Fabrication of 2.x Parts...

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Fabrication of 2.x Parts...

Postby iamwill » Tue Jan 08, 2013 7:56 am

I am trying to fabricate some of the parts for the 2.x laser cutter with my current CNC machine. I am not sure where the problem is though, and wanted to see if anyone else has tried generating gCode from CamBam to cut the parts. Most of the parts are really easy, the ones that I have run into problems with are B17005 and B17042. I can get CamBam to generate a cut path for the wider area on top of the pocket, but not the inner/more narrow pocket area on the bottom. I have tried a few different things, to include generating a rough horizontal profile method before trying to do a waterline cut afterwards, and it still doesn't work. Not sure if it's operator error. i just got CamBam 2 days ago and I am still trying to learn it, so that might be the problem too.

http://www.buildlog.net/cnc_laser/erp/get_doc.php?docNumber=B17005-001
http://www.buildlog.net/cnc_laser/erp/get_doc.php?docNumber=B17042

My thoughts are that the program understands that stock will still be in the way when it tries to start clearing the more narrow pocket and it is not allowing the tool to plunge deeper into that area. Are there any CamBam users that might be able to assist me with this problem? Below I attached a link to the STL that I created. I am pretty sure that it is accurate, and I don't think the problem is there...

http://thebytes.no-ip.org/files/cnc/Parts.stl
http://thebytes.no-ip.org/files/cnc/path1.png This is a picture of the XZ plane looking into the wireframe. You can see the tool path doesn't go deeper than the lip of the piece
http://thebytes.no-ip.org/files/cnc/path2.png This is top view, non-wire frame, the black area is the lip
http://thebytes.no-ip.org/files/cnc/path3.png This is a wireframe showing the same as the second image

Not sure what is going wrong or if I am just not thinking out side of the box... but any help would be appreciated.

One last thing to note. My stock is 1/2 inch thick HDPE. I know most of the parts are only 1/4, but a few are 1/2 so I just figured it would make it easier and I could just mill the top of the shorter pieces.
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Re: Fabrication of 2.x Parts...

Postby Fred » Tue Jan 08, 2013 9:52 am

I'm no expert but have been using CamBam for a while to mill a few things. My first question - why the STL file? I'd suggest the easiest way would be to draw the part in CamBam itself (using the dimensions marked in the documents) and then create the pocket operations and then a final profile operation to cutout the part. I'm busy on a few things at the moment, but if you don't get it working then I might be able to knock up a CamBam file file you at the weekend.

I'm only lurking and thinking about a 2.x build at the moment. One thing that I was wondering (and maybe you were too) is whether some of the kit part that people struggle with could be redesigned to be milled or 3D printed. I'm particularly thinking about the gantry ends that I see people moan about a lot. Maybe that should be another thread though...
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Re: Fabrication of 2.x Parts...

Postby iamwill » Tue Jan 08, 2013 6:51 pm

I didn't even think to design the objects in CamBam. I am still on the pycam mindset where I create everything in a separate program and just export to STL. I am extremely new to this, but I can download all of the PDF files and start that process tonight. I will let you know how it goes. Thanks for the tip.
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Re: Fabrication of 2.x Parts...

Postby Fred » Wed Jan 09, 2013 9:02 am

CamBam is easy to use and has reasonable documentation and support.

Basically in the drawing section you'll draw a circle. Then you select it and click "pocket" and it'll create the operation in the machining section. Set the depth, tool diameter and feed rate as required. CamBam can then generate your toolpath and g-code. A final profile operation will let you cut out the part and will even do holding tabs so it stays in place.

Obviously there's a lot more to it once you get into it, but the basics are simple. Don't forget to check your feedrates. An "air cut" is often a good idea if you're not 100% new to it and worried you may have made a mistake - i.e. shift your Z up so you deliberately "cut" above your stock as a trial run. (My apologies if your experienced at CNC maching but new to CamBam and you know all this.)
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Re: Fabrication of 2.x Parts...

Postby iamwill » Thu Jan 10, 2013 5:31 am

Actually, I have only been milling with my CNC for about a year now. I am comfortable with milling wood, but I have never cut HDPE with it before, that should be interesting. In addition to that, I have never cut any design out from CamBam, I have only used Google SketchUp and PyCam. So far, I like how CamBam works, it's just a VERY time consuming process. (but perfection takes time). Thanks again Fred.
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Re: Fabrication of 2.x Parts...

Postby iamwill » Sun Jan 13, 2013 5:04 am

Below are the parts designed in CamBam and the gCode. It has been milling for some time now, (about 6 hours and it's a quarter of the way done, 1/8" 2 flute bit shaving 1mm at a time at about 40ipm.) so you might want to block off a day if you plan of milling these things out. I am cutting them out of HDPE, and it's my first time working with it, so I am on the side of caution right now.

I did have to stop the machine once to give everything a break, I am not sure how long you can run the Bosch Colt router at 18,000ish RPM's at one shot, but I am pretty sure that 3 hours is pushing it.

Anyhow, if there are any questions, please feel free to ask. It is my first time using CamBam so help is appreciated.

https://thebytes.no-ip.org/files/cnc/buildlog.Part1.nc
https://thebytes.no-ip.org/files/cnc/buildlog.cb
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Re: Fabrication of 2.x Parts...

Postby Kellerkind » Sun Jan 13, 2013 5:00 pm

Hi,
thank you very much for shareing your work.
First of all, please dont be offended if my Questions are stupid, i have very little CamBam knowledge, but i am trying to improve.

When looking at your gcode i am a bit confused, do you try to mill all parts from the thick material ?
If you are, why dont you split the jobs in the thin and thick parts to reduce the ammount of milling required ?
With a 6mm sheet you would just have to do the outline and the holes on most parts.
wouldnt the motor & laser holders inner millings be simpler if they were just a (inner)profile, not a pocket ? not sur how to do this in cambam to have the tool compensation on the inside, but it would also reduce the required milling
Greetings
Nico
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Re: Fabrication of 2.x Parts...

Postby kellogs » Tue May 28, 2013 8:36 am

We have the same issue here in France at Electrolab.fr club.
We plan to cut aluminium and plastic parts and don't know really where to start.
It would be nice to share all our work and we are ready to help.

The downloading links are dead. Any update?

Could we first list all plastic and aluminium parts which can be cut?
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