Ohmic sensor & breakaway torch

Star-Lab plasma table discussion forum
Post Reply
whiskeymike
3 Star Member
3 Star Member
Posts: 345
Joined: Mon Feb 23, 2015 5:23 pm
Location: Austin, TX

Ohmic sensor & breakaway torch

Post by whiskeymike »

I’ve been away from my table for a while and started cutting some things this past weekend. I have a starlabs table with CandCNC, dthc iv and ohmic. I noticed when the torch comes down to find the plate, it taps the plate, dislodges the torch slightly, continues going down an 1/8” (eyeballing it), senses the plate, then comes back up to pierce height, meanwhile the torch breakaway reconnects in the right location, and it starts pierce and cuts. I think this is causing my pierce height to be off. Is this likely a dirty connector, breakaway torch holder needs to adjusted, or something else?
jimcolt
5 Star Elite Contributing Member
5 Star Elite Contributing Member
Posts: 3087
Joined: Mon Jul 20, 2009 11:18 pm
Location: North Carolina

Re: Ohmic sensor & breakaway torch

Post by jimcolt »

Best bet is to contact Starlab….they can offer the best advice on their table.
User avatar
acourtjester
6 Star Elite Contributing Member
6 Star Elite Contributing Member
Posts: 7770
Joined: Sat Jun 02, 2012 6:04 pm
Location: Pensacola, Fla

Re: Ohmic sensor & breakaway torch

Post by acourtjester »

The ohmic sensor should stop at contact, but from what you state it seems to be going past and the floating head switch is being activated. this would put your pierce height off. If your table is using the feather touch from CandCNC there is a led for power and another for torch contact with the metal. First check to see if the torch tip is clean, next move the Z down to touch the metal and see if the led for contact comes on.
DIY 4X4 Plasma/Router Table
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PowerTig 255 EXT
BTA Plasma
3.5 Star Elite Contributing Member
3.5 Star Elite Contributing Member
Posts: 590
Joined: Thu May 12, 2011 4:28 pm

Re: Ohmic sensor & breakaway torch

Post by BTA Plasma »

The 1st thing I would do would be to change your shield or use a little Emery cloth or something to break up whatever's on the end of the shield. Ohmic uses continuity to close a contact circuit to establish the top of the material and if there is resistance to that continuity it will not do that correctly.
whiskeymike
3 Star Member
3 Star Member
Posts: 345
Joined: Mon Feb 23, 2015 5:23 pm
Location: Austin, TX

Re: Ohmic sensor & breakaway torch

Post by whiskeymike »

Thanks guys, will try cleaning things up.
whiskeymike
3 Star Member
3 Star Member
Posts: 345
Joined: Mon Feb 23, 2015 5:23 pm
Location: Austin, TX

Re: Ohmic sensor & breakaway torch

Post by whiskeymike »

Just following up on this for someone troubleshooting in the future. I took a wire brush and acetone to the shield, but it didn’t seem to improve. But as I watched it closer, I realized the torch hose was pulled tight at full Z down. I made some slack and made sure it wasn’t caught up and that did the trick. I found that just as it would touch, the hose would pull it back stopping the shield from making a solid connection.

Hopefully this helps someone else having trouble.
BTA Plasma
3.5 Star Elite Contributing Member
3.5 Star Elite Contributing Member
Posts: 590
Joined: Thu May 12, 2011 4:28 pm

Re: Ohmic sensor & breakaway torch

Post by BTA Plasma »

In addition the 3/4 thick upright that attached to the gantry is a great spot for the ohmic plate part of the sensor if your ohmic sensor is on top of the Z axis. If it is on top of the control box then the bottom of the water bed or frame is a good spot for it. In 2017-present all Ohmic sensors were put on top of the Z axis.
Post Reply

Return to “Star-Lab CNC Forum”