DIY Laser For Ablating Metal

July 17, 2023 by Bryan Cockfield 51 Comments

For those who wish to go beyond through-hole construction on perfboard for their circuit boards, a printed circuit board is usually the next step up. Allowing for things like surface-mount components, multi-layer boards, and a wider array of parts, they are much more versatile but do have a slight downside in that they are a little bit harder to make. There are lots of methods for producing them at home or makerspace, though, and although we’ve seen plenty of methods for their production like toner transfer, photoresist, and CNC milling, it’s also possible to make them using laser ablation, although you do need a special laser to get this job done.

The problem with cutting copper is that it reflects infra-red, so a higher-wavelength ~~blue~~ green laser is used instead. And because you want to ablate the copper, but not melt the surrounding areas or cut straight through the board, extremely short, high-power pulses are the way to go. Here, the [Munich Fab Lab] is using 9 kW pulses of around 30 microseconds each. With these specifications the copper is ablated from the surface of the board allowing for fine details in the range of about 20 µm, which is fine enough for just about any circuit board. The design of the laser head itself is worth a look.

Aside from the laser, the rest is standard CNC machine fodder, but with an emphasis on safety that’s appropriate for a tool in a shared workspace, and the whole project is published under an open license and offers an affordable solution for larger-scale PCB production with extremely fine resolution and without the need for any amounts of chemicals for the more common PCB production methods. There is a lot more information available on the project’s webpage and its GitHub page as well.

Of course, there are other methods of producing PCBs by laser if you happen to have a 20 W fiber laser just kicking around.

Spindle Upgrade Makes PocketNC Faster And Smoother

June 27, 2023 by Dan Maloney 21 Comments

Conventional wisdom says that rigidity is the name of the game when it comes to machine tool performance. After all, there’s got to be a reason for CNC machines that need specialized rigging companies just to deliver them. But is there perhaps a way for the hobby machinist to cheat a little on that?

From the look of [Ryan]’s PocketNC spindle upgrade, it seems like the answer just might be yes. The PocketNC, a much-coveted five-axis CNC mill sized for the home shop, has a lot going for it, but as with most things, there are trade-offs. Chief among these is a lack of the usual huge, heavy castings used for CNC machines, which results in the tendency for the cutting tool to chatter or even stall out if you push the speeds and feeds too far. After a good intro to some of the important metrics of machining, such as “material removal rate,” the video below delves into how MRR affects chip load which in turn results in chatter.

The easy fix for chatter, of course, is to take smaller cuts. But [Ryan] decided to increase the spindle speed to take lighter cuts, but to do it really fast. The hardware for this includes a 3,500 KV high-torque brushless DC motor and a custom spindle attachment. The motor is connected to the spindle shaft using pulleys and a drive belt, and the shaft is supported with stout bearings that can be pre-loaded to fight backlash. The end result is three times the stock 10,000 RPM spindle speed, which lets [Ryan] see a 300% increase in cycle time on his PocketNC. And as a bonus, the whole thing requires no permanent modification to the machine and can be easily removed.

We think [Ryan] did a great job breaking this problem down to the essentials and hacking up a low-cost solution to the problem. Continue reading “Spindle Upgrade Makes PocketNC Faster And Smoother” →

Automate Away The Drudgery Of CNC Manufacturing

June 25, 2023 by Dan Maloney 39 Comments

One of the keys to making money with manufacturing is to find something that you can make a lot of. Most small manufacturers have one or two “bread and butter” items that can be cranked out in quantity, which of course has a quality all its own. The problem with that approach, though, is that it runs the risk of being boring. And what better way to avoid that than by automating your high-volume job, with something like this automated CNC work cell?

[Maher Lagha] doesn’t offer too much in the way of build details, but the video below pretty much tells the tale. The high-volume items in this case are customized wooden coasters, the kind a restaurant would buy for their bar or a business would give away as swag. The small 3-axis CNC router at the center of the work cell is the perfect choice for making these — one at a time. With no desire to be tied to the machine all day to load raw stock and unload completed coasters, [Maher] came up with automated towers that hold stacks of pallets. Each pallet, which acts as a fixture for the workpiece through multiple operations, moves from the input stack into the router’s work envelope and to the output stack using a combination of servos and pneumatics. The entire work cell is about a meter on a side and contains everything needed for all the operations, including air for the pneumatics and dust extraction.

Each coaster requires two tools to complete — one for surfacing and one for lettering — and [Maher] has two ways to tackle that. The first is to allow a stack of coasters to go through the first operation, change tools, and switch the roughed-in stock back to the input stack for the second round of machining. The other is just to build another work cell dedicated to lettering, which seems to be in progress. In fact, it looks as if there’s a third work cell in the works in [Maher]’s shop. The coaster business must be pretty good.

Continue reading “Automate Away The Drudgery Of CNC Manufacturing” →

Learning 3D Printing Best Practices From A Pro

May 26, 2023 by Tom Nardi 13 Comments

It might seem like 3D printing is a thoroughly modern technology, but the fact is, it’s been used in the industry for decades. The only thing that’s really new is that the printers have become cheap and small enough for folks like us to buy one and plop it on our workbench. So why not take advantage of all that knowledge accumulated by those who’ve been working in the 3D printing field, more accurately referred to as additive manufacturing, since before MakerBot stopped making wooden printers?

