New and Struggling Some

[tcaudle]

don't use fixture offsets. Its for doing multiple cuts of the same item in a jig.

You can:

move the entire set of contours with the nesting tool in HSeetCAm BEFORE you do the g-code OR (simpler) just reset you WOR zeros to be the edges of the piece you are trying to cut.

You have two positions on a table:
Table zeros and "HOMES and are absolute and in the same place based on your home switches. Internally CommandCNC measures everything from Homes . The file cuts form WORK zero so you jog out to the place you want XY work zero to be and Zero the X and Y DRO . That is stored as a OFFSET in the control and stays even when you turn it off or you have a power glitch. That way if something happens you simply re-home the axis and it knows where the work zero is . You display is relative to Work zero .

Once you understand there are two co-ordinates involved and that one is fixed and one can be moved its not problem placing material and maeking a cut. I always put a cut at least 1/2" off X0 and y0 on the sheetCAM . That is relative to the Work zero. Never cut to an edge unless you turn off the DTHC .

Three are ways to do NESTING in SheetCAM that can let you cut a sheet of smaller parts . To use a sheet to cut multiple jobs you need to regsiter the material to a known 0,0 (absolute) and then setup the entire sheet in SheetCAM even of you just need part of it. That allowo you to come back and add other parts later in the open areas and turn off those OPERATIONS so they don't cut and layout the new stuff. Just mark you sheets so you can easily match them up. While you can do that with just resetting the work zero you won't be able to nest it quite as close .

You can do a "dry" cut (no torch or DTHC) by clicking the DISABLE TORCH checkbox( You can also disable the touch toffs as well.

[tcaudle]

In this case it makes little difference since the DXF is pretty clean and has tru arcs . Often that is not the case and DXF ends up whit line segments instead of clean arcs . CommandCNC is Linuxcnc at its core so the same POST works for either . There are custom parameters that have to do with the DTHC automation and presets in SheetCAM but the base G-code is the same .
The real secret is the use of the tools in SheetCAM
Since CommandCNC parses the G-code to get the toolpath , if its not on the toolpath dispaly its not going to cut. If there is a problem with the code then it refuses to display the toolpath or the rulers.

[adbuch]

In this case it makes little difference since the DXF is pretty clean and has tru arcs . Often that is not the case and DXF ends up whit line segments instead of clean arcs . CommandCNC is Linuxcnc at its core so the same POST works for either . There are custom parameters that have to do with the DTHC automation and presets in SheetCAM but the base G-code is the same .
The real secret is the use of the tools in SheetCAM
Since CommandCNC parses the G-code to get the toolpath , if its not on the toolpath dispaly its not going to cut. If there is a problem with the code then it refuses to display the toolpath or the rulers.

You have provided some very useful information. I don't really use SheetCam all that much, as my table is Plasmacam and I use Design Edge for creating the cut paths.

David

[TJS]

I am with Tom C. on this one. When I first started cutting I was cutting squares with stars in the middle for practice. Even then it was a huge learning curve for me with inkscape, sheetcam and then Command CNC. Inkscape still is challenging. To take on a large project like the OP posted is even a huge task for me and I have been doing this for a few years. Using a purchased file can be very challenging.
T.J.

[adbuch]

I am with Tom C. on this one. When I first started cutting I was cutting squares with stars in the middle for practice. Even then it was a huge learning curve for me with inkscape, sheetcam and then Command CNC. Inkscape still is challenging. To take on a large project like the OP posted is even a huge task for me and I have been doing this for a few years. Using a purchased file can be very challenging.
T.J.

TJ - I agree as well. That is a large piece of material with many intricate cuts that I personally would not look forward to cutting. I think that the OP would be well advised to start of with some more basic/simple projects to cut while he is getting the hang of it. Also using a sharpie pen holder attached to his torch and drawing vs. cutting would be a good way to go so that he can see what it will look like as the torch moves along the cut paths without wasting so much expensive material.

David

[acourtjester]

There are many tricks to learn in the "What If" shows up. Breaking up a cut routine into separate cutting operations, being sure of where 0,0 position is for a restart. How to work around a miss-fire or lost arc in the middle of a cut operation. And a stated above being sure the G-code is clean or functional before starting cutting. I found having a laser positioner insure where my 0,0 is has been very helpful, I had a 2 step operation the other day where I did a dimple operation one day and the cutting operation a day latter. When the software will do an auto homing at the start moved the table away from my 0,0 on the job. I used a dimple to mark the 0,0 before I stopped for the day and after the homing start I was able to return to the exact position the next day. the second step cut was done without a problem.
Another trick is when a lost arc or miss-fire happens and the G-code moves on, I place a small thin metal piece over the cut area. And move the G-code back to the missed cut start position and restart the G-code there. It allows the pierce and restart of the cut to happen without any problems and complete the cutting operations.

FHD0001.JPG

[TJS]

To the OP. I know there is a lot going on in this post. For me the best tool that I got was the 3D printed pen tool from acourtjester as mentioned to use a pen attachment tool. I have found the easiest way to get the pen tool to work with Command CNC is use the contour method with no lead ins or lead outs and no offsets in sheet cam. If you do get the tool and are having issues, create a new post and I will give you screen shots in sheetcam.
T.J.

[Ingledink91]

thanks a lot of helpful hints Ill keep digging away and sure will have more questions

[adbuch]

thanks a lot of helpful hints Ill keep digging away and sure will have more questions

Did you ever run any of the g-code file provided to you by Tom or myself to find out if you were able to eliminate the unwanted circles?

[Ingledink91]

no sir circles were still present