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### Author Topic: Almost Home!  (Read 7691 times)

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#### Waynec

• 48
##### Almost Home!
« 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

#### Chip

• 2,055
• Gainesville Florida USA
##### Re: Almost Home!
« Reply #1 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

#### jimpinder

• 1,232
• Wakefield, West Yorks, UK
##### Re: Almost Home!
« Reply #2 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.
Not me driving the engine - I'm better looking.

#### Greolt

• 956
##### Re: Almost Home!
« Reply #3 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

#### GaryB

• 108
##### Re: Almost Home!
« Reply #4 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.
Beckwith Decor Products
ArtCam Trainer
Onsrud & Custom CNC tooling Distributor

Wichita/Derby Kansas
http://www.beckwithdecor.com

#### Greolt

• 956
##### Re: Almost Home!
« Reply #5 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

#### Greolt

• 956
##### Re: Almost Home!
« Reply #6 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.    So jump in here if you wish.

#### GaryB

• 108
##### Re: Almost Home!
« Reply #7 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.
Beckwith Decor Products
ArtCam Trainer
Onsrud & Custom CNC tooling Distributor

Wichita/Derby Kansas
http://www.beckwithdecor.com

#### Greolt

• 956
##### Re: Almost Home!
« Reply #8 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

#### Waynec

• 48
##### Wow thanks!
« Reply #9 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!