Adjusting Tower Rotation with Alpha A/B/C in EEPROM?

[cassetti]

Hi Everyone,

Still trying unsuccessfully to get my Rostock MAX calibrated so I can use it to it's fullest extent. I'm still having issues with getting the bed fully level. I have adjusted the endstops countless times, and have finally calibrated the printer_radius setting to adjust for the slight concave motion on the bed. Now I'm having an issue in which my print head raises 1+mm away from the bed on the left side of the Z rail, and to the right of the Z rail closer to the Y rail, the print head jams into the bed

Per 626Pilot's suggestion I have read this post over and over http://forum.seemecnc.com/viewtopic.php ... =20#p23853" onclick="window.open(this.href);return false;

But I'm confused on this part:

If you find that the carriage lifts or dips close to one tower and does the opposite next to one of its neighbors, it's probably the rotation on the remaining tower. Look for Alpha A, B, and C in the EEPROM. You will see the values 210, 330, and 90. Reducing a number rotates the tower clockwise and increasing it rotates the tower counter-clockwise. You should only need to change the rotation by 1/2 to one degree. This is where you have to think of terms of pushing and pulling. On my printer, it was lifting near the X tower and dipping near Z. Y was OK, so I assumed it was the culprit. Changing Y's rotation from 330 to 331 fixed the problem, because that gave Repetier a better idea of where it was starting from. It then knew to move the Y tower a little faster when going towards X, and a little slower going towards Z.

Forgive me but I'm completely stumped as to what he's saying and how to apply it to my situation. I seriously believe I need a very minor tweak to one of these numbers, but which one?? And what letter corresponds to what rail? Is Alpha A the X, Alpha B the Y and Alpha C the Z rail?? So confused, any help would be GREAT!!!

[Eaglezsoar]

Perhaps you should send 626pilot a pm, he may not read your message unless you point him to it.

[626Pilot]

I got confused about my inbox, it said I had a message but I thought I'd already read it so it's been bugging me for awhile. Better to work it out here anyway so more people can get eyes on it.

Can you reupload the attachments to this thread? I tried copy/pasting the attachment code but it didn't work.

[626Pilot]

I dug up some notes I took while I was adjusting the tower rotations. This may help you to figure out my thought process. It's pretty in-depth. The idea is to examine not only the towers, but the arc BETWEEN the towers, because problems often manifest right there.

• For each iteration, I printed out this Onyx bed leveling aid to see where the lines were too fat or too thin: http://www.thingiverse.com/thing:50505" onclick="window.open(this.href);return false;
• The object was printed without adhesive each time. I wanted the bed totally clean.
• You will notice some tower re-leveling. Ideally this should be done each time you think you're done with a tower, and then you should confirm it with another test print. If only Repetier's Z probe logic wasn't horribly broken
• There is an option for radius delta in the firmware, one for each tower. Leave these at 0 unless you want your parts to climb to one side like a 1980s surfer hairdo. I wasn't able to fix anything at all by adjusting these settings.

Code: Select all

Legend
---------------
 High: ^
Level: =
  Low: v

Example: "X to Y: = ^ ="
Meaning: "Level around X tower, then high between X and Y, then level around Y tower."


Problems
---------------
- Lifts between X and Y towers
- Dips between Y and Z towers
- Lifts between Z and X towers

Base calibration - towers centered, towers at stock angles and radius deltas.

	     X: =
	     Y: =
	     Z: =
	X to Y: = ^ =
	Y to Z: = v =
	Z to X: = ^ =


Focusing on fixing Y-Z arc first, Z-X arc less significant but will watch.

---------------
Changing Y rotation from 330 to 330.5:

	     X: _
	     Y: =
	     Z: ^
	X to Y: = ^ =
	Y to Z: = v ^
	Z to X: ^ v

Looks like the X and Z towers need to be releveled - did that.


---------------
Testing again:

	     X: =
	     Y: =
	     Z: =
	X to Y: =
	Y to Z: = v =
	Z to X: = ^ =

Y-Z and Z-X (both of which are next to Z) are off. However, X to Y (opposite Z) is fine. Therefore, the Z tower probably needs some adjustment.


