Problem with drawing? or CAM?

[CNC Darren]

Hi all
I am having a problem with this file or my cam. I am using sheetcam wich I really like, I am using 9.2demo but it should be posting the whole code as I have evaluation days left. I am starting to thing that there is something wrong with the drawing as i have done one simular to this one and it worked before. The only difference is this one has more points around the oval for a smother cut, on the last code you could see the angles around the oval. this has been drawn in Rhino and saved as a R13 and arcs are saved as polylines just like I did the first drawing but this one will only post around 125 lines or about 3/4 around the first(inside) oval. can any of you tell if there is something wrong with the drawing? I'm stumped
Also I am thinking of buying sheetcam but would be interested in checking out any sub $200 cam programs before I buy, any sugestions?

CNC Darren

P.s. not sure if this is the right group for this, plese move if it isnt.

[HuFlungDung]

I don't see anything in that file. But suffice it to say that you should be exporting everything in the form of lines and arcs in your dxf, because that is what your cnc machine needs to base its motion commands on. Whether that is what "explode" does, I'm not sure, but give it a try. Even if sheetcam can make sense of a polyline, it'll probably do just fine with lines and arcs.

[MrBean]

Looks OK in Mach2

Regards Terry.....

[MrBean]

Picture was a bit crap......Here's another.

[CNC Darren]

one thing when I try try import the drawing into mach2 i also get some circles that show up that are not on the drawing? I tried this because i can draw the part and take into account the inside or outside offset but i get circles that are not supposed to be there.

CNC Darren

I'm still pretty new to the software side of this... still need all the help i can get.

[MrBean]

Originally Posted by CNC Darren one thing when I try try import the drawing into mach2 i also get some circles that show up that are not on the drawing? I tried this because i can draw the part and take into account the inside or outside offset but i get circles that are not supposed to be there. CNC Darren I'm still pretty new to the software side of this... still need all the help i can get.

If the circles are light blue in colour, I know the problem you mean, as I've had it myself. Unfortunately I can't remember what the solution was. I think it may have been something to do with IJ mode. You can alter it in config > state.

You can also manually add a G command to your code to alter the IJ mode.

Hope that's of some use to you.

Regards Terry.....

[ger21]

AutoCAD couldn't load it. Try saving as V12, you'll get better results. One thing you can do, on the Save .dxf dialog, is set the max polyline length to a small number, like .05. This will make the curve many straight segments, each .05 long.

I played around in Rhino a little, and found that converting curves to arcs, with a pretty low angle (.01) and tolerance produced a smooth elipse, without straight segments. I'd play around with different Rhino options, and see what Mach2 likes best.

[Bubba]

SheetCam does not like polylines! It uses only lines and arcs to render the Gcode.
Also, many changes have been made since that rendition and is now up to 1.1.6.
Many bugs have been squashed and features added.

Give the new version a try and you may see improvement. When I attempted to open your dxf in acad, I got a blank screen with nothing on it.

Bubba

[MrBean]

I've had no problems with your file. I've opened it ok in all applications I've tried.

Regards Terry.....

[CNC Darren]

Bubba, When I save it in Rino in dxf it asks if I wasnt to save the cruves as polylines or splines. the oval shows up in sheecam using polylines, I can make my tool paths but it doesnt make the complete gcode.

I redrew it taking into account the tool diameter and made the gcode in mach2, its so much easier with SheetCam tho.

CNC Darren

[MrBean]

Originally Posted by CNC Darren I redrew it taking into account the tool diameter and made the gcode in mach2, its so much easier with SheetCam tho. CNC Darren

You shouldn't need to redraw it. I think Mach2 can allow for any sized cutter from the same drawing.

Regards Terry.....

[Bubba]

There is no need to redraw to account for tool size. In SheetCam, you tell it the diameter of the tool and then whether you want inside or outside offset. HOWEVER, all lines have to be "joined"; that is to say NO overlaps, open places, etc. If you have a continious path it will work beautifully.
The biggest probem I have found is not paying attention to the details. I had one the other day that did not trim properly and I ended up with something that looked like () at a connection between two trimmed arcs and sheetcam choked and said it could not do an offset due to "open paths". Zoomd in and cleaned up the offending point and got the desired path.

Bubba