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I'm a beginner. I've a Printrbot Play with a heated bed add-on. I'm using it exclusively with PLA.

It worked great initially, but then I took the nozzle out and put it back in, and the Z calibration was lost (and I didn't know the calibration was a thing). As a result, I started having issues with the piece warping up and not sticking to the bed in the corners and around the edge, when the piece was large and flat.

I've installed the heated bed. I used Kapton tape. All these made it perhaps a little better.

Finally I started tweaking the Z axis calibration (the fine adjustment for the initial distance between nozzle and bed) and that made it perfect. No warping anymore.

But now I have the opposite problem. When printing pieces with large flat surfaces that are siting flush with the bed, it's next to impossible to tear it off at the end.

I went back to using plain blue tape instead of Kapton, but it's still sticking too well to the bottom of the piece. I tried to pry it off by pushing a knife under the piece, but that has put a few scratches on the bed. Obviously I don't want to continue doing that.

What can I do? How to prevent warping, while also making sure the piece does not stick too hard to whatever is underneath?


EDIT: The accepted answer was very good and I don't want to mess with it by adding my own "answer". So here it is:

I ended up adding a glass plate on top of the bed, with a heat conductive layer between bed and plate (it's a funny looking, rubbery, chewing-gum-y material that conducts heat). Now I just apply glue stick on the glass and print. Works great. Large pieces come off on their own sometimes if I let them cool down to 30 C or lower.

I had some issues with the Z calibration sensor due to the plate, eventually got solved, but that would take too long to explain here.

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  • $\begingroup$ Hello @Florin Andrei, I noticed your question has been up for a while now. Have any of the answers below been able to solve your question? If so, would you mind accepting the appropriate answer. If not, what is missing so that we may help you further? Also, if you have figured it out on your own, you can always answer and accept your own solution. Thank you. $\endgroup$ – StarWind0 Feb 7 '17 at 19:14
  • $\begingroup$ I just added a glass sheet on top of the heated bed, and changed the Z sensor to allow for greater sensing distance (ended up gluing thin steel sheet squares on the back of the glass sheet in the 3 places where the printer does the Z calibration). Small items stick to glass as-is. Large items may require a bit of glue stick to prevent corner warping. Everything comes off relatively easy once the bed has cooled down; some items are sticking a bit, but come off when I pry them off with a knife; others (especially the large ones) just pop off on their own when bed temperature drops below 30 C. $\endgroup$ – Florin Andrei Feb 7 '17 at 19:39
  • $\begingroup$ @FlorinAndrei, I don't see an accepted answer. If you haven't, could you please "accept" the best answer? It will clarify which you found best, and throw a few reputation points at the person who answered. $\endgroup$ – cmm Apr 18 '19 at 13:52
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Options to check (in order of probability of occurenece and success):

  1. Z-calibration

Maybe you should perform calibration again. It's possible that nozzle is now too close which causes the filament is spread on the heatbed, which causes that the bottom surface is "too flat". It means all separate filament tracks are spilled and they create "glass flat" surface. You did mention that the model sticks too much even to kapton. It suggests z-calibration.

  1. Temperature calibration

Check if the temperature is not too high. Reducing it a bit can reduce sticking. If filament is too soft then material sticks usually better (causes the same as in #1)

  1. Heatbed cleaning

If your HB is scatched (even not visible scratches) then it's possible that previous printouts left little grains in such scratches. Cleaning HB could then help. Are you using glass? if yes - change glass side to check this option. Eventually replace glass with new one.

  1. Heatbed surface

If your heatbed is scratched then filament can penetrate such scratches and increase sticking.

  1. Filament

Did you change filament vendor? If not then maybe your filament had changed during a time/humidity/sun/cigarete smoke. This is very doubtful option but who knows.

What methods you can use to detach model

  1. Paper knife

I also have the same problem when I use paper glue stick. Some vendors produce such sticky glue that I affraid to break a glass (which I use of course). When this happens I use a paper knife. Glass is scratchproof enough. Be careful - if your model suddenly detaches releasing knife... just be careful. Unmount HB or unmount glass first of course.

  1. Hammer

I know people use hammer to detach sticked model. I would suggest this method only for big and relatively simple elements. Especially for solids (fully filled with the material, without any grid/honeycomb inner structure). One short hit in the same surface as the HB. Be careful of course and unmount HB or unmount glass first.

  1. Fridge

As HB material and filament have most likely different thermal shrinkage factor it might help. And guess what - unmount HB/glass first ;)

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  • $\begingroup$ Yes, the bottom looks perfectly flat; there are no filaments visible there. I didn't know that was bad. The heatbed is just a thick aluminum plate; until now I didn't even know that glass was an option there. I never print directly on the bed, I always use either Kapton or blue tape. Can I print directly on the bed? And where can I read more about the glass option? $\endgroup$ – Florin Andrei Aug 31 '16 at 6:00
  • $\begingroup$ @FlorinAndrei It's not bad to have perfect flat bottom surface - rather the opposite - it's perfect but in terms of your issue it might be the cause of the problem. In terms of HB - please take a look on this link reprap.org/wiki/PCB_Heatbed $\endgroup$ – darth pixel Aug 31 '16 at 6:10
  • $\begingroup$ Can you explain what a hummer is? I presume you don't mean the brand of SUV. $\endgroup$ – Tom Jan 25 '17 at 8:37
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    $\begingroup$ @Tom - yes - why not? :P (fixed) $\endgroup$ – darth pixel Jan 25 '17 at 9:24
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I have only experienced PLA "super sticking" if the print bed is allowed to cool too much. I would suggest running a mild preheat to your bed when you find a print has stuck and the bed is cool. (What you set the temp to for the preheat would depend on the filament in question but start low and work up and you may find a sweet spot/release point for your particular PLA)

I have never encountered PLA "super sticking" printed with rafts on (regardless of printbed temperature).

