Adding Home Switches to my RF-30 Mill/Drill

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RGSparber
Posts: 66
Joined: Sat May 27, 2017 2:12 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
System Serial Number: none
Location: Phoenix, AZ
Contact:

Adding Home Switches to my RF-30 Mill/Drill

Post by RGSparber » Sun Sep 03, 2017 7:53 pm

When power is first applied to my mill/drill, the first thing the Centroid Acorn system does is ask to be taken "home". Home is just a known physical location. Once the software reaches home, it can get to work making parts.

If you are interested, please see

http://rick.sparber.org/AHSCA.pdf

Your comments are welcome. All of us are smarter than any one of us.


Thanks,

Rick

DICKEYBIRD
Posts: 251
Joined: Sat Jul 08, 2017 7:38 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
System Serial Number: n/a yet
Location: Collierville, TN USA

Re: Adding Home Switches to my RF-30 Mill/Drill

Post by DICKEYBIRD » Sun Sep 03, 2017 8:59 pm

Hi Rick, thanks for taking the time to put that article together. The Acorn side of things in your article will definitely be looked at when I finally get to doing home switches on my machine.

Some steel cutting is planned so the magnetic prox. sensors won't be used due to chip accumulation. The plan is to use micro-switches that trip a bit before the home position on all three axes which "turn on" opto-sensors triggered by slotted discs on the end of the ballscrews. Sort of like poor man's servo index pulse homing.

I did this on the X-axis of my Mach3 equipped lathe and it really works a treat. It has double ended stepper motors so the disc/opto sensor was placed on the back side of the stepper to take advantage of the 2.5/1 pulley reduction for even more homing accuracy. It's so nice to be able to home to the same point with high accuracy after a crash and have confidence that you're right back where you started without touching off. All 22 of the tools' offsets were set using x home as the master "tool". I hope Acorn can do the same.

Here's the kind of opto sensor I'm talking about:
http://www.ebay.com/itm/3Pcs-Opto-Optic ... 2749.l2649
Milton in Collierville, TN

"Accuracy is the sum total of your compensating mistakes."

RGSparber
Posts: 66
Joined: Sat May 27, 2017 2:12 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
System Serial Number: none
Location: Phoenix, AZ
Contact:

Re: Adding Home Switches to my RF-30 Mill/Drill

Post by RGSparber » Sun Sep 03, 2017 9:54 pm

I have seen these sensors on a number of machines and never heard that they get fowled by steel swarf. I'm sure it could happen. However, my Z is in an area that never sees swarf and my Y axis sensor point down plus is out of the way. I will have to watch that X axis. If it becomes a problem, I can build a shroud. Swarf triggering the X sensor would be a very nasty fault!

Thanks for the warning.

Rick

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