I’ve had my mini for a bit more than 2 weeks and have printed maybe 20 objects in PLA, HIPS, and ABS. I have very rarely had adhesion problems with my Mini and am very happy about that. However, some objects, especially those with a lot of contact area with the bed and also thicker objects the thing sticks to the bed so well, that I have a whale of a time getting it off. Any tips for removing objects from the bed without damaging them or my Mini?? Does it help to cycle the bed temperature some between warm and cold to get things unstuck? In a couple of instances with ABS I just gave up, destroyed my object, and cleaned up with acetone.
For removing prints from my Taz, I use Calphalon Gadgets Cheese Plane with the slicy part taped over with heavy duct tape. http://www.amazon.com/Calphalon-Gadgets-Dual-Cheese-Plane/dp/B000SDQGL6/ref=sr_1_17/175-3914325-2977455?ie=UTF8&qid=1451859513&sr=8-17&keywords=calphalon+kitchen+gadgets
The trick is to get something with a thin, but very strong leading edge, and wedge the part away from the bed. That puts the most removal force on the part with the least removal force on the bed adhesive, which helps keep the PEI from coming off the bed.
Another thing you can do is carve grooves into the surface that touches the bed. I usually make a bunch of rods about 1mm in radius, and use those to cut grooves in the bottom. This helps make that surface stiffer, provides a little ledge to get your knife under, and reduces the surface area in contact with the bed. I usually space them about 1cm apart and it really helps.
Here’s an example (the top is 3mm thick with 1mm deep and 2mm wide grooves – printed in PETG which is pretty flexible but with the grooves, that surface is much more rigid) – the top of this box with the grooves in it was printed on the buildplate (i.e., it was printed upside down):
On the mini, make sure your nozzle is clean so that it autolevels and sets the nozzle height properly. Alternatively if you’re finding objects to stick too much, use the Z-offset gcode to lift the nozzle a tad higher (.1 to .3 anything greater and you probably have an auto-level problem).
As fore removing really stubborn prints, try a drop of isopropyl alchohol along the edge you intend to get your tool under. The IPA should loosen the ABS from the PEI, which should allow your tool to slip under the print. Don’t use too much IPA or too often, mixed reviews on whether this will deteriorate the PEI… LB advises against the IPA, but a respected expert says it won’t hurt the PEI…
Regardless, find the root cause of why the prints are sticking too well. Nozzle height, bed temp, autolevel…
I use a very thin clam knife, well it looks like one anyway. Let the print cool down and slip the leading edge of the knife right next to the print parallel with the bed and holding the opposite side of the table with your other hand, out of the way of that knife, tap the knife handle very gently until you get under the edge. If you have another clam knife you can move over to the other side and just work back and forth. I use a pair of pliers for my hammer. Its the tapping that gets under the plastic, not force.
I generally find that one clam knife and a couple gentle taps and the print is off the table. No table scars and no sliced up hand! Both are important!
Your mileage may vary and please use caution when dealing with sharp objects.
You are probably too close to the bed for the first layer. In Cura, go to machine settings and set the z-offset to 0.1. Then print and adjust as needed. You want it to hold down, but if you get it right, the parts will pop off when the bed cools. Even large flat ones. Too close, they are hard to remove, too far, and they come off while printing! Negative numbers move closer to the bed, positive moves away. I used a test pattern I found on Thingiverse, scaled it down in Cura, and used that to dial in the offset for my printer. This setup works well for HIPS, ABS, and Nylon for me. For Nylon, I also used the glue stick as recommended by Lulzbot. I haven’t tried any other types yet, but I do have a roll of PLA here I’m planning to test with as well.
To remove parts that stay on, I use the knife the printer came with. It’s a bit dangerous as it’s so sharp, but if you’re careful it’s not bad. I think I might order that cheese slicer and try that though, one less way to hurt myself with this thing. 
The tapping trick helps for stuck on prints as well. Once you get under it, the print gets a lot easier to remove.
This is the pattern I used.
http://www.thingiverse.com/thing:1239440
It’s too big, but in cura, select it, then scale it. I just used the “max” option. It takes about 3 minutes to print, plus warm-up/leveling/cool-down time of about 15 minutes. I generally started it, let the brim go down to make sure it wasn’t going to be too far off, and did something else for a while. It took a bunch of tests, but I finally got a value I’m happy with that sticks down all the way around, but doesn’t smash one side too much.
For cleaning, I help it along with a scotch-brite pad. Heat the nozzle, scrub a bit with the pad. I also did the washers, just to make sure they get good contact. I re-do the nozzle this way every few prints, whenever it’s convenient.
Hey all,
PEI and ABS have such an interesting compatibility. They either bond too well or they lift on the edges due to thermal radiation and cause warping.
If you are having problems with removing your prints, one of the most important factors is make sure that you remove your prints at 50C. This is the best temperature to remove a part without damaging the PEI. Also for extremely difficult prints, you can get a putty knife from somewhere like Home Depot. Then sharpen just one side of the putty knife so that you always have the flat side against the PEI. Just put the edge up against a corner of the print and tap the handle of the putty knife with the handle of your removal tool. This will allow you to get under the part without damaging the PEI from the pressure of lifting. Make sure to keep the bottom of the putty knife as flat as possible against the PEI surface so that you don’t dig into the PEI. I have found that this works well for all of my difficult adhesion issues.