---------------
Changing Z rotation from 90 to 89.5:

	     X: =
	     Y: =
	     Z: =
	X to Y: =
	Y to Z: =
	Z to X: = ^ = (better than last time though)


---------------
Let's try releveling the towers and changing Z from 89.5 to 89.25: (note: this was lazy... don't change two variables at once)

	     X: =
	     Y: =
	     Z: =
	X to Y: = ^ =
	Y to Z: = ^ =
	Z to X: =

---------------
That made Z-X better at the expense of X-Y and Y-Z, so let's backtrack and try going the other direction to 89.6:

	     X: =
	     Y: =
	     Z: =
	X to Y: = ^ =
	Y to Z: =
	Z to X: = ^ =
	
This produces the least vertical deflection of anything tried so far and is "Good Enough."
In other words, close enough to stick and far enough not to block the nozzle.

[cassetti]

Thank you!!

I'll try to dig into this when I have time over the next week and see if I can try to resolve my issue.

[626Pilot]

Thank you!!

I'll try to dig into this when I have time over the next week and see if I can try to resolve my issue.

Please post your results here. Collaboration will make this problem go away faster for everyone involved.

[jmpreuss]

I am having an issue calibrating my max.

Here is what I have at the moment


X: =
Y: =
Z: =
X to Y: = ^^ =
Y to Z: = ^^ =
Z to X: = ^^ =

So things are fine at the towers and the center but all 3 in betweens are high, by a fair amount (plastic barely touches).
It seems that if I adjust all 3 tower rotations it would cancel out. Anyone have a clue what the issue might be and how to address it?

[626Pilot]

So things are fine at the towers and the center but all 3 in betweens are high, by a fair amount (plastic barely touches).
It seems that if I adjust all 3 tower rotations it would cancel out. Anyone have a clue what the issue might be and how to address it?

Can you print out the Onyx calibration as it is now, then change one of your tower rotations by one degree and try again? Post both before and after images.

[jmpreuss]

Can you print out the Onyx calibration as it is now, then change one of your tower rotations by one degree and try again? Post both before and after images.

This is the before

So it seemed from x to y was the worst so I rotated the x by a - half degree. The result was x to y was improved, z to x bad to worse.
The phone rotated the photo so the bottom in the first photo is the left in this one.

So now z to x and y to z are both way too high and any adjustment I make to the z axis rotation will improve one and make the other even worse, just as the x rotation did to the z to y.
My guess is that there is something else wrong. I have trick laser carbon arms, does anyone with those arms know if that changes some other measurements?

[626Pilot]

I did have to change my delta rod length to get prints to go over a certain height after installing my Trick Laser arms. I don't recall exactly but I think the stock was 269 and I had to change it to 271 or so. The specific phenomenon I see here makes me wonder if you might need to try doing the same thing. I'm not sure what else would cause it to lift exactly opposite all three towers.

Try changing the delta arm length and also try printing out this owl if that doesn't help. I used the owl when I was figuring out the arm length. The print would always fail sooner or later until I got the delta arm length right. Scale it to at least 150mm to give the printer a chance to screw up.

Remember to change only one variable at a time and observe its effects.

[jmpreuss]

I adjusted the arm length and that didn't seem to do much.

I went to check again if my towers were straight and during that process I noticed that my heat plate (unheated) is definitely higher in the center than on the edges, even with a glass build plate on it. I don't know if that is the source of my problem (plausible?) but I'm pretty sure I need to correct that. Any clue how? With the screws on the edge I don't see how to lower the center relative to the edges.

[enggmaug]

Maybe, try to screw it upside down, heat up, and leave it like that some time... before putting it back.

Make sure there is nothing underneath in the process... no dirt, no dust, and no proeminent solder on the plate.

[MSURunner]

I did have to change my delta rod length to get prints to go over a certain height after installing my Trick Laser arms. I don't recall exactly but I think the stock was 269 and I had to change it to 271 or so. The specific phenomenon I see here makes me wonder if you might need to try doing the same thing. I'm not sure what else would cause it to lift exactly opposite all three towers

I was having trouble trying to dial mine in across the entire platform this weekend and came across what I think is the solution. I was having to alter things rather drastically to get results, so I dug out a scale and went about measuring all of the critical components to confirm sizing. My tricklaser arms are very close to the 269 (I have them currently set to 268.5 but I think 269 would still have worked). I did have to adjust the Y tower to 209.5, but the biggest fix thus far was the carriage offset. I believe it's set to 35 mm as a default in the .91 and I am betting older Repetiers. Mine actually averaged out to 37.5 across the three carriages. Because the computer thought the arms were further from center than they were, as they were getting to the extremes across the platform from where the tower is, they were lifting up. Amazing what the one little number did to fix about 3 issues...

