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  1. #41
    ok just been down the the cave to try again. I have set things like this K1 n K2 set back to 2 again. i set the setting to

    steps per = 80
    velocity = 1400
    acceleration = 150

    The Torque is a lot better set like this . I can run with out stalling and it seems faster than before.
    I haven't cut anything yet with it like this but i tried to stall the motor by hand and i can but it takes a lot of force to do so.

    what is the difference between velocity and acceleration ?

    Any way it seems we are getting some where. I will try cutting something tomorrow and see how we get on.

    In the long term i think upgrade is in order at some point.
    I would like to say thanks for sticking with me on this. I seem to be learning so much so fast. I should be used to that being a heating engineer . All the help has been much appreciated

  2. #42
    Velocity is just the maximum speed your machine can work at, acceleration is the rate of change from one speed to another, just like your car really.

    Also there is this from the Mach3 documentation;

    "If you canít seem to get the motors to run smoothly there are a few things to check, first the easy one: Some motor drives need to have a longer step pulse and this can be set by changing the Step Pulse setting. "

    I've tried a few values here for my own machine but found no difference I could detect but I'm using digital drivers, it might though make a difference on your machine.
    Last edited by EddyCurrent; 09-09-2014 at 07:45 PM.
    Spelling mistakes are not intentional, I only seem to see them some time after I've posted

  3. #43
    It is strange that mach3 shows 1-5 us in step pulse but the instructions say set it to 10. so i have it set at 10. i will look at that tomorrow and see if it make much deference.

    Ever other forum i read say change the board to a Gecko G540. wondering if its worth it and with it take the 4 wire steppers as i have 6 of them now haha

    HOLD on just looked at
    my video again and noticed my step pulse was set at 2. but the instructions say it needs to be set at 10 . I just found a post that said "if the step pulse is too short the motors don't respond at high step speeds" So im guessing that 2 is a short pules ?
    Last edited by amxen; 09-09-2014 at 08:04 PM.

  4. #44
    I think it's the same as putting extensions onto your house, it gives you bigger and better but if you're not carefull you can exceed the local house price ceiling. In other words you can upgrade and add better parts but the total cost might come to more than it's worth and you'd have been better starting from scratch or selling what you have and move to a different but better machine.

    As the saying goes, "You can't polish a turd" or for those of a sensitive nature, "You can't make a silk purse from a sow's ear"
    Last edited by EddyCurrent; 09-09-2014 at 08:10 PM.
    Spelling mistakes are not intentional, I only seem to see them some time after I've posted

  5. #45
    Quote Originally Posted by amxen View Post
    HOLD on just looked at my video again and noticed my step pulse was set at 2.
    Good observation, more things to try !. Make a note of what you change and the result, so you can look back and determine the best settings.
    Also I think it's fair to say most people set their microstep to 1/8 so aim for that but if the machine can't manage then reduce it like you did.
    Last edited by EddyCurrent; 09-09-2014 at 08:16 PM.
    Spelling mistakes are not intentional, I only seem to see them some time after I've posted

  6. #46
    Mike Glad to hear you now have some movement and are getting there. If you can sell your other kit back on EBay I would because you can get much better motors and drives than those you have. Or at least sell the motors and look at the ones from the link I posted. Good luck. ..Clive

  7. #47
    OK last testing for this evening . I just wend down and changed it all back to how it was and then changed the step pulse to 15 and the dir pulse to 10 . Dont know why them numbers i just thought i would see what happens. I now have it set like this and it seem not to be stalling

    steps per = 320
    velocity = 1700
    acceleration = 160
    step pulse 15
    dir pulse 10

    i have no idea about the step and dir pulse but it seems not to be stalling like this . and i cant stall the motors by hand .
    I did try it faster (1800) but it did start stalling so i wound it back down.

    gonna try cutting some mdf tomorrow. This was the first thing i cut when i got it just to test it
    Click image for larger version. 

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  8. #48
    JAZZCNC's Avatar
    Lives in wakefield, United Kingdom. Last Activity: 10 Hours Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 5-6 years. Has a total post count of 5,433. Received thanks 832 times, giving thanks to others 29 times.
    Ok well I think you main problem is coming from the BOB and the fact it will have slow opto isolators. This is why your getting better results using higher step pulse.
    Try running in Sherline mode and see how it goes because all thou your set at 10 -15 your not getting that as Mach in normal mode doesn't go that high.? Sherline mode gives you wider step pulse so gives the opto's more time to work. You'll find it in port's n pins on first page near Kernal speed. You'll have to restart Mach3 and retune motors.

    To be honest you have several issues here all of which can only be cured with a bullet or a mallet.!! . . . . Crap celectronics give crap results.

    With the high inductance motors you have and only 24Vdc running rubbish drives thru a piss poor BOB then in all fairness your near the end of what should be expected. Sell the lot and buy decent drives. Don't go for the G540 as there are better options for less money and the Gecko is restricted to 3A motors to use it's full capabiltys.
    Your main issue with slow speed is lack of volts but don't go giving the drives more because you'll fry them. Max they will stand is 36V and they won;t like that for long before letting out magic smoke plus 36v isn't much better than 24V with these motors and you'll need 50V drive running 44-46V to get any decent speed from them.

    Now with the stalling and micro stepping then after the short pulse width problem then resonance is the next issue you'll be encountering. Resonance affects motors in differant ways and is often worse when sat on the bench.
    Also the micro stepping plays it's part here as well. Setting the Micro steps too near to full Step 1-1 often makes resonance worse so stalls more. Setting higher makes the motors run smoother so less stalling but this comes at the cost of many more pulses required which in your case makes things worse because your Rubbish BOB can't keep up as it is.!!. . . So it's a double edge sword I'm afraid.!! . . . Fubar'd in both cases.!!. . . Time to get Timmy out.!!

    This is why decent electronics and the quality of the pulses being sent to the drives/motors is so very important.
    Last edited by JAZZCNC; 09-09-2014 at 11:00 PM.

  9. #49
    Thanks for that information Jazz . When i do upgrade the electronics what BoB would you go for ?

    The wonderful world of cnc, I only wonted to cut stuff and ended up being an electrical engineer

  10. #50
    Spelling mistakes are not intentional, I only seem to see them some time after I've posted

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