Staying flat once cooled

[stryker]

Hi Peoples,

First time asking a question here and looking for some tips on a specific issue I have.

I mainly print RELIEFS on my MakerBot using PLA filament. These have a large surface area which sits on the bed and then the design is printed on top and can extrude between 2-20mm. Think of a large coin with a fancy design raised upwards.

They actually print great with the first layers staying completely flat on the bed. I use a thin sheet of glass with Blue Painter tape and the PLA sticks well to it. I then remove the sheet of glass (which was held on by bull dog clips) and prise the print off using a scraper.

The problem is that when resting on a flat surface the print does not sit flat now. If I press one side the other lifts up (like a sea-saw) so the print becomes bowed. My reliefs need to be COMPLETELY FLAT after cooling.

At the moment I have to use a heat-gun until the print gets floppy and then press it between two tiles with some extra weight. Not really ideal and does not work when the top of the relief is not flat so I can't press evenly over the whole print (eg if I have a half face or half balloon relief) then melting and using pressure doesn't work)

Any ideas?

I have a PRINTinZ (Zebra) plate on order but don't know if this will fix the issue.

I hope someone can help - Thanks

[curious aardvark]

yep get yourself some printbite.

It'll stay perfectly flat when printing. And once cooled will just fall off. So you'd never need to stress and bend the print while peeling off.
Plus, no glue, no tape and zero hassle.

[stryker]

Ahhh . . . . That's great. I suspected that the "Peeling off" process might be the culprit. The PrintinZ plate which I assume is similar to Printbite is coming soon and will hopefully do the trick. I'm also researching PEI so I have a plan B as well.

Thanks heaps for your reply

[curious aardvark]

similiar probably isn't the same.
(has a look) nope totally different.

Printbite does not flex. Does not need to.
I think you're going to have exactly the same problem with a flexible printbed. If you have to bend the plate to release the print, then with a very thin print it's going to get bent when you try to release it.
pei tape, sort of works - just not that well.

Try it, might work - but don't think it's anything like printbite.

[wirlybird]

Glue stick or hair spray on the glass should do. Pops off when it cools.

[curious aardvark]

glue stick certainly doesn't 'pop off'.
you have to peel it off, sometimes you have to reheat before you can get the scraper under it.

[wirlybird]

Guess I'm doing it wrong then because it works fine.