Can You Build An Industrial Grade CNC With Only DIY Resources?

May 30, 2022 by Dave Rowntree 14 Comments

[FloweringElbow] aka [Bongo] on YouTube is certainly having a go at this, and we reckon he’s onto a winner! This epic flatbed CNC build (video, embedded below) starts with some second hand structural I-beam, with welded-on I-beam legs, DIY cast aluminium side plates and plenty of concrete to give a strong and importantly, heavy structure.

The ideal machine is as rigid as possible, and heavy, to dampen out vibrations caused by high-feed speed cutting, or the forces due to cutting harder materials, so bigger really is better. For construction of the frame, steel is pretty strong, and the mass of the structure gives it additional damping, but triangulation was needed to counteract additional twisting. He stitch-welded the pre-heated frame in inch-long sections to limit the heat transferred into the metal, minimizing the subsequent warpage. [Bongo] used hacky Vibratory stress relief (VSR) constructed from a washing machine motor and eccentric weight, clamped to the frame, with feedback from a mobile phone app to find the resonant frequencies. There are other videos on the channel devoted to that topic of such stress relief techniques.

Precise enough to cut sticky-backed vinyl at half thickness!

When it came time for adding even more mass, a priming coat was made from a mixture of bonding epoxy and sharp grit, intended for non-slip flooring. The concrete mix used Portland cement, pozzolan (Silica fume) polycarboxylate superplasticiser and 1/2″ glass fiber threads. A second mix added crushed stone for additional mass. A neat trick was to make a handheld vibratory compactor from a plate welded onto the end of old drill bit, mounted in an SDS hammer drill.

Once the frame was flipped the right way up (collapsing the overloaded hoist in the process) it was necessary to level the top surface to accept the linear rails. This was done using a super runny, self-leveling epoxy, and checked by flowing water over it. Once the epoxy surfaces were adequately flat and coplanar (and much scraping later) the linear rails were attached, after creating some epoxy shoulders for them to butt up against. End plates to attach the Y axis lead screws, were added by bolting into the frame with a grit-loaded epoxy bond in between.

The gantry design was skipped for this video (but you can see that here) and once mounted a quick test showed the machine was viable. One curious task was making their own cable-chain from ply, on the machine itself, rather than buying something expensive off-the-peg. Why not? Once the machine was working well enough to mill a flat sheet of steel to nice reflective surface, it was used to mount a DIY drag-knife to cut out shapes in some vinyl, so it has the precision. We did like seeing an XBox controller used to manually jog the machine around! So much to see in this build and other related videos, we reckon this channel is one to watch!

We’ve featured CNC builds many a time, there’s a build whatever your needs and budget, but here’s a good starting point to build a machine, just good enough to build the tools you need. If you don’t happen to have a source of structural I-beam to hand, you can do something quite capable with wood, and if you fancy a go at 3D printing a knee mill, we’ve got that covered as well.

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All The Sticky Labels You Could Ever Need: No DRM, Just Masking Tape

May 9, 2022 by Jenny List 58 Comments

Printable sticky labels are a marvelous innovation, but sadly also one beset by a variety of competing offerings, and more recently attempts by manufacturers to impose DRM on their media. Fortunately they don’t have to rely on expensive printers or proprietary rolls of stickies, as [michimartini] demonstrates with the masking tape plotter. It’s a tiny pen plotter that writes your label onto the tape.

At its heart is the popular grbl G-code to motion parser, and its mechanism uses the lead screw axis from a DVD drive. Not for this project simply another hacked-apart drive mechanism though, for it has a custom-designed carriage for the axis. It’s 3D printed, and to ensure the least friction possible for a pen using only its weight to keep contact with the tape it was heated up once assembled to ensure all parts had a chance to bed in. Meanwhile the tape roll forming the X axis is turned directly by a standard stepper motor.

We like this project a lot, and look forward to any refinements to the idea. Meanwhile, it’s not the first custom label printer we’ve shown you.

This Spherical Lamp’s Pieces Ship Flat, Thanks To Math

May 7, 2022 by Donald Papp 3 Comments

[Nervous System] sells a variety of unique products, and we really appreciate the effort they put into sharing elements of their design and manufacturing processes. This time, it’s details of the work that went into designing a luxury lamp shade that caught our eye.

Top: Finished lamp. Bottom: Partially-assembled.

The finished lamp shade is spherical, but is made entirely from flat-packed pieces of laser-cut wood that have been specifically designed to minimize distortion when assembled into a curved shape. The pieces themselves are reminiscent of puzzle cells; complex, interlocking cellular shapes found in many plants.

As usual, [Nervous System] applied a hefty dose of math and computational design to arrive at a solution. Each unique panel of the lamp is the result of a process that in part implements a technique called variation surface cutting for the shape of the pieces. They also provide a couple of nifty animations that illustrate generating both the piece boundaries as well as the hole patterns in each of the 18 unique pieces that make up each lamp.

As for making the pieces themselves, they are laser-cut from wood veneer, and assembly by the end user takes an hour or two. Watch a video overview, embedded just below under the page break.

We’re glad [Nervous System] takes the time to share details like this, just like the time they figured out the very best type of wood for laser-cutting their unique puzzles and didn’t keep it to themselves.

