jagged lines

**winter42** · 09-06-2016, 10:18 AM

I'm pretty new to printing and while I have worked out a lot of bugs I cant seem to fix this one. On most prints it starts out fine and after several passes the lines become jagged and incomplete. I have tried changing filament,temp,nozzle height,speed all with no luck. The pictures show the issue. Thanks!

http://tinypic.com/r/33a74mt/9
http://tinypic.com/r/20hawi0/9
http://tinypic.com/r/257kepw/9

**mazzi16** · 09-06-2016, 03:54 PM

I'm only a plodder myself,but that looks to me like over extrusion.Have you calibrated your extruder?

**winter42** · 09-06-2016, 04:06 PM

Yeah, I mean its definitely possible I messed it up though. I figured that might have been the issue at first, but when I turned down the extrusion percentage it didn't get any better. I went down incrementally to 10% less. Also the issue is on and off. It happens on most prints but not on others. Even the same part can have the issue one time and not another with no changes in between. Most prints have the issue though.

MODERATOR NOTE: Late post due to delayed moderator approval

**curious aardvark** · 09-07-2016, 07:21 AM

wow that is pretty awful.

Check your belts are tightened, that's not just an extrusion issue. The head is not travelling in straight lines.
I'd have to go for a mechanical fault, not a slicer issue.

**iDig3Dprinting** · 09-07-2016, 08:56 AM

It could be that your nozzle is far to close to the bed so that as it is laying out the filament it squishes out the side. is this a first layer issue or does it occur throughout a print?

**winter42** · 09-07-2016, 09:25 AM

the issue is throughout the entire print. and actually its kind of intermittent as well. I can use the exact same gcode and most times I get this problem but something like 1 in 10 attempts actually prints out correctly and there are absolutely no changes made between attempts. I tried incrementally reducing the extrusion multiplier one percent at a time. I did 1%-10% and even at 10% less the issue persisted.

**AutoWiz** · 09-07-2016, 01:42 PM

When I first got my printer I had similar extrusion problems. For me the problem was the pot adjustment on the a4988 stepper driver was not set right for the mk8 extruder and it was skipping steps. but it was close so it wouldn't always do it. only at certain speeds or after running for a while. In my case, I bought a kit and had to assemble everything and all the other steppers worked fine. but a close inspection of the mk8 extruder shows the stepper motor is slightly different from the rest of the stepper motors on the printer frame so it made sense to me. and the adjustment worked out very well.

**winter42** · 09-07-2016, 05:06 PM

How do you adjust that? I figured out what your talking about and it def does make sense. I hace an mk8, it was a kit and the motor is different. but no idea how to know what the right amount is

**AutoWiz** · 09-07-2016, 06:44 PM

I used a digital multimeter probing the screwdriver that was touching the pot and grounded the meter at the casing for the usb port on the controller board. the voltage should be low. I think on the a4988 chips you should aim for .4 to .6 and if you switch to the drv8825 stepper drivers I like to set those at .7 but by all means try these voltages, print something,. then go .1 or .2v in either direction and try the same print and compare. not enough voltage and you get skipped steps like you see. too much voltage and the motor overheats and shuts down. aside from extrusion problems this is noticeable by a very hot stepper motor.