What a crap video. What’s the point of that if it did not show you nothing ? Not putting this down but you see many people who have already done this. Check it up on YouTube. Just disappointed that the video was so short and show nothing of it working out.

Thats why i don’t really see the advantage over traditional metods… takes too long, makes a lot of noise and dust and the resolution is not really that great. Looks like I’ll stick with the photocopy method for a while.

Tucker and DeRoss emphasized the advantage of quick-change toolholders, such as the Coromant Capto, which integrate with the spindle securely and with high repeatability. The Capto interface is now off-patent and various suppliers offer many extension and reduction adapters, plus adaptations to other machine interfaces. DeRoss reported that roughly three-quarters of all new multi-tasking, multi-functional machines with a B-axis head now come equipped with a Capto spindle.

Assuming your bed is flat (which isn’t should be), is there that much variation across a sheet of PCB?

Coatings remain a key factor in improving the durability of both the insert and the tool body. The “secret sauce” that the OEMs use to achieve the latest coatings remain just that, proprietary and hidden. Sandvik Coromant has released a new version of its Inveio coating, which uses the CVD process Tucker says can be controlled “at the molecular level,” such that the multiple layers stand up in uniform columns. “We’ve really mastered the consistency of how the width and length of each layer aligns. … And we get a big increase in tool life and even wear across the cutting edge of the insert.” Sandvik Coromant’s website doesn’t tell you what the coating consists of, but Tucker reported that it’s TiAlN.

You would spend less time and money putting together a CCCNC and measuring its accuracy to your satisfaction than trying to make an Ant work. But maybe the Bree style marketing is entrancing you?

This one got me thinking.. If the cnc did not move a rotary tool for cutting but a glass fiber carrying UV light. Then a copper pcb with photoactive paint could be exposed by the cnc device..

Hello guys, the video shown in the post refers to the old version of the machine. Now we use a new head with ER8 chuck and different spindle coupling, more rigid and stable. If you want to see the new version , take a look to the other videos in the channel (e.g. https://youtu.be/YpQbVpmD7eY). Moreover it implements probing and ABL since the first version. Our little project is far from being perfect but it’s quite improved since the first version.

I most frequently have problems with _setting_ the top of the workpiece. My z-probe is a fiddle to use, so I tend to use the sheet-of-paper-under-the-bit technique, which obviously isn’t super accurate. I’ve just linked up a joypad to jog it, which is making it a lot easier to zero (compared to a laptop on the next bench), which is helping me zero more accurately.

1. you might be better off using the motor to drive a separate spindle via a pulley (turn the motor upside down) then have that spindle mounted with a couple of bearings that have the smallest out of runout possible (runout = spindle wobble), so the motor provides the power and the bearings reduce the run out / increase the minimum track width you can do Try testing with a dial test indicator (cheap Chinese one would do) Maybe another way might be a cheap hard disk motor from ebay? since they have fluid bearings

Apparently the video link got updated from an old version to an improved newer version after this article was posted.

3. Auto leveling is a must, otherwise you end up with one corner of the board milled, the other not perhaps a inbuilt inductive sensor (blue proximity sensor) might work here which could be mounted near / just above the spindle without getting in the way of the milling.

Usually when one thinks of using a CNC machine for producing PCBs, one thinks of those big, bulky CNC machines that pretty much fill an entire desk. But what if a CNC machine could be small enough to fit on a desk without getting in the way, yet still be useful enough to make single- and double-sided PCBs? This was the idea behind The Ant, the compact PCB manufacturing machine which [Mattia] and [Angelo] designed and open sourced.

the spindle motor selection is bad, it’s a rare motor and while I understand the desire to get a low Kv motor for more torque, since the pulleys are printed, you should go with a more common high Kv motor and slow it down with a larger pulley on the spindle.

When should you consider a tool customized for your unique situation? Sandvik Coromant’s Tucker answered, “when the part count and the ROI makes sense. … Or if there’s a feature on a part that can’t be done with a standard tool.” Tonne said a large percentage of Horn’s sales are made to order or custom solutions and offered the following criteria: “When the part complexity or features have a tighter tolerance than a machine tool can handle. For example, if groove spacing must be within microns and the machine tool has some error due to worn internal parts, a custom solution would be a good choice. If the programming of a feature becomes too complex, an indexable custom solution would be a good option, [as it would] if operations can be done simultaneously, such as chamfering, profile milling, and groove milling.”

