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M2 Z-stop bed leveling contradictions?

Posted: Mon Apr 21, 2014 12:59 pm
by Capt. John
Z end stop is the thickness of a folded sheet of paper, or business card.
Bed leveling is a single sheet of paper? Confusing to me, please explain.

I have my computer with 3D Simplify software controlling/talking to the printer.

Need a little help before proceeding to my first print.

Some instructions are in the M2 assembly guide, some are links to videos.

Past the assembly point and need step by step instructions all in one place.
Which I've yet to find, only pieces of info here and there.

Please help and thanks.

Re: M2 Z-stop bed leveling contradictions?

Posted: Mon Apr 21, 2014 3:44 pm
by jsc
Bed leveling is different from z end stop setting; in bed leveling you only care about getting the bed aligned with the nozzle. Then you set the z end stop height to get it to trip at the right height.

Please see my M2 Tips thread in the tips forum for some different methods, and for some other things that may be helpful.

Re: M2 Z-stop bed leveling contradictions?

Posted: Mon Apr 21, 2014 3:51 pm
by Toby
I had similar frustrations with the documentation being scattered and incomplete so I understand that. The good news is there's just a couple of things you'll need to learn and then it's easy.

As far as I can tell, hardly anyone ends up doing these things the way Makergear teaches. But it might be helpful to run through what Makergear is doing anyway, just to understand. After that I'll talk about different ways of doing it.

To answer your question about the different thicknesses for leveling and z-stop, it's because the way Makergear does it you first level the bed without any reference to the z-stop. That means you manually bring the bed next to the nozzle (one paper thickness for example) and adjust the spider screws so you have that same thickness of separation at several points around the bed. Doing this manually takes a certain amount of dexterity because you have to hold the z-axis knob with one hand at the same time as you measure the distance between the nozzle and bed with the other, and then adjust the spider screws under the bed, which are themselves confusing as to how they tilt the bed this way and that. You can easily go around in circles and never get it right.

Continuing with Makergear's method, once you have the bed leveled you need to set the Z-stop before printing. In this case the folded paper (or business card) comes into play because that is the appropriate distance (more or less) that you want between the nozzle and the bed when the machine starts printing. To set that the Makergear way, you once again manually raise the bed to the nozzle, but this time with the machine turned on so you can see when the z-stop gets triggered. Then the goal is to adjust the bolt that is triggering the z-stop so that it trips the switch when the distance between the nozzle and bed is the thickness of a business card. Because the bed is already leveled relative to the nozzle, theoretically you should only have to do this at one point on the bed. Though since the glass itself isn't perfectly level there can be some little problems with this method, but it's certainly enough to get going.

The real difficulty is that adjusting that bolt is a pain. Access to it is awkward at best, and without the right tools, impossible. You'll need a 7mm wrench (I think, better check that though) that is narrow and long enough that you can reach it in and turn the lock nut to loosen and tighten it. Once it's loosened you can turn the bolt by hand or with a wrench, but as I remember it's hard to reach in there without lowering the bed to gain access. So once again it takes a fair bit of manual dexterity and trial and error until you get it so the z endstop is tripped exactly when the nozzle is a business card thickness from the bed. Then you have to re-tighten the lock nut and make sure you don't turn the bolt in the process. Maybe some people can do that all no problem, but me, I found it difficult. In the video the demonstrator seems to do it easily, but his back is in the way and you can't actually see what he's doing with the things that matter.

Since you're connected via S3D I think there is a much easier way you might want to use. This is described in a document here on the board (by Jin with some others contributing), which also contains a lot of other useful information. I highly recommend it: [Edit: Since you asked for everything in one place, I've copied the relevant section of the docs onto the end of this post.]

viewtopic.php?f=3&t=12

Equally useful for S3D users is a guide for that (also written by Jin) found here:

http://jinschoi.github.io/simplify3d-docs/

This was written one version before the current version, so it could be dated in some areas, but I think it's still bound to helpful.

Anyway, to continue with the bed leveling z-stop setting. The method described in the first doc does both the bed leveling and z-stop at once using the S3D bed leveling wizard. You'll still need something to measure the distance between the bed and nozzle, like a business card or a feeler gauge (which I like because it doesn't wear out and there's no chance of getting paper fibers onto or into the nozzle). Also, there's no way to avoid setting the z-endstop manually once. For that you need the makergear method, but it doesn't have to be exact since you will fine tune it with the S3D method.

For starting out the first time, I'd recommend tightening the spider screws all the way down, then loosening each one about half a turn. That will give you more rigidity in the bed than if the screws are loose to begin with and you have to loosen them more to get the level right. Then do the z-endstop adjustment using any thin measurement device. Then use the S3D method to get the bed exactly level and the z-height exactly where you want it.

From that point on you will only have to do the S3D method to keep the level and z-height properly adjusted. (Unless you do something drastic like change the nozzle or use glass of a different thickness. But I routinely swap glass plates and still never have to do anything but this method.)

