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metric too many decimal places

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2017-03-25
2017-04-24
  • snarkhunter

    snarkhunter - 2017-03-25

    I'm a bit new to PyCAM and excited be how well it works in english. Metric is giving me a problem. PyCAM seems to post dimensions to four places after the decimal (X.XXXX) in english and metric. My Haas mill exepts four decimal places in english, but only three decimal places in metric. Is there a setting to controll the number of decimal places, if so where? If there is no setting for this, can you advise an other technique. Right now I convert to english but prefer metric. Thank you.

     
  • Lars

    Lars - 2017-03-25

    Thank your for your detailed explanation.
    But I am still not sure, if I understand your specific problem :)
    Thus: which specific change do you have in mind?

     
  • snarkhunter

    snarkhunter - 2017-03-25

    In G21 metric PyCAM will post all positions to the fourth decimal place (ex. X34.6823 Y102.3358). The Haas machine I run,  when in G21 metric needs a three  place resalution to recognize the number as valid (ex. X34.682 Y102.336). In G20 english the mill recognizes a four place decimal as a valid number. How can I change the resolution of the numbers that PyCAM posts?

     
  • Lars

    Lars - 2017-03-26

    Ah - ok. What a tricky machine!
    I would recommend to file a bug report to its vendor.

    In pycam you can try to reduce the "Step Precision" in the GCode settings. It defaults to 0.0001. If you reduce it to 0.001, then all values should be formatted with only three digits.

     
  • snarkhunter

    snarkhunter - 2017-03-26

    That was exactly what I was looking for. Thank you very much.

     
  • snarkhunter

    snarkhunter - 2017-04-24

    I recently loaded PyCAM 0.6-svn. I am unable to find this setting in the new PyCAM.

     
  • Lars

    Lars - 2017-04-25

    This version name sounds weird.
    Please try one of the latest releases: https://github.com/SebKuzminsky/pycam/releases

     
  • snarkhunter

    snarkhunter - 2017-04-26

    Again, I Thank You. The virsion of pycam I was using was from https://github.com/SebKuzminsky/pycam/releases ; pycam_0.6_all.deb released by SebKuzminsky Feb 18. I found the name PyCAM 0.6-svn from the 'Help/About'. I used this because it appeared to be the latest debain package. I installed pycam_0.5.1-1_all.deb relased by njh, and all works well for me. I don't know if any of the other pycam-6 have the Step Precision feature because my limited package managment skills are unable to make any of them run. I hope they do or will have this feature. Thank you and all PyCAM developers.

     
  • ammar tello

    ammar tello - 2017-08-13

    Hello everyone :)
    I also have a problem with the minimum step width. I have set it to 0.002 for all axes but when I export the G-code file I have got the following lines:
    X78.099 Z0.006

    X78.097 Z0.005

    X78.095 Z0.004

    So, as you see, the Z axes difference between the first and second step is only 0.001 and also for second and third, and this precision has been not acceptable by my motors, so, is there any suggestion here please?
    Thanks in advance :)

     
  • Lars

    Lars - 2017-08-13

    Hi,

    the current StepWidth logic within pycam is defined as follows (see pycam/Toolpath/Filters.py: line 476):

    • calculate the distances between every two successive locations (for all three axes)
    • if all three distances (x, y, z) are smaller than their defined StepWidth (here: 0.002), then this location is skipped

    For your example it means, that probably some points in between were already skipped, but somewhen the x stepping exceeded the limit - thus the point was recorded.

    I do not have a machine that exhibits this specific physical limitation.
    Thus: could you please try to specify (in detail) a logic that the StepWidth code should follow (instead of the above)?

    Or (maybe even better): shouldn't there be a setting in your controller software (e.g. linuxcnc), that handles this machine limitation?
    (I think, this would be the proper approach for that problem)

    Cheers,
    Lars

     
  • ammar tello

    ammar tello - 2017-08-14

    Thanks for fast rsponse :D
    I want the StepWidth to see if there is a distance in any axes (x,y,z) smaller than (0.002) and skip it, so, in my situation I want the G-code to be like the following:
    X78.099 Z0.006
    X78.097
    X78.095 Z0.004
    I have a servo motors driven by a PLC, and there minimum width is only (0.002) so, its impossible to get a more accurate step

     
  • Lars

    Lars - 2017-08-15

    Ah - ok.
    We should just skip the "below step width" axis (and keep the other axes of the location). This sounds reasonable - I will take a look at that.

     

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