Add Broken Tool Detection to Your CNC Mill

A tool breaking in the midst of a CNC machining operation is always a disaster. Not only do you have a broken tool (no small expense), but if the program continues to run there is a good chance it’ll end up ruining your part too. In particularly bad cases, it’s even possible to for this to damage the machine itself. However, if the breakage is detected soon enough, the program can be stopped in time to salvage the part and avoid damage to your machine.

Many new machining centers have the ability to automatically detect tool breaks, but this is a feature missing from older machines (and inexpensive modern machines). To address this issue, [Wiley Davis] came up with a process for adding broken tool detection to an older Haas mill. The physical modifications are relatively minor: he simply added a limit switch wired to the existing (but unused) M-Function port on the Haas control board. This port is used to expand the functionality of the machine, but [Wiley] didn’t need it anyway.

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3D Printer Transforms to CNC

Superficially, it is easy to think about converting a 3D printer into a CNC machine. After all, they both do essentially the same thing. They move a tool around in three dimensions. Reducing this to practice, however, is a problem. A CNC tool probably weighs more than a typical hotend. In addition, cutting into solid material generates a lot of torque.

[Thomas Sanladerer] knew all this, but wanted to try a conversion anyway. He had a few printers to pick from, and he chose a very sturdy MendelMax 3. He wasn’t sure he’d wind up with a practical machine, but he wanted to do it for the educational value, at least. The result, as you can see in the video below, exceeded his expectations.

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CNC-Telescope With Semi-Nasmyth Mount

[GregO29] had a 10″ GoTo telescope but at 70lbs, it wasn’t really portable. And so he did what any self-respecting CNC enthusiast would do, he put his CNC skills to work to make an 8″ Newtonian reflector, semi-Nasmyth mount telescope of his own design. It also gave him a chance to try out his new Chinese 6040 router/engraver with 800W water-cooled spindle.

What’s all that fancy terminology, you say? “Newtonian reflector” simply means that there’s a large concave mirror at one end that reflects a correspondingly large amount of light from the sky to a smaller mirror which then reflects it toward your eye, preferably along with some means of focusing that light. “Semi-Nasmyth mount” means that the whole thing pivots around the eyepiece so that you can keep your head relatively still (the “semi” is because the eyepiece can also be pivoted, in which case you would have to move your head a bit).

We really like the mechanism he came up with for rotating the telescope in the vertical plane. Look closely at the photo and you’ll see that the telescope is mounted to a pie-shaped piece of wood. The curved outer circumference of that pie-shape has gear teeth on it which he routed out. The mechanism that moves these teeth is a worm screw made from a 1″ spring found at the hardware store that’s on a 3/4″ dowel. Turn the worm screw’s crank and the telescope rotates.

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Clear the Air Around Your CNC Router with a Custom Dust Shroud

Using a CNC router is a dusty business if your material of choice is wood. Sure, you can keep things tidy by chasing the cutter around the table with a shop vac, but that sort of takes the fun out of having a machine that can make cuts without you. The big boy machines all have integrated dust collection, and now you can too with this 3D-printed CNC router dust shoe.

Designed specifically for the X-Carve with a DeWalt 611 router, [Mark Edstrom]’s brush is a simple design that’s almost entirely 3D printed. The shroud encloses the router body and clamps to the mounting bracket, totally surrounding the business end of the machine. The cup is trimmed with a flexible fringe to trap the dust and guide it to the port that fits a small (1-1/4″ diameter) shop vac hose. The hose is neatly routed along the wiring harness, and the suction is provided by a standard shop vac.

Files for the cup are up on Thingiverse; we suspect it’d be easy to modify the design to work with other routers and dust collectors. You might even find a way to shroud a laser cutter and capture the exhaust with a DIY filter.

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Zeroing CNC Mills With OpenCV

For [Jay] and [Ricardo]’s final project for [Dr. Bruce Land]’s ECE4760 course at Cornell, they tackled a problem that is the bane of all machinists. Their project finds the XY zero of a part in a CNC machine using computer vision, vastly reducing the time it take to set up a workpiece and giving us yet another reason to water down the phrase ‘Internet of Things’ by calling this the Internet of CNC Machines.

For the hardware, [Jay] and [Ricardo] used a PIC32 to interface with an Arducam module, a WiFi module, and an inductive sensor for measuring the distance to the workpiece. All of this was brought together on a PCB specifically designed to be single-sided (smart!), and tucked away in an enclosure that can be easily attached to the spindle of a CNC mill. This contraption looks down on a workpiece and uses OpenCV to find the center of a hole in a fixture. When the center is found, the mill is zeroed on its XY axis.

The software is a bit simpler than a device that has OpenCV processing running on a microcontroller. Detecting the center of the bore, for instance, happens on a laptop running a few Python scripts. The mill attachment communicates with the laptop over WiFi, and sends a few images of the downward-facing camera over to the laptop. From there, the laptop detects the center of the bore in the fixture plate and generates some G-code to send over to the mill.

While the device works remarkably well, and is able to center the mill fairly quickly and without a lot of user intervention, there were a few problems. The camera is not perfectly aligned with the axis of the spindle, making the math harder than it should be. Also, the enclosure isn’t rated for being an environment where coolant is sprayed everywhere. Those are small quibbles, and these problems could be fixed simply by designing and printing another enclosure. The device works, though, and really cuts down on the time it takes to zero out a mill.

You can check out the video description of the build below.

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CNC Dummies for Routers

[This Old Tony] has a few videos that have made appearances on Hackaday. His latest one is CNC Dummies for Routers (see below). The subtitle, CNC Basics, is an honest one. If you’re already well versed in GCode and Mach 3, you probably won’t make it through the 14 minute video (although Tony is pretty entertaining even if you know what he’s talking about).

By his own admission, this is really CNC basics for hobby-grade CNC routers and mills. He starts off talking about his custom-built machine along with some common machines in the $500-$5000 range. He then gives a simple sketch of what GCode looks like.

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A Truly Classy Metal-Framed Mini CNC

We’ve seen a number of DVD- and CDROM-based small CNC machines here, but few are as simply beautiful as this one by [julioberaldi] over on Instructables (translated from Portuguese here).

fbis2gciv0ajsdxWe’ll cut to the chase; it’s the frame. Cut from steel sheet scraps with a hacksaw, and welded or soldered together with “bar solder”. It looks like a lot of sanding, painting, and polishing went on. The result is something we’d be proud to have on our desk.

For now, it simply draws with a pen. But watch the video, embedded below, and you’ll see that it runs exceptionally smoothly. If we’re reading the Instructable right, the next step is to turn this into a CNC cutter. We can’t wait to see where the project goes from here.

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