Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Waynec on November 10, 2007, 03:21:39 PM

Title: Almost Home!
Post by: Waynec on November 10, 2007, 03:21:39 PM
I'm a shopbot convert to Mach, with an Ascension controller.  I'm learning to use the Z zero function in Mach 3, and I need a bit of help.

So far, I enter the value of the thickness of the plate, which is .125.  Then I place the plate under the axis on top of the material, and press the Touch button on the screen.  The axis slowly descends until it touches the plate, and sets the Z axis to Zero in the DRO.

When I then cut the Gcode file with cycle start, its cutting .125 OVER the surface of the material.  I thought the purpose of the Z zero is to touch the plate, and then have the macro subtract the plate thickness to provide an exact zero at the surface of the material.

Should I be entering the NEGATIVE value of the plate thickness- i.e - .125?

Sorry to be so thick here.  But its all sort new to me.

Wayne C

Title: Re: Almost Home!
Post by: Chip on November 10, 2007, 05:53:32 PM
Hi, Wayne C

"Should I be entering the NEGATIVE value of the plate thickness- i.e - .125? "

Yes your Gcode should be  Z- .125

Thanks, Chip
Title: Re: Almost Home!
Post by: jimpinder on November 11, 2007, 01:30:54 PM
Wayne - It is a bit difficult to tell you - and a bit simplistic to say that you need to do A B or C.

The thing that Mach 3 needs to know is where it is in relation to the G code program.

Some G code is written from the work table upwards - i.e. Z0 is the work table level - so you can touch your tool tip on the work table and zero the DRO and away you go.
Some G code is written from the top of the work downwards - so you touch you tip on the worktop and then zero your DRO and away you go.

What you need to tell Mach 3 is - where is the tool tip in relation to what the program is expecting - how you do that is up to you. You can touch the tool tip where you like - as long as you know what height it is and then set the DRO accordingly.

On my lathe, for example, I take a cut across the face of the job - and then tell Mach 3 that point is Z0 (because that is how I write my programs). I then touch the tool tip on the side of the work. I measure the thickness of the work, half it, and then tell Mach 3 that is X?? - X0 being an imaginary line down the lathe centre.

You, I assume, do the same for x and y - setting the tool at a point - and telling the mill that is X0 Y0 - i.e. where your program starts - and you must do the same with the Z - i.e. tell Mach 3 where Z0 is - either by moving it to Z0, or moving it to some other place and telling it what height it is at.
Title: Re: Almost Home!
Post by: Greolt on November 11, 2007, 11:48:33 PM
Wayne

There is no Z zero function built into Mach3.  There is "Gauge Block Height" on the offsets page.

However many users have made their own Auto Tool Zero devices usually with complimentary VB scripts to make them function.

There are a great variety of ways to do it.

So you need to let us know what type of device or method you are trying to get working before we can attempt to offer assistance.

Greg
Title: Re: Almost Home!
Post by: GaryB on November 12, 2007, 02:21:09 PM
Wayne if your using the screen set that came with the Ascension that has the touch off button with an input line for the plate thickness on the front screen then your problem is the button script. If I remember correctly that script had a bad line in it.
Title: Re: Almost Home!
Post by: Greolt on November 12, 2007, 04:16:26 PM
OK if you are using a third party screenset and Zero script then post the screenset so we can have a look at it.

Button scripts are embedded into the screenset so posting that will allow us to check it out.

Greg
Title: Re: Almost Home!
Post by: Greolt on November 12, 2007, 04:29:08 PM
On second thoughts I have what I believe is a copy of the screenset that Scott wrote for the Ascension.

I have attached a TXT file that contains the script from that copy.  Also a small screen grab to see if it looks the same.

Compare it to the script you are using and see if it is the same or similar.

This one looks fine and should work if this is in fact the same screenset.

I only got this screenset a couple of weeks ago and I'm sure if it once had a flaw Scott would have corrected it.