[Eaglezsoar]

I did have to change my delta rod length to get prints to go over a certain height after installing my Trick Laser arms. I don't recall exactly but I think the stock was 269 and I had to change it to 271 or so. The specific phenomenon I see here makes me wonder if you might need to try doing the same thing. I'm not sure what else would cause it to lift exactly opposite all three towers

I was having trouble trying to dial mine in across the entire platform this weekend and came across what I think is the solution. I was having to alter things rather drastically to get results, so I dug out a scale and went about measuring all of the critical components to confirm sizing. My tricklaser arms are very close to the 269 (I have them currently set to 268.5 but I think 269 would still have worked). I did have to adjust the Y tower to 209.5, but the biggest fix thus far was the carriage offset. I believe it's set to 35 mm as a default in the .91 and I am betting older Repetiers. Mine actually averaged out to 37.5 across the three carriages. Because the computer thought the arms were further from center than they were, as they were getting to the extremes across the platform from where the tower is, they were lifting up. Amazing what the one little number did to fix about 3 issues...

That was a great catch on your part. With all the possibilities to adjust and you hit on the right one. Amazing.

[lordbinky]

I wanted to note that I change delta rod length to adjust the scaling of my printed parts. So if my 20mm turns out to be 19.89mm. I change my delta rod length by the difference and it clears that up.

Before the latest firmware I would adjust the endstops when trying to get everything perfect, so if a the first layer was slightly higher near a tower and slightly shallow opposite a tower, I'd lower the nozzle height at the base of the tower. This would lift the opposite side of the center point slightly and lower the tower side slightly.

Now that there's software numbers to change this, all that goes out the window and I'm still trying to get a feel for WTF I'm doing when I change the numbers. Sometimes I end up with a blank face just staring at the result of a change, and other times I'm doing an angry hat stomping "Ooooooooooooooooooooo!” that'd make yosemite sam proud.

Glad to see you got your stuff worked out though. I guess I'll double those measurements too now...

[MSURunner]

Okay guys, I think I've got the ticket to making this A LOT easier.

Here's a part I designed to help aid the process of setting the radius calibration. http://www.thingiverse.com/thing:240962 It also labels the axis for those trying to modify the angular measures as well.

[neurascenic]

Print, Leave and place, and apply a gauge?

[MSURunner]

Yes, I used a simple metric scale as the variances going up the tower will likely negate the added precision from a finer tool. Another thing to note is that Horizontal Radius (known as DELTA_RADIUS in the configuration.h) used to be calculated and not entered, but is now in the EEPROM for some reason. So even if you make the corresponding changes to carriage and effector plate distance in the configuration, the horizontal radius will not change until you modify it in the EEPROM, which requires you do the math and enter it yourself.

[geneb]

This is the kind of thing that a short video would REALLY make it crystal clear as to what exactly the user needs to do... hint, hint..

g.

[MSURunner]

This is the kind of thing that a short video would REALLY make it crystal clear as to what exactly the user needs to do... hint, hint..

g.

Haha, I have classes until 3 MST so don't expect anything today because I won't be able to shoot a video until after and a Tech Ed teacher CANNOT put a video up without at least a little basic editing...

[enggmaug]

This is the kind of thing that a short video would REALLY make it crystal clear as to what exactly the user needs to do... hint, hint..

g.

+1

I recently updated to the new firmware, and carefully re squared my printer. I then upgraded to the magnetic arms.

I've been struggling for nearly 10 days to get my printer calibrated, and try to understand repetier's parameters.

Now, I know more about it all, and I better see the impact of delta values radius values, tower rotations etc... however, my printer is still not calibrated.

I'll receive a height comparator soon that looks like this one :
[img]http://img.directindustry.com/images_di ... 081773.jpg[/img]

It's not too expensive (about 20 bucks), and probably will help me to perform calibration.

If I can manage it, I'll write an excell sheet where you can enter measurments you get on specific coordinates, to give you correction to apply to parameters.
I'll surely share it if it does work.

[626Pilot]

If I can manage it, I'll write an excell sheet where you can enter measurments you get on specific coordinates, to give you correction to apply to parameters.
I'll surely share it if it does work.

That would be delightful!

[MSURunner]

Okay, I think I have a good calibration sequence, but I don't have time tonight to shoot the video for it. I'll try to get it shot tomorrow morning and quickly edit it so you guys can test it and if it works for you guys as well, then I'll final touch it!

[626Pilot]

Cool. I don't understand the instructions on Thingiverse.

[Eaglezsoar]

Cool. I don't understand the instructions on Thingiverse.

I second that. I need it explained differently I am plainly confused on how to use that part.