Friday, November 1, 2013

First CNC Router Cut

I spent the evening at the Milwaukee Makerspace.  Tonight I learned how to use the CNC router.  Brant, the President of the 'space spent over an hour training me.  (Thanks Brant!)

I used the CNC router to cut the wood support pieces for the automated pet food dispenser.  The very first thing you need to cut something on a CNC router is a drawing.  The thing you want to make is designed in a 2D software application like SolidWorks, AutoCAD, or Google Sketch.  The application needs to output the results in STL format.  Fortunately, I was able to get the STL file for the wood supports from the Instructables page.

The next step is to load the STL file into a program called CamBam.  CamBam takes CAD drawings and converts them into a script (called G Code) that the CNC software can understand.  Brant and I played around a bit with the settings.  At first, CamBam was confused about how to cut the outside of the piece.  We had to combine all of the individual line segments that made up the outer edge into one long line to make it easier to follow.  Brant spent a lot of time showing me all of the settings in the software.  We got everything working so the machine would cut the hole in the middle, make small indentations for the screw holes, and cut out the entire piece.  The last step was to save all of the commands required to cut the piece as a G Code file.

The G Code text file was loaded into a program called Mach3.  Mach3 is the software that actually controls the CNC router.  It processes the G Code line by line, sends signals to the CNC router and processes the results.  We also had a small amount of setup to do in Mach3.  Basically, we had to center the router in the correct position and height to do the cut completely within the piece of wood.  That only took a few minutes and we were underway.

We programmed the CNC machine to make three passes of .25 inches each.  In hindsight, maybe it should have made more passes.  That might have kept the wood from getting torn up.  The total cut time was only about three minutes per piece.  After the first cut was done, we moved the bed, re-zeroed the router, and cut the second piece.

Here is a link to a short (and somewhat boring) video showing the first cut on the CNC router.  As you will see, we had to hold down the piece when it made the indentations for the small holes.  We fixed that on the second cut by adding more holding tabs and also cut the outline of the entire piece last.

After cutting both pieces, I sanded them and then drilled the small holes for the screws.

I have finished making all of the pieces for the dispenser.  Now, Tim and I need to put it together.

Another great day at the Makerspace.

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