Hackaday Made Me Buy It!

July 11, 2020 by Elliot Williams 44 Comments

Reading Hackaday is great! You get so many useful tips from watching other people work, it’s truly changed nearly everything about the way I hack, especially considering that I’ve been reading Hackaday for the past 15 years. Ideas, freely shared among peers, are the best of the free and open-source hardware community. But there’s a dark downside: I’m going CNC mill shopping.

It all started with [Robin]’s excellent video and website tutorial on his particular PCB DIY procedures. You see, I love making PCBs at home, because I’m unafraid of chemistry, practiced with a rolling pin and iron, and super-duper impatient. If I can get a board done today, I’m not waiting a week, even if that means an hour of work on my part.

Among other things, he’s got this great technique with a scriber pen and a cleverly designed registration base that make it easy for him to do nearly perfectly aligned two-sided boards with a resolution approaching etching. The ability to make easy double-sided boards, with holes drilled, makes milling attractive, but the low resolution of v-cutter milled boards has been the show-stopper for me. If that’s gone, maybe it’s time to take a serious look.

And heck, making PCBs is really just the tip of the iceberg for what I’d want to do with a CNC mill. Currently, I do dodgy metalworking with an x-y table and a drill press, some of which may someday land me in the hospital. But if I had a mill, I’d be doing all sorts of funny wood joinery and who knows what else. I lack experience with a mill, but coincidentally, we just had a Hack Chat on Linux for machine tools this week. You see? It’s all conspiring against me.

The only question left is what I should get. I’m looking at the ballscrew 3040 range of CNCs, and maybe upgrading the spindle. I’d like to mill up to aluminum, but don’t really need steel. What do you think?

Making PCBs The Easy Way

July 10, 2020 by Bryan Cockfield 52 Comments

Building a PCB at home can be fraught. If you’re etching, there are chemicals and the nuances of toner transfer. If you’re milling, getting the surface height just right, and not breaking those pointy little v-cutters is always a challenge. [Robin] has tips for both of these cases, and solves a lot of the common hassles by using a milling machine.

Whether he’s scraping away etch resist or entire copper isolation lines, [Robin] uses a non-spinning scratching tool instead of a v-bit: they’re more robust and cut every bit as well. He’s got tips for using FlatCam and KiCAD to make scratched-out traces. His registration system allows him to get double-sided boards with a minimum of hassle. And as a bonus, he’s doing some experimentation with embedding SMT parts inside the boards as well. Be sure that you check out his whole guide, or just watch the video embedded below.

We’re pretty sure you’ll pick up a trick or two, and maybe you’ll be convinced to bite the bullet and invest in a nice mill. If you’d like a more traditional take on PCB milling, try out our own [Adil Malik]’s guide.

Continue reading “Making PCBs The Easy Way” →

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

July 9, 2020 by Dan Maloney 30 Comments

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.

Continue reading “Turning A Waterjet Cutter Into A Wood Lathe, For No Reason” →

Milling Dies And Injection Moulding Some Acrylic Lenses

July 7, 2020 by Adil Malik 18 Comments

[Zach] over at his channel Breaking Taps has put up an extraordinary account on manufacturing some homemade acrylic lenses. In the end, not only does he produce some beautiful concave lenses, he also covers the complete manufacturing process, from milling the aluminium die used for injection moulding to tweaking the parameters associated with injecting the actual acrylic, he even goes over the limitations of optics produced in this fashion.

What caught our eye in particular, was how [Zach] used the finished product to practically demonstrate photoelasticity originating from the stress induced by the moulding process. You might be familiar with describing the optical properties of a material by a single number, i.e its permittivity. But what happens if in addition to altering speed, the material also alters the polarisation and direction of light depending on the stress distribution within the material? Whilst a quantitative answer gets a bit complicated you can check out [Zach’s] additional videos to visualise the answer in a pretty and colourful way, without resorting to fancy computer simulations! If however, you really want to persist with the simulation route, check out our article on stress analysis in a totally different setting using Finite Element Analysis.

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Linux In The Machine Shop Hack Chat

July 6, 2020 by Dan Maloney 67 Comments

Join us on Wednesday, July 8 at noon Pacific for the Linux in the Machine Shop Hack Chat with Andy Pugh!

From the time that numeric control started making inroads into machine shops in the middle of the last century until relatively recently, the power of being able to control machine tools with something other than a skilled human hand was evident. Unfortunately, the equipment to do so was expensive, and so NC technology remained firmly in the big shops, where a decent return on investment could be realized.

