Greetings Chris,
I loaded your file into LazyCam and got the same thing you did. First, I autoclean the geometry. Then, I pocketed it. It generated an extra tool path offset and I deleted that... I played with it a while and found that if I didn't reset origin to minimum I could get a tool path on the pocket with a .25 cutter. I'll attach the LazyCAM project, I hope this helps. If you try to minimize the origin, it deletes the small arc on the bottom of the C. I do believe LazyCam does not care for the way you made your curves, they are arcs. I converted them to curves (if you double click the curves, you'll see dozens of node points, where a curve will only have three node points). I did this in AutoCAD LT and saved it as an ACAD R12 file. This is attached as "c curves.dxf" and LazyCAM likes this much better and autocleans it to one chain with no problem. Also, it minimized the origin on its own with no problems and pocketing was a breeze (even though I did have to removed an extra offset that the pocketing generated).
There is definately a problem with pocketing and offsetting, but I LazyCam is getting much better. Make sure you download the latest version of it, too. If LazyCAM chokes, first look at the drawing. LazyCAM will catch things we sometimes miss. It hates open chains, redundant entities, some types of curves such as b-splines and splines, anything that smells 3-D and some features of some CAD files. It seems to like AutoCAD release 12 format. Try converting circles or arcs to curves, and if that doesn't work, try polylines, or... if all else fails and you must have the toolpath, try retracing complex curves with short, straight lines (I know, I know... but it worked for me and it is not like I can notice it in the parts I'm cutting). Also, close the file in CAD before opening it in LazyCAM.
I have a closely related problem to your own. When I pocket - although it does not show up in LazyCAM - extra circles show up in the G Code file. An important note is that none of my original geometry remains after I've pocketed and offset everything, I remove it. First I'll pocket but to get clear islands of the letters, I'll then offset those and delete them. The circles appear on the offsets. I sort of think of these as victory laps?
or maybe crop circles?
They show up in odd places, sometimes many and sometimes few as the drawing changes, and sometimes they don't appear in the Mach3 toolpath but when I run the g-code, they show up then. I can delete them in an editor but their appearance does not please me and it takes time to find them in hundreds of lines of code. These look like circular lead-ins because they are always tangent to a toolpath line. Even though I turn all leadins off, the box for leadin in each chain stays clicked and the leadin distance is 0.00 units. Sometimes, some of these circles don't show up until I run the g-code in Mach 3. In the attached file, the cutter will circle the little pink circle twice (once on the circle, and once at an offset) but it is shown in Mach3 only once.
To our programmers, thanks for any help you can give me. I can provide more information if you need it. And by the way, GREAT JOB! on LazyCAM. I am a big fan! That is one hard working program! I do know how to use MasterCAM, Cimatron, and ArtCAM on Haas machines from school, but I can do many of the same things with LazyCAM and an old copy of AutoCAD LT on the CNC router I built in my basement. MasterCAM, Cimatron, and ArtCAM... great programs but I can't afford those. A Haas mill - a really great tool but those cost more money than my car. Using LazyCAM... the best $75 dollars I ever spent! Building a CNC router in my basement was not expensive and great fun too!
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