3D print shifting

After several layer, using all the recommended slicer and repetier setting, the print shift a couple inches on the X axis? i have tried it with a couple different models and it has done it with every one. this just started today for no reason?

You can slow it down a bit, maybe your axis are a bit tight. Slower should help. You can also turn up your drivers a bit if you have a fan on them.

so looks like it must have been a speed issue. i redid it with the exact settings you suggested in the repetier/slic3r settings and so far so good. have you adjusted the firmware or your repetier/slic3r to print faster than what you have the stock firmware and settings set at?

I would not expect the MP CNC to be capable of printing as fast as a dedicated 3d printer. The X, Y, Z axis are orders of magnitude heavier than most printers.

The fact that the MP CNC has been designed around being an “All in One” means it will never rival a dedicated 3d printer in terms of speed (though from what I have seen it rivals expensive printers in terms of accuracy and print quality)

Comprising speed for flexibility and and the ability to mill is more than a fair trade off in my books. It is an impressive design, and fills my needs exactly.

If you require speed for productivity reasons, I would look at either using the MP CNC to help build a dedicated 3d printer using a 3drag or reprap open source design. Or look at upgrading to multiple heads on your MP CNC.

oh, i am more than happy with the way it works, and am looking to do the router attachment here soon. i was just curious how far it has been pushed and was looking for a base line to start. it prints great, and i am working on the heat settings. i am going to mill the build area perfectly flat like we discussed to accommodate any possible un level areas from not being 100% on the legs. i do wonder if i plan to use this specifically for 3d printing, how tall i could safely go with the Z axis. since its moving slow and there is no torque from the extruder, rigidity shouldn’t be an issue.

Right now it is actually printing faster and with a better quality than my dedicated 3D printers. Why would you think slower? I think the trade off is it is larger and a 300mm Z axis would be pushing it at fast speeds. A dedicated printer is a much smaller package and a large Z axis. This cnc is large but has larger steppers, more of them, and is significantly more rigid.

The baseline to start with is the setting I put in the walk though. When you get that working well, start to ramp things up. 200-300mm would be pushing it unless you slowed down for the first few inches of printing. Tallest thing I ever print are the roller F’s everything else tends to be small So I build mine all to the just over roller f height.

Pulled this off this mornings batch. The reverberations are much more pronounced on the over exposed picture.

sweet. i appropriate all your efforts and time you take in responding to post. i am really happy with this machine and will be pushing it to it’s limits as i test what its capable and learn more along the way. thanks for all you do.

I wasn’t trying to down play your excellent design mate, as I am yet to complete my own MPCNC, so it was just speculation at my end.

I was also making the comparison to commercial grade 3d printers (not the typical DIY style most of us are accustomed to).

I am looking forward to completing my own MPCNC and I plan on offloading most of my high volume printing tasks to a MPCNC fitted with a larger 1mm nozzle. http://e3d-online.com/Volcano/Volcano-Eruption-Pack-175

My current printer, a DIY Velleman K8200 will be reserved for small detailed items with a E3D V6 0.25mm nozzle combo. I have heavily modified the K8200 (upgraded z axis, better belts, pullies, drivers, electronics, precision linear bearings and shafts, redesigned x carriage ect) and it now prints at insane detail/quality, but very slowly as a result.

I am very excited to see how fast I can push the MPCNC with the 1mm nozzle. Your results are encouraging. The attached picture shows very impressive print quality. There is very little layer shift (x/y axis movement is maintaining accuracy) , and the z axis movement is consistent (layers seem very uniform). I’m genuinely impressed.

I have the printer running and facing the issue with the part shifting in the Y axis. The filament reel is also on my y axis for the extruder to pull. I tried increasing the voltage to .9v to see if that helped. No luck on that test. I also built a reel system so it wouldn’t create tension on the extruder head. Unfortunely still no improvement. The shifting that I am seeing is right after the first layer and moves in the same direction at what seems to be .3 mm along the y axis. Than around the 20th layer it will shift in the opposite direction and become stable. The only thing I notice is a slight movement in my frame. I have reinforced the the legs because the 3D printer I used previously didn’t perform well (M3D). The x and y axis seems to ride perfectly.

I have used the slicer settings you recommended and even drops speeds to 18 mm/s and still no improvements.

