ABS Adhesion and Corner Lifting

[Ruffturn]

Hello,

I have no idea what to do. I'm out of ideas though. I'm only getting about 20% (if that) of objects to stick. I guess I really do not understand the thermodynamics of plastic.

I'm using a Geeetech Prusa i3 Pro C Acrylic dual extruder (haven't used the 2nd extruder yet though). I'm printing with 1.75mm filament from what I assume is a dependable source for the product. I don't know if I can say what brand it is, but it sounds like something you would keep wooden matches in. The nozzle is the original .4mm. I'm printing with ABS with two-three layers of Elmer's glue after I've scraped and cleaned the glass with alcohol, 100*C initial bed w/ 94*C bed for the layers after that. I'm pre-heating for 1-5-10 minutes once the bed reaches temperature. The extruder is set for .2mm layers at 235*C initial and 210*C after that. In the beginning I was using an initial bed temp of 93*C and 89*C for the layers after that. I've stayed with either 230*C or 235*C (mostly) for an initial extruder temp and I've sequentially dropped my subsequent layer temps from an initial 225*C down to 210*C. I've also tried blue painter's tape with really poor results.

Also, i'm slicing with Slic3r. Please let me know if you need any additional information. I had to re-size the images below; hopefully they are legible.

Here are pictures of some of my screens and the object:

[Mark]

How about change another object? this one is too big and thin, easy to bend...or reduce the distance between the nozzle and bed, see if it works.

[Ruffturn]

Thanks for the quick response. This object curled up, but even smaller prints have trouble sticking. If the object takes much more than an hour it will more than likely come loose.

As far as nozzle-bed distance, the Prusa-i3-Pro C-User-Manual.pdf recommends .5-1.0mm gap. I do have it set slightly more than that because the extruder itself will contact the object and displace it. That was when I did have it set to the thickness of a medium sheet of paper after seeing comments in many places to set it there. I gradually increased the distance until it would no longer contact the object. Both extruders are matched in height and I verified that the extruder I'm using is passing 98mm of filament with a 100mm command. I thought that was probably close enough.

As you can see, I've tried very many things to get this. It's frustrating to not use this as it is intended.

Thanks for your help.

[Mark]

Well I guess you'll gonna need to try PLA...

[Ruffturn]

Please do not misinterpret this as being confrontational. That said, I don't feel that limiting the printer to PLA would be a good idea from at least a couple of aspects. This printer is sold as being capable of printing ABS and I'm sure that others have done so with very good results. If that were not the case, I would have seen other instances of individuals having similar difficulties.

My next idea for looking at this problem is the poor quality of the bottom of my prints. I didn't mention this previously because my main issue was keeping objects stuck to the glass. I felt that general appearance could be dealt with later.

Please see the attached images and tell me if you think that the quality of the bottom side of the prints might have something to do with the adhesion issue that I'm having. I have high hopes that you or someone might be able to shed some light on the problems I'm having. Everything was printed with ABS.

Please let me know if any other information would be helpful.

Again, I thank you for any and all of your assistance.

[Forrest]

I too have had problems getting ABS to stick ... especially toward end of job.
I am using hair spray on borosilicate glass. Have also tried ABS slurry.

For first part of the print (first few mm's), height of nozzle during printing first layer is super critical, much more so than with PLA. it must be squished down on the bed and pretty flat looking. If it is not sticking on perimeter loops, you may as well stop and readjust the offset distance ... and be sure to do a M502 followed by M500 to reset and store to new value after you recompile. (I prefer hairspray as it is water soluble. Make sure you get the kind with a plastic base. (lie "Aqua Net Extra Super Hold") .

For the latter part of the print, I am still working on it, but seems related to temperature in room and drafts ... I have built a case for my G2S and will retry ABS in the next day or two in a more controlled environment. Seems if room is cold and drafty, ABS will warp when upper layers get too cold.

check this https://www.matterhackers.com/articles/ ... g-with-abs
(I do not use PET tape)

Hope this helps ...

[Forrest]

Case over top seems to have eliminated later stage warping problems ...

[Ruffturn]

This has been sort of solved. I still have issues around the perimeter of the bed, but things are sticking much better now. Via email to my seller, who forwarded my issue, I conferred with Eric at Geeetech who was extremely helpful. I also found that the glass bed is bowed upward near the center by a surprising amount. I set the bed height to the thickness of a piece of paper at the center (thanks Mark, you were right & I was wrong in my interpretation of the manual ) and used the ABS config.ini file that Eric sent me. So far, everything that I've printed has stuck with the exception of the larger piece I was trying to print earlier. Since that's my own project from Autodesk 123D, I'm going to have to try and break that up into two pieces somehow, I guess. Regardless, thanks again everyone.