How to safely remove PLA stuck to Buildtak

Topics around mechanical design, controller and electronics. Mods & hacks welcome.
Jetguy
Posts: 3085
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

How to safely remove PLA stuck to Buildtak

Postby Jetguy » Fri Apr 08, 2016 5:29 pm

So I ran into a situation on my N1 where I thought I had a good Z gap on the bed and it turns out I didn't. As such, I printed with PLA extremely close to the build plate and there was no mechanical way to remove the object without damaging the build surface or worse.

I tried the typical methods I normally use:
Refrigerator method to cause shrinking of the plastic VS the glass in hopes of creating a shearing force= fail
Freezer method for an even colder shrink that should cause more force= fail
Brute force was going to end in shattered glass or damaged surface, not to mention potential injury to me.

So the trick was, knowing it was PLA and PLA has a lower glass temp (the point where it's not rigid solid, but also not melted liquid).
I heated the build plate to 110C using the heated bed, waited several minutes, then when poking the object on the edge, got a corner to begin coming up, then used pliers to grab the now soft rubbery layer and twisted the pliers to roll the layer off the bed.
No damage to the surface, no fuss, just a little bit of using the wrong temps to your advantage and knowing the material properties and how it can be defeated.

Again, chemical methods wouldn't work because PLA is a rather resistant plastic. Acetone and alcohol do nothing to PLA, even D-limonene which dissolves HIPS does nothing. I also knew that those chemicals could affect the glue layer holding the Buildtak on and rather than destroy my surface, found a suitable and easy workaround.

User avatar
Trhuster
Posts: 394
Joined: Tue Mar 22, 2016 6:01 am
Location: Sweden
Contact:

Re: How to safely remove PLA stuck to Buildtak

Postby Trhuster » Fri Apr 08, 2016 5:36 pm

What temp did you use on the bed? I used 100C with ABS on the 50 hours castle print and it was really hard work to get it off the plate. Now i testing 50c with Rasie3D PLA and abit bigger gap first layer and see how it works.

Jetguy
Posts: 3085
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: How to safely remove PLA stuck to Buildtak

Postby Jetguy » Fri Apr 08, 2016 5:44 pm

I print PLA with 50C on the bed.
ABS I print with 100C on the bed.

To remove PLA stuck to a bed, I use ABS temps of 110C to make the PLA soft and gummy.


For ABS, this trick should not be required because ABS is a high shrinkage material. ABS is expanded when hot and shrinks 3% when cooled to room temp. This causes huge shearing forces at the bond layer between the glass (very little expansion and contraction) VS the ABS on top. If cooling to room temp is not enough, then this is where the refrigerator or freezer method should make ABS parts all but fall off. In fact, you often hear a loud pop from the part shearing this bond after a few minutes of the cooling.

Jetguy
Posts: 3085
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: How to safely remove PLA stuck to Buildtak

Postby Jetguy » Fri Apr 08, 2016 5:47 pm

Going further, let's say that you saw such a print happening (because you always watch the first layers printing to ensure a successful safe print before walking away) and you saw your nozzle was too close. Now, instinct says to stop right away, kill the print job.

That instinct might not be the best answer in all situations. As long as the nozzle was not scraping into the build surface and damaging it, just too close and thus melting and squishing in the layer, it's actually better to let it continue, print several layers to give it enough structure to be able to remove it. The idea is that if the nozzle is too close, but not actively destroying the build surface, it's also making an insanely thin layer that is really well bonded to the build surface and nearly impossible to remove. By not reacting and killing the print, you build up enough of an object and layer that the above method of using ABS temps to use the glass transition phase of the material can let you get it all off with very little fuss.

User avatar
Trhuster
Posts: 394
Joined: Tue Mar 22, 2016 6:01 am
Location: Sweden
Contact:

Re: How to safely remove PLA stuck to Buildtak

Postby Trhuster » Fri Apr 08, 2016 5:58 pm

For my ABS print i wanted it to be abit to close to the bed so it should not lift from the plate. And it sure did not lift, also full enclosure made it not crack in the layers after it cooled down and that was also a nice suprise when comparing big prints with ABS on other printers in the past.

Was your N1 bedplate really bent like mine was?

Jetguy
Posts: 3085
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: How to safely remove PLA stuck to Buildtak

Postby Jetguy » Fri Apr 08, 2016 6:27 pm

I'm not sure what you mean by bent. The glass is flat, I generally assume the aluminum heater plate never is because of the expansion and contraction rate of aluminum is so great. I took a lot of care going around several times to level the bed, I found even though the supplied metal 0.2mm feeler gauge is great, I still prefer my standard print paper method for "feel".

