I have just finished building a CNC machine. Mechanically t works wvery well. I have downloaded the Mach3 demo software which is also working as it should.
Howeve, I have a problem with G-Code files. I have drawn a template (45 mm square with four 4mm holes at each corner) with CorrelDraw ver.8 and saved as a plt file. When I load this into Mach3, the G-Code produced is dimensionally wrong!. The X and Y values are in the order of 1 or 2 units. Shouldn't it be 45 as I have drawn it?and cut I get a small movements in the X and Y axes. It isn't the machine, for when I manually enter a G-code instruction it works fine. For example, if I enter "G0 X50" the X axis will move 50mm.

Can someone throw some light on this matter. I have absolutely no knowledge of G-Code programming. Thanking you all in advance

Jock

Is there an option on the import for metric units? If so, try turning it off (or on) and see if that helps

Try using a (DXF) File

is there an option on scale that maybe turned on?

Post your g-code file here

Try this file if it dont work Mach3 is set up wrong. if it works CorrelDraw plt file is wrong. :D

Thank you to everyone for coming to my rescue. I have imported Motomitch's file and it work as it should. I noticed that G-Code genrated from his file gave a X and Y value of 45. With my file it gave a value of 2.2 for a value that should be 45. The fact that Motomitch's file generated the correct value must mean that the scaling was not on.

Thinking that maybe the dfx file I generated was incorrect, I used DeskEngrave to create three letters (ABC) at 72 pts, which translate to 25.4mm in height. Imported it in Mach3 and yet again the G-Code was wrong! So where did I go wrong ?

Thanks again to all the help

Post the .dxf and we can see what size the .dxf is.

Sorry Switcher, I was going to say in my earlier reply that I am not able to sendng to the G-Code file. In a hurry to response to everyone's help I forget to mention it.

Being wrong I deleted it, if you think that the G-Code may throw some light I would be happy to re-generate it and sent it on.

Thanks
Jock

Go ahead and post your g-code , couldn't hurt anything, we'll have a look at it. :)

Here are the files for my 45mm square. Thanks for the help

Jock

Don't know why G-Code didn't get sent. Here it is-
Switcher, if you look at it you will find the X and Y values are way out.
I imported the dfx file into Mach3 and generated the code. Juat as I did with Motomitch's dfx, except his came out right.

Don't know why G-Code didn't get sent. Here it is-
Switcher, if you look at it you will find the X and Y values are way out.
I imported the dfx file into Mach3 and generated the code. Juat as I did with Motomitch's dfx, except his came out right.

This is a quick geometry for NC code for others to see so they can help you. I ran your program and loaded your DXF and the G-Code matches what you have drawn. Maybe your WPC needs to be changed.

The move values in your program are imperial equivalents of 45mm. I am assuming that your machine is metric, so you will need to convert those values into metric. I am not familiar with Mach3, but is there an option to output in metric?

regards, Oz

Corel Draw is saving you're drawing in inches, not mm. 1.77 inches. You need to scale it up by 25.4

I have been trying out different things and I have finally found that if I save my files as .plt files they work. With all software that have used I have in fact set it to metric. It must have revert to inches with my knowing.

By using .plt files I am getting very good results. I like to thank all of you for the help and advice extend to me.

Jock

take a look at www.simplecnc.com
It is an easy way to make G-Code file