Precision CNC With Epoxy Granite

Epoxy granite is an overlooked material when it comes to making home CNC builds. As far as time and money goes, when you add in all the equipment it comes out cheaper than an aluminum casting set-up. Epoxy granite has mechanical properties better than cast iron, increased dimensional stability, better vibration damping, and looks awesome when done right. Also, you can cast precision surfaces and threaded holes into your design, which is pretty cool.

In these two videos by [Jørgen Hegner] we get to watch him and a friend make a matching set of precision CNC machines. It’s built in a similar style to other nice builds we’ve featured. This way of making it needs a bigger footprint than a gantry mill and can’t be built as large. However, it solves a lot of mechanical issues and squaring with the gantry design while not being as difficult to get right as a box or knee mill.

After casting they machined the material embedded in the granite to mount the ways. The ways are linear bearings and ball screws. Expensive, but as the footage shows, very accurate.  The rest of the machine is assembled and tuned. Then it gets installed in a home made 80/20 enclosure. We really like the LCD panel that’s incorporated into the front shield of the machine. They really went all out with the CNC control panel. It looks like they can do anything from jog the axis to monitor and control the water cooling for the spindle.

It appears that all the precision work is put to good use as there are some shots at the end of video two of a beautiful clock CNC’d on this machine. Videos after the break.

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Cardboard And Paperclip CNC Plotter Destined For Self-Replication

Last November, after [HomoFaciens]’ garbage-can CNC build, we laid down the gauntlet – build a working CNC from cardboard and paperclips. And now, not only does OP deliver with a working CNC plotter, he also plans to develop it into a self-replicating machine.

To be honest, we made the challenge with tongue firmly planted in cheek. After all, how could corrugated cardboard ever make a sufficiently stiff structure for the frame of a CNC machine? [HomoFaciens] worked around this by using the much less compliant chipboard – probably closest to what we’d call matboard here in the States. His templates for the machine are extremely well thought-out; the main frame is a torsion box design, and the ways and slides are intricate affairs. Non-cardboard parts include threaded rod for the lead screws, servos modified for continuous rotation, an Arduino, and the aforementioned paperclips, which find use in the user interface, limit switches, and in the extremely clever encoders for each axis. The video below shows highlights of the build and the results.

True, the machine can only move a pen about, and the precision is nothing to brag about. But it works, and it’s perfectly capable of teaching all the basics of CNC builds to a beginner, which is a key design goal. And it’s well-positioned to move to the next level and become a machine that can replicate itself. We’ll be watching this one very closely.

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A Polymer Concrete DIY CNC With No Perceptible Budget In Sight

The Jargon File describes a wizard as someone who groks something to a very high degree, or the kind of person that builds a polymer concrete CNC machine with a pneumatic tool changing spindle that they designed by themselves.  It makes you think that maybe Tony Stark COULD build it in a cave with scraps.

It’s a five part video series showing snippets of the build process. The last video gives an overview of the design of the machine. It is all very much in German, so if you speak German and we got anything wrong about the machine or missed anything cool, please fill us in down in the comments.

The machine starts with a 1500 kg polymer concrete pour with some steel stock embedded in it. It is then machined within an inch mm of its life as shown by practically zero deviation over its length when measured against a granite block. The wizard then goes on to make his own spindle, get castings made, and more. We liked his flowery kitchen hotplate, which he used to heat the bearings for an interference fit. It added a certain amount of style.

Unfortunately the videos don’t show the machine running, but we assume this sort of person is happily building arc reactors, power suits, and fighting crime. They probably don’t have time to film “CNC Bearbeitungszentrum im Eigenbau Teil 5”. Videos after the break.

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Professional CNC Vacuum Table Holds Workpieces with Ease

If you do a lot of one-off parts on your CNC machine you’ll know setup is the worst part of the process. Usually you’re using scrap material, you have to figure out how you’re going to clamp it, make sure the the piece is big enough to use, etc etc. Wouldn’t it be nice to just throw the material on the bed and start machining? Well, with a vacuum table as nice as this, you pretty much can!

[Jack Black] has an awesome CNC machine. As he’s been expanding his prototyping abilities, he decided he needed a better way of securing work pieces for machining, so he machined a two-piece aluminum vacuum table.
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Add Fiber-optic Control to Your CNC

CNC machines can be very noisy, and we’re not talking about the kind of noise problem that you can solve with earplugs. With all those stepper motors and drivers, potentially running at high-speed, electrical noise can often get to the point where it interferes with your control signals. This is especially true if your controller is separated from the machine by long cable runs.

But electrical noise won’t interfere with light beams! [Musti] and his fellow hackers at IRNAS decided to use commodity TOSLINK cables and transmitter / receiver gear to make a cheap and hackable fiber-optic setup. The basic idea is just to bridge between the controller board and the motor drivers with optical fiber. To make this happen, a couple of signals need to be transmitted: pulse and direction. They’ve set the system up so that it can be chained as well. Serializing the data, Manchester encoding it for transmission, and decoding it on reception is handled by CPLDs for speed and reliability.

The team has been working on this project for a while now. If you’d like some more background you can check out their original design ideas. Design files from this released version are up on GitHub. A proposed improvement is to incorporate bi-directional communications. Bi-directional comms would allow data like limit-switch status to be communicated back from the machine to the controller over fiber.

This optical interface is in service of an open-source plasma cutter design, which is pretty cool in itself. And if the IRNAS group sounds familiar to you, that may be because we recently ran a story on their ambitious gigabit ethernet-over-lightbeam project.

Be A Hero At Your Next Hackathon With A Foldable CNC

Be the hero at your next hackathon with this foldable cnc. When the line for the laser cutter is four teams deep, you’ll come out ahead. It might even be accurate enough to pop out a quick circuit board. Though, [wwwektor] just wanted a CNC that could be taken from storage and unfolded when needed. Sit it on a kitchen table and cut out some ornaments, or hang it from the front door to engrave the house’s address. Who needs injection molded chrome plated numbers anyway?

It’s based around tubular ways, much like other 3D printed CNCs we’ve covered. The design’s portable nature gives it an inherently unstable design. However, given the design goals, this is reasonable. It uses timing belts, steppers, and ball bearings for its movement. The way the frame sits on the table it should deal with most routing tasks without needing adjustment to stay in plane with the surface it’s set-on. As long as you don’t need square edges.

There’s a video of it in operation after the break. We love these forays into unique CNC designs. We never know what new idea we’ll see next.

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Milling PCBs With An Off-The-Shelf CNC

There’s a lot of little things that can go wrong before you get great results out of a process. We like to read build logs to learn from the mistakes made. [Marc Liyanage] bought a Nomad CNC machine from Carbide3d, and after a bit of learning has gotten some very nice PCBs out of it.

The first trip up he encountered was not setting the design rules in EagleCAD to check for gaps too small for his router bit. After he sorted that, and worked around an issue with Carbide not supporting R values for curves; instead opting for IJK, he made a nice TQFP to DIP break out board.

The next board was a more complicated double-sided job. He cleverly had the machine drill two holes all the way through the PCB to give him a space for two alignment pins. Unfortunately this didn’t work out exactly as planned and he had a slight misalignment with some of the via holes. It looked alright and he began assembling. To his dismay, the clearances were off again. It was a bit of deja vu for us.

We’ve made lots of boards on a CNC machine, and can attest to the task’s finicky nature. It’s certainly quicker than the photoresist technique for boards with lots of little holes. It will take someone quite a few tries before they start having more successes than failures, but it’s very rewarding.