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Author Topic: G code goes crazy on small detailed drawing ONLY. help !!!  (Read 2125 times)

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G code goes crazy on small detailed drawing ONLY. help !!!
« on: August 24, 2011, 06:06:51 AM »

Hi all , I really need your help ! I've been using the Mach 3 program for many years with great success .  Up until now I  have not noticed any problem when entering my G code into the Mach3 program , all G codes over hundreds of drawings have been perfect . The only thing I have changed , or done different is entered a G code from a drawing that has very small detail .

Let me explain ....

Up until now every CAD drawing I have done ( again hundreds of them ) have had detail where as all the objects were a minimum of 3.2mm ( 1/8 ) or more apart from each other . Where as my new drawings require objects to be cut within 2 mm of each other . It was only at this time I realized that once I put the G code into the Mach 3 program , the G code went crazy in some places . So what I did was go right back to CAD , stretch the entire drawing abit , recreate a new DXF file + G code and then re-import the same drawing ( now stretched a bit ) back in to Mach 3 . By stretching to a point where all objects were 2.6 to 3 mm or greater apart from each other , then the G code would become totally stable again . I repeated this process a few times and it is very consistent , the closer the object get together the more crazy the G code becomes .

So in summery , when doing a drawings with a reasonable spacing between the object there is no problem . However as the drawing detail becomes smaller ( objects closer to each other ) the Mach 3 program does not  seem to be able to decipher it properly .

To me it doesn't seem like there is any problem with the CAD drawing , DXF file or G code . It really does seem to me as if the Mach 3 program doesn't have enough resolution to deal with very small detailed drawings . Again I don't have any problems with cutting on my CNC router table when the drawing objects are far enough away from each other .

Any ideas would be greatly appreciated at this frustrating point in time , many thanks in advance . ;D

Regards Sterling

Offline RICH

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Re: G code goes crazy on small detailed drawing ONLY. help !!!
« Reply #1 on: August 24, 2011, 06:22:50 AM »
Sterling,
Never had the problem you are describing.
Post your dxf and the gcode file.

RICH
Re: G code goes crazy on small detailed drawing ONLY. help !!!
« Reply #2 on: August 24, 2011, 08:49:25 AM »
What do you mean by G-code went crazy?  If the contours are closer than the diameter of your bit, CAM will likely create some unexpected results as it can't cut between two contours that are closer than the bit diameter.  To see if that's the problem, just reduce the bit diameter in CAM and see if the code looks better.
Re: G code goes crazy on small detailed drawing ONLY. help !!!
« Reply #3 on: August 24, 2011, 09:46:37 AM »
The jewelry guys never mentioned anything like that, and they do some ultra fine detail. I too would have to think it is a cutter diameter issue. Or you have multiple overlapping lines and your post is trying to do it all.

The handle "CNC is the future" , made me chuckle, I learned NC/CNC back in 1972, that's when I knew it was the future.