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Hello Guys

After being ill with sepsis for the better part of this year I am getting back to my CNC machine. I built a 4th ( rotary ) axis previously and am getting to know it. My machine bed is 2.6m by 1.3m and rather than move the rotary around I was looking at moving it to the " far " side of the Y axis, there isn't a lot of clearance between the bottom of the gantry and the top of the rotary.

I was thinking of a movable limit switch that normally would protect the spindle from crashing into the rotary assembly, but was switchable so the rotary could be accessed.

One way was with a light beam at either end of the table.

I have looked on youtube and online without any luck, I may be using the wrong search expressions.

Have any of you had and luck with an interrupted light beam as a limit / Esc switch? if so what did you do.

Thanks and best regards, ed

Sorry about your illness. Not fun, though I never had sepsis.

Anyway, regarding the limit switch, why make it more complicated than necessary? I would use a simple mechanical limit switch, or a magnetic hall switch. Light is not suitable because... it is light. You risk a lot of false triggers or no triggering, or too early or too late triggering with light. Of course, IR is also an option, but not even that is suitable unless you really take car of light leaks. A beam across the machine is totally unreliable unless it would be laser. Anyway, why complicate it when you can solve it easily and reliably with a simple mechanical switch.

Hello

Thank you for your reply and comments, sepsis isn't fun, I was surprised to find out here in Australia, sepsis kill more people each year than breast, prostrate and colorectal cancers combined, most infections are from small nicks and cuts, ( mine wasn't ) I'm a lot more careful now of cuts and nicks than I was.

I thought of a mechanical switch but the physical shape and size of the rotary axis would make fitting something hard or impossible, I did do a search and found a likely solution on Youtube https://www.youtube.com/watch?v=7wkSdFPBep0&list=PPSV It is using an interrupted laser and looks like it will do the job.

Thanks again and best regards

Ed