Found this recently, looks really interesting. Instructions on how to build your own CNC machine; will be released in November along with a website. The CNC can be built for ~$800. That’s a lot cheaper than buying one. However, some will argue that depending on your team, it’s probably not worth it. The big dogs have enough money and resources to buy their own CNC machines, but everyone else could/has been getting along fine without them. The big deal is that they can machine parts, specifically complex ones, quickly and accurately. So that’s something to be considered. My team was vaguely thinking about buying an old, used one, but it was a dream.
No $800 CNC can make parts very accurately or quickly. But if you have the patience, you can turn out some REALLY cool stuff, that you could not by hand, or manual machining. That router would not be sufficient for aluminum, but would certainly be useful for plate work from plastic and wood type materials. I started to build one, but bought a small knee mill instead.
Anyhow, if a team has the time and the money, building a CNC is certainly a fun project. Even if you can’t use it to make parts for the robot, you can still make signs, gifts, and things. And you can always continually improve and redesign the machine once you get it going.
If anyone wants to learn how to build a lathe from melted down soda cans and engine pistons, take a look at David Ginger’s line of books.
Yeah, this kind of a CNC probably wouldn’t be top-quality. And it wouldn’t be able to cut metal. That’s the big deal. But you’re right, it would be a great project.
However, at least for my team, we already have a big “CNC/shop bot” for our school. It’s just not super great at cutting metal. So we don’t really need another machine to cut wood.
I disagree with both of these statements, based on personal experience.
Now, it won’t cut parts Fast, Cheap AND Accurately, but it will do any two of these quite well. Often the sacrifice is Fast.
Robomaster, a wood router with carbide bits will easily and happily go through Aluminum, as much as you want. Again, not fast.
I built a similar machine several years ago for about $400, intended to be sued to drill out Printed Circuit boards. But, it is a full 3-axis CNC machine, with an envelope of about 11 x 11 x 4 inches. I used a Dremel tool instead of a router, and the entire machine was about 1/3 as “robust”. But I can form aluminum parts with it - albeit very, very slowly. For example, a 4" AndyMark aluminum wheel might take 8 hours :ahh: to produce. The limiting factor is what the Dremel can bite off in one pass - about 10 thousandths. So an inch of depth takes 100 passes - and the table moves at 0.1" per second when cutting like that. (It moves a lot faster in PC Drill mode…). My machine has 0.00025" precision and 0.003" accuracy over 10 inches.
We used a wood router to cut out pockets in our pit cart frame in 2005. It was made of 3/16" 6061 aluminum. We used a plywood template, a pre-drilled hole to start, and we cut out a 8"-ish triangle from the sheet in about a minute. Plain wood router with a carbide bit, about 25 of those triangular holes were cut. (Gloves, full-face shield, hearing protection and other protective gear were mandatory)
So, taking both those personal experiences together, I can easily see that machine in the OP cutting aluminum with 0.001" accuracy, assuming someone builds and adjusts it very carefully.
