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pain in my ox

Discussion in 'CNC Mills/Routers' started by dcarlisle, Mar 21, 2015.

  1. dcarlisle

    dcarlisle Well-Known
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    dcarlisle published a new build:

    Read more about this build...
     
  2. dcarlisle

    dcarlisle Well-Known
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    ok so I am totally new to cnc everything went together easily as for the machine the software is driving me nuts
    I really need some help
    I have toasted one xpro board already lesson learned always unplug it :banghead:
    so now for some of my setup
    i'm using windows 8 using grbl 3.6.1 for controller and xpro version 0.9 for my board
    after many settting changes to grbl I froze machine and it wouldn't work at all after 2 days of reading finally found setting to make it work I have attatched pic of my settings
    the machine know moves but the distance it moves is way off x and y the z seems fine
    so when I change 100 to 53.333 the steppers chatter as they move
    I have tried changing the current it does not help and they are still nowhere close to being accurate
    I have
    steppers open build nema 23
    gt3 belts
    and 20 tooth pully on machine
    I have the jumpers set to 16
    I have changed jumpers around and tried everything I have read I was up till 2 am last night trying to get this thing to work this has been going on for a week now
    I know that it is something in the settings I am just not smart enough to figure it out :mad:
    with the current setting below the z axis is dead on but the x and y are way of I'm just not sure how to change them
     

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  3. Serge E.

    Serge E. Master
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    No panic, there is a bit of math involved to get the initial steps/mm 'right' followed by possibly some tweaking - measure longest travel to get as precise as possible for your machine.

    Looks like you are using the values found in https://github.com/grbl/grbl/wiki/Configuring-Grbl-v0.9 which, at least for the X, Y and Z steps/mm not always right for any given machine since these values depend on the hardware being used (belt, pulley, acme screw, micro step, ...) Typically, Z will be different from X and Y since it uses a screw instead of the belt. X and Y would be equal - same belt, pulley and stepper.

    One of the calculators to figure out the 'right' numbers can be found at :

    But there is a very good one in the resources section here :

    I'll have to look up my settings, which are for GT3 and 20 tooth pinion (pulley), but 1/8 microsteps. It would be just doubling these for your 1/16 microstep configuration.
     
  4. dcarlisle

    dcarlisle Well-Known
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    Thanks serge i have tried the one for the shopko i gkt the numbers but couldnt get it to work with those either
    ill try the calculator from open builds
     
  5. dcarlisle

    dcarlisle Well-Known
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    Ok still trying
    went to http://homepage.ntlworld.com/r.j.noble/ShapeOko/grblcalc/
    put in

    x/y belt pitch =0.08
    x/y motor Steps /rev =20
    x/y pulley teeth =20
    x/y microsteps = 8 microsteps

    and got
    x/y steps per mm 39.3700787401575
    x/y max steps 721.784776902887
    x/y max steps 1385.454545455

    so for line 100 I put in 39.370
    and for line 110 put in 721.784
    move x and it moves but it chatters almost sound like a woodpecker
    I have changed my jumpers to 1/8th
    so im still back at settings from grbl
    when I move the machine 10mm it goes 117.475 or 4 and 5/8 inches
    with jumpers on 1/8th it moves a lot smoother than on 1/16

    still unsure what to do my wife says it looks neat and keeps asking if I can cut anything yet :rolleyes:
    i'm still trying one day I might get it
    I got the x axsis to move the right amount but the steppers or chattering really bad and moves really slow
     
  6. Serge E.

    Serge E. Master
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    I have gone through the same thing, especially with the wife. :oops: I need to get myOX in gear and stop playing with SketchUp now that temperature in garage is warmer.

    It sounds like you need to adjust the max feed rate ($110 for X and $111 for Y) - how fast it moves while "cutting", and the acceleration ($120 and $121) - how fast it ramps up and down. At least for fixing the 'slow' aspect ... I had similar problems until someone told me to boost those numbers.

    The actual feed rate will depend on what you are cutting into and how agressive you can or want to be in that material (depth of cut, tool, etc.) Depending on the program used to generate the G-code, you might get help in figuring those. Otherwise, it will be to look through charts, ask around and/or calculate.

    I'll have to look up my settings to try and be of more help.

    If you have X moving the right amount, use the same setting for your Y (presuming you are using same model of stepper motor, the same pinion & belt configuration).

    Then, for precision, measure actual travel with near maximum width and length. You might need to do some minor tweaking.
     
