Monthly Archives: June 2012

Ring light for CNC

I recently put LED strip lights under the cabinets in the kitchen, and had a few left over.  They are pretty basic white 12v LED lights, similar to the ones you see here.  While milling a circuit board the other day, I found myself using a flashlight to see how things were progressing.  It was also hard to photograph the process, so I thought I would install some lights.  Pretty straightforward process.  The strips are made of small segments which can be cut off the roll.  I cut 4 sections off, and arranged them in a square.  Soldered the corners up and left a longer lead which would go through my cable raceway to the computer running the show.

The LED’s I had are backed with a 3m adhesive, so mounting them under my z-axis was pretty easy.  Peel and stick!

From there, I opened up the computer case and cut the leads off one of the molex connectors.  The power things like cdroms/hard drives, and contain both a 5v(red) and 12v(yellow) power source.  I connected the Leds up to the 12v, and now whenever the computer is on the LEDs light up the work piece.

 

New sign for the workshop

Took a shot at making up a sign for the workplace.  Learned quite a bit in the process, and wanted to document a few of those learnings for the proverbial ‘next guy’.

I used 3/4″ mdf.. and a 1/4″ upcut spiral bit to do most of the cutting.  The circle logo and ‘aperture’ letters are .4″ above the surface, and the ‘laboratories’ letters are .2″.  I profiled the letters after the overall pocket was created with a 1/8″ bit to get more definition.  This all worked ok except for a few things:

  • An ‘R’ and an ‘I’ in laboratories popped off.  The MDF doesn’t hold well when the letters get small.
  • I re-routed those letters and then glued them on.  In that process I realized that NEXT time i would just route all the letters out of another (thinner sheet) and glue them on.  It would save many hours of pocketing work.
  • Glueing the letters would also allow for easier painting as you could paint everything seperate and then glue them on.
  • On the topic of paint, for $3 for a 1/2 quart home depot will create color matched ‘sample’ paints… awesome for this kind of work.
  • Be careful when shopvaccing around the machine while its working.  At the end I looks like a skipped a few stepper moter steps on the x axis, so i have some rough edges on the right side of my letters.  I vaguely recall the router pinching the hose against a letter while vaccuming.. that may have caused it.  If it didn’t.. well thats a problem for another day.

So I learned a lot, and have a fun sign for the garage – its about 36″ long for reference.

Isolation routing

I had very good success with my isolation routing endeavor.  After having to remember how to do things in eagleCAD, the actual manufacturing process was very straightforward.  To start with, I got the eagle files for an arduino board from adafruit.  I needed this to ensure the through-holes would line up so my board would end up being an arduino ‘shield’.  From there I laid out my components.  I won’t get into the actual circuit, but a few things to note:

  • You will be well served by increasing the trace width to .032″.  The smaller traces I have (seen below) will machine, but are a little small for comfort.
  • When you do the wire layout wizard tell it to put wires on the bottom of the board.  One-sided.
  • For optimal wiring I needed a few traces that ‘crossed’.  Normally you would bring them to the top of a two-sided board.  I wasn’t ready to mill two sides and try to get them to line up.  So I basically put in a 0-ohm resistor as a ‘jumper’ to cross over traces.

So this is my diagram:

From there to get the gcode to mill your board you need to run pcb-gcode.  This is a eagleCAD addon that does a wonderful job of creating gcode.  Installation is well documented on their site, so I won’t cover off on that.  There is no shortage of options to configure, but I didn’t change anything other than my machine type (mach3).  To run the setup options you type “run pcb-gcode-setup” in eagleCAD.

From there you can do your configuration.  Mine is included here, FWIW.

After you have everything configured, you have it work its’ magic by typing “run pcb-gcode”.  The output will e a file showing what the board output will look like.  Remember it will be ‘mirrored’ as its the bottom of your board.  You can close the preview, and the actual gcode will be in your eaglecad folder.  There will be two files, a boardname.bot.etch.tap and a boardname.bot.drill.tap file.

I ran the etch file with a 60 degree 1/4″ v-carve bit.  I ran it on 1″ pink foam first to verify it wouldn’t crash, but then ran it on my copper circuit board.  The etch file was awesome, and everything went smoothly.

The drill file was a little weird though.  It kept going back to x0,y0.. I think maybe for bit changes?  Sometimes it would go back to x0,y0 with z0.. so it would drag the drill bit lightly along the surface.  So I ended up hand editing the gcode a bit.. removing all the tool changes.  I have never edited gcode before, and this was very easy to do.  Its basically just three steps that get repeated:

G00 Z0.1000 (raise bit)

G00 X-2.0000 Y1.4000  (move to new hole)

G01 Z-0.0320 F10  (drill new hole)

You just take anything extraneous out.  And then run it on your machine with the bit zeroed an inch up (air carve!) to verify everything looks good.  My drill/etch files are attached at the bottom of post so you can check them out.  Only other change was I must not have had the material thickness setup right in pcb-gcode, so the drill depth didn’t go all the way through.  Easy search/replace on the drill file to replace the depth with a new one.  That’s the (G01 Z-0.0320 F10) above.  Just change the -.0320 for example to whatever depth you want.

I used a .9mm drill bit for this task, and all my components fit well in that hole.  From resistors, to regulators.

BRIEF VIDEO

Snapshot of the board below.  You’ll see some scratches going to bottom-right (0,0) from the problem I noted above.  You will also see the size difference in the traces.  I will ensure I use all larger ones in the future.

Here is another photo after a light sanding to clean up the burrs.. pretty good!

Gcode:

motherShip_daughterboard.bot.drill.tap

motherShip_daughterboard.bot.etch.tap