User avatar
Trhuster
Posts: 394
Joined: Tue Mar 22, 2016 6:01 am
Location: Sweden
Contact:

Re: How to safely remove PLA stuck to Buildtak

Postby Trhuster » Fri Apr 08, 2016 7:01 pm

I mean the heated alu plate.

Image

Jetguy
Posts: 3085
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: How to safely remove PLA stuck to Buildtak

Postby Jetguy » Fri Apr 08, 2016 7:28 pm

Perfect example of why I need to walk away from the forum and only post in a Wiki.

I'm not blaming you, it's just an observation/problem.

I started this thread on a simple tip based on experience about a specific stuck to the bed surface situation. Now it's turned into a "my bed's warped" discussion.
I'm all for asking questions, learning, and just generally helping people.

To be direct, I said I do not expect for the bed aluminum to be flat or stay flat. It's not thick enough to stay flat and IMO was never meant to be the primary "flat" surface. Basically, I wouldn't expect anyone to put a straight edge to it and take a picture unless the intent was to make a shipping/warranty damage claim. In other words, so bent even using rubber pads and glass it was unusable. It's not milled, it's not thick, it's heated, it's got stress points from the leveling mounting. I honestly don't expect one to stay flat for long in this service and design.

While yours shows what I fully expect to be normal, I cannot make a call or even reasonably discuss what is and is out of warranty.
IMO (which doesn't really count), what you showed is what I expect to see if I did it to mine at this exact moment.

User avatar
Trhuster
Posts: 394
Joined: Tue Mar 22, 2016 6:01 am
Location: Sweden
Contact:

Re: How to safely remove PLA stuck to Buildtak

Postby Trhuster » Fri Apr 08, 2016 7:36 pm

I posted this pic when i got the printer in my own thread. Was not my intention to ruin this thread.

Jetguy
Posts: 3085
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: How to safely remove PLA stuck to Buildtak

Postby Jetguy » Fri Apr 08, 2016 7:43 pm

Again, sorry, I do not want to discourage you from asking questions. I just like things organized into a repeatable answers and thus asking about a bed being warped and what is and is not acceptable is a different and big enough discussion to warrant it's own topic.

Same with printing and bed temps and so forth.

Jetguy
Posts: 3085
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: How to safely remove PLA stuck to Buildtak

Postby Jetguy » Fri Apr 08, 2016 7:46 pm

Again, sorry, I'm not trying to be mean or rude to you, just explain why I just went through this yesterday, the forum format seems to not be the most effective use of my skills and knowledge.

Zettlinger
Posts: 412
Joined: Mon Mar 21, 2016 11:48 am
Location: Roosendaal, Netherlands

Re: How to safely remove PLA stuck to Buildtak

Postby Zettlinger » Fri Apr 08, 2016 8:06 pm

It also takes something i need to train myself more on too ..... the ability to ignore and selectively read and answer people. Saves a lot of stress and annoyances.

firesped
Posts: 854
Joined: Mon Mar 21, 2016 9:23 pm
Location: Tucson, AZ

Re: How to safely remove PLA stuck to Buildtak

Postby firesped » Fri Apr 08, 2016 8:46 pm

when I was doing my last few prints. I was running at 50c. It was sticking too much so I adjusted the temperature to 40c. I also installed a Z-Spring, because I felt the Z-screw was slipping causing less gap between the nozzle and the bed. I did a successful print that day at the 40c bed temperature then started another print up that night. due to the location of my printer, at night, 40c was not a high enough temperature to make the raft secured to the bed. I did find a mess of stringy filament under the bed. and the rest of the print went up into the hotends.

just waiting for my V2 hotends and other parts now.
RL name: Michael Nolen
printers:
raise3D N2 kickstarter Early Bird
Trinus Deluxe (running smoothieware on Azteeg X5 GT board)
Monoprice Maker Select v2

Charles
Posts: 164
Joined: Mon Mar 21, 2016 5:14 pm

Re: How to safely remove PLA stuck to Buildtak

Postby Charles » Fri Apr 08, 2016 9:46 pm

Welcome back Jetguy. When did you get a N1? I thought you had a N2?

I've found it relatively easy to remove PLA from the buildtak. I'll keep the tip about heating the plate to a higher temperature if I run into a problem with removing items.

I did have problems with removing some ABS items since I had the nozzle too close. Too bad heating up the bed wouldn't help.

Jetguy
Posts: 3085
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: How to safely remove PLA stuck to Buildtak

Postby Jetguy » Fri Apr 08, 2016 10:20 pm

I now have both an N1 and an N2- meaning I can effectively develop and improve all 3 models since N2+ is just a tall N2.