That’s why we asked Eric Utley, an applications engineer with Protolabs, to stop by the Hack Chat this week. With over 15 years of experience in additive manufacturing, it’s fair to say he’s seen the technology go through some pretty big changes. Hes worked on everything from the classic stereolithography (SLA) to the newer Multi Jet Fusion (MJF) printers, with a recent focus on printing in metals such as Inconel and aluminum. Compared to the sort of 3D printers he’s worked with, we’re basically playing with hot, semi-melted, LEGOs — but that doesn’t mean some of the lessons he’s learned can’t be applied at the hobbyist level. Continue reading “Learning 3D Printing Best Practices From A Pro” →

Wood game piece being carved by a CNC mill with a hacked rotary axis

This $12 CNC Rotary Axis Will Make Your Head Spin

May 15, 2023 by Michael Shaub 19 Comments

[legolor] brings us a great, cheap rotary axis to add to your small 3 axis CNC mills. How are you going to generate G-Code for this 4th axis? That’s the great part, and the hack, that [legolor] really just swapped the Y axis for the rotation. To finish the workflow and keep things ~~cheap~~ accessible to all there’s a great trick to “unwrap” your 3D model so your CAM software of choice thinks it’s still using a linear Y axis and keeps your existing workflow largely intact. While this requires an extra step in Blender to do the unwrapping, we love the way this hack changes as little of the rest of your process as possible. The Blender script might be useful for many other purposes too.

The results speak for themselves too! We thought the 3D printed parts were suspect in a CNC setup, but for the small scale of game pieces and milling wood, the setup is stable enough to produce a surprisingly accurate and detailed finish. If you want to try the same approach with something larger or a tougher material, [legolor] has a suggestion of a tailstock setup that’s still under $100 USD. Continue reading “This $12 CNC Rotary Axis Will Make Your Head Spin” →

CNC Feeds And Speeds, Explained As A First-Timer

May 5, 2023 by Donald Papp 35 Comments

If you’ve ever looked into CNC cutting tools, you’ve probably heard the term “feeds and speeds”. It refers to choosing the speed at which to spin the cutting tool, and how fast to plow it into the material being cut. They’re important to get right, and some of the reasons aren’t obvious. This led [Callan Bryant] to share his learned insights as a first-timer. It turns out there are excellent (and somewhat non-intuitive) reasons not to simply guess at the correct values!

A table of variables and how they relate to one another (click to enlarge).

The image above shows a tool damaged by overheating. [Callan] points out that as a novice, one might be inclined to approach a first cutting jobs conservatively, with a low feed rate. But doing this can have an unexpected consequence: a tool that overheats due to spinning too quickly while removing too little material.

CNC cutting creates a lot of heat from friction, and one way to remove that heat is by having the tool produce shavings, which help carry heat away. If a tool is making dust instead of shavings — for example if the feed rate is too conservative — the removed pieces will be too small to carry significant energy, and the tool can overheat.

[Callan] makes a table of variables at work in a CNC system in order to better understand their relationship before getting into making a formula for calculating reasonable feed and speed rates. Of course, such calculations are a reasonable starting point only, and it’s up to the operator to ensure things are happening as they should for any given situation. As our own Elliot Williams observed, CNC milling is a much more manual process than one might think.

Retired Welding Robot Picks Up Side Hustle As CNC Router

April 11, 2023 by Dan Maloney 19 Comments

Who says you can’t teach an old robot new tricks? Nobody, actually. That saying is about dogs. But it applies to robots too, at least judging by the way this late-90s industrial beast was put to use in a way it was never intended: as a giant CNC router.

The machine in question is an ABB IRB6400, a six-axis, floor-mounted industrial machine that had a long career welding at a Eurorail factory in Austria before [Brian Brocken] made its acquaintance. He procured the non-working machine — no word on what he paid for it — and moved the 2-ton paperweight into his shop, itself a non-trivial endeavor. After a good scrubbing, [Brian] tried to get the machine started up. An error prevented the robot controller from booting; luckily, there’s a large community of ABB users, and [Brian] learned that one of the modules in the controller needed replacement.

After fixing that — and swapping out the controller’s long-dead backup batteries, plus replacing the original 1.44 MB floppy drive with a USB drive — he was able to bring the machine back to life. Unfortunately, the limited amount of internal memory made it difficult to use for anything complicated, so [Brian] came up with an application to stream coordinates to the controller over a serial port, allowing for unlimited operation. With that in place, plus a simple spindle mounted to the robot’s wrist with a 3D printed adapter, [Brian] was able to carve foam blocks into complex shapes. The video below shows everything from delivery to first chips — well, dust at least.

This build seems to be a significant escalation from [Brian]’s previous large-format CNC machine. He must have something interesting in mind, so stay tuned for details.

Continue reading “Retired Welding Robot Picks Up Side Hustle As CNC Router” →