Hope this helps!
The key is resist the temptation to pry up with whatever tool you’re using. As everyone has been recommending, tap to slide the tool under the object.
You shouldn’t let ANY print cool down all the way before removing it (I learned the hard way and was corrected by support). If your print can’t be pried off chances are it’s cooling down too much and/or is squished too close to the bed (which can be fixed with a z-offset and/or changing your first layer width percentage…this can have a negative effect on your parts lifting on the corners during printing though).
I added this code to my end G-code after my 3rd bed replacement:
M190 R50 ; wait for bed to cool to ABS removal Temp (50C)
G1 X145 Y175 Z156 F1000 ; move to cooling positioning
M140 S50 ; turn bed temp to ABS removal temp
M84 ; steppers off
G4 S21600 ; Hold bed temp for 6 hours (hours*3600) S<time in seconds>
M140 S0 ;Shut off heated bed
There are only two things that might change print to print. One is change the bed temp on lines 1 and 3 to the removal bed temp for whatever material you’re using. Second, I added a small line of code for the number of seconds the bed should wait before turning off. This is really just there as a safety measure if I leave the house for days on end and forget I had a print going so eventually it will shut off. The value for this is in seconds. This is useful if you know a print is going to finish about 3am and you’d like it to hold the bed temperature until at least 8am. I have mine set for 6-8 hours which works great if the print finishes right after I hit the sack.
I’ve also been trying better removal techniques than prying up on the corner of a thick part. If the part is taller, I hit it lightly on all sides with the blue end of the knife and that helps loosen most parts up nicely so that no prying is needed. So far after many prints the bed still looks new. Hopefully I’m onto something here. Hope this helps!
Jim
I’ve seen a couple posts about not letting the bed cool all the way. It would be nice if this were officially documented and for which materials, including what the removal temp should be for each. Or do you go with 50C for everything?
With HIPS, and a couple smaller ABS parts I’ve done, I’ve found that the parts generally release if I let them cool all the way. So when I get there, I don’t have to do anything to release them, they are just sitting loose on the bed. Sometimes I need to use the knife to help them along, but not too often. Rarely, one is on there pretty good, but after setting the Z-Offset properly, they generally come off by themselves. When I first got the machine, I had a few parts stick really, really well. Tapping with the knife got them off eventually. If I’m there at the end and try to remove at 50C or so, I always need the knife. I seem to remember reading in the book that came with it that removing parts when the bed is too hot will damage the PEI as well.
I just saw this in another thread…
https://www.lulzbot.com/learn/tutorials/pei-print-surface-troubleshooting
So it sounds like the temp they move the bed forward at is the one you want to hold it at. It would be nice if that were a little more clear and if the default profiles in Cura included the temp hold code. I’ll have to add that to mine. I don’t mind using a tool to get the parts off if it means prolonged life for the bed and PEI.
Hello,
I have attached a screen shot of the TAZ manual with the recommended removal temperatures.
Here is the link to the TAZ profile information. This also has the removal temps indicated:
Thanks Nick!
So, I take this to mean that Lulzbot officially recommends part removal at those temps, and NOT letting the bed cool all the way? If so, is the GCode posted earlier a suggested method to achieve that? I can’t always be there right when the job ends. I don’t mind keeping it warm if that’s the best way to protect the PEI.
Yes, that is the official Lulzbot stance on part removal
I don’t know if they’ve been updated, but at least the official Lulzbot ABS-fine profile I pulled from their site 6 months ago moved the bed forward at 60C. I went through 3 warranty replacement beds using that temp. The code I posted I added to the ABS-fine profile end gcode moved the bed forward at 50C and holds in there for as long as you specify (in seconds). Keep in mind since the hold command is still running the gcode (basically it’s a delay command), once you’ve removed the print you will need to cancel your print since the code will run until the wait command is done.
Jim
Thanks for all the helpful responses. That gives me some things to try. Luckily I only have a few minor scratches on my bed so far.
Some of my prints go for a long time, sometimes I leave them to print over night. I would not want to have my printer bed on for a long time after the print is done. Why not just re-heat the bed to whatever temperature you think works and then remove?
I have owned 3 printers since May 2015 and never messed up a bed removing a print.
Per Lulzbot’s recommendations, removing the part while the bed is heated without cooling down is better for your PEI surface rather than letting it cool down and heating it back up.
They used to say before you could reheat and remove, but further testing has shown the bed lasts longer if you don’t let it cool down. Hence why I added the hold bed temp code.
Your results may vary and you are free to do whatever
However, the Lulzchoppers may be in whisper mode
Jim
You mean the PEI material would last longer or the electric heating element? PEI is usually damaged by the user cutting or gouging when removing parts.
That should work.
Never got anyone to answer what is going to wear out when you let the heated bed cool down and then re-heat to remove objects… if needed. Leaving the heat on because turning it on and off would wear out the heater? That would be like leaving your toaster on all the time because the on and off cycles would wear it out. The PEI material on the bed is a wear item, it won’t last forever and the life cycle would depend on how many cuts and gouges it got. 