cnc hacks

907 Articles

A person putting a screw into a CNC spoil board on the left of the image. Their drill is chartreuse and black. Clamps hold a rectangular board down at all four corners. The spindle of the CNC is just visible on the right hand side of the image.

Workholding Options For The Beginner CNC Operator

July 23, 2024 by 6 Comments

Designing a file to cut on a CNC is only part of the process. You also have to keep it in place while the machine does its work. [Garrett Fromme] walks us through five different work holding techniques.

Since every project is different and stock material can vary from thin veneer to much larger pieces, there’s no one right work holding method for every project, and not all methods are applicable to all materials. A vise is great for small projects that need to be held very securely and won’t be damaged, vacuum tables can make switching pieces quick in a production environment, fasteners will hold a piece securely at the expense of your spoil board, clamps are fairly versatile but fiddly to setup, and tape and CA glue are quick but require more consumables.

[Fromme] does a quick demonstration of setups with these different methods and their limitations, which is a great place to start for the beginner CNC operator. Just like 3D printers, CNCs are a far cry from the replicators in Star Trek that can automagically create what you ask it to, but proper workholding lets you waste less material and operate the machine more safely.

Our own [Elliot Williams] had a look at how CNCs aren’t as automated as you think. If you do need some CNC clamps, you might try these printable parametric clamps, or if you want something more beautiful, give these metal toe clamps a go.

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A LEGO CNC Pixel Art Generator

June 14, 2024 by 2 Comments

If you are ever lucky enough to make the trip to Billund in Denmark, home of LEGO, you can have your portrait taken and rendered in the plastic bricks as pixel art. Having seen that on our travels we were especially interested to watch [Creative Mindstorms]’ video doing something very similar using an entirely LEGO-built machine but taking the images from an AI image generator.

The basic operation of the machine is akin to that of a pick-and-place machine, and despite the relatively large size of a small LEGO square it still has to place at a surprisingly high resolution. This it achieves through the use of a LEGO lead screw for the Y axis and a rack and pinon for the X axis, each driven by a single motor.

The Z axis in this machine simply has to pick up and release a piece, something solved with a little ingenuity, while the magazine of “pixels” was adapted with lower friction from another maker’s design. The software is all written in Python, and takes input from end stop switches to position the machine.

We like this build, and we can appreciate the quantity of work that must have gone into it. If you’re a LEGO fan and can manage the trip to Billund, there’s plenty of other LEGO goodness to see there.

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The Cheap CNC3018 Gets A Proper Revamp

June 8, 2024 by 24 Comments

Many people have been attracted to the low price and big dreams of the CNC3018 desktop CNC router. If you’re quick, you can pick one up on the usual second-hand sales sites with little wear and tear for a steal. They’re not perfect machines by any stretch of the imagination, but they can be improved upon, and undoubtedly useful so long as you keep your expectations realistic.

[ForOurGood] has set about such an improvement process and documented their journey in a whopping eight-part (so far!) video series. The video linked below is the most recent in the series and is dedicated to creating a brushless spindle motor on a budget.

As you would expect from such a machine, you get exactly what you pay for.  The low cost translates to thinner than ideal metal plates, aluminium where steel would be better, lower-duty linear rails, and wimpy lead screws. The spindle also suffers from cost-cutting, as does the size of the stepper motors. But for the price, all is forgiven. The fact that they can even turn a profit on these machines shows the manufacturing prowess of the Chinese factories.

We covered the CNC 3018 a while back, and the comments of that post are a true gold mine for those wanting to try desktop CNC. Warning, though: It’s a fair bit harder to master than 3D printing!

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Betta Aims To Bring Wire EDM To The Desktop

May 17, 2024 by 35 Comments

Just as practical nuclear fusion has been “only 20 years away” for the last 80 years or so, the promise of electrical discharge machining (EDM) in the home shop seems to always be just around the corner. It’s hard to understand why this is so — EDM is electrically and mechanically more complicated than traditional subtractive manufacturing techniques, so a plug-and-play EDM setup seems always just out of reach.

Or perhaps not, if this 3D printed 4-axis wire EDM machine catches on. It comes to us from [John] at Rack Robotics and is built around the Powercore EDM power supply that we’ve previously featured. Since wire EDM is a process that requires the workpiece to be completely immersed in a dielectric solution, the machine, dubbed “Betta,” is designed to fit inside a 10-gallon aquarium — get it?

A lot of thought went into keeping costs down. for example, rather than use expensive sealed motors, [John] engineered the double CoreXY platform to keep the motors out of the water bath using long drive shafts and sealed bearings. The wire handling mechanism is also quite simple, at least compared to commercial WEDM machines, and uses standard brass EDM wire. The video below shows the machine going to town of everything from aluminum to steel, with fantastic results on thin or thick stock.

