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Weiss VM32 CNC Conversion

Thanks @Mike R that does make sense.
I’m going to make a bushing to fit between the two bearings.
I was thinking about it last night and I think I understand the problem. The outer races are supported but the inner races are not. So when the nut is tightened, the two inner races are pulled together without anything to prevent them from being over loaded.
 
Spent some time after dinner to make a spacer.
Took a bunch of measurements to establish the thickness of the step in the top plate. Worked out to be .3635"
Just happened to have a length of aluminum stock that was 19mm OD, same as the OD of the inner race. Bored it out to 15mm and cut it off at .370 then sanded it down to be .3635".
IMG_2162.jpeg
(dang the Vise-Grips lefts some marks! Good thing the ballscrew doesn't travel that high)
IMG_2163.jpeg
Slid the bottom bearing on, then the spacer, the mount and the upper bearing. Snugged it up till I could not detect any axial play. There is some lateral play but the old bearings were that way as well.
While I had the column on the bench where I could spin the lead screw by hand and feel what was happening, I marked the minimum and maximum travel extents of the headstock carriage. Turns out to be 338mm. The Sharpie marks are on the side of the column.
Assembled the whole thing again and tested it out under servo power. Smooth like butta' over the full length of the travel.
IMG_2164.jpeg
 
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Getting down to the final stages.
Figured out the gear ratio for the servos.
Settled on 200 inches or 5080 mm/minute max travel speed.
Bit of math to figure out the gear ratio from there.
The servo drives are programmed with their own program and then the CNC controller has to be programmed with the values for ball screw pitch, max travel speed, and max acceleration.
Still struggling to get the axis calibrated as something seems to not be working correctly.
Back to the documentation I go.
 
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David said:
Finally getting down to the final stages.
Figured out the gear ratio for the servos.
Settled on 200 inches or 5080 mm/minute max travel speed.
Bit of math to figure out the gear ratio from there.
The servo drives are programmed with their own program and then the CNC controller has to be programmed with the values for ball screw pitch, max travel speed, and max acceleration.
Still struggling to get the axis calibrated as something seems to not be working correctly.
Back to the documentation I go.
Click to expand...
Looking forward to the results. Do take your time. A few weeks is more than fine.......
 
Alrighty!
Thanks to @breezy on the Masso forum I have sorted out my configuration issues.
I was all kinds of messed up in my thinking.
I had the PPR set to the encoder resolution. :rolleyes::rolleyes::rolleyes:
I had the gear ratio set to the PPR so 4x what it should be. :rolleyes::rolleyes::rolleyes::rolleyes:

So I have re-input the axis setup numbers.
Distance per rev = 5mm
Pulses per revolution = 2000
Max feedrate = 1000mm/min (till I get comfortable)

All the axis move smoothly.
 
The only thing with having the sensors inline with the travel is if you're machine ignores the stop or you over ride it for any reason and you fat finger the direction you're going, you break the sensor or its mount. Now the nice thing here is the mounts are 3D printed so its just a nuisance, nothing to cry about, unlike crushing a proximity sensor between 2 solid masses... :eek:
 
Mike R said:
The only thing with having the sensors inline with the travel is if you're machine ignores the stop or you over ride it for any reason and you fat finger the direction you're going, you break the sensor or its mount. Now the nice thing here is the mounts are 3D printed so its just a nuisance, nothing to cry about, unlike crushing a proximity sensor between 2 solid masses... :eek:
Click to expand...
Yup been there done that on my cnc router.
I have a fail safe for the X and Y in that there is a physical stop on the negative end of both axis. I'm going to adjust both axis so that the prox sensor triggers just before.
On the Z, an over travel would likely tear off the mount.
On the plus side because I'm using servos, as soon as they lose a step they throw a fault and stop.
Also using NC switches so that helps prevent an accident too.
 
David said:
Oh you're killing me!
Click to expand...
I'm busy killing myself. Finally at the point where I can assemble the Wing Gauge project and for the life of me I cannot find the piece of 10mm diameter tube I turned on the lathe. I found the original stock that even has an 8mm dimple in the end from the drill.

But two things. It's 150mm long on the parts list but my drill bit isn't that long. But oddly then there shouldn't be a dimple in the original stock. Very confused here.

I too have hard stops that physically stop the travel if the limit switch fails which is also NC so if a wire breaks it's the same as the switch tripped.

I've thought about positioning the switch so the metal moves over the top of it into the mechanical stop. But haven't tried to see how sensitive or repeatable that is. And repeatability is what it's all about.
 
jcdammeyer said:
I'm busy killing myself. Finally at the point where I can assemble the Wing Gauge project and for the life of me I cannot find the piece of 10mm diameter tube I turned on the lathe. I found the original stock that even has an 8mm dimple in the end from the drill.

But two things. It's 150mm long on the parts list but my drill bit isn't that long. But oddly then there shouldn't be a dimple in the original stock. Very confused here.

I too have hard stops that physically stop the travel if the limit switch fails which is also NC so if a wire breaks it's the same as the switch tripped.

I've thought about positioning the switch so the metal moves over the top of it into the mechanical stop. But haven't tried to see how sensitive or repeatable that is. And repeatability is what it's all about.
Click to expand...
One thing that I like about the servos is as soon as they error out they stop as compared to steppers which just keep trying until stuff breaks.
 
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