ABS print lifting - a little help please

[howardsmith 0]

I'm having trouble printing a particular part with ABS, I've tried heating the bed at different temperatures (90,100,110), using all sorts of different glue sticks, and even trying to make some slurry (which I failed at), but each time the print lifts at a particular point. There are also occasionally certain bits on the piece that look burnt, I don't know if that's normal with ABS. I understand that abs shrinks, and that having a large surface area increases those chances, but is there anything that screams out at more experienced users as to why this isn't succeeding;

[gr5 2,167]

110C bed temp is good. Even if it only gets to 105C keep it at 110C. You have a big brim so that is good too. Let's concentrate on 3 more things:

1) Bottom layer needs to be squished flat - yours looks perfect but lets unscrew the 3 screws 1/8 turn anyway. Just do it. Don't relevel just turn them all 45 degrees rotation.

2) slurry. Okay so are you printing on glass? You have a UMO or UM2? Let's start over - clean all the glue off the glass. Use windex or any glass cleaner.

You want PVA glue which is found in glue stick, elmers wood glue, or hair spray. Hair spray has additives so if you use that then use non-scented at least. I prefer wood glue mixed with 1 part glue, 10 to 20 parts water then I paint it on with a paint brush and let it dry until it's invisible (it dries faster if you heat the bed). Even if you already did this, do it again because oils from the ABS or your fingers may be on the bed now.

3) Final thing - make it a heated chamber. While bed is heating up find one of those boxes meant for reems of paper - for the copy machines. Turn the box upside down and put on top of the printer. Use some blue tape to hold it there. Then cover all the wall openings - preferably with saran wrap so you can see through but make it easy to open the front one so you can watch the start of the print. Ideally you want 40-50C and no hotter. The only problem with hotter is the X,Y and E servos (extruder not issue on UMO) don't want to exceed about 80C. So keep the air under 50C. This should be trivial with an open box upside-down on the top as warm air is always leaking out but you can use a thermal temp probe to verify if you have one.

[gr5 2,167]

One more thing - it helps there e no bottom air gaps underneath the bottom layer if you go a little extra hot bottom layer. 245C is usually fine but you might want to go 260C and possibly print slower (this is default in Cura anyway) - certainly no faster than 40mm/sec bottom layer - 30C might be safer.

[howardsmith 0]

Thanks for the response. Sorry I forgot to say but yes I'm printing on an Ultimaker 2 with a heated bed. I plan on doing a print using your suggestions, but as an aside is it worthwhile raising the main print up from the bed with the use of supports to help avoid the lifting issue? Thinking mainly about the large surface area which curls up - could that be avoided with supports do you think (even though the finish would be worse).

Unfortunately the same thing happened, only this time I rotated the print and the side which usually stays stuck down now curled up. This is the edge that faces the opening of the UM2 so I'm guessing the air flow isn't helping much.

I've tried a different print, after wrapping the front in cling film and this time they finished printing with a degree of success, unfortunately some of the prints with a larger height have warped ever so slightly towards the top. I think I'll give it one more go before heading back to PLA.

Edited May 8, 2015 by Guest
re-printed

[howardsmith 0]

As a quick update I've been printing with ABS so far and whilst I'd say the results are far from perfect they are acceptable (warping is very visible but it's not impacting the end result). However I've just set off another print and I'm concerned as there are small lumps of burnt abs appearing here and there. Why does this happen? There's nothing in the troubleshooter guide dealing with this so it's a new one on me.

[madness 2]

Hello Howard!!

I am a new printer with only 6 weeks experience actually printing, but I am doing commercial jobs in ABS with excellent results. Stick with the ABS!!! I spent 5 weeks nursing PLA through the print process and when I finally got it right, man, the ABS was just hands-free printing…

Sooo, I learned all my printing techniques from the UM forums, the guides especially, and I have some tutorials of my own to humbly share…

But I have a question, Are you a brand new printer? I had never even seen a 3d printer when I got mine… and, is this a US UM2? Sorry I cannot find your locale, …

anywhooo… if you are a new printer, then bed leveling may be your prob. Forget the 'a level bed affects the first few layers of print”...bs...at the high resolution the UM2 prints at, the ENTIRE print is affected...under/over extrusions, sagging, filament not extruding at high temp….everything!! is affected by your bed level. I have moved the glass trying to remove ABS prints before cooling after I figured out how to level the UM2.

I have a 30 min step leveling process that removed all the errors in bed leveling, lol… I think… but, I am so new, I need to get it reviewed by the admins for errors/ignorance, etc .

I have 216 hours of print time on my UM2, have never had 1 problem, and have never had to “atomic pull” the nozzle… when I switch ABS colors, the whole nozzle plug comes out...everytime...w/o fail...and I worry it will get caught in the feeder...(gr5 or !Robert has a post about that ABS plug/feeder, I think).

I am thinking we have a tutorial prob here, in the UM forums, with info, reviews and posts older than about Oct/Nov 2014 confusing new folks. I don't own a magic UM2 from Fabrc8...I just did what the forums/guides told me to do and it works everytime. ...lol I am running a plastic-covered, combat printing machine...all of the forum advice turned my gorgeous UM2 into a ghetto-looking machine...but...it prints...w/o fail...10 friggin' hours a day or so…

I hope this helps and generates a bit more discussion !!!

Happy Printing-

MadNess