While Rack Robotics is going to be offering complete kits, they’re also planning on open-sourcing all the build files. We’re eager to see where this leads, and if people will latch onto EDM with the same gusto they did with 3D printing.

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Mostly Printed CNC Gets A Few Upgrades

May 7, 2024 by 8 Comments

The Mostly Printed CNC is famous for two things. First, being made mostly from 3D printed parts and commonly available steel tubing. Second, because of the materials used, its rigidity isn’t fantastic. But any CNC router is better than no CNC router, and [Alan Reiner]’s “Mostly Mostly Printed CNC” upgrades the base MPCNC into a much more capable unit.

MPCNC purists may want to look away, as the video below shows [Alan] committing the heresy of adding linear rails to his machine. The rails were sourced from VEVOR and at less than $100 for 10 meters, it must have been hard to resist. The rigidity wasn’t amazing — witness the horrific chatter at around the 5:15 mark — but [Alan] sorted that out with some aluminum extrusion and printed adapters.

Those upgrades alone were enough to let [Alan] dive into some aluminum cutting, but he also wanted to address another gripe with his base build: the Z-axis backlash. The fix there was to add another lead screw nut on an adjustable carrier. By tweaking the relative angles of the two opposed nuts, almost all of the backlash was taken up. [Alan] also replaced the motor coupling on the Z axis with a Lovejoy-style coupler, to remove as much axial compliance as possible.

Along with the motion control mods, [Alan] improved work holding and added an enclosure to tame the chip beast, along with some upgrades to the control electronics. The results are pretty good and appear well worth the modest added expense. Maybe a wireless controller can be next on the upgrade list?

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Plasma Cutter Gets CNC Treatment At Low Cost

May 3, 2024 by 8 Comments

[Daniel] has been metalworking on a budget for a while now. Originally doing things like plasma cutting on old bricks, he used his original plasma cutter to make an appropriate plasma cutting table complete with a water bath which we presume was not only safer but better for his back. Since then he’s stepped up a little more with what might be the lowest-cost CNC plasma cutter that can reliably be put together.

The CNC machine uses a handheld plasma cutting torch as its base, which uses a blowback start mechanism making it usable in an automated CNC setup without interfering with the control electronics. This is a common issue with other types of plasma cutters not originally meant for CNC. The torch head only needs slight modifications to fit in a 3D printed housing designed for the CNC machine which involves little more than slightly changing the angle of the incoming copper tubing and wire and changing the location of the trigger.

With those modifications done, the tool head is ready to be mounted to the CNC machine. [Daniel] has put together a bill of materials for building the entire project for less than $400, which includes the sub-$200 plasma cutter. It’s an impressive bit of sleuthing to get the price down this low, but if you’re still using your plasma cutter by hand on bricks in the yard like [Daniel] used to do make sure to check out that DIY plasma cutting table he built a few years ago too.

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Electromagnets Make Vertical CNC Cutter A Little Stickier

April 12, 2024 by 10 Comments

Workholding is generally not a problem on a big CNC plasma cutter.; gravity does a pretty good job of keeping heavy sheet steel in place on the bed. But what if your CNC table isn’t a table? The answer: magnets — lots of magnets.

The backstory on this is a bit involved, but the condensed version is that [Lucas] needed a CNC plasma cutter big enough to cut full-sized sheets of steel, but lacked the floor space in his shop for such a beast. His solution was to build a custom CNC machine that stands more or less vertically, allowing him to cut full sheets in a mere fraction of the floor space. It’s a fantastic idea, one that he put a lot of effort into, but it’s not without its problems. Chief among them is the tendency for the sheet metal to buckle and bulge during cutting since gravity isn’t working for him, along with the pesky problem of offcuts slipping away.

To help hold things in place, [Lucas] decided to magnetize the bed of his cutter. That required winding a bunch of magnets, which is covered in the video below. Mass production of magnets turns out not to be as easy as you’d think. Also unexpected was the need to turn off magnets when the cutting torch is nearby, lest the magnetic field bork the cutting plasma. [Lucas] grabbed some code from the LinuxCNC forum that streams the gantry coordinates over serial and used an Arduino to parse those messages. When the torch is getting close to one of the magnets, a relay board cuts power to just that magnet. You can see it in action in the video below; at around the 18:15 mark, you can see the sheet bulging up a bit when the torch comes by, and sucking back down when it moves on.

The amount of work [Lucas] put into this project is impressive, and the results are fantastic. This isn’t the first time he’s relied on the power of magnets to deal with sheet steel, and it probably won’t be the last.

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