M3 - Z height changes at start of print

[Evan]

Hi All,

I have had my M3 for a month or so now. I am very happy with it but I occasionally (more so lately) I have been experiencing this issue;

- I start a print and the nozzle gauges through the Kapton Tape. The previous print/s, sliced in Simplify3D with exact same profile had no issue.

This seems to happen randomly as far as I am aware. I shutdown via Octoprint on my android tablet (not tablet supplied with printer) as per the instructions, switching off the M3's power after the light goes off. I have spoken with support and they are looking into it but I was hopeful somebody here may know why this is happening.

Normally I would go through the bed levelling process after this happens, but the last time I chose to re-print the previously sliced objects and again they start just fine, no gauging.

To date, the nozzle has gone no lower then the thickness of the Kapton - no damage or marks to the glass as yet, but I'm wondering how long that will be the case.

Cheers

[sthone]

I think support is going to be that way to go here....

Not to discourage anyone from asking questions in the forum but unfortunately none of the old pro's on the forum here have M3's so it doesn't seem like any of the specific M3 questions are getting answered unless it's a printing problem that crosses over to the M2.

Surprisingly I think most of us have still only seen the stock pictures on the website. Someone really needs to post some decent pictures of one of these things out in the wild.

I know I've had this problem on my Rev. E M2 when the z endstop switch holder has slid down the shaft a bit. I ended up putting a metal shim under it so it can't do that anymore..... but I think they attached the bracket on the M3 to the z motor now so that may no longer be an issue. (again I could be wrong as I haven't seen any pictures besides the stock ones on the site.)

The only other thing I can think of is the actual arm on the endstop switch is bending a little bit when the table drops on it after finishing a print. (does the M3 table still just free fall after the print?)

-Steve

[Evan]

Hi Steve,

Thanks for the reply. I think your right regarding support - whom I have been in contact with. Saying that they were not able to help me with this issue as they could not replicate the problem at their end with my gcode files.

So the same issue occurred this morning. Before that the printer had been working flawlessly for a week and a half with out issue. The Kapton my M3 shipped with was torn to bits from the nozzle scrapes so 3 days ago I put a nice new sheet of PEI on the glass. And now the new PEI has some nice gouges in it. Still, that's better then the glass being damaged!

Weird thing is - when this happens and without me re-calibrating/re-leveling, the next file I run will work at the correct height. Same S3D profile settings but a different part. I'm wondering if it has anything to do with the fact I am using a iPad through my wifi to control my M3 via Octoprint and Chrome browser. I wonder if I should have ordered the Android tablet at the time of purchase.

I'm not sure about the endstop switch holder. I can't see how mine could slide down? (image attached)

I have also uploaded a few pics of my M3 in operation. I am certainly very happy with the M3. I am still amazed I can print ABS without an enclosure. my Zortrax sitting next to it still has issues with ABS, with ABS juice on a perforated heated plate.

[Evan]

Sorry - forgot to add. The M3 bed comes down under power, not just dropping.

[3dPrintingMD]

My advice. In S3D, delete all your profiles.

Goto the Makergear Github, and download the .fff file for the M3.

Create a new stl file.

Try to print.

[sthone]

I'm not sure about the endstop switch holder. I can't see how mine could slide down? (image attached)

Yeah looking at that new bracket there's no way that thing is moving... (that's a nice upgrade they did there) and come to think of it when the bracket slides down on mine it makes the nozzle farther away from the bed not closer.

I'm at a loss here too... the initial starting height is controlled by the firmware (least that's how I understand it) so I wonder if there's an issue there or an issue with the motor. When the bed raise does it go up smoothly? any pauses? if you raise the bed by hand does it move smoothly along the entire travel?

Not exactly sure if the M3 with octoprint is exactly the same as the M2 running it with a raspberry pi but using a different tablet should not matter (least I wouldn't think so) I use a phone, table, laptop, and my desktop and they all do the same thing. Maybe the entire process is different though... On the M2 I slice on S3D then upload it to Octoprint on the Raspberry PI and then tell Octoprint to heatup the printer and then start the print.

-Steve

[Evan]

3dPrintingMD - thanks for the heads up on those profiles. The speeds are quite a bit slower to the M2 profile that installs with S3D. I will try the new M3 one as soon as possible though.

Steve - MG Support have given my a few new things to try, so will run through those as soon as I can. As for the printing process with Octoprint - what you describe is pretty much how I do it. I slice with S3D on my Windows PC and then send the file through dropbox to either my Ipad or Android tablet. I then kickoff the print through octoprint. It works 95% of the time without issue!