Dc42IR Calibration Problems on Rostock Max V2


  • administrators

    You could also try 8 factor calibration in case there is some bed tilt.

    Is there a particular pattern to the height errors? For example, high spots between pairs of towers?

    Did you run auto calibration a couple of times before doing those 4 runs in report-only mode?



  • @dc42:

    You could also try 8 factor calibration in case there is some bed tilt.

    Is there a particular pattern to the height errors? For example, high spots between pairs of towers?

    Did you run auto calibration a couple of times before doing those 4 runs in report-only mode?

    Ok, so I finally got to doing it remotely today, so I haven't/can't do anything physical to adjust anything until Monday. But I was able to run a 9 factor:
    Calibrated 9 factors using 16 points, deviation before 0.047 after 0.043
    Calibrated 9 factors using 16 points, deviation before 0.043 after 0.043

    Followed by S-1 report:
    Bed probe heights: 0.028 -0.083 0.088 -0.024 -0.042 0.059 -0.005 -0.039 0.061 0.026 -0.002 0.052 -0.036 0.034 0.010 0.003, mean 0.008, deviation from mean 0.044

    9 again:
    Calibrated 9 factors using 16 points, deviation before 0.044 after 0.040
    Calibrated 9 factors using 16 points, deviation before 0.048 after 0.043

    8 factor:
    Calibrated 8 factors using 16 points, deviation before 0.047 after 0.045
    Calibrated 8 factors using 16 points, deviation before 0.047 after 0.044

    And then I started getting "G32
    Error: G-Code buffer '$s' length overflow"

    So that's where I'm at now. Looks a load better than it did!



  • Can you run M665 and M666 to see what the results were?



  • @number40fan:

    Can you run M665 and M666 to see what the results were?

    M665
    Diagonal 311.755, delta radius 145.957, homed height 360.711, bed radius 140.0, X 0.295°, Y -0.288°, Z 0.000°
    M666
    Endstop adjustments X-0.53 Y0.27 Z0.26, tilt X0.17% Y0.23%



  • Increased the rod length quite a bit. I know David (DC42) says not to let it calibrate rod length if you know the exact length, but if it helps with calibration, I can't see why not. Your 9 factor proved that. You can save the results with M500 if you wish and when you get back to the machine, see what happens with a print. When I had massive effector tilt, it had to do with rod spacing. It was a cheap DIY delta that had a 3mm difference between the top and bottom widths of the diagonal arms.



  • @number40fan:

    Increased the rod length quite a bit. I know David (DC42) says not to let it calibrate rod length if you know the exact length, but if it helps with calibration, I can't see why not. Your 9 factor proved that. You can save the results with M500 if you wish and when you get back to the machine, see what happens with a print. When I had massive effector tilt, it had to do with rod spacing. It was a cheap DIY delta that had a 3mm difference between the top and bottom widths of the diagonal arms.

    Yup, I haven't measured the rods myself other than a quick guess with a decent ruler as I don't have a jig for proper center to center right now. And everything I read basically said "DON'T DO IT" to using the automatic rod adjustments. So that's the first time I've used the autocal with rod adjustment. Each of the rods came to me with 300.15 written on them and I'd assume that since TR uses a jig for manufacturing them…they might actually be exact. I'm not sure what to believe on that front now.



  • Grumble. It seems calibrating a delta is never complete.
    My effector tilts a little bit too. It sucks but I think the bigger the radius, the worse the tilt on the outter edge. So, smaller radius means no tilt. There is some math out there to calculate the radius based on many angles and variables but no doubt it is a labor of love it seems. My Prusa clone printer is so darn reliable, thank god I got that to use while I toy with my Delta.

    I'd LOVE to see 3 IR probes, one for each tower! I think that is the only way…

    How is your dimensional accuracy?


  • administrators

    You can use a nozzle contact Z probe, such as the one we've just started selling (https://www.duet3d.com/DeltaSmartEffector) or a piezo probe, to avoid the problem of trigger height changes caused by effector tilt. But whatever causes effector tilt causes other geometrical issues too.



  • Thank nozzle z probe is cool. Too bad not for Diamond hotends, which is the source of all my delta problems. 1 color was easy.



  • What kind of effector do you have, Eddie? Is it a printed version?



  • Ah, diamond hotend effectors, I been through about 3 different designs and no less than a total of 20 printed effectors.
    I come to think it is not the effectors but the silly want the diamond hotend is mounted to the effectors which is by zipties. Granted they are tight but whose to say it is perfectly level after pulling on the ties one at a time … Such a pain to assemble a diamond hotend on a delta effector and getting a good seal.

    Maybe I should change to a metal effector, I see them on ebay, like this - http://www.ebay.com/itm/272746591437

    The China diamoned hotend nozzles are about 2x the size of the official one, not sure how that would work out.

