making my machine distance work accuratly
i was trying to switch my machine from inches to mm, did that, now:
i was able to make the mm work but my problem is the machine move in wrong distance. (was wrong distance in inches also so my gear ration and all that were wrong)
i dont undertsand how to set my pitch.
the acme screw has 11 thread per inch but i want my machine in mm so 0.44 thread per mm.
also for X and Y i have a pulley,
the setup is made by cnc router parts, its called the nema 34 pro. it has 64 teeth on the motor and another pully 20 teeth for the rack. and the ratio is 3:2:1
the gear rack has 20 pitch (rack and pinion setup)
for the lead screw it its a 0.5'' per rev.
now is someone can help figure out my stepconf and where to put this info.
i am getting very close, everthying is moving, linuxcnc is super smoot, i just have trouble with the right distance.
thanks for your input, its been countless hours in trying to make this work, i have a xml file for mach giving by the supplier. thanks JohnT to convert it but didnt work so i am trying to setup from scratch.
cheers!
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If your mechanics are inch, set up your config in inches and just use G21 for metric.
John
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i load my metric gcode than what do i do to make the machine use the g21. do i have to edit the gcode?
very very beginner here.
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(ie G0X25.4 would move exactly one inch).
As for getting the scaling right, I find stepconf a little confusing.
The final number you want to see in the INI file is the number of steps per inch or steps per mm.
One complication may be that the rack is likely to be an imperial DP rack. That means that a 20-tooth pinion will have a pitch-circle diameter of 1", so the movement is 3.14159….. inches per rev.
I am not entirely clear what the gearing is between the motor and the pinion on the rack.
If you have a 64-tooth pulley on the motor and a 20-tooth pulley on the rack pinion, and a 20-tooth rack pinion then:
One rev of the motor is 64/20 turns of the pinion, which is 10.0531 inches. (which sounds much too big, by the way)
Assuming no microstepping that is 200/10.0531 steps per inch = 19.8943.
So, the number you want to see in the INI file is 19.8943. If all my assumptions are correct. But you probably do have microstepping, and I am not sure that the 64:20 ratio on the drive to the pinion is right either.
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64 teeth on the motor pulley
20 teeth on the rack pulley
so i was thinking on the stepconf to do 3 to 1 but the step conf ask on how many teeth so do i put 64 to 20?
for Z, the screw move 0.5'' per revolution.
on the stepconf it ask for
driver microstepping:
pulley teeth :
leadscrew pitch:
i am confuse on the X and Y i dont have leadscrew. what do write there.
on the Z i dont have pulley teeth so what do i write there?
its a bit confusing, i mean i can make my motor purr with wahtever setting but seem that its screws up the distance so those are extremely important setting i guess.
the driver microstepping, what is it exactly? some forum post say you write 1, 2, 10 or 16? this really confuse me.
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Well, 64:20 is not 3:1, if you put 3:1 then it will be inaccurate.the setup is Y and X
64 teeth on the motor pulley
20 teeth on the rack pulley
so i was thinking on the stepconf to do 3 to 1 but the step conf ask on how many teeth so do i put 64 to 20?
Stepconf tries to help out by doing the maths for you. But, as you have found, it isn't always helpful.
So that's either 2tpi in the Imperial setup, or 12.7mm pitch in a metric setup.for Z, the screw move 0.5'' per revolution.
If there is no pulley involved, then just use 1 for both sizes.
The leadscrew pitch is how far the machine moves for one turn of the screw. In the case of a rack system that means how far the machine travels for one turn of the rack pinion.i am confuse on the X and Y i dont have leadscrew. what do write there.
on the Z i dont have pulley teeth so what do i write there?
How many teeth are on the rack pinion, and what size are the teeth? This may be given in DP, mod, or possibly circular pitch.
Do you have a link to the rack and pinion specifications?
It is a setting on the drives. You need to make this number match what the drives are set to.the driver microstepping, what is it exactly? some forum post say you write 1, 2, 10 or 16? this really confuse me.
Normally a stepper motor has 200 steps per rev, but you don't have to step in full steps. Most drives allow you to move half, a quarter, a 16th or sometimes even smaller divisions of a step.
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www.linuxcnc.org/index.php/english/forum...-setting-to-mm#29938
The scale values you have from your converted file are good.
2037 for X and Y or 2037.18 if you want to be a little more right.
4000 for Z assuming 1/2-10 5start acme w/ 10x microstepping
Unless you have a rotary axis, you might want to get rid it in your ini file, just to avoid confusion.
Also, you can get better help if you describe or take pics of the electronics you have.
I know you said you have cncrouterparts rack and pinion drives. Did you get their electronics kit also?
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my motor is 200 steps.
ill try all that tonight when i get home.
thanks for your help, this very confusing.
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the rack is 20 pitch and 20degres pressure as it say on the cnc router parts site.
Unfortunately there are three ways to define gear pitch.
1) Module. The pitch-circle diameter divided by the number of teeth. Normally used for metric gears, bigger numbers = bigger teeth.
2) Diametric Pitch. The number of teeth divided by the pitch-circle diameter. Normally used for Imperial gears. Smaller numbers = bigger teeth.
3) Circular Pitch. The pitch-circle circumference divided by the number of teeth.
I think we can be sure that your rack isn't 20 mod, as that would mean teeth 60mm wide.
Assuming 20 DP the distance-per-rev is (pi * number-of-teeth) / 20
If it is 20 circular pitch, leave out the pi.
You can tell by measuring how far you need to move the gantry for one rotation of the pinion.
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