The Cheapest CNC Milling Machine

PCB Milling was on my TODO list. So I thought I'll give the cheapest CNC mill a try that isn't made from card board. You would be surprised how far I got within two days of messing around with that. The fun alone was worth every penny of this purchase. Enjoy!

Links to parts and tools (affiliate links):

My camera and lens (4k 60fps):

plz share :-)

Twitter: @bitluni
reddit: u/bitluni

Music:
Jeremy Blake - Powerup!
Wayne Jones - Brain Trust
Gunnar Olsen - West Coast Trip
Silent Partner - Hold On a Minute
Andrew Langdon - Keys
Francis Preve - Komputo
Quincas Moreira - Grasshopper
Dan Henig - Low Life High Life

#electronics #maker

[bobblaine]

FlatCAM to generate gcode from gerber and bCNC to run the machine work for me. Also, flip the spindle mount over. It will stabilize the depth of cut. The machine actually supports probing if you hook the copper of the board up to the A5 pin on the header and ground the spindle (be sure to isolate the copper from the machine). This will allow you to probe and compensate for errors in the height of the copper on the PCB and control the isolation width. I've made a bunch of very high quality boards with this machine - not as good as having them manufactured, but a lot faster.

[esamottawa]

One of my first programming jobs was programming a CNC machine ... in 1978. That machine was state of the art and worth over US$100, 000. Seeing this video and knowing the price is such a thrill.

[white.cleric]

I worked on CNC machine for couple of years, so here is some advice to make your experience better:
- Use ArtCAM to generate g-code. It not only has a versatile array of options and code encodings, but also takes in consideration material warping due to pressure from the mill, so it will generate path to counter the warp. I don't know about any other software that does it. ArtCAM can have a tool base, takes into consideration angle of a tool tip when generating a path, so it will not damage any unwanted parts, if the tool can't reach in there, so your connectors wouldn't be eaten away by the too wide of a tool. Additionally it can work with reliefs too. Back in the day I modeled and milled pendants, buttons, badges, plaques, etc from brass, copper, plexiglass, graphite (real soft, but very dusty) and aluminum sometimes.
- Use Mach3 to run the code. It is very cheap and versatile, supports a lot of machines, and it is highly configurable. If you use ArtCAM in the combination with Mach3 you want g-code type "G-Code Arcs (mm) (.tap)"
- When choosing materials you need to take into consideration if they are more brittle or elastic. Brittle materials you can easily mill, like brass ZAMAK 3 and ZAMAK 5 type. Widia tool is the best since it is very hard and can take a lot of pressure. I even managed to mill steel, although you will need a way stronger motor for that, then the one that came with the machine, and at least 4500 RPM and very slow feed rate.
- Copper and aluminum on the other hand you don't want Widia or it will break as soon as it touches the material and you will have jagged edges. This is because elastic materials are bending around the tool and heat it up, then pull it back. Widia can take a lot of pressure, but only vertically, even a smallest amount of pressure on the sides and it will break. If you drop it, it will break. For those kind of materials you actually want stiria tools. They are waaay better. They are a bit softer than Widia tools, but for elastic materials, they are perfect.
- Other than brass, you also want fluid to help with milling, to keep your tool cool and to assist during movement. For copper you want machine oil, which works for steel too, for aluminum I found that 70% alcohol works best, and plexiglass is milled perfectly with water. Otherwise plexiglass will mill with mate surface and most often you want clear surface where mill is passing thought the material.

Listen to my advice, or not, its up to you, just wanted to share a bit of experience and most importantly have fun in your craft :)

[bazookamoose]

This was adorable to watch, being a machinist my self, and brings me back to the days when I was a teen - Making PCB by hand and going to Radio-Shack. Lots of rookie mistakes (not that you were looking to be a "machinist" by any means). So much fun to do this stuff when you have a mill that works for you! Definitely need the right tools for the right jobs though. You'll want something along the linnes of a 2 flute 1/16 straight endmill, maybe even carbide, but if you use HSS (high speed steel) it would be easier to do what you are looking for without adjusting for the taper of that engraving tool. You could do a 1/8th for a majority of the dead space between traces, then when you want closer, you use a smaller tool to get closer to the tolerances you are looking for. Changing tools is key to these kind of works. You can get very very intricate with a 1/32nd tip, but you have to go fast and light around the traces and do multiple outlines on the contour passes. Neat buy for something that cheap! I was surprised actually that it could mill out even that amount of material like that. Build out a small blower fan and a nozzle to help blow out the "swarf" so your cutter doesn't dull out or break, keeps it cool too for the cut.

[pancake_crab]

Some quick recommendations:
1. Bolt it to something heavy. Like a metal plate or block of wood. The added mass will help with any vibration (and keeping the mill from dancing across the table).
2. Check the bed's height with a feeler gauge. This will make setting the tool height easier, and you'll be able to measure for any tilt in its mounting.
3. Add a wasteboard that you can then mill flat relative to the machine head. Even with software correction it will still help with accuracy.

[webbastler]

Just as a hint from a machinist/mechanic: Tools usually come with a rated cutting velocity or Vc. Using that and using the diameter of your tool you can calculate the recommended spindle rpm using this formula: (Vc [m/min]*1000)/(PI*diameter). In the case with your tools I would just set the spindle speed to max really since assuming the tool tip from that 60° cutter has a dia of 0.5mm and a rated Vc 0f 50 you'd be looking at 31000 rpm

[Lonely_Wiz]

just a tip: dont let your wires create loops. Although this is a very small piece of circuit and the wires aren't that big, it is a long going habit of mine.
Once, in my electrical classes, our teacher explained why you should never let your wire create loops, and he demonstrated it. It basically becomes an inductor, and it can lead to some metal melting, and eventually a huge fire.

