I'm fairly new to inkscape and would appreciate some help with a pcb that I wish to cnc cut on my home built machine. I import a pdf file to Inkscape then using the gcode extensions create the orientation, select and modify the tool then produce the path to gcode requesting a single pass of 0.2mm depth and a lift clearance of 0.5mm all this goes well and the code loaded into my machine operates as instructed by the gcode stream
BUT the questions are
1. although I have requested only a single pass cut the machine gets gcodes to do a second cut at the same depth later in the workflow.
2. for each sharp bend or small radius of the pcb track the cutter retracts and cuts numerous times to produce the profile of the track, is this normal or is there a way to instruct the machine to leave the tool in the cut position and continue to trace out the track.
Most of the time executing the gcode file seems to be in retracting and repositioning the z axis
For question #1, could it be possible that there are 2 paths, on top of each other?
#2 - I might guess that you have a lot of individual 2-node paths, which are not joined. If it's a relatively small drawing, you could join them individually.
Using the Node tool, select 2 adjacent paths
Select 2 overlapping nodes by dragging a tiny selection box around them
On the Node tool control bar, click Join Selected Nodes button
Repeat until all paths are joined
If it's a large file, you might want to try installing an extension which was made for just this purpose. https://github.com/fablabnbg/inkscape-chain-paths Do you need instructions for installing it?
If my guesses were not correct, you're welcome to share the SVG file (or PDF) and we can look for other possible problems.
PDF is not a great filetype for such work, as it contains extra vector/image information that can interfere with editing and output from Inkscape. DXF is a better choice, if your PCB software can output. Better still is SVG.
Feel free to share a PDF that has problems, if this is the only filetype you can work with.
Bryn, Tyler, Thank you for your replies I'm not sure if there are two paths on top of each other but am sure that there are a lot of nodes which require connecting. The pcb is for a friend and the PDF is the format he has supplied me with, I will see if he can provide me with a DXF or SVG file and try that. I will download the extension and see if that helps, Bryn thank you for offering further assistance on this if required I'll give it a shot and cry for help if required.
Overall I am pleased with the performance of Inkscape, UGS and my homebuilt CNC but 1 hour 30 Mins to cut the boardwhich is fairly complex 135mm X 100mm seemed a little excessive and is mainly due to the Z axis activity, this is not a big deal in itself but it would be nice to see if this time could be reduced.
Hi Brynn, I have downloaded the extension and confirmed the two files are in the extenions subfolder. Could you give me some guidance regarding the use of this extension please? the ideal would be to cut one pcb track in one operation then retract Z and move onto another track but I dont know if this is asking too much. I have attached the file I am working as requested.
In the SVG file (or PDF or DXF which is open in Inkscape) you should find the new extension in Extensions menu > Modify Path > Chain Paths.
But first, I would suggest to look and see if there are 2 paths on top of each other. Because if there are 2 paths on top of each other, it will probably confuse this extension. So you'll want to delete one of them. If there aren't 2 paths on top of each other, then I don't know why it tries to cut twice. Do you need help with that?
There are some brief instructions at the download site. But I've just learned a lot more about this extension by testing it. Generally, you need to determine how far apart the end nodes of adjacent segments are from each other. And that's the number you need to enter in "Max distance to connect". Even though they look like they are on the same spot, they might not be, precisely. So you need to look closely using the Node tool, to figure that out (unless you already know).
If the nodes are not precisely on the same spot, and you don't check "Snap connecting end nodes together" the extension connects the nodes with a new segment. If the nodes are precisely on the same spot, and you don't check the "Snap...." option, it still connects the nodes with another segment (even though the new segment has no length). I would consider this....well, certainly not the best design.
All the time I've known about this extension, I assumed it was joining the nodes, meaning that 2 end nodes become one non-end node. But no, without using that "Snap...." option, it puts a new segment between the original end nodes. The option could use a better text description (imo), because snapping is not exactly what it does. It seems to have more to do with how the nodes are joined, than snapping.
