PDA

View Full Version : Weird circle G03 in Rhinocam Mach3 inch post



btsioles
12-29-2012, 12:56 PM
Hello,

I searched and couldn't find anything about this. I'm using a buddy's Rhinocam to generate gcode for my machine running mach3. It's Rhinocam Pro 2.0.4.

I have various MOPs in the single file for machining a guitar body. The simulations and everything look great in Rhinocam, but when I open the resulting Gcode in Mach3, I can see a big circle that runs through the part. I found this out after machining the part, and having it ruin the part.

I've attached an image from mach3 showing the circle. This doesn't apear in any of the toolpaths in Rhinocam. It's during the inital horizontal roughing operation. Here is a section of the gcode, with the bolded line being the culprit:

X2.4273Y6.0226I0.8044J-0.2479
G01 Z1.5904
G00 Z2.0000
X16.1006 Y9.6531
G01 Z1.6404 F30.0
Z1.6154 F50.0
G19
G03X15.8321Y9.7421Z1.5654J-1.0577K-0.0202 F50.0
G17
G02X16.3582Y9.8080I0.4091J-1.1318 F70.0
X16.7370Y9.5287I-0.1039J-0.5374
X16.7106Y9.3160I-0.3410J-0.0657

If I delete that line from the file, the circle disappears. Has anybody experienced this before?

Hopefully someone knows what I need to adjust to make sure rhinocam doesn't output any weird stuff like this. I looked in the post settings, and don't really know what might need to be changed. Any help would be greatly appreciated.

Thanks!
Bobby

awerby
12-29-2012, 05:47 PM
Have you got "Absolute" selected in the Mach3 postprocessor configuration? If it thinks circles are relative, you can get errors like that.

Another thing you can do is to stop letting it make arcs (G02,G03) and have it output everything as line segments. It makes the code a little longer, but you don't get hung up in the IJK stuff.

Andrew Werby
www.computersculpture.com

btsioles
12-29-2012, 06:37 PM
Thanks for the reply Andrew. I will check for absolute mode. With regards to lines and arcs, I always arc fit by going into the tool path and clicking the arc fitting button, then save the tool path. Now I did post a version without doing that and got the same result. Is there some where else you are referring to like a hard setting? I just want to make sure I fully understand.

Thanks again!

Claude Boudreau
12-29-2012, 07:15 PM
Thanks for the reply Andrew. I will check for absolute mode. With regards to lines and arcs, I always arc fit by going into the tool path and clicking the arc fitting button, then save the tool path. Now I did post a version without doing that and got the same result. Is there some where else you are referring to like a hard setting? I just want to make sure I fully understand.

Thanks again!

Do a search for Crop Circles , sounds like it.

http://bobcadsupport.com/techfaq/index.php?action=artikel&cat=1&id=56&artlang=en

http://www.cnczone.com/forums/792318-post28.html check the last paragraph on that post.

Hope this help , good luck

btsioles
12-30-2012, 12:59 AM
Thanks for the reply Andrew. I will check for absolute mode. With regards to lines and arcs, I always arc fit by going into the tool path and clicking the arc fitting button, then save the tool path. Now I did post a version without doing that and got the same result. Is there some where else you are referring to like a hard setting? I just want to make sure I fully understand.

Thanks again!

So, looking at the post processor -> circle tab -> Arc center section, it was set to Vector from center to start. I changed it to absolute, and then reposted, and in Mach, it was yelling at me about, "radius to end of arc differs from radius to start...etc". So, I went into mach and changed the IJ setting to absolute. I restarted mach, and reloaded the file, and it loaded this time, but the silly arc is still there. I put everything back to how it was.

I decided to look at my operation again. I'm using facing, and 40% tool width. I figured that perhaps it's getting confused transferring between paths, and so I changed it to 35% width to see what that might do, and sure enough the paths look clean in mach. No goofy arc ruining the part. I think I'll just leave it alone, and move on. I haven't had this issue before, and have machined various archtop's, so... whatever...

Thanks for the help!!!
-Bobby

preeb
10-22-2014, 04:56 PM
Maybe there's a line overlap in one of your curves? You will still be able to run everything fine in both CAD and CAM but you will risk the crop circles in Mach..