Just to be clear, I'm flogging my own method here and there are many other ways people have devised that you can find if you do some searching, especially in the old Google Groups:

https://groups.google.com/forum/#!forum/makergear

Lastly, let me say that this is really worth getting right. The better your bed leveling and z-height adjustment the better your prints, to the point where it is often the difference between success and failure. I do these adjustments before each print (it takes about 1-2 minutes), and it's been a long time since I've had any problems with bed adhesion or layers not bonding or anything like that. Of course, you'll soon get into issues of preparing the glass as well, but that's a whole new discussion.

Welcome to the fun! Hope this was useful and not information overload.

Edit: Here's a copy of the section of the docs on bed leveling/z-height using S3D:

Bed Leveling and Z-height Adjustment Methods
---------------------------------------------------------
From Toby:

This method assumes that your bed and z-height have been leveled once but might be in need of minor adjustment from print to print. It also assumes that you are using Simplify3D, though it is likely to be adaptable to other printer-control software.

It may be desirable to pre-heat the bed to your printing temperature before starting.

In Simplify3D open the Bed Leveling Wizard (under Tools on the main screen) and set the "Z height for leveling moves" to 0.0. (In versions earlier than 2.1, it will be necessary to also keep the Machine Control Panel open and accessible on the screen. Depending on your computer and operating system this may involve resizing and repositioning these windows. Put the Machine Control panel in jog mode.)

Click the "Manually enter leveling positions" radio button and put the following locations in the manual portion of the dialog:

100 175
100 75
150 125
50 125

Once entered, they will not need to be entered again. The first three coordinates are the locations of the adjustment screws in the spider. (Note: It would be nice to verify this or find the exact values.)

In manual mode, start the Bed Leveling. The nozzle will move to the home position. Click "Next" and it will move to the first position listed above and then Home in Z. (For versions earlier than 2.1 it seems the nozzle doesn't home at this point. In that case, click Home Z in the Machine Control Panel.) Now adjust the spider screw beneath that position to your desired distance from the nozzle (usually in the range .006" to .01") using a feeler gauge. Tightening the spider screw will increase the gap between the bed and the nozzle, while loosening it will decrease the gap.

Repeat at each of the remaining positions by clicking "Next". The final position has no adjustment screw and serves to verify that the bed has been properly leveled and the z-height set. If it is not correctly adjusted at that position, then repeat the procedure for the first three positions.

Once this is done the bed is both leveled and the z-height is properly adjusted.

Re: M2 Z-stop bed leveling contradictions?

Posted: Tue Apr 22, 2014 12:41 am
by Capt. John
Awesome info that will help things along.

Thanks!

Re: M2 Z-stop bed leveling contradictions?

Posted: Wed Apr 23, 2014 4:34 am
by Capt. John
3D_Parts.jpg
(161.81 KiB) Downloaded 3209 times
Made my first parts today, including the bigfoot head on the SD card that came with my M2.

Tried to print an extended spool off Thingiverse for the M2. Never got this right.
Extended spool file printed off to the side, not centered like my successful builds?
This build failed 5 times: http://www.thingiverse.com/thing:91358

How can you center builds that are centered in S3D, but print off the center of the build table?
Why does this happen?

Long-long journey for me. Reading instructions has never been my strong suit, but with the help
this board supplied, my new M2 is no longer a paper weight.

Re: M2 Z-stop bed leveling contradictions?

Posted: Wed Apr 23, 2014 4:39 am
by jsc
The object appears centered in the S3D view, but not on the table? Check under Preferences/Machine that your build volume dimensions are set correctly. They should be 200, 250, 200. Origin offset should be all zeros. Are you using the Center and Arrange button?

Re: M2 Z-stop bed leveling contradictions?

Posted: Thu Apr 24, 2014 5:36 am
by Capt. John
200-250-200 in the general options under the preferences tab.

All zeros in origin offset.

Machine prints in 2 quadrants so far, plus centered.

Model sits in the center of the build cube in S3D when arrange is clicked.

When the bolt touches the z-stop bend spring is that where you check with a business card,
or does this spring flipper need to be compressed?

Spool holder finally came out right:
Parts3D.jpg
Parts3D.jpg (72.08 KiB) Viewed 28635 times

Re: M2 Z-stop bed leveling contradictions?

Posted: Thu Apr 24, 2014 6:34 am
by Toby
Capt. John wrote: When the bolt touches the z-stop bend spring is that where you check with a business card,
or does this spring flipper need to be compressed?
With the M2 turned on there's an LED on the z-endstop that lights up when the bolt compresses the flipper a certain amount. That's when you want the nozzle to be a business card away from the glass bed.

Re: M2 Z-stop bed leveling contradictions?

Posted: Wed Jul 15, 2015 8:08 am
by Vineto
Great guidance one of the forum member. I am trying to get the print for 3D quilt cover and it making it cut at top....Anyone here to help or guide?