Can you put up a picture. That usually helps explain a lot. Any modifications done, did you buy it from me, what material are you printing, how long is your z axis?

Try printing a spiral vase part and see if it still shifts

I have an 8 inch height build area. The last picture is the part that I am testing. It’s a wing nut. My z-assembly is very loose and not rigid. Due to my limitations on printing volume, I was not able to print the rigid middle z parts. I am attempting to print it tonight with the extra support on the frame. I am noticing random blobs about 5 mmm long and 2 mm wide after the first layer is complete.

The extruder was bought from you, my motors are similar to your spec, I think the voltage is a bit lower on mine. I am also using the ramps just like your parts list.

Right now I am using hatchbox pla filament.

I will try the spiral vase after my last attempt here for the night.

Hmm, I would say you need to tighten up the the middle. The rigid middle z wasn’t always used, it should work just fine without it, it was more for milling aluminum. To tighten up the middle tighten all the bearing bolts that have plastic on both sides that should tighten it up significantly. Should be 8 of them. Try printing something a little simpler like a cube, at like 30mmx30mmx30mm. Problems show up a little better in a larger simple object.

That zip tie on the extruder bracket, is it causing the extruder to lean, it will limit your z travel as well? It needs to be perpendicular to the build plate and clamped in pretty well.

Not that it the cause but that has to be way more than 8 inches of z travel from your build plate to the first z bearing bracket is only 8"?

I tightened the bolts and even had to add some gorilla glue to the extruder mount for more stability. The Z-Axis has improved but it still leans. It looks like the lean is due to the middle ends. I tired tightening those bolts but it still leans. I did print a 30mmx30mmx30mm square. Attached below are some photos.

What I noticed is the on +Y side, it was smooth and straight. The face on the -Y was really rough. I am not sure if this is even considered shifting. I am thinking something along the lines of feed rate?

After the square I decided to make the middle end piece and replace the weak ones I made on the previous printer(The software that the M3D couldn’t infill like the slicer can). I had even worse shifting and looked at the steppers on the x, and y axis. Noticed the set screws actually fell out of the pulleys. Finally I had a successful first layer but then noticed something strange as it was layering. It was not even when layering on the first layer and causing think streaks (see photo below). The 2nd layer the extruder head would literally crash and shift. I decided to drop the extruder voltage back down from .9v to .5v. Had a successful print but then the next print of the middle see did the same thing. This is the first time working with slicer so I’m not sure what would be the next area to look into.

Here is the first layer picture.

Okay, you are really close. 3D printing is a bit tricky at this point. Lets start with the easy one. The first layer of the middle end part is way too close. That first layer is by far the hardest to get right but once you know what to look for it’s easy.

You should just be able to see each individual line, yours is kinda smeared.

The other stuff, is a bit more complicated. One at a time.

Hi vicious1,

I am also facing the same X-axis shifting issue. The build area of mine is 400mmX400mmX250mm.
As you see the attached pictures, the printing is shifted to left on X-axis. (latest firmware and recommended slicer settings are used.)
Actually the issue is disappeared when the feed rate is reduced by half. (printing speed 15mm/sec)

After several trials and errors, I find it is caused by the shaking of the head.
If the Z height is too tall, head is far from the middle and it is weaken from the rapid movement.
Do you think my analysis is reasonable? If so, do you have a recommended Z-axis height?
And could you let me know Z-axis height of your printer? Your printing result(corner.jpg) seems excellent.

Thanks in advance.

Your Z height is the largest I have seen so far on a MPCNC. Since most people are building these as cnc routers the z height only needs to adjust by a few inches. But it looks like you are after a very high volume 3d printer. You will probably have to reduce your z height by a lot to get really good results. Hopefully Vicious chimes in on this and can guide you in the right direction to get the most volume with a good print quality.

I planned it as a multi-purpose tools including large 3d printer, so I was greedy for Z height :slight_smile:

Actually I saw Ashraf made bigger 3d printer than mine https://www.youtube.com/watch?v=Oo45NmwzsGc
But I think I overlook he used bowden extruder to reduce the head weight. I think he will face the same problem if he mount heavier tools such as dewalt 660…
Do you think 4 inch height is best for MPCNC?