Also, just like the N2, I took the N1 down to beyond the bare frame to fully understand every nut and bolt. That's why I have posted much about it, I just got it and it takes days to do the print, baseline, teardown, rebuild, and re baseline to ensure I didn't get it wrong on assembly.

bwulfe
Posts: 32
Joined: Wed Apr 06, 2016 9:55 pm

Re: How to safely remove PLA stuck to Buildtak

Postby bwulfe » Sat Apr 09, 2016 3:57 pm

I have found that the official "Buildtak" spatula works much better than the putty knife that ships with the printer. Some of my early PLA prints were definitely difficult to remove; prior to obtaining the new spatula. It has beveled edges on one side that make it easier to pry-up an edge. the 90 degree angle mount of the handle also makes it easier to press into your object; without the risk of gouging the Buildtak surface. I found it on a few sites; but Amazon seemed to be the only one offering any discount from the full MSRP (Just 9%; but free shipping if you are Amazon Prime.) Here is a link to the Amazon page: http://www.amazon.com/BuildTak-BT30185-Spatula/dp/B017XGEDOM/ref=sr_1_1?ie=UTF8&qid=1460216616&sr=8-1&keywords=buildtak+spatula

Apollo
Posts: 1
Joined: Sat Apr 09, 2016 6:11 pm

Re: How to safely remove PLA stuck to Buildtak

Postby Apollo » Sat Apr 09, 2016 6:20 pm

Hi there,

I don't have any Raise3D printer yet but am interested. But I did have Buildtak on my other printer surface and didn't really like it because objects would stick to it way too much even when everything has cooled down. I only print with ABS and it's a pain to remove large flat objects and switched to another print surface that I used before on my Ultimaker 2. No idea what they are called in English or what the material is. I heard some people talking of PEI coated material but no idea what this is. But it works, sticks like kapton tape when hot and doesn't stick at all when cold.

I had to use a lot of force to remove prints from my Buildtak and when I printed objects several times on the exact same spot the Buildtak even came off. That's why I don't use it any more. Additionally there were some bubbles unter the Builtak since I bought it as a foil with adhesive tape. Seemed like I applied it perfectly but after the first print there were numerous bubbles that ruined the print. The under side was important in my case. So maybe you should switch the printing platform's surface to something else like the one I mentioned. There are already several options available

Apollo

Andy Cohen
Posts: 170
Joined: Mon Mar 21, 2016 4:43 pm

Re: How to safely remove PLA stuck to Buildtak

Postby Andy Cohen » Sat Apr 09, 2016 9:02 pm

One thing for sure... BuildTak can be controversial! I think we have established that it has issues and should be used with caveats.
We are currently testing a ZebraPlate on other 3D printers (not the R3D). It seems to work quire well. Stick is quite strong, but you can bend the plate and get a thin edge under the object to slowly work the object off without any damage to either the plate or the object. However, like so many other surfaces we have tested which slowly grip too much after lots of prints I would not recommend it until after it is has been used a lot.. as in hundreds of prints. Also, a Zebraplate for the N2 would be about $78. They also make a sheet that can go on another plate. Not testing that as of yet.

User avatar
John@Raise3D
Posts: 483
Joined: Fri Feb 26, 2016 8:42 am

Re: How to safely remove PLA stuck to Buildtak

Postby John@Raise3D » Mon Apr 11, 2016 1:13 am

This is the good part of N-series printer--it offers you flexibility on these things. If you like BuildTak, then you can use it as it is. If you don't, flip it over and you get a nice glass plate that you can apply glue, spray or whatever. If you don't even like the glass plate, then take it out and use whatever you think works for you. The key thing is to find something works for your printer.

Andy Cohen
Posts: 170
Joined: Mon Mar 21, 2016 4:43 pm

Re: How to safely remove PLA stuck to Buildtak

Postby Andy Cohen » Mon Apr 11, 2016 4:17 am

John@Raise3D wrote:This is the good part of N-series printer--it offers you flexibility on these things. If you like BuildTak, then you can use it as it is. If you don't, flip it over and you get a nice glass plate that you can apply glue, spray or whatever. If you don't even like the glass plate, then take it out and use whatever you think works for you. The key thing is to find something works for your printer.

As I mention in another thread... Heads up... if you flip the plate and use glue stick of Aquanet on the other side, you should be sure to remove the stuff before you flip the plate back to the BuildTak side otherwise getting the plate off will get tricky and messy.


Return to “Hardware”

Who is online

Users browsing this forum: No registered users and 2 guests