PROBES!!! What is going on?????


  • administrators

    @my67nova:

    As for other stupid things, if my bed is more than 120mm from Y home and I try to home it it does not go back all the way to the switch and then reads -247 on the screen and tries to home the other direction and crashes

    That suggests that your homey.g and/or the Y section of your homeall.g file doesn't specify enough movement in the G1 S1 Yxx command.



  • Just found that the homing files needed to be edited. How about the slow speed issues? From above;

    Now at slow speeds <40mm/sec my steppers sound like a machine gun and curves have artifact squigglies. Belts are tight and there is no binding or sticking. Chrome plated linear rods hand polished with Igus bearings. .09 Sanyo Denki steppers with inertial vibration dampers. Does interpolation work when set to 32? From what I saw it does not. If not can I turn it on, I thought I did…..(turn it on)



  • Not seeing 32 as a valid micro stepping mode. https://duet3d.com/wiki/G-code#M350:_Set_microstepping_mode

    Also, the Wiki states this "Note: microstep interpolation is available on the TMC2660 drivers used on the Duet WiFi and Duet Ethernet, but only when microstepping is set to 16. In other configurations, specifying I1 has no effect."

    Edit. Also 322 steps per mm in your M92? That seems a very strange number because it's not divisible by much other than 2.



  • So is that the problem? I have .9 steppers and assumed that 32 was the correct setting for these. According to the data sheet as far as I understand they do handle 32 microstepping. The 322 is what I needed to get them to print exactly a 100mm line. Did I do that incorrectly? Did I do everything wrong???



  • It doesn't sound like you did anything wrong really except learn stuff about 3d printing. By seeing what works and what doesn't. Probing is a minefield. If you have a solid corexy or cartesian it isn't really necessary as you can manually level your (flat) bed and you're there. For deltas it just saves you a lot of time.

    I'm biased as I now sell piezo hotend probes which do work, but a plain old microswitch is very accurate, it's deploying it by servo or whatever that makes its accuracy between probings less than a fixed probe (providing you're talking about an accurate fixed probe).

    Use the steps per mm that works for you. Some filament is easier to grip and feeds more for any given number of steps than others.



  • What is the accuracy of the piezo probe? Pics?



  • www.precisionpiezo.co.uk

    Standard deviation in testing was 0.007mm so I claim accurate to 0.01mm +/-0.007.



  • @DjDemonD:

    …........................
    Use the steps per mm that works for you. Some filament is easier to grip and feeds more for any given number of steps than others.

    Simon,

    I agree that's OK for extruders because as you say, filament can vary. But for X and Y axes? Surely not.



  • @my67nova:

    So is that the problem? I have .9 steppers and assumed that 32 was the correct setting for these. According to the data sheet as far as I understand they do handle 32 microstepping. The 322 is what I needed to get them to print exactly a 100mm line. Did I do that incorrectly? Did I do everything wrong???

    The motors might well handle 32x microstepping, but according to the wiki, the Duet stepper drivers don't support it. The modes are 1,2,4,8,16,64,128 and 256. Because you have 0.9 degree steppers, you have 400 steps per revolution whereas the "normal" 1.8 degree steppers have 200 steps per revolution. If you set Duet to 16X, each microstep will be 1/16th of 400 and will be the equivalent of setting 32x on a 1.8 degree, 200 step per revolution stepper. So I revolution at 16X microstepping will require (400 x 16 = 6400 microsteps).

    The easiest way to set the steps per unit (IMO) is to use M92 to set them at the default 16X, then if you want to change micro stepping, use M350 after the M92 and the steps will be recalculated. Then you can play around changing the micro stepping using M350 and not have to worry about re-calculating anything.


  • administrators

    The drivers do support x32 microstepping. I've just corrected the description of M350 on the GCodes wiki page.



  • Whew! How about interpolation? It appears the chip does.


  • administrators

    Interpolation from x16 to x256 is supported by the drivers.



  • How do I enable x256?



  • Do your stepper still sound like a machine gun? That's what got me thinking that maybe you were using an unsupported micro-stepping mode. It appears that is not the case so just wondering if you still have the "machine gun" sound problem.



  • Turns out I had 2 torn belts! Stupid Chinese washers with sharp edges.



  • Actually I take some of that back! It still seems like it is taking extremely course steps, so much so that the table and build plate are vibrating. If you look close the build plate you can see it. The belts and fasteners are tight yet it is cogging badly at slow speeds. Is there a way to access the stepper drivers directly to tune them? I will try to post a video in a bit.

    You can see when it starts to resonate.

    Her are a couple videos;

    https://youtu.be/pn6OguBRFQQ

    https://youtu.be/2D5_UHoHaOE


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