Take care, great project!!

[davidlanham]

I respect a guy who sharpens his crowbar.

[BobStraitFTW]

I do this exact thing on that exact machine. Get either a .4mm end mill or a dual flute v bit. Use flat cam for gcode production. It also helps to 3D print a spoil board that has a corner you can slot the PCB into so you don't have to line up the pcb to the machines x and y axis every time.

[SeanChYT]

Good job! I mill prototype PCBs with that CNC type too, only a larger version. I am able to achieve somewhat finer resolution by using a probed Z height map, but this step will slow down the process somewhat so it depends on what is necessary. Prototypes are meant to be quick, so only do what is actually required. I think your results are very good, knowing you just got this machine. I also built an acrylic/wood enclosure with dust extraction, an enclosure to protect the motherboard, active cooling of the stepper motors, emergency off switch, push-pull style blowing and sucking away the milled chips close to the router bit using Loc-Line flexible hose, drag-chain on top for the router and Z-stepper cables, additional ball bearing for securing the lower section of the Z lead screw, end stops, plastic end caps for the 2020 profiles, and other miscellaneous things, but none of that is really required or perhaps worth the effort.
I also used a pro CNC router some years ago to mill boards, and of course it is possible to achieve better results with pro machinery that are more precise and heavy-duty, and also closer to 20000 or 30000 RPM instead of ~8000-9000RPM, but they cost ~100 times more. If I need quality boards, I finalize a more compact PCB design and order from JLCPCB like everyone else.
I now use FlatCam and Candle. Sometimes I use cheap Chinese V-bits (0.1 or 0.2mm), and sometimes I use (also) cheap, second-hand refurbished 0.4mm end-mills from professional CNC shops that sell lightly used bits on eBay. I usually use very thin double-sided tape to stick the PCB to the backer board instead of hold-down nuts.

[stuarttaylor]

A really easy way to improve your clamping is to add a piece of material on the other side of the bolt. The idea being to support both sides of the washer so that it stays closer to flat; probably easiest just to use a few scrap pieces of whatever you are cutting.
Alternatively drill a couple of holes through the plate and clamp through those holes.

[flomojou]

Wow, this brings back memories when I first tried to mill boards of my own. It's really difficult to overestimate just how difficult this is, to get usable results with medium thin traces and pads. You find out really quickly that no board is completely flat, which can spell the difference between no trace and breaking a bit when you're using extremely thin v-bits. You really need to probe the board with a small mesh size to capture all the potential dips and bumps. Use silicone oil or another light oil to prevent chips from sticking to your bit as well as extending the bit's life, and run the spindle speed as high as it will go with carbide bits.

[TheNamelessOne]

I bought same CNC over 5 years ago, slightly larger 2418 model.
The least rigid parts are X axis rods. 2418 model has 10mm rods, and it's still not enough to mill aluminium. I wanted to swap them to linear rails, but forgot about this project. Your video made me remember about it, and now I'll find it and finish the upgrade.
And the reason I forgot about CNC was 3D printer. You should buy it too. :)

[adagioleopard]

I'd bet AvE would approve of his package opening skills

[seanjournot]

When cutting metals it is extremely important to properly set your spindle speed. This controls the velocity of the cutting edge through the metal. Small air cooled spindles operate at RPM's so high that you are limited to very small diameter tools. For instance, if your spindle is running at 24000 RPM you will not want to use a tool larger than about .010" (.254mm) in aluminum. Using too large of a tool will increase cut speed so high that it will quickly dull and start pushing around material instead of cutting it.



When using very small tools make sure they are of very high quality; miniature tools are difficult to properly manufacture. The last time I used a micro end mill I believe I paid $50 USD, (it was a .050" long reach reduced shank square mill i think), and snapped it in half 3/4 of the way though the job. Small tools are tricky to work with.



I would also recommend using liberal amounts of lubricant, tap magic is great for aluminum, but in the end this machine is simply too small to effectively use larger tools and will always struggle cutting metal no matter what modifications you make or tooling you select.



If you really want to cut metal pick up a mini mill with an R8 collet; that is about the bare minimum to make anything useful.

[jao_cnjao_cn]

Nice CNC! You deserve many likes to contribute to the replacement of broken tools. That said: I think that for the use of conical tools you should take more into account that the plates are not completely flat, so you could use only very thin cylindrical tools and mill the material in successive passes of only 0.2 or 0.3 millimeters in order to preserve your expensive bits. Or you can previously map the surface of the plate and add the shape to your z coordinates so that the tool always penetrates the same depth into the plate

[Justafa]

Landed here over complete accident and ended up watching all this video feeling joy and happiness. Cheers man! :D

[lutzderlurch]

I like, how the beat of the music matches connecting piecs, clipping or tightening zip ties etc.

[jnoonan]

This is very fascinating. I must say, I really appreciate that in all of your findings (mistakes), you kept the chuckle and remained positive. It made the video very pleasant to watch. Keep it up, thanks.

[wulf-]

I gotta say, this is the first time I have seen someone open a cardboard box with a chain saw! Made my day!