On the other hand, Tonne said “high-pressure coolant has become more prevalent as more and more insert seats are added to each cutter. If you have a cutter with 20 pockets, you need the inlet pressure and coolant volume to be high enough to supply each pocket. Tangential milling systems like Horn’s 610, 406, and 409 systems are also a reason high-pressure coolant is beneficial. The strong core, high feed rates, and smaller chip flutes of tangential cutters require volume and pressure to evacuate chips. When slotting and profiling difficult-to-machine alloys, the cooling and chip-removal capabilities of high-pressure coolant are required.

“A standard coolant system on a typical machine might be in the range of 80 to 200 psi,” he continued. “For each coolant outlet at the pocket pressure is divided. For a 100-psi system and a 20-pocket cutter, that means the outlet pressure for each coolant output is approximately 5 psi. There is no magic number for each application, but more is definitely better.”

Walter USA also makes an indexable threadmill with special inserts. (For 7/8"  [22.23 mm] diameter and below it also makes a solid-carbide version of the tool.) According to Pollock, the design cuts the chip and folds it in on itself such that it pulls away from material. The tool features a multi-row arrangement that requires multiple revolutions to cut a complete thread, Pollock explained. “Depending on the thread pitch, it could take as many as four or five times around to make the complete thread. But the lower engagement forces produced by our design allow us to feed the tool faster, and we can actually reduce the cycle time to be even faster than cut taps. Normally, when switching from tapping to thread milling, it is common to expect improved thread quality, improved tool life, and improved cost per part. But that also means knowing you’re going to have to sacrifice cycle time, because thread milling typically takes a little bit longer. Not with this tool.”

I assume the reason most home PCB makers would choose to mill their boards is to avoid the chemicals and lab setup.

Speeding setup adds efficiency, and there have been improvements on the margins. DeRoss said Sandvik Coromant is now using bigger screws on some of its milling cutters, because “sometimes the smaller screws are hard to handle. After they’re used, they can start to lock up in the cutter. So, the bigger screws are a little easier to remove.”

When your traces get smaller, yes, the variatian in a PCB is enough to aircut at one end and cut wayy to much depth and go over your traces on the other end.

The Ant actually has it’s own Youtube channel. There even is what purports to be a tutorial video (a better demonstration of it’s overall capabilities I hope) although I am posting now but will not have time to watch until later.

For Sandvik Coromant’s DeRoss, the driving factor in picking a solid-carbide tool over an indexable is the need to achieve a superior surface finish. Wiper inserts can be added to an indexable tool to improve the surface finish, but DeRoss said the only way to compete with the solid tool’s higher flute count is to slow the process. Pollock explained that by its nature, an indexable tool will never present a continuous cutting edge as perfectly as a solid tool. “Even though a long-edged indexable tool might line up well, maybe even to the point where you don’t feel a witness line, there is almost always a witness line. … There will always be a little bit of mismatch due to an indexable tool being an assembly. It is [comprised of] inserts put into a steel body. It is never going to have a pocket in the perfect location, and you’re never going to be able to grind the insert to an exact size. There’s always going to be a little bit of a stack up. That is not true with solid tools.”

I’m using a CNC to make PCBs (not a small one like here but a regular CNC with a full alu frame). It take me 10/15 min max to do a 10×15 cm circuit (tracks, drill, text, board cutout), I got a very good accuracy and without using any chemical product. that why I switched to this way of doing PCBs instead of the traditional method.

I like the idea and design, but so many of the parts are tiny for the sake of being tiny and cost more and are less common than slightly larger versions would be.

Maybe I’m not seeing the same video – all I’m seeing is a bed leveling procedure. Hopefully that’s not all it can do.

With SMT, you’ll drill a lot less holes. Drilling etched PCB with donut pads is a lot easier as it help to center the drill bit.

Congratulations: you’ve just invented the photoplotter. Welcome to the 1980s! But that’s not a slam – hobby technology is often 30 years behind industry, because it takes that long for the components to come down in price to the level needed by home gamers.

The other recurring issue is securing small parts reliably. Due to the small work area, large clamps designed for bigger machines are no use. Doesn’t help I’m often wanting to machine to the edge of a part. It’s not exactly a flaw in the machine itself, but the size seems to make it hard to secure items properly.

