How to fine tune a Rostock Max V2?

[PannDemic]

So I have been scouring the internet, and not been very successful.
I have looked at OpenDACT but can't get it to run on my Windows 10, and the manual html page just screws things up more.
Anyone know of a good manual for what each setting in the firmware does to correct a misalignment?

I am at my wits end in an effort to dial this thing in.

Thanks

[bob64]

So... what's not aligned? Describe the problem more?

[PannDemic]

So I have the Center(x0, y0)=0.00mm, X-tower(x-110, y-62)=0.00mm, Y-tower(x110, y-62)=0.00mm, Z-Tower(x0,y127)=0.00mm

But I can not figure out how to make a meaningful adjustment to the opposite towers
X-Opp(x110,y62)=-0.19mm, Y-Opp(x-110, y62)=0.11mm, Z-Opp(x0, y-127)=-0.28mm

I know that the other settings can adjust those values, but I am not clear as to how.

[bob64]

Check and make sure your glass/onyx/heated bed insulator/top base melamine plate is flat with a straightedge first.

[PannDemic]

I checked that across all 3 axis, no gaps that I could see.

[nebbian]

Your frame is probably not square.

You can either square it up with a set square, wire, calipers, and a lot of patience, or you can use this calculator to adjust your parameters:

http://escher3d.com/pages/wizards/wizarddelta.php

[Eric LB]

I have EXACTLY the same Opp tower z height problem as PannDemic, right down to the numbers, and probe locations. Couldn't be any closer! My bed (borosilicate glass) is flat as can be, towers are square, parallel, and equidistant to the limit of my measuring abilities. One of my towers is 1 mm taller than the other two,but this is compensated for by stop screw adjustment and tech support said this would not affect calibration. If it is the problem, it would be a real job to dissemble the whole printer to correct. So I am predicting that I will need to use the least squares calculator to adjust my firmware. Perhaps this is a firmware issue present in all or the majority of Rv2 firmware as there is at least one thread on the forum in which multiple Rv2 owners report the identical Opp tower problem???

But I think I will need coaching. Is Delta radius the same thing as horizontal radius? Do I use the 6 factor option? I will have no problems with selecting the probe sites ,( although I don't have a dial indicator, I feel very comfortable and very accurate using automotive feeler guages). I need help with the terminology of the entry fields in the calculator - as applied to the stock Rostock firmware. Is it a matter of taking the probe measurements, running the calculator ( plugging in current EEPROM numbers and probe measurements into the calculator), then updating EEPROM settings to the new calculated values????

Have you had success PannDemic?

[Eric LB]

In another thread (Does your Rostock Max v2 hold its calibration?) Nebbian advised that the "high between towers" issue is caused by either wrong steps/mm or more likely twist in the towers. Of significance is that Nebbian is speaking from experience with two builds. I am going to attempt to check for twist, given its likelyhood due to the melamine construction (which I have grown to really dislike due to its softness and deformability). If this doesn't work, I wonder if the calculator will.

[Eric LB]

Nebbian, I didn't realize it was you above? How did you use wire in getting your twist out? If I do have to resort to the calculator, what values in my EEPROM correspond to " initial tower angular position corrections"? Is "endstop offset (steps)" in my EEPROM the same as "endstop corrections"?

[Eric LB]

Okay so I checked tower squareness to the bed glass and ran diagonal measurements between adjacent towers and sited down the printer faces from the top - and things are parallel and there appears to be no twist ( at least, if it does exist, it is below the level of observing it by any means I can think of).

And I still have the "high between towers problem and by the same amount as I did before checking all this: .25 mm, .33mm, and .48mm. I really doubt this is a tower angle problem or a steps/ mm problem. What next? The calculator? I really don't want to introduce a tower twist just to see what would happen. I have asked tech support, still waiting on an answer.

[Eric LB]

I laid a straight edge across the bed between towers ( so across the area that would dip if the bed was at fault) and probed with a piece of paper : my bed is flat on all three sides, no dips.

[nebbian]

I don't have a Rostock printer, both of mine are of the Kossel design, so I'm not sure how exactly to solve it in your case, but here goes.

Twist is difficult to see. You won't notice it just by looking. A small amount of twist will result in those raised areas between towers. You need to use a very large set square and measure each tower carefully in 3 places. Each measurement is done by putting one leg of the set square against the tower, and resting the other leg against the horizontal frame.

The three measurements are as follows:
1) Bottom leg pointing across the build plate
2) Bottom leg pointing at the opposite tower on the left
3) Bottom leg pointing at the opposite tower on the right

Measurement 1 is used to ensure that the top triangle is perfectly above the bottom one (so it's not 'leaning' to one side or the other).
Measurements 2 and 3 are used to stop twist.

You won't be able to notice twist without doing measurements 2 and 3. You need a square that is at least 30 cm long on each arm.

OK so once you can see your twist, how do you go about removing it?
The only reliable way I've found is to use wire and turnbuckles, and strategically tighten and loosen the appropriate turnbuckles, which pulls the frame into line. A picture of an early solution is attached.

Since then I've moved the turnbuckles to the top of the frame, which means less chance of the effector fouling on the turnbuckles. Your printer will probably be different to mine.

[nebbian]

I should also mention, it's well worth taking the time to ensure that all your towers are parallel to within 0.05mm. You can use a set of digital calipers to measure this. You need to measure the distance between the towers, at both the bottom and top.

[Eric LB]

Thanks for the photo and explanation. I did do the square in three directions for each tower using a 16" square: no twist. Need to get digital calipers to read tower distances. Think I'll use a metal bar plus inside caliper to get the distances, comparison not absolute numbers being of interest. If it turns out that all my towers lean outward equally and only slightly (a suspicion I have though not proven,) is there a mathematical adjustment to firmware, or is it going to turn into a an issue with Seemecnc tech support?

Steps per mm are 80 which is the standard default for all Rostock Max v2s

[Eric LB]

Okay, I measured my tower separations. And my suspicions (that occurred when I noted near but not exactly perfect results with the square) have turned out to be true. My towers are not parallel. I purchased it for the advertised build area, but it looks like I erred.

x to Y tower distances were equal top and bottom and were used as reference standard for the other measurements. Y z and z x base measurements were each less than the reference by .56mm, the Y z and z x top measurements each exceeded the reference by .1 mm. So by definition my towers are not parallel and slightly out of perpendicular (x and Y are the towers not perpendicular to the base if my square is to be believed).

The unfortunate thing is that this geometry is determined by the cnc laser cut melamine top and bottom plates and is NOT adjustable in any way. The towers are a very tight fit in the melamine slots. Seemecnc would say by design, but they put too much trust in their laser cutting files/ cnc machine. FWIW I have come to detest melamine as I observe it's tendencies to crush deform. It is a very weak material which is dimensionally stable but WEAK. I myself have owned and used a cnc routing machine for ten years now, and I am 100% sure this is a cnc/laser cutting problem. Furthermore there are multiple other Rostock owners with the same "high between the towers" problem, judging by posts I have read on the forum.

[Eric LB]

My bad. What I should have done all along was call Matter Hackers support. The procedure is this: first calibrate with the end stop screws; second, put crazy glue on the end stop screws,; in Matter Control go options, calibration and follow the prompts for the 13 pointnbed probing procedure. Matter Control will then tell your firmware how to fly your nozzle in a flat plane - straight over the Opp tower positions. The tower spacing deviations, twist etc, are all within accepted limits for lazer cnc machining (I of all people being a cnc guy should have known this!).