Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Leeway on December 30, 2006, 07:54:12 PM

Title: Setting different zero.
Post by: Leeway on December 30, 2006, 07:54:12 PM

Hi all. Been a while. I ran into something today and I'm not sure how to go about implementing it. I'm not sure if it's a Mach thing or I should deal with it in Sheetcam.

I have my machine zero set 3/4" above the actual table. I have a piece of 3/4" plywood mounted to the table and it is pocketed to accept my blanks for some dado's.
I make some other parts for different things that are nested in another piece of 3/4" screwed to the first. It's not exactly 3/4" between the two zero's. it's actually .7658. Question is how can I change the zero's when I change the nesting plates? Right now I do it hit and miss. That takes awhile.
I haven't researched many of the features in either Sheetcam or Mach, but thought maybe someone could point me where to look or what to set.
Tolerances can vary about 1/64th or so in my parts.
Thanks.

Title: Re: Setting different zero.
Post by: Brian Barker on December 30, 2006, 08:01:11 PM

If you have fixtures and you would like to keep the Zero's you could use fixture offsets to make this happen. Just type G55 into the MDI line and set it up. Once you do that you will have the location of that fixture (as long as you have home switches) in machine cords,

Title: Re: Setting different zero.
Post by: Chaoticone on December 30, 2006, 08:01:28 PM

Can you use fixture offsets?


Brett

Edit
Oopps, Brian is fast.

Title: Re: Setting different zero.
Post by: Leeway on December 30, 2006, 08:08:42 PM

Thanks Guys. I looked at that or actually just scanned over it today. It wasn't obvious that this would do it. It's fairly easy for me to set the z to the lower fixture. The upper one is where I would like some software help. I'll try your suggestion. Thanks again.

Title: Re: Setting different zero.
Post by: Graham Waterworth on December 31, 2006, 04:48:37 AM

The other way is to program all your Z axis moves from the top of the table e.g. all Z moves are plus.

Graham.

Title: Re: Setting different zero.
Post by: Leeway on December 31, 2006, 06:13:11 AM

Thanks Graham. I plan on making or buying a touch off probe at some point. The limit switches I use are just cheap micro switches and I'm not sure they would be accurate enough.
I'm using a PC 690 router and when I change the bits, all bets are off. It's gonna have to zero at the fixture.  :)