MakerGear Forum

I had a sheet of buildtak gouge after resetting the starting height for the new surface and I had recently calibrated the z offset that went bad during a leveling. Not sure if the starting height did not save properly for the buildtak. I did get an app from MG to set the starting height without having to run through the leveling process.

Right now the printer is doing well with blue tape, something that I can put on rather easily. I go to war with polyimide tape and end up back with blue tape.

I am in a support thread with Buildtak/Matterhackers and some questions I am not sure how to respond to.

Have you made sure that your Z limit switch is not loose and moving around at all?

This Z limit switch is what stops the bed from crashing into the bottom of the printer, right?

We do not have experience with the Makergear M2 specifically, but I imagine there should be a Z endstop somewhere. Otherwise the printer would not be able to home itself.. Does the printer print at a consistent height above the bed when you are not using the BuildTak? If not, you should probably contact Makergear about that.

I seem to recall that the revision E. printer doesn't have this and the endstop is controlled electronically. Is this correct?

Thanks,
Jerold

I am in a support thread with Buildtak/Matterhackers and some questions I am not sure how to respond to.

Have you made sure that your Z limit switch is not loose and moving around at all?

This Z limit switch is what stops the bed from crashing into the bottom of the printer, right?

The Z-limit switch on the Rev.E is down at the bottom of the rear Z-axis support rod - behind the Z-motor. (On the earlier models it is at the top of the rod.)

We do not have experience with the Makergear M2 specifically, but I imagine there should be a Z endstop somewhere. Otherwise the printer would not be able to home itself.. Does the printer print at a consistent height above the bed when you are not using the BuildTak? If not, you should probably contact Makergear about that.

I seem to recall that the revision E. printer doesn't have this and the endstop is controlled electronically. Is this correct?

Not quite. The Rev E does have a Z-limit switch, it's just at the bottom of the rod. Every time you start a print, the firmware causes the plate to move up a few mm, move down and tap that switch to set the limit, then the machine moves the bed up a set amount less the amount that you tell it to when you use the Z-Adjust application. So it's critical that you get that measurement correct in the Z-Adjust Application, otherwise it is possible to gouge your surface.

And if you originally used the QuickStart Application to determine that number without running through the entire Starting Height and Leveling sequence, the Starting Height adjustment is not saved to the firmware.

So what you want to do is - determine what that adjustment is using the Z-Adjust Application (the app you got from MG), and save it from that to your firmware, and you shouldn't have any more problems. The Z-Adjust App does write the results correctly to the firmware without having to run through the leveling.

These are the instructions I followed to calculate the Z offset.

Reset your printer (with the reset button near the USB port or cycle the power)
Open a control software (like Pronterface, the Machine Control Panel in Simplify3D, or the "G-code..." window in the Quick Start app (in the "Advanced" tab))
Connect to your printer.
Move the X and Y axis by hand so that the nozzle is above the center of the bed
Heat your hotend and bed and wait for them to reach temperature
Send the command "M206 Z0" without the quotation marks (no quotation marks for all commands) to set your Z-offset to 0 mm
Home your Z-axis
Send "G1 Z0 F1200" to move the bed up to the new Z = 0 position.
Manually jog the Z-axis up until the nozzle is just barely touching the bed.
To get finer control than 0.1 mm send "G91" (relative positioning) then send "G1 Z0.01" to move the bed up by 0.01 mm and "G1 Z-0.01" to move it down.
Check your current Z-position (the "position" radio button must be checked in the G-code window for the Quick Start app) it should be close to 11 mm
Send "M206 Zxxx" replace 'xxx' with the absolute value of your current Z-position.
Send "M500" to save your new Z-offset
Home the Z-axis
Reset your printer

M503 now shows a z-offset of 10.39. That is the result of the previous post instructions. I saved this value to the printer firmware with M206/M500.

So then I am supposed to use the M2E Z Offset Adjustment v0.50 app with the feeler gauge to adjust this offset based on the surface I am printing to. The firmware Z-offset is essentially the starting point of the glass barely touching the nozzle tip. Since the buildtak is thicker than blue tape, this application adjust for the proper distance for the bead of plastic.