Rafts will give you a sacrifical grid of PLA between your actual finished piece and the bed itself. That way you can "pry" the printed object from the bed and have more leaway for increased leverage without damage to your actual piece(use a plastic razor blade common in cell/tablet screen replacement kits and you generally won't scratch your printbed/printbed coating/tape). The lattice/net of the raft would also, generally, have less, in contact with the printbed surface area than a finished piece and thus have less holding power.

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  • $\begingroup$ IMO raft is usually used to increase sticking. Additionally raft will cause the bottom surface less sleek. The same is with HB temperature. We use heating the bed to increase sticking. When I don't use any additional materials like paper glue or hairspray then (depending on filament vendor) my models detaches itself when my HB cools down under 40C $\endgroup$ – darth pixel Aug 31 '16 at 4:30
  • $\begingroup$ A raft, in my experience, is used to increase the footprint of a piece to help"somewhat with sticking" and thus avoid tip over. However, I've also found them useful as a medium to remove larger, flatter, pieces as well. That's just personal experience--it's worked well for me. (You are correct that they can make for more cleanup to the finished piece though re. removal). As for the bed, yes, heating to the correct temperature does make PLA stick more. However, I've found pieces easier to remove if the bed is not fully cooled, but of a low enough temp to not warp the printed piece. $\endgroup$ – WarOrdos Aug 31 '16 at 10:16
  • $\begingroup$ hmm... interesting. My experience is absolute the opposite but, well, the man can learn everyday. $\endgroup$ – darth pixel Aug 31 '16 at 10:34
  • $\begingroup$ Darth, what are your thoughts on removable, and flexible, print beds? I've never used one. How effective are they and would that be a potential option for the original poster until he gets the underlying issue resolved? $\endgroup$ – WarOrdos Aug 31 '16 at 23:29
  • $\begingroup$ worth to try I think. I've never used flexible bed but I can imagine it solves too-sticky-problem. How else could it be? $\endgroup$ – darth pixel Sep 4 '16 at 11:15
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Pour some 70% IPA along the edge of the model with a Q-tip, it will pop out right away. For larger models aaply IPA from a wash bottle. This method also works well on other plastic to glossy surface bonds, like, for example, hot melt glue to arylic sheet, see this -> https://www.youtube.com/watch?v=u9kdiZMqfmM

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Several factors to consider, but don't get discouraged, it is definitely something you can solve. Consider this...

Z height: Lower Z squishes first layer more and increases sticking, higher Z results in less plastic contacting the print surface and reduces sticking. Tweaking your Z-height can help you dial-in your first layer adhesion.

Print Temperatures: Higher extruder and bed temps during printing will tend to increase sticking. Lowering temps will reduce sticking. Run several tests, just a few degrees can make a difference and finding the right balance can take some trial and error.

Removal Temperatures: There is typically a warm bed removal temperature that works best, when the bed has cooled but not all the way.

Anti-warp "tabs": If you're making your own models, you can add a breakaway tab to the ends of parts that are prone to warping. This improves surface area for hold down where you need it, but takes minimal post processing to remove.

Dry your filament: Warping is generally much worse when filament absorbs water from the air. Some filaments such as polycarbonate are VERY prone to this, but even PLA warping can be reduced by drying the filament. To dry your filament you can use a low temperature in your oven, make a drying bucket, or my favorite, put it under a vacuum with a vacuum pump.

Removal tricks: Various methods of rapidly cooling the edge of the print with canned air, alcohol, etc. can really help. Thin metal spatulas can work wonders.

Try PEI on your print surface: PEI is awesome. Many common filaments stick very well while it's hot and release easily when it's cool. Check out the way Lulzbot attaches their PEI print surface to all their printer beds. It's a pretty easy and cheap mod. The other factors I listed still matter, but PEI makes it MUCH easier.

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    $\begingroup$ Note that using PEI and PETG may lead to actually bonding the PETG to the PEI. Use a spray or glue on the PEI to be able to get the print of when cooled down. $\endgroup$ – 0scar Sep 4 '18 at 14:40
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I suggest that you make a support not that much massive (this kind of problem is often cause of a massive part printed directly on the bed). You should place some easily destructible material between your part and the bed.

I don't know your part, but even if you have a plane under it, don't stick it to the bed. Let a gap, like, 5 mm minimum, which you will fill up with support. Of course, your support must be something light.

For example, try to use the meshmixer supports (meshmixer is free) or some lattices supports if provided with your software's printer. As they're supports and not the part, you can destroy it more easily, without the preoccupation to save it, just caring about your bed.

Of course, it depends on the amount your "sticking" problem, if small things are sticky too, this won't save you.

For non-used to supports people, support is often a solution to main deformations and sticking problems. Deformations because it dissipates the heat better, sticking because it's much less massive material to remove.

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