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First print problems with my brand new dolly (i3 clone)

Posted: Fri Nov 30, 2018 3:26 pm
by MikaTuunanen
Well, now that I've conquered other problems with building the printer, I've got to point where I should be able to print something and I've come across new problem(s).

Splicing benchy in Slic3r Prusa Edition 1.41.1+win64 with pretty much untouched Prusa I3 MK2S settings.

I'm using Fiberology EASY PLA (temp 200 - 220C) - first layer 215C and rest 210C with bed temp set to 60C.

Included is photo of the first few layers of ever first benchy try.

Obvious problems, first layer doesnt stick well. Nothing extra added to bed other than that tape which it came with.
Second layer showing under extrusion? I tried several times to calibrate extrusion rate and I got close (bit under) what I wanted. Problem is that I didnt find a pattern. Adding steps to extruder over certain point and it seemed that it extrudes less after that etc. Didnt notice anything I could translate into skipped steps or such problems. Filament was pulled quite steadily every try.

I started print try with G28 followed by G29.
Bilinear Leveling Grid:
0 1 2 3
0 +0.035 -0.101 -0.316 -0.591
1 +0.294 +0.037 -0.255 -0.544
2 +0.679 +0.319 -0.017 -0.338
3 +1.157 +0.763 +0.473 +0.202
After that I just loaded benchy.gcode to pronterface and hit print. It warmed the bed to 60C and then G28 homed all axis again (does this wipe the G29 result?). Then extruder to 215C after which it went it's merry way trying to print.

So. Now I understand what one person said that building a printer is one thing, getting it to print is another. 8-D

Re: First print problems with my brand new dolly (i3 clone)

Posted: Fri Nov 30, 2018 7:19 pm
by Moorviper
looks strange
but you are too much away from the heatbed with your noozle.
it looks like the steps aren't set correct.

btw your printsurface looks like "bluetape".
This is the same i started with. With similar results ...
Then i used and use allready a PEI sheet from prusa.
The sheet which is delivered with the orballo MK42 is also really nice but i killed it because i was stupid ;-)

Re: First print problems with my brand new dolly (i3 clone)

Posted: Fri Nov 30, 2018 11:17 pm
by Stefan
I'd definitely bring the head down at least 0.1mm (and then possibly more). Also be sure that after you use G29 that you have M420 S1. It may be automatic in Marlin now, but previously the bed leveling info would not be used unless you activated bed leveling. And yes, G28 kills that G29.

That first layer should be slightly squashed. If it has a circular cross section it is probably too high off the bed.


Re: First print problems with my brand new dolly (i3 clone)

Posted: Sat Dec 01, 2018 11:13 pm
by MikaTuunanen
Added G29 and M420 S1 to benchy.gcode.. Fiddled a bit with the (clone?) pinda sensor and had to alter extruder a bit since hobbled gear did grind on the printed part.

Now ordering pronterface to extrude 30mm extruded ~30mm. Give or take fractions.

Drove several layers on the benchy (damn night and very slim indoor walls - gf doesn't like whirring printer next room when trying to sleep).

Looks much better but there's still some issues. (Images arent the best, had to take by hand with phone and it's not the most steady option)
IMG_20181202_001626.jpg (2.08 MiB) Viewed 4030 times
IMG_20181202_001616.jpg (2.06 MiB) Viewed 4030 times

Re: First print problems with my brand new dolly (i3 clone)

Posted: Sun Dec 02, 2018 4:44 am
by Stefan
Definitely improving! I think you first layer is still too high; the extrusions should be more squashed together to create a solid layer. Maybe another 0.05mm. The other thing I think I see is your z-travel per line may be a little too much. Measure the distance from the bed to some point on the extruder. Send a command G0 Z10, then measure from the bed to the same point. Did the extruder actually move 10mm? I also think I see a little z-wobble. A few lines of extrusion are either inset or proud; this can create a pattern if the printed object is tall enough.

Good news is that this stuff is all tunable. Building a machine that can do what yours does is already an accomplishment.