Machsupport Forum
G-Code, CAD, and CAM => G-Code, CAD, and CAM discussions => Topic started by: iqchallengedd on April 30, 2011, 10:50:47 AM
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I want to make some one piece jigsaw puzzles that are less than perfect fit. It will make it easier to get the pieces to go in. I want to cut the pocket 1/16th bigger than the piece. I could accomplish this by telling SheetCam that I'm using a 1/8" bit when I'm actually using a 1/4" bit. But I like to think I could order this procedure in Mach. I think I'd be less likely (over the years to come) to get confused. I can draw the elephant (or whatever) in SketchUp and then use the offset function of that program to create an image that is 1/16th bigger. The problem with that is that I have to carefully go at the drawing with the eraser tool to get rid of the inside image before exporting it to SheetCam. Is there some way I could take my elephant (in its actual size) to SheetCam as I usually do, and then give Mach a command to cut it with the 1/16" offset. I stupidly thought I could just bump the X and Y up to 103% (or whatever) to accomplish this. But, of course, that does not work. Thanks for any help.
Picture below shows elephant enlarged with offset tool (in SketchUp) and inside image being erased.
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The way I would do this it to cut both the pocket and the puzzle piece at the some time. I would CAM the drawing using NO offset, that is to say cut right on the line. Then use a cutter to give you the proper amount of play between the parts.
Mike
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Your first instintive thought was your best (;-) Just add notes to the file explaining how the file is to be cut and with what size bit.
There are many ways to do it. Scaling will work IF you scale from the CENTER of the drawing so the scaling is applied equally. OR cut both parts from the same exact spot.
Tool offsetting will work once you learn to apply it properly.
offsetting the image in CAD will work
Just a some thoughts, (;-) TP
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Thanks for the responses. I guess there is no mechanism for doing it electronically. I'll just have to do it with the bit manipulation. Thanks again.
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DO you mean by use of the scale feature? Sure it will.
(;-) TP
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Actually, that's the first thing I tried. That doesn't work. Here's why: If you take an eight foot 2 x 4 (1-1/2" x 3-1/2") and increase it to say... 103%-- the length will increase by 2.9". The width will only increase by 0.1" (if I did my math right). So the border is far from equal moving around the piece of lumber. I asked a CAD savvy architect about it and he explained that scale was totally different from offset. So the 2 x 4 was scaled-up but the offset went crazy. My desire is to maintain an equal offset all around the piece. It started off as a need to make a lose-fitting puzzle. But now I'm no longer thinking about how to fool the machine by dialing in a different size bit. That's too limiting. I'd like to think I could make a groove ANY thickness around the elephant simply with the keyboard. And-- you can with CAD (SketchUp in my case). But you end up with having to clean up the drawing. It would be far nicer if I could get my SheetCam or Mach3 to handle it. It has become a challenge for me. I'm positive that the geniuses who design these software programs can do it. They may have elected not to because of the lack of demand for it. But I'm sure they could.
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I don't know about sketchup but many cad or cam software has the option to keep or delete the original vector.
Maybe sketchup has it.
Jeff
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I don't know about sketchup but many cad or cam software has the option to keep or delete the original vector.
Maybe sketchup has it.
Jeff
Ah! That would be helpful. Thanks
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You could do it in CAD and would assume that you could do it in most CAM software even LC.
Just do an offset of the original and then turn off / un-enable the original and use the offset.
You would offset the one such that it would cut one profile, say the boarder of the elephant, and then offset differently for the clearance or puzzle piece.
Not difficult and you only need one profile to begin with.
RICH
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Thanks for your response Rich. And thanks to all. I contacted Les Newell, creator of SheetCam. I asked him to read the thread. He said "Use finish allowance". I've always noticed this box in the process menu but didn't know what it was for. He advised me to put in the amount of offset desired to get the result I need. I haven't had a chance to test it yet but I'm confident it will work as he said. ;D
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Interestingly this is exactly the same issue I ran into when experimenting with inlay work. The solution I used was to thicken the line of the .dxf image then create one toolpath cutting on the inside of the line and then create the other toolpath cutting on the outside of the line. I used the toolpaths opposite to the way you would because I wanted my parts to fit together without any gap at all. http://www.machsupport.com/forum/index.php/topic,12444.msg125920.html#msg125920
Tweakie.
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"Interestingly this is exactly the same issue I ran into when experimenting with inlay work."
Yes. In face to face discussions I've used the inlay example to get people to understand what I was wanting to accomplish. I've disguised my real goal because I didn't yet want "the world" to know what I was doing, AND, because I thought the "puzzle" analogy would cut to the chase. What I'm really doing is trying to kick off a small business using my CNC router to make foam tool mats. It begins with a wrench lying on a light box with a camera perched above. So that gives you an exact silhouette of a wrench. Mechanics would struggle to get the wrenches in and out of such a perfect fit. So I needed some way to dial in a "factor" as needed. Some wrenches might be adequately lose with 0.010" wiggle room while others might need twice that (or more). So I needed a solution that would solve more than one situation. Hopefully Les (Mr. SheetCam) has told me how to make it happen.
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I've disguised my real goal because I didn't yet want "the world" to know what I was doing
Sneakie. ;D
Glad to hear you have it sorted.
Tweakie.
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If you used a "real" CAD program instead of Sketchup, Offsetting the line should take about 5 seconds. Sketchup is not really a good choice for doing 2D CAD drawings, imo.
This free 2D CAD program has been getting outstanding reviews.
http://www.3ds.com/products/draftsight/download-draftsight/?xtor=SEC-6-GOO-[]-[]-S-[draftsight]
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Have you tried scaling by its aspect ratio and not 1:1.
(;-) TP
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This free 2D CAD program has been getting outstanding reviews.
http://www.3ds.com/products/draftsight/download-draftsight/?xtor=SEC-6-GOO-[]-[]-S-[draftsight]
I'll sure test drive the bugger. Thanks
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Have you tried scaling by its aspect ratio and not 1:1.
(;-) TP
Don't know how. But I'll check. The more solutions, the better.
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Tested SheetCam's "finish allowance". Problem solved.
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This free 2D CAD program has been getting outstanding reviews.
http://www.3ds.com/products/draftsight/download-draftsight/?xtor=SEC-6-GOO-[]-[]-S-[draftsight]
Worked a few hours on learning it. I'm more than a little slow. After a while I decided to try to open a drawing (.dwg) in SheetCam, my favorite (and only) CAM program. Guess what? Not compatible unless you know something I don't know. So back to SketchUp and its .dxf files or maybe another CAD program.
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http://www.freecadapps.com/swdetails.php?page=category&value=UTL-CVS&orgvalue=UTL&review=10067&rowcolor=ffffcc
Try this program, it is supposed to be free.
jeff
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Thanks, I will.
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"Worked a few hours on learning it. I'm more than a little slow. After a while I decided to try to open a drawing (.dwg) in SheetCam, my favorite (and only) CAM program. Guess what? Not compatible unless you know something I don't know. So back to SketchUp and its .dxf files or maybe another CAD program."
Spoke too soon as usual. Apparently the drawings CAN be saved as DXF files. Haven't yet confirmed it but there is an option for it so I'm confident that you can.