PM-45M-CNC Setup and Configuration with Mach3

Hey guys, Great Thread! Very helpful, I appreciate it! I even learn from you guys too, so its very, very helpful!

To answer the last question, YES they are ball screws, the delrin is just on the end of the nut there, but yes, absolutely, ball screws on all 3 - X, Y, and Z Axis on the 45M-CNC and new 940 CNC thats coming out.
 
OK, good to hear they are ball screws, fine pitch for a Ball Screw thanks for the quick reply.
I have one tip : Put a stop on the arm of the switch box, so it can't be rotated too close to the spindle head, otherwise it can catch on the quill's spring cover and when the Z axis raises....ouch,.....don't ask how i know, ,lol. I just glued a small wooden block to prevent this happening again.
 
Gentlemen, quick question...

What are your fastest rapids on your PM45CNC's? I seem to be maxing out at 20ipm and I'm starting to get this CNC thing down...which means I need to try and make things go faster and consequently break other things faster!

Joking aside, is everyone else in the same boat as I in respects to travel speed?

Also, sometimes when profiling and moving in a direction that requires the use of both axis at once my machine will start to get jerky and move one axis, then the other while going around radius and things of the like. (Imagine stair-stepping rather than a smooth radius). While not horrible, it is very, very annoying. It is also slowing down cycle times and giving me spotty finishes.

Has anyone else noticed this? I'm curious if it is mach, bobcad, or the machine itself...perhaps the motion controller?
 
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MUCH faster than 20 ipm, can't remember where mine are at right now, but the horizontals are around 100 (or more), the Z can sometimes do 75 or so, but sometimes the steppers may skip going up, so I have it around 75 or 50 ipm right now.....i'm still a new user so have not settled on a number yet, just being conservative. Could counterbalance/spring the weight of the head to get faster Z's someday. Don't forget to experiment with the acceleration rates also, (sliding friction is less than static,inertia..yada yad yada)
 
Whoohoo!! We're cruising now! Obviously the "Velocity in IPM" in the motor tuning and setup is where to configure the speed. Not sure why I set it at 19.98... Thanks for the info Damo! Now I actually have rapids.

Unfortunately, as predicted, just like a teenager with a mustang; I've gotten myself in trouble with the speed! Something has gone horribly awry!
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Actually this has happened before and I just put the gib back in place and tightened it without really giving it a good lookin'. But I looked close this time and the tension screw isn't actually engaging the gib at all, just sort of pushing on its side. Now it slides out every time I rapid North on my Y. Is anyone else's Y axis gib looking like this?
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I looked at my PM45 932M and it is very different and is engaging fully.
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lol, kind of funny, JUST yesterday i was tuning up my backlash and noticed that there is marginal overlap of the adjuster screw heads over the end of the gibs....especially since the fit of the OD of the screw head is not as precisely located radially by the hole I.D as it could be...vs screw pressure. I modified a fender washer into a "tab" with a hole in it to provide better overlap, it's not necessarily worth starting with a fender washer as you may end up making the same from scratch easier. An even better way may be to weld up the "point" of the gib to get it closer to the adjuster screw centerline. Part of the problem is that at certain gib positions the screw head is past the outside of the hole entrance (axially and then radially) , then when tightened in this (erroneous) position it performs an unwanted chamfering procedure...
 
Right now, I'm trying to diagnose some Z axis noise, I think it is just chatter from backdriving the unloaded manual drive gear (backlash) . I may try to grease the manual Z drive gear. This requires moving the CNC electrical cabinet. If so I may try to add a lubing port so that the cabinet does not have to be removed. I tried putting some load on the manual shaft as a diagnostic aid , it does help. Could possibly be the handle bearings also. I don't think it is critical, just annoying. Even if it is chatter at the drive gear at least this part of the ball screw is never in contact with the ball screw bearing nut. So wear here is not critical, but still would like to avoid any and the noise.
For reference:
http://cdn1.grizzly.com/manuals/g0755_m.pdf (see figure 52 p. 34 )
 
lol, kind of funny, JUST yesterday i was tuning up my backlash and noticed that there is marginal overlap of the adjuster screw heads over the end of the gibs....especially since the fit of the OD of the screw head is not as precisely located radially by the hole I.D as it could be...vs screw pressure. I modified a fender washer into a "tab" with a hole in it to provide better overlap, it's not necessarily worth starting with a fender washer as you may end up making the same from scratch easier. An even better way may be to weld up the "point" of the gib to get it closer to the adjuster screw centerline. Part of the problem is that at certain gib positions the screw head is past the outside of the hole entrance (axially and then radially) , then when tightened in this (erroneous) position it performs an unwanted chamfering procedure...

Glad I'm not the only one with this issue, I figured it was something that needed to be modified but just wanted to confirm that it wasn't some sort of "Quick release gib feature" that I missed. I may just sink a small screw screw into the gib so the adjustment screw can engage on that or go your route and machine up something with a tab. I'm not familiar with welding cast so I'll leave for another day (I'm assuming the gib is cast iron?).

As you stated, the chamfering procedure is interesting...Almost funny. Sure is efficient though!

I've also got some noise in my Z. Only while traveling up though. If you figure it out, would you mind passing on your findings?
 
VERY IMPORTANT WARNING: On MY Vista laptop when using <SHIFT> to overide STEP Jog Mode into continuous....you MUST release the directional key BEFORE you release the shift key, otherwise the axis will continue moving at Rapid speed until it crashes or hits a limit . This is problem is pretty easy to find on google...I believe some think the culprit is the motion card and not Mach3....but I have not gotten that deep into it yet. My PM45CNC was bought in Spring 2015...if that helps, I don't have the exact Controller date or other I.D yet.
 
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