My new CoreXY completed build- Issues

Hi All,

I just completed a CoreXY build, and it is working perfectly fine except for one nagging issue.



A quick summary of the printer, it is a self made CoreXY utilising clone Hiwin MGN9 linear rails with 400 steps 48mm stepper motor on X,Y and Extruder(MK8) bowden.
The Z axis is using a typical cantilevered platform, also using Hiwin MGN9 linear rails. The lead screw is a M8,2mmlead integrated into the stepper motor. The 2mm lead gives 0.01mm full step resolution and the extruder is the typical e3d V6. Using MKS SBase and Smoothieware.

At first it was giving massive Z wobble but I realised it was probably due to me constraining the lead screw with the top bearing as well as constraining the delrin nut(now I mount it backwards). You can see the evolution of the print quality photos below from the top. Took me 3 weeks to troubleshoot this.

Top to Bottom -> Z wobble, Missed steps , 0.2mm layer height and 0.1mm layer height.




Now that I've resolved it , I'm getting other issues but I'm not sure whether it is Z wobble or Z Banding or is it a slicer issue.

This is the "skin" quality for 0.2mm layer height.




It appears to be mild Z banding/ Z wobble but when I print using 0.1mm layer height the skin is good and smooth and you don't see any Z banding at all,



So why is 0.2mm layer height giving more Z related issue but not 0.1mm? Filament issue? Slicer Issue? Temperature Issue? Is the lower layer height masking the issue?

One possibility is that the heated bed temperature is fluctuating too much. Is it stable to within +/- 0.2C of the target?

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I can still see banding in the 0.1mm print, just much less defined. Little bit of "shadowing" around the porthole in the bow as well.

From the sideline they still look like some good prints for starters! Certainly up there with what you'd get off any of the commercially available machines.

The banding seems "cyclic", suggesting either something happening per turn of the z screw or as suggested above the bed temp fluctuating (will that have an effect that far up off the bed?). Could extruder temp fluctuations contribute to it?

I've had quite a bit to do with those MG9 rails, and they can be fickle.

You need to get grease inside them, not just wipe it on the rails or they will play up. On genuine Hiwin there's a little membrane you have to push through with a hot pin or something and then there's a special little tip for a mini grease gun...it's a pain in the arse.

Last time I spoke to them they recommended EG/HG rails due to the fact they were cheaper, had an extra race of bearings, a grease nipple and better performance over all especially regarding play. Just what they said.

What size bed is that?

Quote
dc42
One possibility is that the heated bed temperature is fluctuating too much. Is it stable to within +/- 0.2C of the target?

Yup it is very stable.

Quote
hobbymods
I can still see banding in the 0.1mm print, just much less defined. Little bit of "shadowing" around the porthole in the bow as well.

From the sideline they still look like some good prints for starters! Certainly up there with what you'd get off any of the commercially available machines.

The banding seems "cyclic", suggesting either something happening per turn of the z screw or as suggested above the bed temp fluctuating (will that have an effect that far up off the bed?). Could extruder temp fluctuations contribute to it?

I've had quite a bit to do with those MG9 rails, and they can be fickle.

You need to get grease inside them, not just wipe it on the rails or they will play up. On genuine Hiwin there's a little membrane you have to push through with a hot pin or something and then there's a special little tip for a mini grease gun...it's a pain in the arse.

Last time I spoke to them they recommended EG/HG rails due to the fact they were cheaper, had an extra race of bearings, a grease nipple and better performance over all especially regarding play. Just what they said.

What size bed is that?

It is something cyclic, that's why I'm ruling out extruder or bed temperature cause these doesn't happen "periodically". Same goes to the Hiwin Rail.

It is a 200X300 MK3 aluminium heat bed.

Hmm I'm going to try other filament as well to see if the issue persists.

Did you ever solve this?

I am looking at something similar. Personally I am attributing it to the nozzle not being properly fixated so that it will be ever so slightly tilted by being dragged over plastic.

How lose is your hotend when you try to push it side to side touching the nozzle?