Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: rcjarvis on March 16, 2008, 11:00:38 PM

Title: How to: Modify z origin when work in progress.
Post by: rcjarvis on March 16, 2008, 11:00:38 PM
HI guys, I'm new at cnc . I'm a sign craft er and often nesting 2 or more projects in one sheet. I would like to know if it is possible to change the  value of the Z-axis for a portion of the toolpath in progress without stopping the machine(when v grooves need be deeper because of varying letters sizes). Sometimes some portion of lettering are to shallow (Barely touching surface) because of the variance of the sheets.

might seem like a dumb question but sometimes I'd like to just press the page down button and give or take a few thousands of an inch, Of course, it's not like I'm  machining parts for NASA or anything ...

Thanks for your help !
Dan
Title: Re: How to: Modify z origin when work in progress.
Post by: Hood on March 17, 2008, 04:48:54 AM
Do a search for Torch Height Control. Not sure if it will work but  its just something I have in the back of my mind that someone wanted this before and thats how they achieved it.
Hood
Title: Re: How to: Modify z origin when work in progress.
Post by: M250cnc on March 17, 2008, 03:17:01 PM
You can also buy cutter holders with an adjustable nose cone.

That should totally eliminate the problem, as this is how they do it on bespoke engraving machines.

The cutter is spring loaded and the nose cone sets the depth. This method would be especially useful on shields/plaques etc

Although in some instance i myself would want to adjust the Z height so i am learning also.

Phil_h
Title: Re: How to: Modify z origin when work in progress.
Post by: rcjarvis on March 17, 2008, 09:50:06 PM
Have any links or pics of such holder?
Dan
Title: Re: How to: Modify z origin when work in progress.
Post by: M250cnc on March 18, 2008, 10:07:18 AM
Just do a google search

Phil_H
Title: Re: How to: Modify z origin when work in progress.
Post by: Tweakie.CNC on March 19, 2008, 12:50:21 PM
This may be of help, but it does involve stopping the machine though.

I have individual 'axis enable' switches fitted to my control box. When making signs that are longer than the table I pause Mach, cut spindle power, disable the Y axis, release the work (vacuum table), manually wind the table to it's new position (leaving the work in the same position relative to the tool). Clamp work, apply spindle power, enable y axis, restart Mach. This sounds more complicated than it actually is to do but as Mach is unaware that any changes have been made it continues with the job just as if my table size was much larger.

In your case, I think, pausing Mach, disabling the z axis, winding it down to the required position, enabling the z axis and restarting Mach would work.
Title: Re: How to: Modify z origin when work in progress.
Post by: jimpinder on March 19, 2008, 03:11:22 PM
I don't really want to get involved in this one, and I don't know how to do it (yet) until I think about it a bit, but as far as I understand what you want to do is watch the job, and if it is not cutting to the correct depth (because of variances in the material) adjust the cutting height up (or down) to suit - as the program proceeds ?

Is that right - as I say I don't know how to yet, but Mach3 is so versatile that there must be a way without invoking any special tools or whatever. I would have thought that you could augment the Z axis controls with a couple of buttons, (up and down) and just press them to achieve the result you want.  That is what I should be aiming at. A computer is there to do what you want, you should not have to bow to the computer.
Title: Re: How to: Modify z origin when work in progress.
Post by: rcjarvis on March 19, 2008, 04:42:58 PM
Hi Jim, Do you read minds ? This is exactly how I should have addressed the problem. Maybe my English is not as good as I thought (French speaking Québecker)!!!!  I think Mach 3 is a great software and probably has a feature like this, or needs a macro to kick it in to gear. Allthough Tweakie might be coming with something, I don't mind having to stop the machine, but I like to keep it simple.

I googled couplers, holders nose cones, and not much help there, anyways, like Jim, I  like to make the computer simplify things for me, and a few simple clicks of a up or down button sound simpler to me, or maybe to shortcut other keys to serve this matter.

