Y axis not homing

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Rocketdc
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Y axis not homing

Post by Rocketdc »

I've got an ldr table that's only a year old and last week the torch was touching down, but not firing. After some troubleshooting it seems the mic-03 cable that plugs into the hypertherm power source was faulty. I just got the new one plugged in and went to home the table before testing it out and now the Y axis won't home. It keeps moving then goes in the opposite direction until I stop it.

The cnccommand screen says 'axis Y on limit switch error'. E stop is tripped and when I override it I can move the gantry fine, but the second it stops from the manual movement, at anywhere on the table, the e stop kicks on again. Last few times I tried to home it one side moved while the other stayed put.

This has never happened before, I'm assuming it's just random that these failures occurred at the same time? Any thoughts on what to check?
weldguy
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Re: Y axis not homing

Post by weldguy »

That all seems very coincidental. I would go over all of your cables and connections first if you haven't already and be sure nothing was knocked loose during the replacement of defective cable.
Rocketdc
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Re: Y axis not homing

Post by Rocketdc »

The issues don't seem to be connected. The cable I replaced to the power source was nowhere near the wiring for the box and limit switches.

Looks like it's a faulty limit switch.
adbuch
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Re: Y axis not homing

Post by adbuch »

Does you table use mechanical limit switches or proximity sensors?
David
Rocketdc
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Re: Y axis not homing

Post by Rocketdc »

adbuch wrote: Mon Jun 20, 2022 6:41 pm Does you table use mechanical limit switches or proximity sensors?
David
It uses mechanical switches, I ordered a replacement so hopefully I'll have a definitive answer when that one arrives.

Would the proximity sensors be a better way to go?
Last edited by Rocketdc on Mon Jun 20, 2022 8:38 pm, edited 1 time in total.
adbuch
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Re: Y axis not homing

Post by adbuch »

I think that mechanical limit switches should work fine, but are more prone to mechanical failures. I've got mechanical limit switches on my Plasmacam table and have had no problems so far in the 5+ years I have been using my table. But other Plasmacam owners have had limit switch failures, and luckily they are easy to diagnose and replace.

Both my CNC Router Parts Pro4848 and Avid CNC Pro4824 cnc router tables use proximity switches which also work fine, and are less prone to failure since there are no actual mechanical moving parts. I think I would just replace your defective limit switch with the identical part and leave it at that. Maybe order a few spares to have on hand for just-in-case.

David
Rocketdc
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Re: Y axis not homing

Post by Rocketdc »

adbuch wrote: Mon Jun 20, 2022 7:53 pm I think that mechanical limit switches should work fine, but are more prone to mechanical failures. I've got mechanical limit switches on my Plasmacam table and have had no problems so far in the 5+ years I have been using my table. But other Plasmacam owners have had limit switch failures, and luckily they are easy to diagnose and replace.

Both my CNC Router Parts Pro4848 and Avid CNC Pro4824 cnc router tables use proximity switches which also work fine, and are less prone to failure since there are no actual mechanical moving parts. I think I would just replace your defective limit switch with the identical part and leave it at that. Maybe order a few spares to have on hand for just-in-case.

David
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Good to know, thanks David. I think you're right, I'll probably order some spares so I'm not stuck waiting for a delivery the next time. They're pretty cheap, these are only $10 a piece.
adbuch
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Re: Y axis not homing

Post by adbuch »

I hope that the replacement switch resolves your issue and that you are up and cutting again soon. By the way, if you wanted to do a test, you could swap your x and y switches and see if the problem follows the switch. You could also remove the switch wiring and use an Ohm meter to check the functionality of the switch. Some of these switches are NO (normally open), some are NC (normally closed) and some have a terminal for each on the same switch. I would also try unplugging and reconnecting the wires to the switch just in case you have a loose or corroded/oxidized connection.

David
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Re: Y axis not homing

Post by Rocketdc »

adbuch wrote: Mon Jun 20, 2022 8:12 pm I hope that the replacement switch resolves your issue and that you are up and cutting again soon. By the way, if you wanted to do a test, you could swap your x and y switches and see if the problem follows the switch. You could also remove the switch wiring and use an Ohm meter to check the functionality of the switch. Some of these switches are NO (normally open), some are NC (normally closed) and some have a terminal for each on the same switch. I would also try unplugging and reconnecting the wires to the switch just in case you have a loose or corroded/oxidized connection.

David
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I'll keep that in mind. I checked each switch and was flipping them on and off to see how the diagnostic page and connections at the box were responding and I could feel this switch was sticking on and not snapping back when I let go so I'm assuming that's the root of it. You're suggestions are easy to follow up with though and helpful to pinpoint the problem! Kind of a frustrating week, I have orders to fulfill and I'm now pushed back a couple weeks waiting for a few cheap parts. Not complaining, still better than no orders and a machine sitting idle.
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Re: Y axis not homing

Post by adbuch »

I very much agree! In this challenging economy - better to have orders to fulfill than none at all. My orders really took a nose dive in the last month or so, but now starting to pick up a little bit.
David
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