so I'm hoping the WhamBam arrives soon.

We've been printing for a couple of weeks now (I printed a chess set, largest has 4 cm diameter and is 10 cm tall, some pieces on blue tape, some on the PEI) and are starting to venture into our own designs.

Intended project is box tops & bottoms that are ~90 mm x 65 mm x different heights with openings. We tried one on blue tape (a bottom with no openings) and ended up chiseling it off the bed with a steel putty knife (I don't recall if heat was on or not). We tried a top with openings on the PEI, missed that the heat had turned back on, but between the bed not quite level (forgot to re-check it) and the PEI being warped we killed it after the openings were printed around. It was not going to be usable, but we did print enough to be able to confirm the opening spacings (needs work still) so it was not a total loss. Came off the PEI easily (<2 mm thick when we stopped), we managed to miss the damaged parts mostly.

So the question: when the WhamBam arrives, is it better to print PLA at 60 °C, or do I keep playing the game of turning it down (and saving the waiting time of it heating up)?

Answer 1

I print PLA on a PEI bed at 60°C. I have also printed PLA on an aluminum bed at 60°C with Elmer's Glue Stick for bonding, which worked better for me than PLA. I recently switched to Aqua Net Hairspray on the aluminum bed at 60°C, which also worked well.

I have found no reason to avoid bed heating with PLA.

If the object is stuck too tightly on the PEI bed, you could try adding hairspray. It acts as a glue, but also as a release agent, and, being soluble in water, you can help release the object with a few water drops.

Answer 2

Received and installed the WhamBam system, and it works great! Have been letting it heat to 60C, which I'm pretty sure is not making it all the way thru the magnet, flex steel plate, and the PEX surface, but parts are adhering great and pop right off the PEX just by the act of picking up the plate, even a large box bottom (~68mm x 95mm) came off so easily I thought it had lost adhesion - my wife printed several items earlier and they came off the same way. I am impressed with the system!

We had lost a blade off the hot end fan (and turns out it was 3 blades), initial prints had failed to adhere on the PEX, the PLA didn't appear to be extruding properly, and the fan irregularity was very irritating. Internet searches indicated the plastic melting temp was not accurate enough. Replaced the fan and every print since has been great.

EDIT 6/14/2019 Here is a youtube clip of a freshly printed door knob (screen door latch) coming off a 60C bed, no problem!

And a larger box, ~65 x 98mm, that popped right off.