    It seems to be good enough for now, just need to dial things in to the .. microns.. Zip ties and microns just doesnt seem right, like duct tape and precision. 😛



  • Blah, that eBay listing shows zip ties too

    I am using this effector -
    https://www.thingiverse.com/thing:854622



  • @Eddiie:

    Grumble. It seems calibrating a delta is never complete.
    My effector tilts a little bit too. It sucks but I think the bigger the radius, the worse the tilt on the outter edge. So, smaller radius means no tilt. There is some math out there to calculate the radius based on many angles and variables but no doubt it is a labor of love it seems. My Prusa clone printer is so darn reliable, thank god I got that to use while I toy with my Delta.

    I'd LOVE to see 3 IR probes, one for each tower! I think that is the only way…

    How is your dimensional accuracy?

    Ha no kidding. One of my Rostocks at home is still in the same pile of parts it was almost 2 years ago because I basically gave up on it. I was never able to reliably print anything larger than 100mm circle. And even that was not great. Anything under that and it was flawless beautiful prints. Also note that a Rostock was my very first 3D printer….over four years ago!

    Dimensional accuracy on the machine in question is undetermined...I haven't even been able to get a solid print out of it since I started this maddening upgrade process last month. Tomorrow when I get back to the office I can load up filament and test with the results I was able to get yesterday operating it remotely.



  • @dc42:

    You can use a nozzle contact Z probe, such as the one we've just started selling (https://www.duet3d.com/DeltaSmartEffector) or a piezo probe, to avoid the problem of trigger height changes caused by effector tilt. But whatever causes effector tilt causes other geometrical issues too.

    I'm frankly not sure I'm willing to spend MORE money on the same machine. Every time there's a new fangled thing that is supposed to make it better and awesome all I ever get is a headache and marginal improvement if any. $500+ extra into it and I'm still no better off than the original machine with manual calibration mixed with some formula and guesswork. If the readings I've posted above are finally right and I can get some prints I will be truly amazed!

    What say you about the automatic arm length calculations here? Everywhere I read that I shouldn't, but that 8 and 9 factor FINALLY shows decent results.



  • This morning I run G32 and here's the results, bed @60C, nozzle@ 200C :
    Calibrated 8 factors using 16 points, deviation before 0.089 after 0.043
    Calibrated 8 factors using 16 points, deviation before 0.047 after 0.043
    Calibrated 8 factors using 16 points, deviation before 0.048 after 0.039

    So I'm thinking that's looking pretty good now. I fire off an XYZ calibration cube print and it looks terrible!
    First layer is still doing exactly the same thing I've been seeing for weeks now. Toward the right side of the machine (between Z and Y tower and around to the front) the first layer prints SUPER thin, just measured 0.07 and the left side between X and Z towers is 0.19 or 0.17 depending on how far forward or aft it is measured.

    The 'cube' is supposed to be 40x40x20 and I'm measuring ~39.16x39.14x19.91.

    This is still with NO H offsets in the bed.g. Just the 8 factor calibration



  • Did you save the results before printing?

    After running auto calibration and before doing anything else, run the bed mesh compensation and see what your bed map looks like.

    Don't forget that you can calibrate the steps of each motor too. Find an accurate way to measure the movement of the X, Y and Z carriages. Command 100mm movement and measure actual movement.



  • Any progress today?



  • @number40fan:

    Did you save the results before printing?

    After running auto calibration and before doing anything else, run the bed mesh compensation and see what your bed map looks like.

    Don't forget that you can calibrate the steps of each motor too. Find an accurate way to measure the movement of the X, Y and Z carriages. Command 100mm movement and measure actual movement.

    I'm going to post pictures in a bit if I can get a chance. I haven't done any mesh compensation yet, I'll look at that tomorrow I guess.

    I'm not horribly concerned about the steps/mm thing. Those measurements are pretty darn close and could just be shrinkage of materials. I won't worry about perfect dimensions until I get the rest sorted out. Simply being able to print a good looking object is the primary concern right now. So far everything I've printed looks horrid with wavy walls and banding.

    @number40fan:

    Any progress today?

    Sort of …it's printing. Which is better than it was before. Sadly I've now also experienced some interesting heat creep type problems which I never had before...so I'm trying to understand what changed that as the only hot end related changes were to a PT100 and the all brass heat block, which I'd have thought would reduce such type of problems.



  • Here's images of the 40x40x2 block. And a 75mm diameter 0.2mm high calibration disk.
    http://imgur.com/a/1iV34



  • There you are….took me a bit to find this thread again. Do you have a way to measure the width of the diagonal arms near the carriages and at the effector? Reading above, someone in the "shop" has a large caliper. Might have them check the uprights/tower spacing, if you could. Place a flat bar on the inside from tower X to Z and measure how far away Y is. Do this for all three towers at the bottom, middle and top. There has to be something seriously wrong to have your calibration disk to come out like that.

    One last thing, can you post a picture of how you have your Z-probe mounted?


Log in to reply