Optical Limits

[IndHobby]

Optical Limit/Home Switches from IndustrialHobbies.com

Protect your CNC investment with Optical Limit/Home switches from Industrial Hobbies. These bad boys are as tough as they look, we started with a solid piece of 6061 aluminum and milled out just enough room for 2 optical switches and the support components. Being optical, accuracy is second to none and will provide years of incredible reliability.

The entire assembly is completely sealed against contamination from coolant, oil, metal chips, dust, and just about any other foreign material found in a machine shop. Being machined from solid aluminum these limits are practically bulletproof and can take the normal beating that a harsh machining environment can dish out.


Trigger bar is O-ring sealed on both sides
Front cover is completely sealed with a rubber gasket
I/O lines travel through ½ OD tubing
Output signal is active Hi and is designed to connect directly to a parallel port or other logic device.


Mounting slots (which are under the cover) allow for a bolt spacing of .44" to 1.71" using either 5/16 or 8mm cap head bolts.
Most people will need 2 - 8mm cap head bolts to fit the existing bolt holes in the front center of the saddle (for the X-axis) and 2 -5/16 bolts to align with 2 holes you will need to drill and tap in the side of the saddle for the Y-axis.


Software Compatibility
We have tested this with MACH 2 which works great. We are working to test it with other CNC controller packages, if you are using another package and are interested in using the Optical Limit/Home please contact us (phone preferred) so we can discuss software setup parameters.


Electrical Specifications:
Input Voltage Volts 5
Input Current Milli-Amps 200ma
Max Output Current per Switch * Milli-Amps 50ma
* Each Optical Limit/Home contains 2 complete optical switches (left and right).


A Little History

We designed these Optical Limit Switches after we lost a 7-hour part run to a normal switch failure. The part we were machining was just about done when cuttings and coolant shorted out the normal micro-switches. The machine E-Stopped properly but required a re-homing, after all the chips were removed. Unknown to us coolant had filled up the Y-axis switch; the machine re-homed what appeared to be correctly but was actually about .05 off. When the program was restarted… well you get the idea.

The part was a prototype to get shipped off to Swiss Precision Instruments, as you can guess we had to start from scratch.