Z-axis artifacts (wobbling, irregularities, waves, ribbing)

Mike_Kowalczyk · 2015-06-22T13:42:47.000Z

Also have seen this issue on some printrbots, just not as pronounced. Anyone have a solution?

mmark · 2015-06-22T13:52:19.000Z

Thanks for you reply,

I’ve checked my cura settings and the filament diameter - everything seems correct.

Antonio_Bencini · 2015-06-22T14:06:27.000Z

try to extrude 100mm manually and measure the real amount of filament extruded

INVENTion · 2015-06-22T16:16:28.000Z

I’ve had the same problem and I’ve reduced it, originally, using Simplify3D software. However, it is still there.

I’ve read somewhere it has to do with the threaded rod. Mine is pretty wobbly so first thing is to try to make the z screw the most straight it can be.

Bigsean1225 · 2015-06-22T17:02:26.000Z

What layer height are you printing at?

jesseslone · 2015-06-22T17:09:46.000Z

I’ve had this problem before, and I think the reason Antonio_Bencini is mentioning it is because it becomes more pronounced with over-extrusion, which it looks like you have a little of. I find that I run an extrusion multiplier around .898 and I get much less of it. The last time it was bad on one side for me, it was because my Y belt was loose, so that would be my next step, to double check the x and y belts, as well as the stepper mounts. I have wobble in my Z-screw as well, but those things usually take care of it. The next step would be to adjust the layer height to something directly calculated from the steps and pitch of the acme screw. I know for my Simple Metal it works out to something like .1975 or something like that. I think you’ll see the most improvement by fixing the over-extrusion though.

ianadan · 2015-06-23T07:19:07.000Z

Hi Mark

You say this is getting more pronounced over time, so I guess we’re looking at a little Wear and Tear here as well as a few other things. I also have a Jr v2 (amongst others) and it’s a good printer when on form.

You may want to print something to keep the Z rods from moving as the Z goes higher. The 8mm rods are fine but they can flex as there is more torque on them.

Tighten all the screws. If you find one a bit loose in the wood, treat the threads with wood glue, screw them as far as they will go and then, when it dries, turn it a bit more - it should help the grip again. If you think the wood maybe too worn, and you have access to a laser cutter, the complete DXF are available on youmagine.com, as are lots of PB original wood plans.

The Z screw is a 3/8" ACME screw. I’m sure there are some tables that will tell you the optimal layer height.

As mentioned before, check all the belts. Tight but not overtight as the motors will suffer, especially on the Y and X when they bend round the bearings.

Ian

mmark · 2015-06-24T14:40:09.000Z

Don’t you check the stepper calibration if you measure your prints?

mmark · 2015-06-24T14:41:57.000Z

I’ve noticed the same with mine actually… I think its time to replace the wooden thing witch Printrbt supplied me with - any good alternatives?

mmark · 2015-06-24T14:42:16.000Z

between 0.1 and 0.25

mmark · 2015-06-24T14:44:27.000Z

Or do you mean like this?
http://help.printrbot.com/Guide/How+to+Calibrate+your+Printer/81

mmark · 2015-06-24T14:44:48.000Z

like so?
http://help.printrbot.com/Guide/How+to+Calibrate+your+Printer/81

mmark · 2015-06-24T14:50:53.000Z

Hi, thanks!
The wooden coupler witch needs to hold the 3/8" ACME screw attached to the motor is not the most sturdy one. It allows the 3/8" ACME screw to slide sideways easily.
Also, I’ve noticed that the white nylon (?) thing (the one witch is threaded) can be moved (~0.5 - 1mm) back and forward.

Is there for both a good alternative?

Cheers!

jesseslone · 2015-06-24T15:01:14.000Z

What happens if you go up to a 0.3 layer height, is it more or less visible?

Antonio_Bencini · 2015-06-24T15:02:43.000Z

here is easier

jesseslone · 2015-06-24T15:05:20.000Z

Edit: This is not in response to the Video:

That is one way, but with different filaments you always have slightly different diameters. I was referring mainly to slicer settings, where the extrusion multiplier is. In cura, it’s called the “Flow Multiplier”. I would recommend printing something like a 10mm cube and reduce the multiplier by .02 over a few prints and see if that helps. If you are over extruding, and you calibrate the printer steps for x and y with a test print, the values will be inaccurate. I run test prints with the filament until I start to see evidence of under-extrusion, then back off a little.

mmark · 2015-06-24T15:10:38.000Z

looking at the Octo’s in that video my problem should be underextruding… Wil try non the less!

mmark · 2015-06-24T15:11:56.000Z

If you are over extruding, and you calibrate the printer steps for x and y with a test print, the values will be inaccurate.
Also true… Will print a couple of test cubes! Thanks

chomperman · 2015-07-01T22:08:47.000Z

Buy a proper z couplers from printrbot. It will fix the majority of your problems.

mmark · 2015-07-05T13:34:08.000Z

Hi everyone; thanks for the replies! The problem was the wooden coupler and the nylon nut-thingy. After a year of printing it is worn out causing clearance - the rod could move how it want to move.

I ordered a better coupler.

Not really sustainable quality parts Printrbot…