Rapid Prototyping PCBs With The Circuit Graver

Walking around the alley at Hackaday Supercon 2024, we noticed an interesting project was getting quite a bit of attention, so we got nearer for a close-up. The ‘Circuit Graver’ by [Zach Fredin] is an unconventional PCB milling machine, utilizing many 3D printed parts, the familiar bed-slinger style Cartesian bot layout and a unique cutting head. The cutting tool, which started life as a tungsten carbide lathe tool, is held on a rotary (‘R’) axis but can also move vertically via a flexure-loaded carriage driven by a 13 kg servo motor.

The stocky flexure took a lot of iteration, as the build logs will show. Despite a wild goose chase attempting to measure the cutting force, a complete machine solution was found by simply making everything stiff enough to prevent the tool from chattering across the surface of the FR4 blank. Controlling and maintaining the rake angle was a critical parameter here. [Zach] actually took an additional step, which we likely wouldn’t have thought of, to have some copper blanks pre-fabricated to the required size and finished with an ENIG coating. It’s definitely a smart move!

To allow the production of PCB-class feature sizes compatible with a traditional PCB router, the cutting tool was sharpened to a much smaller point than would be used in a lathe using a stone. This reduced the point size sufficiently to allow feature sizes down to 4 mils, or at least that’s what initial characterization implied was viable.  As you can see from the build logs, [Zach] has achieved a repeatable enough process to allow building a simple circuit using an SMT 74HC595 and some 0402 LEDs to create an SAO for this year’s Supercon badge. Neat stuff!

We see a fair few PCB mills, some 3D printed, and some not. Here’s a nice one that fits in that former category. Milling PCBs is quite a good solution for the rapid prototyping of electronics. Here’s a guide about that.

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CNC Intaglio-Esque Engraving

Intaglio is an ancient carving technique for adding details to a workpiece, by manually removing material from a surface with only basic hand tools. If enough material depth is removed, the resulting piece can be used as a stamp, as was the case with rings, used to stamp the wax seals of verified letters. [Nicolas Tranchant] works in the jewelry industry, and wondered if he could press a CNC engraving machine into service to engrave gemstones in a more time-efficient manner than the manual carving methods of old.

Engraving and machining generally work only if the tool you are using is mechanically harder than the material the workpiece is made from. In this case, this property is measured on the Mohs scale, which is a qualitative measurement of the ability of one (harder) material to scratch another. Diamond is the hardest known material on the Mohs scale and has a Mohs hardness of 10, so it can produce a scratch on the surface of say, Corundum — Mohs value 9 — but not the other way around.

[Nicolas] shows the results of using a diamond tip equipped CNC engraver on various gemstones typical of Intaglio work, such as Black Onyx, Malachite, and Amethyst with some details of the number of engraving passes needed and visual comparison to the same material treated to traditional carving.

Let’s be clear here, the traditional intaglio process produces deep grooves on the surface of the workpiece and the results are different from this simple multi-pass engraving method — but limiting the CNC machine to purely metal engraving duties seemed a tad wasteful. Now if they can only get a suitable machine for deeper engraving, then custom digitally engraved intaglio style seal rings could be seeing a comeback!

Intaglio isn’t just about jewelry of course, the technique has been used in the typesetting industry for centuries. But to bring this back into ours, here’s a little something about making a simple printing press.

A Medieval Gothic Monastery Built Using CAD / CAM

Just because you’re a monk doesn’t mean you can’t use CAD. The Carmelite monks of Wyoming are building a grandiose Gothic Monastery, and it’s awe inspiring how they are managing to build it.

The Carmelite monks needed a new, larger monastery to house their growing numbers, and found a parcel of land near Meeteetse Creek in Wyoming. The design of their new Gothic monastery was outsourced to an architectural firm. Gothic architecture is characterised by key architectural elements such as pointed arches, large stained glass windows, rib vaults, flying buttresses, pinnacles and spires, elaborate entry portals, and ornate decoration.

After some research, the monks settled on using Kansas Silverdale limestone for the monastery. Cutting and carving the elaborate stone pieces required for such a project, within time and cost constraints, could only be achieved using CNC machines. Hand carving was ruled out as it was a very slow process, would cost a whole lot more, and it wouldn’t be easy to find the artisans for the job. So when it came to shortlisting vendors for the vast amount of stone cutting and carving required for construction, the monks found themselves alarmed at how prohibitively expensive it would turn out to be.

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Heirloom Knife Will Carve Pumpkins For Years To Come

Halloween may be behind us, but that just means that we’ve reached the best time to buy pumpkins. After all, it’s still fall, and there are pies to be made and tables to be decorated. Why should carved-up pumpkins be restricted to spooky season?

