Creating 'holding tabs' or 'bridges'...

First - this is a CNC Wood Router and I am attempting to 'cut' an outlined piece of wood - yes... my guitar pick guard. My final expected piece will the be very curved outline, routed out of a piece of plastic with small 'tabs' or 'bridges' left at strategic places in outline which 'hold' the routed outline to the blank. I will remove the blank from the table, and then use a knife or some other cutting tool to to cut through the tabs which will free my routed pick guard free.

I have my contour defined in DCAD. When I switch to DCAM to start creating the tool paths, there doesn't appear to be an option to create 'holding tabs' (little sections of the material that remain and span the routed gap so the actual outlined piece does not start moving around during the routing process). There is a 'bridge' function of course - but that appears to be method of connecting multiple contours together to create a single machine tool path. The DCAD Help file indicates that function - but that is not applicable to me - my outline is a single outline.

It seems to me a 'workaround' would be to take my outline, create a second copy parallel to it - offset by at least my expected tool width. Then I have my two elements or contours that I could 'bridge' to create my holding tabs. That's a fine idea - but because this is an imported DXF and is VERY curved - these curves amount to a gazillion little straight lines. 'Selecting' just the outline and then trying to figure out how to 'stretch' it or otherwise create an offset 'parallel' outline of some dimension .25" (or greater) just seems ENORMOUS to me.

Here is a 'picture' of the outline I am trying to route...

http://www.cnczone.com/forums/attach...d=277724&stc=1

Any ideas out there?

Thanks!
Arden

(and I apologize for all the posts... Dolphin wants me to 'learn', 'use' and 'say good things'... right now - I'm at the 'learning' part - hopefully REALLY quickly to the 'use' part...)

Sorry I cannot be of more help. I',m pretty darn new too and what I'm reading is that holding tabs are something of a 'trial and error' but should be a button click option suggestion.
I did find this.
http://www.cnczone.com/forums/dolphi...ding-tabs.html
Since this is more like 2.5D and similar to what I do with my Plasma CNC cutter I can tell you that SheetCAM will do what you are expecting with holding tabs, lead in/lead out etc. It also does nesting and many other things. I know your investment here is with this toolset. Just noting something very popular w/ us flameheads in the 2.5D space. It'll output the Gcode you need.

We'll this is an old old link to a ZIP file that does seem to explain how to do tabs but I have not been able to see the video. Only sound. Maybe it'll show on yours.

Dolphin CADCAM > 2d Tabs on contour to hold part in blank - Page 2

the Zip here: https://app.box.com/s/wvkq9idbzrr1nq5sm0ys

CountryGuy - you are a WEALTH of good information. I was able to download and view (and hear) the complete video. I had already resolved my issue by using a modification of the fellows solution - partial machining. My outline was a total of 776 segments around the outside. I created a number 'GoRound's each one being a partial machining where I 'skipped' a number of the short segments - thus leaving my tabs. The end result came out pretty nice. I THINK I attached the picture...

There's a video on youtube of how to do this. I've only tried it once. You can pick which part of your contour you want the tabs to be in and stop and start the contour to make the tabs.
https://www.youtube.com/watch?v=-XHwadk0RaM

Thanks cjg - but I have already canned this useless software and moved onto other far more user friendly and affordable software. DolphinCAD has been one of THE most useless 'investments' I have made for this hobby of mine. They gave me a SUPER discount at $200 - and that has been WAAAAY too much for what it does and how it does it. My sympathies to anyone who got snookered into a full-price purchase.

Am I bitter?? yes... I use commercial 'canned' software for a lot of things every day. I was doing CAD drawings on software before Windows was a glimmer in Bill Gates' eye, and those apps in the early 80's were far more intuitive than this software EVER was. Sorry Dolphin - there is no love lost for your software.

Irwinger

Sent you a PM irwinger when you get a moment to read it.:)

Quote:

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Originally Posted by irwinger

Thanks cjg - but I have already canned this useless software and moved onto other far more user friendly and affordable software.

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If you don't mind, would you please share what software you moved onto?