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gizmatron
(@gizmatron)
Eminent Member
newbie questions

hello there.. new to 3D printing and my first post.. Ok bought the Mk2S kit.. assembled same day with a few breaks.XYZ calibrated first time.. first print.. hideous time with the live Z calibration using the included G2 tool.. useless.. found the calibration square print on here and 30 min later all sorted.. have printed my daughter a marvin and I've done a batman and a prusa logo in two colors, although I didn't spot there was an actual file for that I just printed the single color one and hit change filament at the right point manually.. worked fine.. I have two small points

one: when my printer does the bed leveling 9 point test before each print it usually leaves a tiny dot of filament at each point as it seems to drip ever so slightly from the nozzle,it then pulls a very thin string as it moves to the next point.. I have to pick them off and pull away the string each time, especially the one in the middle of the hotbed or it interferes with the print once it starts.. is this normal and if not how do I stop it..
two: I tried to print the treefrog from mt sd card and there appears to be an error in the code.. after a few layers it jumps to the right and prints the following layers off to the side, way outside the brin line, obviously this is also trying to print in mid air so fails dismally and makes a huge mess.. can I download the file again from somewhere? or is this something on the printer I can adjust.. it only does it on this model and I tried 6 times and it jumped at the same point each time and it's a big jump..maybe half the width of the model..

cheers Gary

Postato : 04/04/2017 12:35 am
StephanK
(@stephank)
Reputable Member
Re: newbie questions

1) Yeah, this can happen, it's a matter of how "runny" the filament gets at the temperature used during the mesh bed leveling. Print frst layer a bit cooler, use different filament will help. Another way to fix this once and for all would be to change the slicer start gCode script so the bed leveling happens at a slightly lower temperature. I thought I've seen changed scripts for Prusa Slic3r on the forum but can't find a link right now.

2) When you install the drivers from here: http://www.prusa3d.com/drivers/ a copy of all those files ends up on your hard drive as well. Folder name is 3DObjects or something like that.

But it is more likely that you still got an issue with x-axis motion. Keyword: "Shifted Layers".

When you power off the print, does the x-axis move freely (and smoothly) along the whole axis? If not, try again with the belt unhooked. (This is meant to find out where possible binding occurs belts or the rods/bearings.)

Some point to check:

- Belt tension: too lose belts might skip, too tight belt could cause increased friction.
- Your motor pulley might be lose or not tightened against the flat side of the motor shaft.
- The belt might be rubbing somewhere along its path (check for rubber debris)
- or the idler wheel might not turn freely
- it's more likely to happen in silent mode, as in silent mode the motors get less current and therefore have less torque and skip easier.

The treefrog is not the easiest print, it likes to warp/curl at certain points around the legs and when the nozzle bumps it, it could cause skipping and with skipping comes shifted layers as well.

Postato : 04/04/2017 3:24 am
gizmatron
(@gizmatron)
Eminent Member
Topic starter answered:
Re: newbie questions

OK.. I think my problem is either not enough belt tension on the X axis or something rubbing, I'm going to dismantle and test it all.. when it does the bed levelling it does 1,2,3,4 points no problem however moving right to left from 4 to 5 there is a stuttering sound and it regularly sticks between the two points and fails the calibration.. as this is the center point at which the model is mostly printed I can see how it would screw things up.. last night i left the buddy bulldog printing and the last half of its head was printed the same 7/8mm off to the right.. so something is jumping. The odd thing is it only does it moving right to left.. points 1,2,3, and 7,8,9 smooth and perfect. maybe i have a a looser cable tie on one side the the X axis paired bearings?

Postato : 04/04/2017 1:25 pm
gizmatron
(@gizmatron)
Eminent Member
Topic starter answered:
Re: newbie questions

OK here's my issue. without doubt "layer shifting" now just to find out why... already tightened the belt.. i'll remove it and eliminate any binding problems

Postato : 04/04/2017 6:26 pm
gizmatron
(@gizmatron)
Eminent Member
Topic starter answered:
Re: newbie questions

Just for info.. sorted totally, it was just the X axis binding.. cleaned out the drylin bearings with contact cleaner and puffed a little dry graphite powder lube on the rails and problem gone plus it's quieter.. prints beautifully now. PLA and ABS so far.. time to try some TPU and PETG next

Postato : 05/04/2017 12:17 pm
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