lathe index mark sensor

[Karl_T]

I'm needing a sensor to mark the exact same spot on the lathe spindle once per turn. Its used for threading as the index mark. My control vendor, Camsoft, recommends a rocker switch and cam type arrangement. It would be just like the old fashioned points in a gasoline engine.

I thought of just using engine points, but I don't think they'd last long in a lathe. And running backward would probably break them.

I'm not finding a part like this. Any suggestions?

Karl

[n174k]

Karl,

We spoke on the phone at the end of March about this subjectand indicated we have a module that will do what you describe. You then posted in the CamSoft Forum your circuits to accomplish this task. What are you really trying to accomplish.

n174k

[Karl_T]

I probably should have bought your item. My home designed module to amplify the index pulse does not work well at high speed. I'm guessing its a scanning problem, the index pulse can come between scans???? Not sure here, but performance is not acceptable.

Anyway, I didn't find a mechanical switch that I thought would be reliable. So, I'm installing a slot sensor and will be hooking this up to a high speed Opto 22 input. The sensor has just microseconds of responce time. I just finished the mechanical part of the slot today. The sensor will stay on for 1/2 of a full spindle revolution.

This should give a very accurate timing mark to Camsoft. I'll know for sure in a few days.

I'll paln on posting again to the thread on your marker pulse about my woes with the home made version. And what i did to sovle the issue.



Karl

[n174k]

Karl,

Our module does not care whether the encoder is single ended or differential output and has been tested up to 4000 rpm of the spindle and did not miss a revolution. The threads repeat perfectly on 4 pitch threads at 400 rpm running over the same part 10 times as reported this week from my customer threading pipe couplings. He has successfully run up to 800 rpm with 8 pitch threads in another production run. This is a Motch VTL 24" chuck with CamSoft CNC Pro control system installed last December.

n174k

[n174k]

Karl,

This module only requires a spindle mounted encoder with a 1:1 ratio.

n174k

[Karl_T]

Originally Posted by n174k Karl, Our module does not care whether the encoder is single ended or differential output and has been tested up to 4000 rpm of the spindle and did not miss a revolution. The threads repeat perfectly on 4 pitch threads at 400 rpm running over the same part 10 times as reported this week from my customer threading pipe couplings. He has successfully run up to 800 rpm with 8 pitch threads in another production run. This is a Motch VTL 24" chuck with CamSoft CNC Pro control system installed last December. n174k

Don't rub it in <VERY BIG GRIN>

That "Not invented here" syndrome has really cost me big time on this job. Your module should be required equipment on any Camsoft CNC lathe. The other option, using VIRTINDEX, is not for any serious use.

Karl

[dmelacom]

Originally Posted by Karl_T I'm needing a sensor to mark the exact same spot on the lathe spindle once per turn. Its used for threading as the index mark. My control vendor, Camsoft, recommends a rocker switch and cam type arrangement. It would be just like the old fashioned points in a gasoline engine. I thought of just using engine points, but I don't think they'd last long in a lathe. And running backward would probably break them. I'm not finding a part like this. Any suggestions? Karl

Look into electronic ingnition sensors with matching control unit if your going to try automotive components. They are no contact. They are cheap in the junk yard. There is also a company that makes a retrofit to go from points to trigerless ignition. They use a light beam to trigger the coil. Its UNI...... something , call an auto-parts store. It's a common upgrade...

not sure if the precision is going to be repeatable to the needed tolerance??? Or if the output is compatible.....