Back to my English classes now...
Dan
Title: Re: How to: Modify z origin when work in progress.
Post by: jimpinder on March 19, 2008, 04:54:23 PM
I would hate to have to reply in French - let me think about it for a bit. Yes a Macro should do it, but it is how to activate it whilst a G Code program is running. I would have thought it best to have the X axis go up (or down) a preset amount - maybe 0.5mm - I take it you are metric??? - so that you didn't have to do too much - just press the button, if that is not enough, press again.

Title: Re: How to: Modify z origin when work in progress.
Post by: Hood on March 19, 2008, 05:06:21 PM
Did you do a search for Torch Height Control, I think that is how it works, never used it so not certain.
Hood
Title: Re: How to: Modify z origin when work in progress.
Post by: Hood on March 19, 2008, 05:09:50 PM
OK did a search for you ;)
Is this what you are wanting http://www.machsupport.com/forum/index.php/topic,2656.0.html

Hood
Title: Re: How to: Modify z origin when work in progress.
Post by: Overloaded on March 19, 2008, 08:36:28 PM
Hello Hood,
 I set this up on my home PC. Just playing around.
In screen4, I put 3 oemdro's on the run screen
oemdro 27   max
   "       65   lowest
   "       25   speed
This is the only way I quickly figured how to change the values. How do you change them normally ? Without modifying a screen ?
Anyway, the up and down limits work fine, and the speed changes but the speed dro only accepts values between 5 and 100.
5 is too fast. The average "quick" hotkey hit moves the axis .025". Unless maybe it is in mm. The file I was running was in inches though.
One other thing is that all remaining Z moves in the file will be "off" by the amount that the Z was changed by the hotkeys.
Could cause problems later in the finished part.
Works perfectly for what it was intended though.
Thanks,
RC
Title: Re: How to: Modify z origin when work in progress.
Post by: rcjarvis on March 19, 2008, 10:09:22 PM
If this can be of any help, I work  with inches !
And thanks a lot for your effort everyone.

Dan
Title: Re: How to: Modify z origin when work in progress.
Post by: rcjarvis on March 20, 2008, 10:12:35 AM
Thanks a lot hood, I wish I had found the thread you just posted in my search trial. I'm going to try this procedure on a dummy-cut this morning.Too bad we can not revert to original settings but hey, miracles are hard to create, they usually happen... So I,ll try this and will post again later to sum-up this thread!

An inspiring group effort !

Dan
Title: Re: How to: Modify z origin when work in progress.
Post by: rcjarvis on March 21, 2008, 12:01:38 AM
Ok , in short:

Config/ ports and pins/ input signals,  browse to to thc up-down, enable up and down and click emulated,  Hotkey should be left and right "Brackets" (  [ , ]  ) then go to mill option and click "alllow thc up and down even if not in thc mode...

Yes it works, but Z can only go up above +0,2 inches. If I start with a z -0,100 deep, I can cut get up ( not down) to +0,5, from there I can go down, but no lower than +0,2. Increments vary from 0,008 to 0,018 on fast clicks.

I'm really close to the goal. If I could get +/- 0,005 increments per click in -0 depth. I tried playing around with other options in mill options. I wonder if thc should be on in input signals.

Dan.

Title: Re: How to: Modify z origin when work in progress.
Post by: Hood on March 21, 2008, 06:58:46 AM
Yes it works, but Z can only go up above +0,2 inches. If I start with a z -0,100 deep, I can cut get up ( not down) to +0,5, from there I can go down, but no lower than +0,2. Increments vary from 0,008 to 0,018 on fast clicks.

I'm really close to the goal. If I could get +/- 0,005 increments per click in -0 depth. I tried playing around with other options in mill options. I wonder if thc should be on in input signals.

Dan.


Not sure I truelly follow what you are saying as I have never used this but in the previously linked to thread there is this
http://www.machsupport.com/forum/index.php/topic,2656.msg16540.html#msg16540

Is that what you are looking to do?

Hood
Title: Re: How to: Modify z origin when work in progress.
Post by: jimpinder on March 26, 2008, 04:38:59 PM
I found something in Configuration when I was looking at it yesterday - is this what you are looking for

Config/Ports and Pins/Mill Options   -  Allow THC UP/DOWN control even if not in THC mode.

I have no idea how it works though.