Build Tak Disaster

So i recently purchased a buildtak sheet from their website to try out on my ormerod 2.
It came through and after fitting it i tried a large yoda print.
Initial impressions seemed superb no warping at all with pla.
That was until i tried to remove the print.
It wouldn't budge, try as i might the bond seemed stronger than the PlA itself.
So strong that i ended up smashing the glass trying to remove it.

Anyone had similar issues, any advice on how to make the bed (i can't believe I'm saying this) less adhesive?

Olly

For really stuck-on prints I use a very sharp knife pressed flat on the bed, and push it under a corner of the print - just pushing hard, no sawing motion. My knife of choice is a very sharp new kitchen vegetable knife, but I have also used the blade of a (new) craft knife. Once the blade starts to get under the print, a steady pressure results in the whole print slowly lifting off the bed (accompanied by many cracking noises).

Dave

I don't know whether it would work with this material but if I get a difficult to remove object (normally a large area, low height print) then I take the bed off and put it in freezer for 30 minutes. Print almost falls off after that.

Quote
bobtidey
I don't know whether it would work with this material but if I get a difficult to remove object (normally a large area, low height print) then I take the bed off and put it in freezer for 30 minutes. Print almost falls off after that.

That's what I do too.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I have been using BuildTak for about 7 weeks now and have also had trouble with parts almost impossible to get off. The solution for me as to print the first layer higher and hotter. Best is to start high and print lower and lower until it stick well. That way you don't risk the part getting too much grip. It is my experience that the best height lies within 0.1 mm meaning changing the height just 0.05 makes all the difference.

With PLA I print first layer at 220 and the rest at 195. Its the best upgrade I have made so far. I haven't used the heated bed at all, just turn on the printer, turn on the heat on the nozzle, home the axes and I am ready to print. All the waiting is gone .

I use a stainless turner that I have sharpened, with that I can easily pry of the part without too much force and not damaging the BuildTak.
The only downside is that dc42's z-probe can not measure on it, I have to have white stickers in the corner and can not home in the center of the bed..


Edited 1 time(s). Last edit at 01/30/2015 12:18PM by fotomas.

Quote
fotomas
The only downside is that dc42's z-probe can not measure on it, I have to have white stickers in the corner and can not home in the center of the bed..

That's news to me! What is the surface of the Build-Tak like? Is it opaque, transparent, or translucent? It might be possible to do a software change to make it work.

EDIT: I have asked the supplier for a small sample of Build Tak for testing.

Edited 1 time(s). Last edit at 01/30/2015 01:23PM by dc42.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

The surface is black kind of opaque. It reminds me of frosted glass or sand blasted aluminium.

I have lowered the print head all the way down so it touches the bed without any registration on the sensor. I assume that the best registration is at a specific height over the table so a modification putting it closer to the breed won't help?

I even tried to block the LEDs with a piece of paper, no effect...

I will gladly perform some tests just tell me what to do.

/Tomas

Thanks guys nice suggestions, will try when i get a new glass bed!

The firmware on the board has a threshold for the signal levels. If the received signals from both LEDs are below the threshold, the firmware assumes that the probe is high above the bed. This is to avoid false triggering. I'm thinking that if the BuildTak surface has a very low reflectivity to IR, the received signals may below the threshold even at probing height. If that is the case, I can measure the received signals if I get a sample of BuildTak, and if they are strong enough, I can decrease the threshold.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

So there is a tiny bot of hope then, looking forward to hear about your findings.

/Tomas