Category Archives: CNC

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

Isolation routing

Working on a little project for the home theater cabinet, and wanted to make a small circuit board to remove what would otherwise have been a point-point wiring mess.  I am a rookie at eagle-cad, but can cobble together a schematic/board eventually.  In the past I have sent my boards off for manufacturing, but I wanted to try my hand at milling one.  There is a great plugin in called pcb-gcode that works well with eagle cad.  While it has tons of configuration options, don’t be daunted.. using the defaults and a 60 degree 1/8″ v-bit the results look as though they could be impressive.

I ran the trial on 1″ extruded foam to get a feel for the process.  PCB-gcode kicks out two files, one for routing, and the other for drilling.  The image above is just the routing, which includes  a small ‘dot’ on the pads which would be useful for centering a drill bit later.  I have not yet run this on copper, as I didn’t have any small enough drill bits.  I ordered up two #65 or .90mm bits from Midwest Circuit Technology.  As soon as those arrive I will route/drill the board.

After it is completed, I am sure I will recall a few things I left out of the schematic…

Dust seperator for the CNC

I have a love/hate relationship with MDF.  It sure machines nice, and paints well if you seal it with watered down glue first.  But the DUST!  My 5hp shopvac has a steady reduction in suction as the filter clogs up.  It’s capacity is noticably diminished only 1/2 way into a machine run.  I have been looking at Bill Pentz’ cyclone page for a long time, with dreams of building one.  Sourcing of the metal, room in the garage, and downright dislike for sheetmetal cuts has dissuaded me from going down that route (thus far!).  I recently came across the ‘Thien Separator’ which in concept seemed like a good comprimise.  Didn’t look like it would take long to make, could be adapted to a shopvac/5 gal bucket and had nominal sheet metal work.

So, with that in mind grabbed a bucket, a caliper, and my mouse and drew something up.  Initial design didn’t take long to get drawn, and over a couple of days I made minor tweaks until I got a chance to run it on the machine.

Clogged the shopvac BTW.

So you can see the pieces outlined, from the first run.  Piece on the left is the bottom of the bottom.  You can see the 120 degree cutout, the bucket groove, holes for bolts, and the profile cut.  On the right is the bottom of the top.  Groove for the sheet metal, and a hole for the outlet to the vaccuum.  Along the top are the risers which mount the incoming line (it’ll make more sense in a later pic) and an aborted ring made to support the outlet.  I hit the y-axis limit switch, and had to redo that later.

I pulled the pieces and cleaned them up.  I then also machined a 1/8 groove in the top of the bottom piece which was needed to receive the sheet metal (not pictured).  Below you will see a picture of the bottom sitting on the bucket.  You can see where the incoming material will circle around, and fall into the slot – landing in the bucket.  At least thats the plan!

For the sheet metal, i picked up a roll of 10″ galvanized flashing.  I trimmed it down to 8.4″ (8″ + two 1/4″ slots + wiggle room).  It was pretty thin (not sure what gauge) so I cut two pieces and doubled them up.

Pretty straightforward assembly from here.  Work the metal into the 1/8″ slots, sandwich the top and bottom.  Tighten the threaded rod.  Insert the inlet blocks, and glue them in.  Silicone around the edges.

Here is a picture of the final product.  I am going to test drive it with a garbage can liner in the bucket, as it would make disposal real slick.  Right now the seperator sits on the bucket with a friction fit, and with the vaccuum on i don’t detect any leaks.  I will post updates on effectiveness after my next CNC run, but a quick cleanup of the dust on the floor, shows most of it ends up in the pail!

EDIT:

Ran the system on both the CNC and the Tablesaw today, and the seperator worked swimmingly!  Nothing of note in the shopvac, about 4 inches of dust/shavings in the bucket!

Wine bottle ring

I had a friend turning the big 4-oh and he was having a little dinner event.  I was bringing a bottle of wine, and as he thinks the CNC machine is pretty cool I wanted to make him something.  As my wife indicated all the birthday cards we had in the house were too girly, I thought a ring of some sort on the bottle would work out nicely.

I broke out he calipers, and measured the neck on a bottle I had in the house.  Pretty straighforward to draw up the ring in CAD, and add the text.  This was my first text engraving, and all I had on had was a 60 degree v bit I had purchased for isolation routing circuit boards (which I haven’t actually done yet).  I loaded up some maple on the CNC machine, and put a piece of contact paper (for lining kitchen drawers) on it.

maple with contact paper

I then routed the text, and blasted the letters with some black spraypaint.  The contact paper made a great mask.

I then routed out the circles, and did a light sanding on all sides.

One note, be aware not all wine bottle necks are the same size.  We ended up taking the ring to the wine shop, and had to test bottles to ensure it fit on the one we purchased!

Machining trays for WarMachine mini’s

So this is a peek into my really dorky side.  The general idea is a needed a tray to transport my mini’s from the kitchen counter to the game table.  The end result is much more complicated than it needed to be, but i learned a lot in the process.  One of which is you probably shouldn’t use the old 1/4″ bit you’ve had for 8+ years for moderately fine work.  The other is how hard maple is to plane/join.  I have never actually worked with a real hardwood before, so that was fun.

Video of the process.

Image

Image

Monitor mount for CNC machine

I needed a to replace the stock monitor mount on my 19″ lcd as the base took up too much room, and didn’t leave any for the keyboard.  The VESA mounts are standard 70mm spacing, so it was pretty easy to draw up a replacement.  The only thing I forgot to account for is the on/off toggle on the back, so I had to add a notch for that during install.

Video

First (probably not last) CNC Oops.

Just wanted to upload a picture on why you want to ensure you have mill-friendly (plastic/wood) hold-downs on your cnc table.  I didn’t have the bit retract set high enough, and in the middle of a high-speed jog the bit went right through my nice new nylon hold-down.  At least there was no damage done!

CNC hold down blocks

First order of business, prior to even calibrating the machine is to create some hold down blocks to clamp the work.  My friend had used these pretty cool ones called pinchblox, but their website seems to be out of commission, so I decided to make my own.  Basically they have a notch on each end, one for 1/2 inch material, and the othe for 3/4 inch.  They go in the t-slots milled in the cnc table and then clamp down with a nylon wing nut.  I could have made them out of wood, but wanted to try some plastic as I have never really worked with that material before.  I looked up a local plastic supplier (Lion Engineering) and went and visited them.  They were very accomodating and gave me a 30 minute tour of their facility.  I had no idea there were so many types of plastic.  I had planned on UHMW, as I had at least heard of that, but they talked me into some high density which was about 1/2 the price, running around $20/sq ft.

It machined very nice, and I created a little video documenting the process.  Hopefully future posts will be a little more exciting than clamps..

Machining the plastic hold downs