  7. Michael

    Michael Veteran
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    Hi dcarlisle - was just checking out the new builds and stumbled across your post - Nice looking build.
    The xpro ships with default setting which are intentionally low - helps avoid really horrible crashes when things aren't right early on. Below are the settings we use on our OX derivative - if your kit is all OB parts (primarily pulleys and belts and standard 1/8th usteps) these should work pretty well for you. Also - don't use the mass settings changer in GRBL Controller - it writes setting to the wrong place (at least it had been, haven't checked this in about a month). Just be aware that these are rather rapid settings - probably should be ready to cut power until you get comfortable ;). If you need anything else you can always email us at support@spark-concepts.com.

    $0=10 (step pulse, usec)
    $1=255 (step idle delay, msec) This will hold the motors while not moving
    $2=0 (step port invert mask:00000000)
    $3=6 (dir port invert mask:00000110) Check this for your system
    $4=0 (step enable invert, bool)
    $5=0 (limit pins invert, bool)
    $6=0 (probe pin invert, bool)
    $10=3 (status report mask:00000011)
    $11=0.020 (junction deviation, mm)
    $12=0.002 (arc tolerance, mm)
    $13=0 (report inches, bool)
    $14=1 (auto start, bool)
    $20=0 (soft limits, bool)
    $21=1 (hard limits, bool) Change to 0 (zero) if you do not have limit switches/homing switches
    $22=1 (homing cycle, bool) Change to 0 (zero) if you do not have limit switches/homing switches
    $23=3 (homing dir invert mask:00000011)
    $24=50.000 (homing feed, mm/min)
    $25=1200.000 (homing seek, mm/min)
    $26=250 (homing debounce, msec)
    $27=3.000 (homing pull-off, mm)
    $100=26.670 (x, step/mm)
    $101=26.670 (y, step/mm)
    $102=200.000 (z, step/mm)
    $110=7500.000 (x max rate, mm/min)
    $111=7500.000 (y max rate, mm/min)
    $112=1500.000 (z max rate, mm/min)
    $120=100.000 (x accel, mm/sec^2)
    $121=100.000 (y accel, mm/sec^2)
    $122=100.000 (z accel, mm/sec^2)
    $130=510.000 (x max travel, mm) Check these travels for your setup (dont think they work without homing)
    $131=770.000 (y max travel, mm) Check these travels for your setup (dont think they work without homing)
    $132=170.000 (z max travel, mm) Check these travels for your setup (dont think they work without homing)
     
    GrayUK, Serge E. and sgspenceley like this.
  8. dcarlisle

    dcarlisle Well-Known
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    Thanks Michael,
    Well tried your settings and did not work do well
    its a stock op ox with g3 belts and 20 tooth pulleys
    as for mass setting changer is that the box you pull up I have been typing in the command
    such as $100=26.67 in command line
    as for when I put the above settings in the machine moves then the x and y steppers start clicking on and of I tried to take video but it to large to send
    as for this computer stuff im totally lost I know enough to get into trouble
    i'll be sending you a pm also
    thanks for all the help
     
  9. Serge E.

    Serge E. Master
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    What commands (g-code) are you sending to test ? Knowing this might help us help you better ...

    Maybe give us a fresh dump (picture) of your settings as well given you have tried many things since the last dump/picture.

    If the computer used for connecting to your controller has Internet, someone could do a TeamViewer (or similar) remote session, seeing at least the computer side of things, to help you. Not certain I would be the best person at this time to connect, not having version .9 installed (parameters are numbered differently), but I could always give it a try as there is not that big of a difference ... would have to be after 5 PM or during the weekend, if it's me.

    A Google HangOut, if your computer has a webcam, could also give the person an easy peak and listen to your machine.
     
  10. Serge E.

    Serge E. Master
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    Just remembered you bought as a complete kit from "smw3d".

    Have you contacted them for support ??

    Since it's their kit, they should be able to put you on the right track quickly with an email or two, especially if it is just a question of values for the GRBL parameters. They probably have a 'cheat sheet' for the kit you bought (?) Anything in the documentation that came with the kit ?

    Just checked their web site - the controller is left out of the kit. But they should be able to help out ... they are a V-slot dealer, so a presence should be here (I forget who it is).
     
  11. Jonny Norris

    Jonny Norris Veteran
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    Sounds like motor tuning and acceleration problem.
     
  12. Paruk

    Paruk Master
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    With a G3 belt/pitch 3mm and 20 teeth pulley you can calculate that 1 full rev will give a move of 20 x 3 =60mm. Your stepper does 200 steps (200 x 1.8 degree) for a full rev, meaning if your driver is set 1/1 each step will give a move of 0.3mm (60mm/200=0.3). If you have a setting of 1/16 micro stepping 1 full rev needs 3200 steps (200 x 16 =3200). In that case each step will give you a move of 0.01875mm (60mm/3200=0.01875). So, to have your machine moved 1mm you need to make 53.3333333333333 steps (53.33333 x 0.01875=0.9999999375).

