1 (edited by brandon 2015-02-15 23:17:34)

Topic: Other than demon possession, any ideas? Massive print shift.

My printer decided to do this about an hour into the print.  It just went off track and shifted about 45 degrees and four inches from its original position.

Any ideas?

SOLVED: Due to extrusion drag.  Lowering my flowrate has helped immensely.  there are other adjustments to still be made but this has apparently solved the lion's share of the problem.

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Re: Other than demon possession, any ideas? Massive print shift.

It's called step skipping and it can be caused by a few things:
- belts too loose (slipping) or belts too tight (binding)
- stepper drivers getting too hot (do you have a fan on the board?)
- motor getting too hot (check VREF and put a fan on the X motor)

This is along the X axis so focus your efforts there.

3

Re: Other than demon possession, any ideas? Massive print shift.

Actually on further inspection it looks as though the print shifted over a full inch.

4

Re: Other than demon possession, any ideas? Massive print shift.

I have no idea how to check the belts and I already adjusted the x axis motor so I will try throwing a fan on it next.

5

Re: Other than demon possession, any ideas? Massive print shift.

maybe something connected to extruder snagged on something and caused it to misaligned the head or disorient it. filament jam, wires, etc

Solidoodle 2 with Deluxe kit cover & glass bed with heater. and 2nd board SD2 used not 3rd and alum platform not installed yet still wood. also need cooling fan installed to board. use Repetier Host couple vers. Slic3r also have all free ware STL programs

6

Re: Other than demon possession, any ideas? Massive print shift.

jagowilson wrote:

It's called step skipping and it can be caused by a few things:
- belts too loose (slipping) or belts too tight (binding)
- stepper drivers getting too hot (do you have a fan on the board?)
- motor getting too hot (check VREF and put a fan on the X motor)

This is along the X axis so focus your efforts there.


Could be any of those, but don't forget the possibility of interference between the bushings and rods.  It looks like OP is using the stock carriage.  If it is anything like mine, it royally sucked.  I too had massive X skipping issues that was only resolved by replacing the stock rods with smooth hardened shafts and linear bearings (lawsy carriage).  I took my calipers to them and determined they were out of tolerance. 

OP, how old is your printer?  Mine started with the X axis issues when it has less than 1 roll of filament thru the stock setup.  Welcome to solidoodle quality control sad

SD4 w/ RUMBA, E3D Volcano, all bearings, glass bed

7

Re: Other than demon possession, any ideas? Massive print shift.

Not sure how old mine is as I bought it from a shop that wasn't using it anymore.  They had upgraded to different printers and sold this one off as second hand.

Going to cool off the board in back and try running another print now to see if that does anything.

8

Re: Other than demon possession, any ideas? Massive print shift.

Well the fan had no effect so I am going to go onto belts and motors next even though I already did the motor.  Does anyone have a decent guide on doing the X axis belt?

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Re: Other than demon possession, any ideas? Massive print shift.

Two theories:
1) Overextrusion and it is catching the nozzle
2) Add a fan for your X motor http://www.thingiverse.com/thing:128526

Belts could be an issue, but would be persistent with multiple prints. Personally, I slide my X carriage all the way to one end, then check tension 75% away from said end and I do this with both sides. At this point, you want it to be able to pinch the to lines together, but feel a little give....not too much force.
Belts can settle and stretch. It's just wear and tear. If this seems to be the problem after adjusting belts time after time, it would be wise to upgrade to some fishing line wink

Printit Mason and Printit Horizon printers
Multiple SD2s- Bulldog XL, E3D v5/v6/Lite6, Volcano, Hobb Goblin, Titan, .9 motor, Lawsy carriages, direct Y drive, fishing line...the list goes on
Filawinder and Filastruder #1870.....worth every penny!

10

Re: Other than demon possession, any ideas? Massive print shift.

Okay, I have started with the print on that fan holder.  I can not find a way to adjust the X belt tension though.

ALSO, should the carriage arms that the extruder rides on the X-axis be greased.  I am noticing that one is fairly clean while the other one has lines in it as if it was catching or something.  Photo attached.

Another ALSO, I am going to try turning down the flow rate to see if it is overextruding.

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11

Re: Other than demon possession, any ideas? Massive print shift.

Thank you, turning down the flow rate has apparently helped a lot. I have completed two prints with setting the flow at .8 and the third print looks pretty good so far.

Now I am getting some drift in the print at time to time but about 1-3 mm here and there.  I am going to look into printing a better carriage that I can tighten the belts up with.