Success with Cyanoacrylate

Cyanoacrylate "crazy glue".

Based on an Ultimaker Google Group post and Florian's comment on my ABS warping post, I went out in search of some cyanoacrylate to try and glue the first layer to the platform in order to avoid the warping when using ABS.
I located some glue that is mostly cyanoacrylate in the local hardware store. I sprung for the big 10g bottle of this "crazy glue", even though in my experience it dries up long before it gets used up.
The first problem is that this trick involves applying the glue to the corners of the print "while printing [the] first layer". If you've ever seen one of these Ultimaker machines run a small part, you'll realize there are two issues with that. The first is that the layer takes about 15 seconds to print, which isn't much time to futz around gluing the corners. The second issue is that if you get your fingers in the way of the moving head in that small print area you'll either a) hurt your fingers and/or b) shift the print by making the stepper motor skip (it's operating open loop, so it doesn't measure where the head actually is, it just counts steps, so if one or more steps fails to move the head, the location of layers above the skip are displaced).
So what you want is for the machine to stop for you so you can do the needful and then tell it to start printing again. Fortunately there's a code for that.
The G code M0 stops the machine and waits until the user presses the button on the Ulticontroller. If you don't have an Ulticontroller, you can still use it with a timeout via the S parameter.
So the workflow is

• slice the stl file to gcode
• manually edit the gcode file to insert the wait code
• load the file into the printrun program
• start the print
• when it pauses, apply the glue to the corners
• press the continue button (or let the wait timeout)
• continue the print

So, where do you insert the G code when you edit the file? Here's the first few lines of the part G code file.

;TYPE:CUSTOM
M92 E854.177692541
G21        ;metric values
G90        ;absolute positioning
G28 X0 Y0  ;move X/Y to min endstops
G28 Z0     ;move Z to min endstops
G92 X0 Y0 Z0 E0 ;reset software position to front/left/z=0.0
G1 Z15.0 F400
G92 E0         ;zero the extruded length
G1 F75 E5
G1 E4.5
G92 E0         ;zero the extruded length again
G1 X100.0 Y100.0 F3500
G1 Z0.0 F400
G90 ;set positioning to absolute
G21 ;set units to millimeters
M105
M106
M113 S1.0
M108 S25.0
;TYPE:SKIRT
G1 X57.35 Y111.134 Z0.1 F9000.0
G1 F2400.0
G1 E1.035
G1 F9000.0
G1 X63.234 Y117.017 Z0.1 F1500.0 E1.0935
G1 X138.734 Y115.05 E1.6242
G1 X142.65 Y111.134 E1.6631
G1 X142.65 Y88.866 E1.8196
G1 X138.724 Y84.941 E1.8586
G1 X61.285 Y84.932 E2.4028
G1 X57.35 Y88.866 E2.4419
G1 X57.35 Y111.134 E2.5984
G1 F2400.0
G1 E1.5984
G1 F1500.0
;TYPE:WALL-OUTER
G1 X64.15 Y91.75 Z0.1 F4500.0
G1 F2400.0
G1 E2.6334
G1 F4500.0
G1 X71.25 Y91.75 Z0.1 F1500.0 E2.6833
G1 X71.25 Y93.85 E2.698
G1 X66.25 Y93.85 E2.7332
G1 X66.25 Y106.15 E2.8196
G1 X126.65 Y106.15 E3.2441
G1 X126.65 Y93.85 E3.3305
G1 X121.65 Y93.85 E3.3656
G1 X121.65 Y91.75 E3.3804
G1 X135.85 Y91.75 E3.4802
G1 X135.85 Y108.25 E3.5961
G1 X64.15 Y108.25 E4.1
G1 X64.15 Y91.75 E4.2159
G1 F2400.0
G1 E3.2159
G1 F1500.0
M0 S30 ; wait to apply glue
;TYPE:WALL-OUTER
G1 X128.65 Y94.15 Z0.1 F4500.0
G1 F2400.0
G1 E4.2509
G1 F4500.0
G1 X128.65 Y105.75 Z0.1 F1500.0 E4.3324
G1 X133.85 Y105.75 E4.369
G1 X133.85 Y94.15 E4.4505
G1 X128.65 Y94.15 E4.487
;TYPE:WALL-INNER
G1 X128.65 Y93.75 F4500.0
G1 X128.25 Y93.75 F1500.0 E4.4899
G1 X128.25 Y106.15 E4.577
G1 X134.25 Y106.15 E4.6192
G1 X134.25 Y93.75 E4.7063
G1 X128.65 Y93.75 E4.7456
G1 F2400.0
G1 E4.1456
G1 F1500.0
;TYPE:WALL-INNER


Too much glue, 2nd layer separates.

The location I used was after the first TYPE:WALL-OUTER that defines the corners (see the line in yellow), right after the extrusion retraction preparing for the jump to the second outer wall. This should leave less of a blob.
The first time I did it I applied too much glue and the second layer was pretty much mush, so it separated from the first layer.
The second time I was more careful, and used a Q-Tip to smear the drops of glue out a bit. I also increased the extrusion temperature from my normal 230°C to 240°C to get the second layer to stick to the (now colder) first layer.
I also turned off the cooling fan by unplugging it at the extrusion head. There's a code for that too (M107, fan off), but this didn't work for me. Something to investigate later.
This yields the desired result, although now, the blue tape is starting to lift from the print bed, so the print was still distorted a bit.

Successful attempt, although the blue tape is lifting at the corners.

You can't really see the tape lifting in the picture, but the hole is supposed to be round (naturally).
Before the print, I did do the best I could to make the tape adhere to the bed. If you shine a light from below the acrylic and you run your fingernail backwards over the tape if the tape isn't pressed down completely you can see a mark where your finger nail presses the tape fully into the bed.
The slight curvature can maybe be seen better when the part is removed from the printer.

Only slightly warped part.

Still, it's good enough.
You can see the part on Thingiverse.