If the end nodes are not precisely on the same spot, and you do check the "Snap...." option, it does join the end nodes, but it joins them with a smooth node, creating a curve. If the end nodes are precisely on the same spot, and you check the "Snap...." option, it does join the nodes, and without creating a curve.
So it depends on exactly how the file is set up (node placement) and whether you would want a curve where the nodes are joined, as to how you set it up.
Edit
You're welcome to share the SVG, PDF, or DXF file, if you aren't sure about what to do. Then we could tell you exactly what to do. (Sorry, but I can't use the NGC file.)
Brynn, Thank you for your explanation of the problem and use of the extension which I have now started to get my head around, this Flickr Video https://www.flickr.com/photos/129788915@N06/48509413732/in/dateposted-ff/ shows the problem of the Z axis activity which I'm sure is caused by your suggestions.In the meantime i have asked my friend if he can supply me with DXF or SVG files rather than PDF.
One other problem I came across when doing the test cut was the need to map the bed of the machine for irregularities as when only cutting 0.010" deep the track can run to nothing as it in fact did toward one edge. I will clock the surface manually to check the bed accuracy then try a couple of mapping programs. The machine is a long term development and learning curve!
Once again thanks for the help I am now much wiser to the problem than I was before.
The way the cutting head lifts up and down twice in the same place gives me the idea the path might not be joined there. But I'm only guessing. And for that matter, I was guessing that the Chain Path extension might help. I still don't know if the paths were originally connected or not.
I don't think it matters from my point of view, whether you share a PDF, SVG, or DXF. Because once they are open in Inkscape, they should be essentially the same (assuming they all come from the same parent file). So the PDF should be fine.
Hi Brynn The fact that the job takes longer is really no big deal it just occured to me that the task was not very efficient in it's execution, I think i will try to download a pcb file fron the internet and see how that cuts in a more efficient manner. Overall my project was to build the cnc machine as a more versatile replacement for a Taylor Hobson Pantograph engraver which was limited by the type being copied, this has been achieved and I am happy with the results using Hershey Text extension. The pcb because a friend asked if it was possible. Next job might be coffee cup coasters.
Beginners' Questions PCB Gcode
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I'm fairly new to inkscape and would appreciate some help with a pcb that I wish to cnc cut on my home built machine. I import a pdf file to Inkscape then using the gcode extensions create the orientation, select and modify the tool then produce the path to gcode requesting a single pass of 0.2mm depth and a lift clearance of 0.5mm all this goes well and the code loaded into my machine operates as instructed by the gcode stream
BUT the questions are
1. although I have requested only a single pass cut the machine gets gcodes to do a second cut at the same depth later in the workflow.
2. for each sharp bend or small radius of the pcb track the cutter retracts and cuts numerous times to produce the profile of the track, is this normal or is there a way to instruct the machine to leave the tool in the cut position and continue to trace out the track.
Most of the time executing the gcode file seems to be in retracting and repositioning the z axis
Any suggestions would be appreciated.
Jim
For question #1, could it be possible that there are 2 paths, on top of each other?
#2 - I might guess that you have a lot of individual 2-node paths, which are not joined. If it's a relatively small drawing, you could join them individually.
If it's a large file, you might want to try installing an extension which was made for just this purpose. https://github.com/fablabnbg/inkscape-chain-paths Do you need instructions for installing it?
If my guesses were not correct, you're welcome to share the SVG file (or PDF) and we can look for other possible problems.
PDF is not a great filetype for such work, as it contains extra vector/image information that can interfere with editing and output from Inkscape. DXF is a better choice, if your PCB software can output. Better still is SVG.
Feel free to share a PDF that has problems, if this is the only filetype you can work with.
Have a nice day.
TD
Bryn, Tyler, Thank you for your replies I'm not sure if there are two paths on top of each other but am sure that there are a lot of nodes which require connecting. The pcb is for a friend and the PDF is the format he has supplied me with, I will see if he can provide me with a DXF or SVG file and try that. I will download the extension and see if that helps, Bryn thank you for offering further assistance on this if required I'll give it a shot and cry for help if required.
