Homing/Limit Switches

#1

Looking for info on homing/limit switches. Did any of you guys with beta units use them? If so what kind did you use and where did you get them? Where/how did you mount them. Personally I think they are a necessity to keep from damaging the equipment. Looking at different ones online they run the gamut in styles and prices. I did find the micro versions somewhere for about $30US for 6 of them. Some of the videos recommended using 6 switches instead of just 3 so you cover all of the directions. Also most of the tutorials I watched recommended using the Normally Closed versions instead of the Normally Open. I see that a lot of them can be used either way depending on connections on the switch. I know that you can set soft limits but I don’t think I could put much trust in them. Any help appreciated.

#2

Hi Heyward,

I’m new to the CNC world, but I use the heck out of limit switches in 3D printing.
You have already discovered one of the larger issues, ‘N.O.’ vs ‘N.C.’
I prefer to use normally closed for one reason. If the switch/wire/connection fails
the limit switch will go to the ‘open’ state, so the controller will think we hit the limit and stop.
A switch that is normally open and has a problem will not stop anything.

As far as switches go, OMRON makes great mechanical, and sealed mechanical.
I would think a sealed switch would be better than a non-sealed one. The other options are opto-electric, or magnetic.

As far as where you would mount them on the Long Mill, I have no ideas…

Archer

#3

Thanks for the info. I’ll check out the OMRON switches. Definitely want sealed ones for dust protection. I’m not sure about opto vs magnetic but I’ll research that too.

#4

No no one that I know of in the Betas used them at all. I personally never found a need for them. You can’t damage this machine by going to the limits of the rails. Also through the years all these machines have been developed Chris and Andy also have never seen the need for them either. That isn’t to say you can’t use them. Its up to each one.