The only problem is that it’s 2022, and we’re still expected to use those terrible little serrated knives to carve our pumpkins. Those orange-handled garbage ‘knives’ are hardly suited to cut the lid, much less carve any of the intricate designs that come in the little booklet. So what’s a pumpkin-carving enthusiast to do? If you’re [XYZ Create], you make your own out of walnut, maple, and a gently-used jigsaw blade that’s still way sharp enough to tear through pumpkin flesh.

[XYZ Create] started with a nice chunk of walnut, which he split lengthwise in order to insert the blade, which sits in a cavity within a thin piece of maple. Once [XYZ Create] had the handle ready to go, he inserted the jigsaw blade and epoxied the sandwich together. After sanding down the edges to make a comfortable grip, he finished off the build by rubbing a bit of carving board wax into the handle. Check out the build video after the break.

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Turning A Waterjet Cutter Into A Wood Lathe, For No Reason

On the shortlist of dream tools for most metalworkers is a waterjet cutter, a CNC tool that uses insanely high-pressure water mixed with abrasive grit to blast sheet metal into intricate shapes. On exactly nobody’s list is this attachment that turns a waterjet cutter into a lathe, and with good reason, as we’ll see.

This one comes to us by way of the Waterjet Channel, because of course there’s a channel dedicated to waterjet cutting. The idea is a riff on fixtures that allow a waterjet cutter (or a plasma cutter) to be used on tubes and other round stock. This fixture was thrown together from scrap and uses an electric drill to rotate a wood blank between centers on the bed of the waterjet, with the goal of carving a baseball bat by rotating the blank while the waterjet carves out the profile.

The first attempt, using an entirely inappropriate but easily cut blank of cedar, wasn’t great. The force of the water hitting the wood was enough to stall the drill; the remedy was to hog out as much material as possible from the blank before spinning up for the finish cut. That worked well enough to commit to an ash bat blank, which was much harder to cut but still worked well enough to make a decent bat.

Of course it makes zero sense to use a machine tool costing multiple hundreds of thousands of dollars to machine baseball bats, but it was a fun exercise. And it only shows how far we’ve come with lathes since the 18th-century frontier’s foot-powered version of the Queen of the Machine Shop.

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3D Carver Makes Magnetic Fields Visible

The history of science is full of examples when a 3D physical model led to a big discovery. But modelling something that’s actually invisible can be tough. Take magnetic fields – iron filings on a card will give you a 2D model, but a 3D visualization of the field would be much more revealing. For that job, this magnetic field following 3D carving machine is just the thing.

What started out as a rapid prototyping session with servos and hot glue ended up as quick and dirty 3D carving rig for [Frits Lyneborg]. The video shows his thought progression and details how he went from hot glue and sticks to LEGO Technics parts and eventually onto Makerbeam extrusions for the frame of his carver. A probe with a Hall effect sensor is coupled to a motor spinning a bit that cuts into a block of floral foam. A microcontroller keeps the Hall sensor a more or less fixed distance from a rare-earth magnet, resulting in a 3D model of the magnetic field in the foam, as well as a mess of foam nubbles. Despite a few artifacts due to in-flight adjustments of the rig, the field presents clearly in the block as two large lobes.

Carving foam isn’t the only way to visualize a magnetic field in three dimensions, of course. If you’d rather have a light show based on the local magnetic field, try this 3D compass build we covered a while back.

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X-Carve, The Logical Upgrade To A Shapeoko

When it comes to small CNC carving machines for hackerspaces and extremely well-equipped garages, the Shapeoko, or something like it, has been the default machine. It’s dead simple – a Dremel attached to linear rails – and is useful for everything from milling PCBs to routing complex woodworking project to plotting designs with a pen. Now, [Bart Dring], the guy behind the Buildlog.net lasers and Inventables have teamed up to create the next generation of carving machines. It’s called the X-Carve, and while it’s fully compatible with the Shapeoko 2, it adds a few improvements that make for a much better machine.

The X-Carve does away with the Dremel-based spindle and replaces it with something that can produce torque. There’s a 24VDC spindle in the stock arrangement that will give you speed control through Gcode. There is, of course, adapters to fit the Dewalt and Bosch routers most commonly used in these types of machines.

As far as the gantry goes, the X and Y axes are makerslide; no change there. The Z axis leadscrew has an optional upgrade to Acme threaded rod, an improvement over the M8 threaded rod found in just about every other DIY machine kit. The entire machine is basically all the upgrades a Shapeoko should have, with stronger corners, NEMA 23 motors, and increased rigidity.

There are a few versions of the X-Carve, ranging from an upgrade kit to the Shapeoko 2 to a fully loaded kit with a square meter of machine space. The big, high-end kit ships for around $1250, but a smaller kit with 500mm rails, NEMA 17s, and threaded rod lead screw is available for around $800.

[Bart] and [Zach], the founder of Inventables sat down and shot a video going over all the features of the X-Carve. You can check that out below.

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