    You'll have to make sure that your drivers are set to 1/16 if you use that value in your software setup. If your driver is set to 1/8 (for example) but your software works with the 1/16 value (=53.33333) it tells the driver to move 53.33333 steps for a mm but when the driver moves the motor 53.33333 steps you'll get a travel distance of 2mm (200x8=1600 steps/rev, 60mm/1600=0.0375/step, 1mm/0.0375=26.66 steps/mm).

    So assuming that you've set your driver correctly to 1/16 micro stepping for the X/Y axis, having a G3 belt and 20 teeth pulley, the values for $100 and $101 must be 53.33333. Use as many decimals as allowed by the software to get maximum accuracy. For $102 you should use 200 if you use the ACME screw of OB.

    So with the mentioned hardware you get:

    1/1 driver setting = 3.33333 steps/mm
    1/2 driver setting = 6.66666 steps/mm
    1/4 driver setting = 13.33333 steps/mm
    1/8 driver setting = 26.66666 steps/mm
    1/16 driver setting = 53.33333 steps/mm
    1/32 driver setting = 106.66666 steps/mm

    etc.

    I might be wrong, but this is what my calculation gives me.
     
  13. dcarlisle

    dcarlisle Well-Known
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    Serge thanks for all the info and help
    this first video is of the original setting from grbl 3.6.1 https://github.com/grbl/grbl/wiki/Configuring-Grbl-v0.9
    machine moves like I think it should I am just using the cursers on grbl control page up down and right the are set to 10 mm biut it is moving way more than that

    this video is where i changed the x settings to what mike suggested
    100=26.6667
    110=7500.00
    120=200.00

    when I move the x it chatters if I change
    $1=255 it moves one step then starts chattering
    once again
    trying to use grbl 3.6.1 and have xpro .9 version
    I hope the videos show up
     
  14. Jonny Norris

    Jonny Norris Veteran
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    wow thats loud.. or is that a really sensitive mic? The max rates and acceleration seem low.. im using 6000mm/min max rate and 1000mm/sec acceleration. But suggest you try upping yours to 1200mm/min 400mm/sec to start with.

    May be wrong, but generally you get a louder noise from the motors when there's no micro stepping happening, which going by your video looks and sounds like your in full step mode. Or could be your rates are that low they don't take the motor above the 30 kilohertz needed to stop the coils from switching on and off, Hard to tell.
     
    #14 Jonny Norris, Mar 24, 2015
    Last edited: Mar 24, 2015
  15. dcarlisle

    dcarlisle Well-Known
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    Its that loud using max rate of 7500
    and acceleration of 100
    ill try your rates and see what happens thanks
     
  16. Jonny Norris

    Jonny Norris Veteran
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    7500 is pretty fast, and 100 acceleration id say was pretty slow, Though shouldn't make a huge difference to the noise unless too fast.

    How warm are your drivers getting?

    Just to rule out the pulleys not slipping as that will make loud chattering, its an idea to use a marker pen to mark the tip of the motor shaft With a line into the pulley wheel, if you haven't done so already.
     
    #16 Jonny Norris, Mar 25, 2015
    Last edited: Mar 25, 2015
  17. Jonny Norris

    Jonny Norris Veteran
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  18. Jonny Norris

    Jonny Norris Veteran
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    And just occurred to me, isn't 1/8th micro stepping imperial? You should be using metric with a metric belt and settings. Ie 1/5 - 1/10 etc
     
  19. Paruk

    Paruk Master
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    Which drivers will give that option? The ones I've seen all go 1/4 - 1/8 - 1/16 - 1/32. If that's true, ****, I've to set everything to imperial. But then….. belts are metric, ACME, too I believe (pitch 2mm). Confusing. Please elaborate on this one.
     
  20. Jonny Norris

    Jonny Norris Veteran
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    No, sorry to worry you bud, it makes no real difference only to rounded setup figures.

    My bad, remember having a similar issue a while back and I've got it confused with playing around between metric and imperial stepping, now remember it makes no odds. Sorry for that.

    I do remember having an issue with a bad ground. Worth checking, make sure you don't have a ground loop.
     
