Question; I have a 4'x4' plasma table running on Mach3. We are setting the table up and trying to get to as close as perfect as possible before we start cutting metal. In Correl draw we made a 10" circle with the center cut out, so a donut. The border of the circle is 1' We have a pen attached to the torch and are drawing on a piece of paper. There are small flat spots on the circle and the lead-in, lead-out lines are not lining up exactly (within about 1/32") Through experimentation to see where these flat stops are coming from I override the feed rate in Mach3 to the maximum speed and noticed that the machine creates these flat stops at cardinal points on the circle. I've turned the constant velocity up to the highest setting, but still there's a slight pause.
Is this something that can be adjusted in Mach3 or Sheetcam?
One problem may be on how you are generating the file that you import into sheetcam.
I also use CorelDraw to generate my drawings. If I save it as a straight DXF file, then I get circles made up of lots of small straight segments. If I save it as a SVG file, then I get a smooth curve. The problem with SVG files is that you have to insure that ALL of your line weights and colors are the same or the file will come out as a layered drawing and you will have to generate several G code files. (it shows up as multiple colors in the layer section Sheetcam when you generate the operation)
There is a add-on to CorelDraw called DXFtool which will generate DXF files with smooth curves. Works very well but is only available for X6 and below.
Thanks for the help Willy. I'll give it a go. When I run the simulation in sheetcam the imaginary tool in sheetcam doesn't stop. When I run it through Mach3 the table stops at the cardinal points ( leadin is at 3, then stops for a sec. at 12, 9, 6) Yet when looking at it closer today on the outside circle, the machine doesnt stop from 3 - 9. But stops at all the cardinal points on the inside circle and at 3,9,6 on the outside circle.
So is there a setting in Mach3 or sheet cam that would stop the table stopping at these points?
When corel outputs a DXF file, you get a lot of nodes along the circumference of the circle (at the end of each segment) and it sounds like you have the motion mode set to exact stop so Mach3 will stop at each node and then accelerate to the next. Go to the Gen config screen and make sure the motion mode is set to CV.
I tried SVG and that's going to take some work to figure out. As for CV, it's on. The nodes are at the 12 - 9 - 6 - 3 o'clock position and if I try to remove the nodes obviously the circle becomes a mess.
I made another circle and moved the lead-in lead-out lines to the 1 o'clock position. Now the table cuts through the 9 o'clock node on the inner circle as opposed to the previous circle where the table would cut through the node at the 12 o'clock position on the outer circle.
So is there a setting that I'm missing to tell Mach3, Sheetcam or the table to not stop at the nodes and keep cutting?
SVG is easy once you get used to drawing with the same line weight all the time in Corel.
Try this. Go into corel and draw a circle. Save it out as a DXF file and also as a SVG file. Now process both of them thru Sheetcam.
Now load the DXF G code file into Mach and run it while looking at the tool path screen (you don't need you cutter/ table running). Notice that it takes several lines of G code to cut out the circle with a very slight pause at each line/node.
Now load the SVG G code file and do the same thing. It should only take 1 line of code to cut the same circle with no pauses.
Depending on your setup (computer, table, electronics, etc), this can give you the problems you are having. There may be other factors but this is the problem I had when I first started.
The other solution is to purchase DXFTool from Leonard software. It will give you nice smooth curves from CorelDraw. The only problem is that it only works with versions up to X6. If you are using X7 or above, stick with the SVG.
Good morning Willy, thanks for the response. We are using Coreldrawx8 and when we made a circle in a circle (outer circle was 8"x8" Inside circle was 7"x7" So a donut) and exported it in SVG to sheetcam it was quite distorted. It was a single layer and was combined. So once again we must be missing something in Coreldraw.
I use X7 and drew your donut and it came out perfectly.
I drew 2 circles, converted both to curves, grouped as 1 unit, and then saved (not exported) as a SVG file. Then I imported the SVG into sheetcam and generated the G code, loaded it into Mach and ran it. With 2 circles, you get more nodes and each circle had 4 lines of G code,. It seemed to be 1 line for each quadrant of the circle.
Cutting a perfect circle
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