Fast forward a few decades, and everything that makes the computerized version of NC possible is cheap and easily available. Servos, steppers, drivers, and motion control components can be plugged together into CNC machines that can move a tool to a fixed point in space with incredible accuracy and repeatability. But without CNC software, none of it means a thing.

Enter Linux CNC, the free and open-source CNC package. With support for realtime operation, one-step installations, and a huge range of capabilities provided by a team of volunteer developers and supported by an active community, Linux CNC has democratized the world of CNC machines.

Andy Pugh is a frequent contributor to the Linux CNC codebase and a moderator on the forum. He knows a thing or two about Linux CNC in particular and Linux in the machine shop in general. He’ll stop by the Hack Chat to share his experiences with the Linux CNC project, tell us how Linux can revolutionize the machine shop, and maybe share a few stories from the world of CAD, CAM, and using Linux to make a few chips.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, July 8 at 12:00 PM Pacific time. If time zones have you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Continue reading “Linux In The Machine Shop Hack Chat” →

Machine Builds Rise From The Ashes

June 13, 2020 by Elliot Williams 8 Comments

I was enchanted by a failed project this week. [Andrew Consroe]’s CNC scroll saw doesn’t work yet, but the emphasis is on the word “yet”. Heck, even when it does work, it might not make sense, but that’s not the point anyway.

A scroll saw table has a vertical reciprocating blade perpendicular to a table, a lot like a band saw but with a shorter blade. You push the wood sheet to be cut into the blade, and because it’s thin, you can twist and turn all sorts of interesting jigsaw-puzzle shapes. [Andrew] automated this with an X-Y gantry and an innovative geared rotating ring, needed to keep the wood fed into the cutting edge of the blade.

It’s a crazy contraption, and a difficult and unique movement planning problem, and watching it move in the video is a joy. But it’s not working either: errors in the motion add up over a cut, and he’s ended up snapping a blade on every piece. And this is version three of the device!

But here comes the inspiration. First, the only reason he’s filming this is to keep a log of how the project looked at this phase — he’s already planning out the next one. Second, this is the soul of learning by doing. You don’t learn anything unless you’re trying something new.

And finally, [Andrew]’s project reminds me of why I love machine builds in the age of rapid prototyping. Blazing through three entirely different machines cost him essentially nothing. Tearing apart version one left him with the same stepper motors, aluminum extrusions, and electronics as when he started out. Except that he now knew so much more about his particular problem space. Now he’s ready to go again.

So if you’re at all robotically inclined, but you’re looking at the cost of motors, belts, bearings, and steel, don’t think of it as an expense for this project, but for years’ worth of iterations, and maybe even fully different machines.

Just be sure to take [Andrew]’s lead and get it down and documented before you take it apart! Heck, send it in to Hackaday and it’ll live forever.

CNC Scroll Saw Makes Promising First Cuts

June 4, 2020 by Tom Nardi 41 Comments

When we talk about CNC machines, we almost invariably mean a computer controlled router. Naturally you can do other forms of automated cutting, say using a laser or a water jet, but what about adding computer control to other types of saws? [Andrew Consroe] recently put together a postmortem video about this experimental CNC scroll saw. While he never quite got it working reliably, we think his approach is absolutely fascinating and hope this isn’t the last we see of the idea.

Those who’ve used a scroll saw in the past might immediately see the challenge of this build: while a router bit or laser beam can cut in any direction, a scroll saw blade can only cut in one. If you tried to make a sharp turn on a scroll saw, you’ll just snap the fragile blade right off. To work around this limitation, [Andrew] came up with the brilliant rotary table that can be seen in the video after the break.

By combining motion of the gantry with table rotation, he’s able to keep the blade from ever making too tight a turn. Or at least, that’s the theory. While the machine works well enough with a marker mounted in place of the blade, [Andrew] says he never got it to the point it could reliably make cuts. It sounds like positioning errors would compound until the machine ended up moving the work piece in such a way that would snap the blade. Still, the concept definitely works; towards the end of the video he shows off a couple of pieces that were successfully cut on his machine before it threw the blade.

While we’ve actually seen DIY scroll saws in the past, this is the first computer controlled one to ever grace the pages of Hackaday. While some will no doubt argue that there’s no sense building one of these now that laser cutters have reached affordable prices, we absolutely love this design and how much thought went into it. At the very least, we figure this it the beefiest doodle-drawing robot ever constructed. Continue reading “CNC Scroll Saw Makes Promising First Cuts” →