Greg

PS:  Scott I have no desire to step on any toes.  ;D  So jump in here if you wish.
Title: Re: Almost Home!
Post by: GaryB on November 12, 2007, 05:31:32 PM
Greg the screen set I'm refering to is the one Custom-CNC was shipping with the Ascension, which was a revised 1024 set.
As I believe Wayne has had his Ascension for over a year but has just gotten around to installing I believe he may have this screen set, he only has to open up the button script and correct if it is not working for him.
The one you have posted is Scott's own revised screen set for his Ascension not the one that shipped with the Ascension.
Title: Re: Almost Home!
Post by: Greolt on November 12, 2007, 05:39:16 PM
OK thanks for that Gary.  Then I go back to my previous post.

Wayne can you post your screenset and we can check the script out and it's relation to screen changes
that have been made from the Mach standard.

Greg
Title: Wow thanks!
Post by: Waynec on November 13, 2007, 08:43:48 PM
I just checked back in, and I'm so impressed by the support here.  I'm so new that I'm sure I seem a total idiot, but you guys still make sure I'm up and running.  That's impressive.

I do have the Ascension, and the modified screen set for it.  Its attached here.  But I do like Scotts screen set.  If that works, I'd like to install that.

I use Artcam cam software, which allows me to locate Z zero at the top or bottom of the material, and writes the appropriate code.  With the Z Zero plate, I typically tend to code Zero at the top of the material.

Thanks so much for the support.  I'm really enjoying the Mach software and its versatility.  I just took a look at the Flash screens and whats possible there- wow!

Title: Re: Almost Home!
Post by: GaryB on November 13, 2007, 10:29:26 PM
Here you go Wayne try this
Title: Re: Almost Home!
Post by: Greolt on November 13, 2007, 11:37:54 PM
Wayne I put together this screen with a more comprehensive zero script.

The old one had no allowance for overrun.

This one is an adaptation of one that Scott wrote.

You'll find that it works quite well.

Greg

EDIT:  I think the Mach version you have must be a bit old.  Update it to the latest lock down version.
Title: Re: Almost Home!
Post by: Waynec on November 15, 2007, 08:21:20 PM
Well, I'm closer.  I downloaded the screenset and loaded it.  I tried the Z Zero routine, and it seems to work.   I inputted -.125 into the input box.

It seems to zero correctly- that is it lowers to the plate, and then ascends to 2.0 inches.  But when I run a file, it runs ABOVE the surface of the material I just zeroed to.

So, how do I set the amount the routine RAISES the Z axis after touching the zero plate?

And how do I look at this routine or make value changes?

THanks again for the help.

Waynec
Title: Re: Almost Home!
Post by: Greolt on November 15, 2007, 08:51:08 PM
Wayne both Gary and I posted screens with scripts.  Which one are you referring to?

Greg
Title: Re: Almost Home!
Post by: GaryB on November 15, 2007, 09:08:03 PM
He refering to yours Greg. yours had the 2" retract
Wayne, click on edit button scipt and selet the auto tool button while flashing, the editor will open then edit the line G0 Z2 to G0 ? whatever height you need.
how much are you off after running a zero routine to your material. You shouldn't need the - in front of your plate thickness for that routine.

Greg what part of Aust are you located? I'm a transplanted Victorian
Title: Re: Almost Home!
Post by: Greolt on November 15, 2007, 09:18:07 PM
Yeah as Gary said do not use a negative number in the DRO.

Just measure the plate thickness and put that in as a starting point.

Then it is important to fine tune that amount by trail and measure.

My plate is 1.52mm but to be accurate I need to enter 1.49.

G'day Gary.  I'm in Geelong.

Greg
Title: Re: Almost Home!
Post by: GaryB on November 15, 2007, 09:34:57 PM
They still got the baywalk bollards there? been a long time for Geelong. Hail from the gateway to the Grampians - Stawell
Title: Re: Almost Home!
Post by: Greolt on November 15, 2007, 10:19:16 PM
Yeah you wouldn't know it now.

They've cleaned up the bay side of the city a lot.  All cafes and broad walks now.

Greg
Title: Re: Almost Home!
Post by: Waynec on November 17, 2007, 08:15:07 PM
Finally got a chance to check out the new Zzero routine.  It works fine.  Thanks so much for your help.  I also tried the GO TO Z, and the To Go buttons.  Now that I have these, I'm pretty much set for now.

I can adjust the plate thickness amount to get things dialed in.

Thanks again for the help.

WayneC