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### Author Topic: Perfect Square?  (Read 24992 times)

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#### kolias

• 1,154
##### Perfect Square?
« on: August 23, 2009, 10:09:44 AM »
Looking at the tool path screen, Lines N45, N50, N55, and N60 are tracing the outline of a square. The square looks like a square (I made it in ACAD) but the axes numbers vary.
N45 Y9.0788
N50 X3.5166
N55 Y1.9398
N60 X-3.6224
Why such a big difference in the numbers especially in the Y axis? (gcode attached)
Nicolas

Nicolas

#### RICH

• 7,427
##### Re: Perfect Square?
« Reply #1 on: August 23, 2009, 10:29:10 AM »
Take a look at line N30 as that is where the z plunges and is the start of the square.
When in Mach3, just scroll down by one line at a time and watch the display to see each move.
RICH

#### ger21

• 6,295
##### Re: Perfect Square?
« Reply #2 on: August 23, 2009, 11:02:51 AM »
9.0788 - 1.9398 = 7.139 tall
3.5166 - (-3.6224) = 7.139 wide

You have a perfect square.
The numbers just dictate where you drew it. Might be a good idea in AutoCAD to place you're drawing at the origin. (0,0) If the bottom left corner was at the origin, your code would look like this.

N45 Y7.139
N50 X7.139
N55 Y0
N60 X0
Gerry

2010 Screenset
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JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html

#### kolias

• 1,154
##### Re: Perfect Square?
« Reply #3 on: August 23, 2009, 02:46:55 PM »
9.0788 - 1.9398 = 7.139 tall
3.5166 - (-3.6224) = 7.139 wide

You have a perfect square.
The numbers just dictate where you drew it. Might be a good idea in AutoCAD to place you're drawing at the origin. (0,0) If the bottom left corner was at the origin, your code would look like this.

N45 Y7.139
N50 X7.139
N55 Y0
N60 X0

Gerry that is excellent, never thought about it
Nicolas
Nicolas

#### edvaness

• 506
##### Re: Perfect Square?
« Reply #4 on: August 24, 2009, 02:26:34 PM »
Nicolas ,

Even if you don't start your drawing at the 0,0 origin in Autocad , just go to tools/ move ucs , to any point you want, usually lower left , unless your doing a circle.

Ed
Ed VanEss

#### kolias

• 1,154
##### Re: Perfect Square?
« Reply #5 on: August 24, 2009, 07:41:37 PM »
9.0788 - 1.9398 = 7.139 tall
3.5166 - (-3.6224) = 7.139 wide

You have a perfect square.
The numbers just dictate where you drew it. Might be a good idea in AutoCAD to place you're drawing at the origin. (0,0) If the bottom left corner was at the origin, your code would look like this.

N45 Y7.139
N50 X7.139
N55 Y0
N60 X0

I made another drawing in Acad and moved the UCS to the bottom left of my drawing; so the bottom left point is at 0,0

Then after I import the dxf to Lazycam and made the gcode from what I can read the X=3.0173  and Y=2.3773 (code attached)

That means that if I jog my axes to a point I have sat the paper on my table, zero the DROs and start the gcode the axes will move again away before they satrt to draw the object.

I'm sorry if I dont understand but all I want to do at this moment is to grasp how to make the machine start the work wherever I have the axes and all DROs are zero.
Nicolas
Nicolas

#### edvaness

• 506
##### Re: Perfect Square?
« Reply #6 on: August 24, 2009, 09:49:44 PM »
I don't use lazycam , so can't help you there, but apparently 0,0 wasn't at the origin in lazycam.

Ed
Ed VanEss

#### ger21

• 6,295
##### Re: Perfect Square?
« Reply #7 on: August 24, 2009, 09:50:18 PM »
Can you post the .dxf?

Imo it's far easier to move the square in AutoCAD than move the UCS. I've used AutoCAD daily for over 10 years and never move the UCS.

What I'd recommend, is to set up a template with two lines, one along the X axis and one along the Y, both through 0,0 and draw your parts at 0,0. Just delete the two lines before you export.
Even if your parts origin is 0,0, it's unlikely that all your parts will start cutting right at 0,0. I don't use LazyCAM, but you'll need to tell it where you want it to start.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html

#### RICH

• 7,427
##### Re: Perfect Square?
« Reply #8 on: August 24, 2009, 10:39:17 PM »
Nicolas,
Lets see if i can help.
1. Use the shape file ( SHAPES LCMRO HCIR) that is available for download along with the manual in members docs.

The square was drawn such that the origin is at X & Y=0.
Just import it and then export it to MACH3 Mill.

2.In Mach3 Mill, click "Ref all home" then click each... zero the X,Y,Z axis. You have now set home as X, Y,Z equal to 0.
If you look at the display you will notice that the there is no x or y move because home has been set to X &,Y,Z =0.

3. Rewind the program,  ref all the axis to zero.
Now put the value of 1.0 in the X & Y dro's. Now you will see that home is set to the other corner of the square at namely X & Y =1. If you dry run the program you will see that there is a move from where you set home to where
the program begins. Look at the program , line N60 there  is a rapid move to X0.0 and Y0.0.
To get there from "home" the machine must move to the other side of the square which is at X & Y =0.

I think is what you wanted to know,
RICH
« Last Edit: August 24, 2009, 10:59:37 PM by RICH »

#### kolias

• 1,154
##### Re: Perfect Square?
« Reply #9 on: August 24, 2009, 11:09:23 PM »
I don't use lazycam , so can't help you there, but apparently 0,0 wasn't at the origin in lazycam.

Ed

Can you post the .dxf?

Imo it's far easier to move the square in AutoCAD than move the UCS. I've used AutoCAD daily for over 10 years and never move the UCS.

What I'd recommend, is to set up a template with two lines, one along the X axis and one along the Y, both through 0,0 and draw your parts at 0,0. Just delete the two lines before you export.
Even if your parts origin is 0,0, it's unlikely that all your parts will start cutting right at 0,0. I don't use LazyCAM, but you'll need to tell it where you want it to start.

I think Ed has a point here. I did not check in LC if the origin was at 0,0 because I assumed LC will do it automatically. I will be more careful next time.

Sorry Gerry I deleted the dxf for this file, felt was not important. I will try to do what you are saying in Acad. I used to be pretty good in Acad but haven't use it for at least 10 years and therefore my knowledge is pretty rusty.

I know that not all parts will start cutting at 0,0. What I try to learn here is to make a simple drawing, get the gcode thru LC, jog my axes to a point and zero the DROs, and then I will assume when I start cutting (actually right now is drawing with a pen only), the cutting will begin at that point.

RICH I will try what you say and post the results tomorrow. Sounds good
Nicolas
Nicolas