Overall I am pleased with the performance of Inkscape, UGS and my homebuilt CNC but 1 hour 30 Mins to cut the boardwhich is fairly complex 135mm X 100mm seemed a little excessive and is mainly due to the Z axis activity, this is not a big deal in itself but it would be nice to see if this time could be reduced.
Thanks again for the help,
regards Jim
Hi Brynn, I have downloaded the extension and confirmed the two files are in the extenions subfolder. Could you give me some guidance regarding the use of this extension please? the ideal would be to cut one pcb track in one operation then retract Z and move onto another track but I dont know if this is asking too much. I have attached the file I am working as requested.
Thanks again
Jim
In the SVG file (or PDF or DXF which is open in Inkscape) you should find the new extension in Extensions menu > Modify Path > Chain Paths.
But first, I would suggest to look and see if there are 2 paths on top of each other. Because if there are 2 paths on top of each other, it will probably confuse this extension. So you'll want to delete one of them. If there aren't 2 paths on top of each other, then I don't know why it tries to cut twice. Do you need help with that?
There are some brief instructions at the download site. But I've just learned a lot more about this extension by testing it. Generally, you need to determine how far apart the end nodes of adjacent segments are from each other. And that's the number you need to enter in "Max distance to connect". Even though they look like they are on the same spot, they might not be, precisely. So you need to look closely using the Node tool, to figure that out (unless you already know).
If the nodes are not precisely on the same spot, and you don't check "Snap connecting end nodes together" the extension connects the nodes with a new segment. If the nodes are precisely on the same spot, and you don't check the "Snap...." option, it still connects the nodes with another segment (even though the new segment has no length). I would consider this....well, certainly not the best design.
All the time I've known about this extension, I assumed it was joining the nodes, meaning that 2 end nodes become one non-end node. But no, without using that "Snap...." option, it puts a new segment between the original end nodes. The option could use a better text description (imo), because snapping is not exactly what it does. It seems to have more to do with how the nodes are joined, than snapping.
If the end nodes are not precisely on the same spot, and you do check the "Snap...." option, it does join the end nodes, but it joins them with a smooth node, creating a curve. If the end nodes are precisely on the same spot, and you check the "Snap...." option, it does join the nodes, and without creating a curve.
So it depends on exactly how the file is set up (node placement) and whether you would want a curve where the nodes are joined, as to how you set it up.
Edit
You're welcome to share the SVG, PDF, or DXF file, if you aren't sure about what to do. Then we could tell you exactly what to do. (Sorry, but I can't use the NGC file.)
Brynn, Thank you for your explanation of the problem and use of the extension which I have now started to get my head around, this Flickr Video https://www.flickr.com/photos/129788915@N06/48509413732/in/dateposted-ff/ shows the problem of the Z axis activity which I'm sure is caused by your suggestions.In the meantime i have asked my friend if he can supply me with DXF or SVG files rather than PDF.
One other problem I came across when doing the test cut was the need to map the bed of the machine for irregularities as when only cutting 0.010" deep the track can run to nothing as it in fact did toward one edge. I will clock the surface manually to check the bed accuracy then try a couple of mapping programs. The machine is a long term development and learning curve!
Once again thanks for the help I am now much wiser to the problem than I was before.
Regards Jim
The way the cutting head lifts up and down twice in the same place gives me the idea the path might not be joined there. But I'm only guessing. And for that matter, I was guessing that the Chain Path extension might help. I still don't know if the paths were originally connected or not.
I don't think it matters from my point of view, whether you share a PDF, SVG, or DXF. Because once they are open in Inkscape, they should be essentially the same (assuming they all come from the same parent file). So the PDF should be fine.
Hi Brynn The fact that the job takes longer is really no big deal it just occured to me that the task was not very efficient in it's execution, I think i will try to download a pcb file fron the internet and see how that cuts in a more efficient manner. Overall my project was to build the cnc machine as a more versatile replacement for a Taylor Hobson Pantograph engraver which was limited by the type being copied, this has been achieved and I am happy with the results using Hershey Text extension. The pcb because a friend asked if it was possible. Next job might be coffee cup coasters.
Thanks again for the help.
Jim
You're welcome.