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Author Topic: Limits - Am i being too smart ;)  (Read 5779 times)

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Offline ger21

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Re: Limits - Am i being too smart ;)
« Reply #20 on: March 15, 2016, 03:18:02 PM »
Your previous post said 0.6.
Yes, .06 is not bad.
Gerry

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Offline Davek0974

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Re: Limits - Am i being too smart ;)
« Reply #21 on: March 15, 2016, 03:24:11 PM »
Yes, the previous one was measured when the sensors were not working correctly, the new PSU has sorted that out 100%
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
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Offline ger21

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Re: Limits - Am i being too smart ;)
« Reply #22 on: March 15, 2016, 03:46:01 PM »
Now 0.00 to -0.6mm I think that's acceptable??
Gerry

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Offline Davek0974

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Re: Limits - Am i being too smart ;)
« Reply #23 on: March 15, 2016, 03:51:34 PM »
Bugger, apologies, typing too fast.

0.06 :)
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Offline Hood

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Re: Limits - Am i being too smart ;)
« Reply #24 on: March 15, 2016, 04:16:35 PM »
It sounds not too bad for a prox, especially a cheapo.
I preferred to use optos on the machines before I had Index homing capability. I did a test when I first got the optos fitted to a manual Bridgeport conversion. I still had a digital readout connected so was able to see where the axis was via the glass scales. I homed the machine and zeroed the Digital Readout then jogged away and homed again. I did that 100 times and only once or twice did the display not show 0.000mm and the couple of times it did read something else it was 0.005mm.

The optos were bought from the USA, they were inside a waterproof enclosure and had a spring loaded rod held central and a flag on the rod which was blocking the opto until the rod was pushed one way or the other. Can't recall the place I got them from as it was so long ago but I think they changed hands and stopped selling them anyway. I made a few of my own up as it was a great idea. As said however all my machines can home to the Index pulse of the encoder now so I have no need for them, just decent quality mechanical switches are all I need.
Hood

Offline Mogal

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Re: Limits - Am i being too smart ;)
« Reply #25 on: March 15, 2016, 04:23:17 PM »
Sorry for stepping in, but 0.06mm or 0.002" is considered good?
I've been struggling with a new computer / wiring scheme.

My last program run was 3 hours, and at the end of it, the machine reported:
X = 0.0059" Y = 0.0004" and Z = 0.0002" <-- This was using the "verify" function.

Is this acceptable? I think I might have some binding on my X axis causing the losses there.
"Verify" never returns "Verified correct" I have mechanical limit switches.

Thanks,
Chris

Offline Davek0974

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Re: Limits - Am i being too smart ;)
« Reply #26 on: March 15, 2016, 04:38:39 PM »
Is that with servos/encoders or steppers?

I could probably tighten up a bit more by slowing the homing rate down a bit more, slotted opto's would certainly be better though.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
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Offline Hood

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Re: Limits - Am i being too smart ;)
« Reply #27 on: March 15, 2016, 04:39:55 PM »
Verify is not really telling you whether your Home switches are good or not, what it is saying is the axis is out of position with reference to the home position as defined by the homing procedure.
Now it could be your home switches are not accurate and the axis was actually where it was or it could be the home switches are fine and the axis had lost position or lastly it could be a combination of both.
Simplest way to see would be Home, jog off relatively slowly and then Verify. If it is out then you will know your home switches are not the best, if it is not out then it is likely missing steps issue.

Regarding 0.06mm being good, all depends on the type of machine and how much you rely on using the Home switches as a reference, for me, on a metal cutting machine, it is not great, in fact it is poor. On a wood router however it is probably more than is required.

Hood

Offline Hood

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Re: Limits - Am i being too smart ;)
« Reply #28 on: March 15, 2016, 04:47:08 PM »
Dave, it was steppers on that first retro, geared 3:1 if I recall.
Hood

Offline Davek0974

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Re: Limits - Am i being too smart ;)
« Reply #29 on: March 15, 2016, 04:51:38 PM »
I think it will work for a while, this is a mini multipurpose machine and I can easily upgrade sensors later if needed, i'll try slowing homing a little more and check that as well.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
Plasma table, Mach3 V062, Step motors, C&CNC THC.