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The laser module shown cutting shapes out of a piece of cardboard that's lying on the CNC's work surface

Giant CNC Partners With Powerful Laser Diode

April 30, 2022 by Arya Voronova 13 Comments

[Jeshua Lacock] from 3DTOPO owns a large-format CNC (4’x8′, or 1.2×2.4 m), that he strongly feels is lacking laser-cutting capabilities. The frame is there, and a 150 W CO2 laser tube has been sitting in a box for ages – what else could you need? Sadly, at such a scale, aligning the mirrors is a tough and finicky job – and misalignment can be literally blinding. After reading tales about cutters of such size going out of alignment when someone as much as walked nearby, he dropped the idea – and equipped the CNC head with a high-power laser diode module instead. Having done mirror adjustment on a few CO2 tube-equipped lasers, we can see where he’s coming from.

Typically, the laser modules you see bolted onto CNC heads are firmly under three watts, which is usually only enough for engraving. With a module that provides 5 watts of optical power, [Jeshua] can cut cardboard and thin plywood as well he tells us even 10 W optical power modules are available, just that he didn’t go for one. We reckon that 20 W effective power diodes are not that far into our future, which is getting very close to the potential of the blue box “40 W but actually 35 W but actually way less” K40 laser cutters we cherish. [Jeshua]’s cutter is not breaking speed limits, but it’s built on what’s already there, and the diode is comparatively inexpensive. Equipped with a small honeycomb surface and what seems to be air assist, it’s shown in the video cutting an ornamental piece out of cardboard!

We hackers have been equipping CNCs with laser diodes for a while, but on a way smaller scale and with less powerful diodes – this is definitely a step up! As a hacker, you should have at least some laser cutting options at your disposal, and this overview of CO2 cutters and their availability can get you started. We’ve also given you detailed breakdowns about different sides of laser cutting, be it the must-have of safety, or the nice-to-have of air assist.

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CAD Sketcher, It’s Parametric CAD For Blender

April 27, 2022 by Anne Ogborn 37 Comments

It’s very early days for CAD Sketcher, a new parametric CAD add-on for Blender by [hlorus], but it looks very promising.

We do a lot of 3D work and like Blender as an environment. It’s always annoying that Blender doesn’t do parametric modeling, so we’re forced into a dedicated CAD package. Blending the two for that robot ocelot is always particularly annoying.

CAD Sketcher lets the user make a ‘sketch’, a 2D drawing. They then constrain it, saying “this line is vertical, that line is parallel to this one”, until the sketch is fully defined. It’s a normal part of parametric modelling. This is powerful when your model needs refined over and over.

There’s an old adage, “Better a tool that does 90% of the job well than one that does 100% poorly”. For CAD systems, (and much other software), we’d suggest “Better a tool that does 90% of the job well and works with whatever does the other 10%”.

3D render of gaurd — Guard Drawn In CAD Sketcher And Blender

We tried a test part, and being in Blender’s universe showed its value. CAD Sketcher doesn’t do bevels and rounds yet, and probably won’t for a while. But Blender’s perfectly happy doing them.

It’s not going to put SolidWorks out of business any time soon, but it’s a very promising new development. We hope it gathers some community and encourage contributions.

We cover CAD frequently, like the recent advances with CadQuery and the port of OpenSCAD to WASM.

[thanks paulvdh]

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No-Laser CNC Engraver Is Something New Under The Sun

April 27, 2022 by Dan Maloney 28 Comments

Hooking up a laser to a CNC gantry isn’t exactly an Earth-shattering innovation, but it does make for a useful tool. Even a cheap diode laser mounted to an old 3D printer can do engraving, marking, or even light-duty cutting. But what about a laser engraver without the laser? Can that be of any use?

Apparently, the answer is yes, if you can harness the power of the sun. That’s what [Lucas] did with his solar-tracking CNC engraver, the build of which is shown in the video below. The idea is pretty simple — mount a decent-sized magnifying lens where the laser optics would normally go on a laser engraver, and point the thing at the sun. But as usual, the devil is in the details. The sun has a nasty habit of moving across the sky during the day, or at least appearing to, so [Lucas] has to add a couple of extra degrees of freedom to a regular X-Y CNC rig to track the sun. His tracking sensor is simplicity itself — four CdS photocells arranged with a pair of perpendicular shades, and an Arduino to drive the gimbals in the correct direction to keep all four sensors equally illuminated. He had some initial problems getting the jerkiness out of the control loop, but the tracker eventually kept the whole thing pointing right at the Sun.

So how does it work? Not bad, actually — [Lucas] managed to burn some pretty detailed designs into a piece of wood using just the sun. He mentions adding a shutter to douse the cutting beam to allow raster patterns, but even better might be a servo-controlled iris diaphragm to modulate beam intensity and control for varying sun conditions. He might also check out this solar engraver we covered previously for some more ideas, too.

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Micromachining With A Laser

April 19, 2022 by Al Williams 3 Comments

[Breaking Taps] has a nice pulsed fiber laser and decided to try it to micromachine with silicon. You can see the results in the video below. Silicon absorbs the IR of the laser well, although the physical properties of silicon leave something to be desired. He also is still refining the process for steel, copper, and brass which might be a bit more practical.

The laser has very short duration pulses, but the pulses have a great deal of energy. This was experimental so some of the tests didn’t work very well, but some — like the gears — look great.

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