Hi all. Im after some advice on plasma cutting designs into saw blade/discs. Ive done this once before but how i positioned the workpiece, it was about 1/2 inch off from side to side. What i did before was make a design of the same size as the disc(a circle the same diameter, with a design inside), cut out the detail and then closed the code before it wanted to cut the outer circle.
When positioning the 1st cut i placed the torch where the arrows are on the enclosed pic. But this is whats given me the error. Ho do i position my torch into the centre? Would this be done on sheetcam? Or mach 3? Im assuming itll be a simple fix. Im still a newbie at this kind of stuff
Thanks.
Picsart_23-03-18_22-41-44-682.png
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Chris - I don't use sheetcam, but my suggestion would be to experiment using a sharpie pen holder attached to your torch and draw it first to figure out what adjustments you need to have the center of your image correspond with the center of the circle.
Is it the part in sheetcam where theres a square with 3 rows of 3 dots on, ive always selected the bottom left of the square. Is this to position the torch?
Thanks david. Its on th to do list.
I think what you are doing above is a good way to do it, you may have just been off on your positioning. In the past I have done the same thing and placed a large square on the table and placed the circular object in the square and then line the torch nozzle center at the crotch of the square. So long as your circular dimension is correct in your drawing everything should cut where it is supposed to.
SquareIt.png
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You can center your circle on 0,0 in SheetCam. When you import the drawing pick the dot in the center. You might want to center your job on 0,0 as well otherwise the display will look goofy with only one quadrant showing as being on the material. But it should still cut fine.
Then just zero your torch in the exact center of your blade. It should cut your design as you have it drawn.
djreiswig wrote: ↑Wed Mar 22, 2023 10:08 am
You can center your circle on 0,0 in SheetCam. When you import the drawing pick the dot in the center. You might want to center your job on 0,0 as well otherwise the display will look goofy with only one quadrant showing as being on the material. But it should still cut fine.
Then just zero your torch in the exact center of your blade. It should cut your design as you have it drawn.
That is some great advise! I do something similar with Aspire for cnc routing. Plasmacam has its own system where the work coordinates for the part being cut are the position on the drawing of the particular part.
dreiswig is correct in that your drawing origin must match the origin you select in SheetCam.
You can cut it the way you show with the arrows but that has to be your origin in drawing and sheetcam. I think that is your issue if it is off.
Most guys I have seen use the center selected in SheetCam. I do not, I always use the bottom left corner as that is 0,0 or the origin in all my drawings.
I hope that didn't confuse things.
Dennis
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If you use the bottom left corner as 0,0, then it will be much more difficult to align your saw blade than if you set 0,0 to the center of your drawing. Then you can drop the saw blade on the table and jog the torch to the center of the hole in the blade and zero your x & y. Now your drawing will be cut centered on the blade.
I normally use the lower left corner as my origin when cutting sheet unless I need to align to the center of an object.
Yes I agree. Although I don't use Sheetcam, for round parts I generally use the center of the part as 0,0 and reference this to 0,0 on the machine.
David
Everything above is right of course, here's my two cents
If it's really fussy I mark the start on the steel sheet, drop my torch on my start as close as I can get it and manually turn the torch on/off real quick.
This leaves a little mark.
Then I measure how far I'm off (if any) from the fire mark to my zero and use an incremental move on the control console to shift the head that amount.
If I'm being really fussy I then redo the test fire to make sure I'm right on the start.
For me, this gets my cut within 1/32" on the first iteration which is close enough for my parts.
I'm glad I clicked on this thread, even though I still can not figure out how using the center dot in sheetcam affects part zero. I thought, and use it this way, that that option is for table placement?
I use Qcad for generating the dxf. Torch home is lower left as viewed from above in sheetcam. To put multiple parts on one sheet, I have used the various dots to input new parts so they do not overlap previously placed parts, then in nesting mode, drag the new part to manually place it.
Is the conundrum faced in the authors original post based more in the torch control program? As in, I use CandCNC. Now I have not yet placed a presized round object on the table to cut, so I have not yet run into the issue stated to find zero.
I think I have a grasp on weldguy's idea using the square, but that square would have to be "square" with the table's x and y would it not? Otherwise if it's askew even a little, the zero point of the circle would be off center. Or....?
Thank you guys so much for all of your sharing of experience and knowledge learned. I hope to be able to someday be adding to this site, instead of always taking. But like beeson1987, I too am still new to this.