    #20 Jonny Norris, Mar 25, 2015
    Last edited: Mar 25, 2015
  21. dcarlisle

    dcarlisle Well-Known
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    Thanks for the help Johny
    My drivers are not getting that warm at all
    I tried your settings and still chattered set 100 at 53.33333
    had the jumpers set to 1\8 or 8 setting still chattered pulled the one jumper of for 1/4 no more chattering x stepper moved fine
    so set 100 to 26.6666 I have jumpers set to 1/8th motor moves and chatters
    set
    110 to 7500
    120 to 100
    then I changed 110 to 75 tried then to 75000 no difference
    set back to 7500
    changed 120 to 10 tried ten to 10000 no difference
    I'm beginning to wonder if the board is bad
    suggestions on a board think im going to order another one and try
     
  22. dcarlisle

    dcarlisle Well-Known
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    Should of said x moved fine but still was not close to moving the right amount moving 2 times as much so I droped step/mm by 1/2 and started to chatter
    I feel really stupid I have tried everything and can get it to move like it should but it travels 3 times as much so should change things by a 1/3 and should work but nope just isn't happening
     
  23. Nick W

    Nick W Veteran
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    to get the correct Steps Per Unit (SPU) value, use this formula.

    Correct SPU value = ( Current SPU value * Entered distance value ) / Measured distance value
     
  24. Jonny Norris

    Jonny Norris Veteran
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    Do you have a ground between the board and psu? Or Board and mains earth? If so remove it so you only have + and - common from psu and input from pc. Really sounds to me as a ground issue.

    I have very limited experience with grbl, I recall having similar issues as you are with it, however never got to the bottom of it before almost immediately deciding to go back to a mach 3 bob. So can't really advise on grbl I'm afraid.
     
  25. dcarlisle

    dcarlisle Well-Known
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    I am powering board from power supply only have the + - hooked to board I have the power supply plugged into power strip tried plugging power supply in directly and no difference maybe I should try mach 3 at this point im willing to try anything
    my question is if it is the board mach 3 won't help will it?
     
  26. Jonny Norris

    Jonny Norris Veteran
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    Okay that sounds correct.

    For mach 3 need a mach 3 compatible board. these things are only one or the other afraid to say.

    Worth searching this forum for other posts as im sure ive seen this issue come up before in regards to the xpro, failing that contacting xpro directly and see if they can help. Going down the route of mach 3 would usually require individual drivers, a motion controller, a break out board and the mach 3 license, so does get relatively expensive in comparison.

    Other things that come to mind is the xpro repeatable current is 1.7a so really on the low side for nema 23's. So you want the pots for the x and y's cranked right up, if you don't have already. And what power supply are you using? do you gantries move freely without too much resistance with xpro not powered?
     
    #26 Jonny Norris, Mar 25, 2015
    Last edited: Mar 25, 2015
  27. dcarlisle

    dcarlisle Well-Known
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    I have cranked the current already doesnt make difference
    thanks
     
  28. Serge E.

    Serge E. Master
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    Actually, it's binary. No micro stepping, then 1/2, 1/4, 1/8, ... with some controllers allowing up to 1/256 - all powers of 2.
     
  29. Paruk

    Paruk Master
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    @dcarlisle , sorry to say, but I think you're jumping from one to the other thing without a systematic approach. That way it's going to be hard to find the real problem. I suggest at first you start with going through all your cabling and check:

    1. Are you using shielded cables? If so, go to 2, if not replace them for shielded cable. It makes a very big difference.
    2. Are all wires connected correctly and firmly to boards, power supply, steppers, drivers etc., if so go to 3, if not correct it than go to 3
    3. Set your drivers to the required micro stepping with the dip switches, after that, do NOT touch them anymore until everything else is set right, go to 4
    4. Set your software to the right values for your micro stepping, right feed speed, travel speed, acceleration speed etc.

    When you're sure (and I mean really sure!) that you all did that in a logical and systematic manner, test again. If you still don't get the results you want, concentrate on your software settings and only change one thing at a time to see if that makes a difference. Obvious that if you change travel speed from 100 to 500, but nothing changes, you'll first have to find out why that change did not make a difference before moving on. I learned that getting to understand how what works and why makes a big difference in getting your machine to work as you want.

    Oh, and take out the biggest error to start with, the human error. Humans are in error by default, so in most cases problems can be traced back to them. :)

    Take your time and work systematic. Good luck!;)
     
    #29 Paruk, Mar 25, 2015
    Last edited: Mar 25, 2015
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  30. Paruk

    Paruk Master
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    I tried that calculator too. But with the right input which is:

    x/y belt pitch =0.11811023622
    x/y motor Steps /rev =200
    x/y pulley teeth =20
    x/y microsteps = 8 microsteps

    and got
    x/y steps per mm
    26.666666666773335
    x/y max steps 488.88888889084444
    x/y max steps 2045.4545454463637

    Those values seem to be correct. The belt pitch in Inches is NOT 0.08 BUT 0.11811023622 (3mm/25.4=0.11811023622)
     
    sgspenceley and GrayUK like this.

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