Okay sorry - I thought you were using an actual application, the Z-Adjust app - not the G-Code adjustments method with the QuickStart app.

Use either one or the other. There is a link to the Z-Adjust app here, but if you have performed the changes by modifying the G-Code directly, you don't need to redo it.

Z-Adjust Application: viewtopic.php?f=3&t=3666

And yes, you would perform either the Z-Adjust App or the G-Code adjustments that MakerGear gave you each time you change the print surface thickness. It all boils down to that gap, which changes when you change the thickness of the surface material.

I thought the G-Code Z-offset process was a calibration technique (no feeler guage) for z-offset and the starting height utility/M2E Z Adjust app were essentially setting the starting gap using the feeler guage. Is this correct. You can use the M2E Z Adjust to find z-offset and then use g-code to enter it into firmware memory? If so, that would be great because entering codes to move the bed 0.01 mm was kind of hard.
.

Huh! For some reason I can't post this - something squirrelly going on here:

Z-Offsets are nothing more than extremely small adjustments to the Starting Height of the bed before your print starts.

The reason that previous users had to use Z-Offsets, was that it was just about physically impossible to turn the screw that contacted the Z-Stop with enough accuracy to get the Starting Height correct. So we went in and adjusted the starting point for the plate from inside the software with Z-Offsets, which physically moved the bed a little closer or farther away from the Starting Height that was coded into the firmware.

Rev. E machines do not have to set a Z-Offset. They set a much more accurate Starting Height in the beginning, using the QuickStart Application, and then the machine keeps that much more accurate setting, and you don't have to worry about it anymore.
Now say that you want to change the surface that you are printing on. The machine thinks that the Starting Height is still at the same place that it was the first time you set it, and it moves the plate up into position, but since now the top of the plate is higher because of the new surface on it, you whack into the nozzle and it causes the hot nozzle to either gouge the material or drop the bed down because it hit something.

Unfortunately, you cannot just use the just the QuickStart Application again to set the Starting Height unless you re-perform the Leveling function as well. That is because the Starting Height information is not saved to the firmware unless the whole process is performed. (This throws off a lot of resets for people who do not re-run the leveling process and save the Starting Height too early in the process.)

You CAN use the Z-Adjust Application, which does the same thing as the QuickStart app, but without having to go through leveling again. It just sets the Starting Height and saves the information to the firmware. It is just as accurate at setting that initial Starting Height as the Quickstart app. Once you use the Z-Adjust app, your Starting Height is set correctly, and there is no need for further Z-Offset adjusments.

Now when you become an expert, and want to start making minuscule adjustments to the Starting Height to start impacting how the bed is placed for a certain filament, (PETG comes to mind), then you can go in and use either the Z-Adjust application or the G-Code adjustments to really, really, really fine tune the placement through coding. But it's really not necessary for this purpose, you are just trying to reset your Starting Height.

Rev. E machines do not have to set a Z-Offset.

Makergear support had me use G-Code to identify the Z-Offset then store it to memory on my Rev E. M2! It was initially 7.08, but I was able to determine (with lots of G1 Z0.01 entries) it should be 10.76. I saved it to the printer and it returns the offset value when I send M503. Not sure why they had me run through these on an Rev E M2 if there isn't a need for it.

So it sounds like when I decide to use a sheet of BuildTak, I need to simply use the feeler gauge and the Z-Adjust Application (M2E Z Adjust) until I "barely" feel resistance. This should eliminate the risk of gouging if done correctly. I am using S3D to slice and my extrusion width is 0.40 and primary layer height is 0.20. The first layer height is set to 90% and width at 100%. First layer speed is 50%

This printer is great, just a huge learning curve for me.

Appreciate your willingness to help me out!

Jerold

Yep! That will do it. (Not sure why they had you reset for a different bed surface using the G-Codes either - as you found out, it does take a long time to do it 0.01 mm at a time. They might have misunderstood the situation.)

Okay, looks like I had a bad jpg before, I'll go edit the post to pop in the diagram.