[BobCAD-Trainee]

Hi guys,

Ive watched various videos and tutorials now on setting the home using Mach 3 but there seems to be an issue. Infact i think there is more than one issue. Using the Keyboard Cursor Keys the X,Y and Z axis doesnt traverse smoothly. When i press a cursor to traverse the x axis the spindle moves either in the + or - direction for a few seconds before stopping. The motor seems to jam or buzz louder at this point but if i release the cursor key and depress it shortly thereafter then travel resumes for another 2 or 3 seconds before the behaviour repeats itself. This behaviour is present on all axis. Now however on the Y axis which has 2 ball screws the two mottors dont jam or trip out at the same time causing the carrage to twist out of alighnment as one motor is still driving and the other is stopped ! I am sure if i had time I could get to the bottom of this if it was my own machine but ive been called into fix this for friends and they bought the machine second hand so I dont know what twiddling has been done, what faults may be present etc but i think this is a software issue as its present on all axis. Now to further confuse matters if I press REF ALL HOME then all axis traverse smoothly ! I know im missing something basic but I need pointed in the right direction and preferabally a breakdown of what i need to check, or edit in the config to ensure this works. Im not an expert with electronics so if its a fault on the control board I dont know how i could diagnose this. Can anyone help ? Thanks !

[ger21]

It could be 100 different things, but it's NOT the software.
It sounds like your seeing resonance, which is causing the motors to stall.
What are the specs on the motors and drives, and what voltage are you running at?

If you run the Mach3 Drivertest.exe in the Mach3 folder, do you get a smooth, flat line, and a steady pulse rate?

[BobCAD-Trainee]

Hi Ger21, I dont know and i cant try as the machine is not at my location. :/ I know this makes it awkward to problem solve. Its not my machine. Ive some friends and they live 20 some miles away. I hope to visit again in maybe 2 weeks time but I need to have a clear picture of what Im going to try to achieve. What am i looking for when i run drivertest ? Should i get a flat smooth line with a steady pulse rate or is that bad ?

[ger21]

Yes, a flat line and steady pulse rate is what you want.

[BobCAD-Trainee]

Sorry to bother you again Ger21 but I would like to point out that the motors do operate smoothly and the axis travels fine after pressing the Ref All Home button in Mach 3 so can you explain why it dosent when traversing the axis using the cursor keys on the PC Keyboard ? I dont understand why it can work in one situation and not in the other !

[ger21]

First, I doubt that the drivertest will show the cause of the problem, but it's good to know where we stand on that front.

It's very possible that the velocity for the motors is set too high, which is causing them to stall. Homing is done at a slower speed, which may be why it's fine.

[BobCAD-Trainee]

Ok Gerry, Well my next question is how do i adjust the motor speed ? Theres bound to be a configuration for that somewhere?

Thanks again