I’m in the process of building three of these for a local hackerspace, and while I don’t have them built yet (waiting on 3d printing at the moment), it seems that there is a lot of effort to use the smallest possible components. Making it just a little bigger would let you use more common (and therefor cheaper) components

That’s not to say the tool manufacturers aren’t trying to tighten these tolerances. Tucker said Sandvik Coromant was the first company to machine the bodies in a hardened state, making for a “much more accurate cutter” (as opposed to heat treating them after the pockets were cut). He added that Sandvik Coromant aims for 0.0005" (0.0127 mm) in radial runout for the pockets, and is now looking at new materials and different processes to achieve tighter tolerances. What’s achievable when assembling the cutter on the shop floor “depends,” he said. For example, ground inserts would be needed to come close to maintaining this tolerance. On top of that, they should all come from the same batch. But if it is a truly indexable tool and using randomly selected production inserts, “you’re probably looking at five-tenths to a thou from insert to insert with ground inserts,” said Tucker.

Very true. I’ve thought a lot about this and I now have a small PCB mill at work, it isn’t perfect but it saved me from the hassle of setting up the place to do chemical etching, which would require God knows what procedures to dispose and store the acid, access to a water tap, etc etc a lot of paperwork,and headache you still need to drill the holes for through-hole legs and vias.

Thanks for changing the video. That’s better because we get to see what this baby can do. Much better.

The bed is never flat. If you’re carving with a v bit, the width is proportional to the depth. When the difference between success and failure is 0.1mm, then bed levelling is almost always necessary.

Uses a crappy set screw chuck; would rather see ER-11 I can purchase a $180 1810 Chinese CNC from Amazon. They take 3 hrs to put together and get running with bCNC. This is with solid leadscrews and a much beefier spindle.

But not everyone thinks coolant is always, or even often, needed and high-pressure coolant (700-1,000 psi) appears to be controversial. In Pollock’s opinion, high-pressure coolant is useful for grinding and turning, but is not needed in milling. High-pressure pumps “bring a lot of vibration into the cut,” not to mention “screaming like a banshee” whenever they’re running. In fact, Pollock said, “there are materials where we prefer not to use coolant. Carbon steel is one. We much prefer to cut it dry. If we need chip evacuation, we might try to get some air on it.” And if the material calls for a liquid coolant, such as titanium, Inconel, stainless steel, or aluminum, a low-pressure coolant is sufficient.

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For its part, Walter USA has developed an ultra-low pressure CVD coating process that Pollock said allows it to “put more aluminum into a titanium aluminum nitride coating. We often recommend titanium aluminum nitride for milling, because it’s very tough and it’s very thin, so it handles the interruption of milling very well. But by putting more aluminum in the titanium aluminum nitride you can run a lot faster, because aluminum is the part that resists the heat. It can take a lot more heat like an aluminum oxide insert, but it’s not as fragile as that coating due to the titanium.” He described the approach as a blend that manages to achieve the benefits of both a PVD titanium aluminum nitride coating and a CVD aluminum oxide coating. It required modifications to the furnace, but naturally Walter won’t say much more than that, other than the name: Tiger-tec Gold.

I have some issues with z-height – sometimes a workpiece isn’t flat (either not secured flat, or just isn’t flat itself – sometimes curved). That’s not a machine issue though, but unfortunately cncjs lacks the ability to compensate for it.

Pollock said Walter USA has also introduced a unique coating for its tool bodies, “to help protect the steel and avoid chip wash.” He said the industry in general has transitioned from simple case hardening and through hardening to a steam oxide process that produced a black surface that controlled rust, to nickel plating, which produced a flat silver look. “Now the industry seems to be going back towards black. But ours is not just the steam oxide process; it’s an actual coating that’s even harder and more wear resistant, called Walter BLAXX.” Tucker teased that Sandvik Coromant will introduce a new milling cutter body in October 2022 that has eight times the life of the materials now in use.

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20×20 extrusions are much more common than 10×10 (as are the screws, nuts, brackets, etc) and you could go with 20×60 or 20×80 for the sides and have them be one-piece. I haven’t checked yet, but this may cause problems with the rails, potentially requiring a size up. I haven’t looked at the costs of that.

I have to agree with Hobgoblin. The CCCNC (Cheap Chinese CNC) is bigger, better, faster than this, but with no larger a desk footprint than a keyboard+monitor+mousepad. And if you want smaller, there are several size variations available, and you can extend or shrink the X and Y work area easily, to get any reasonable size. The one I got is generically known as a “3018” mill, meaning a 30cm x 18cm working area, which is about the maximum size you can go using 20x20mm rails and 8mm guide rods and lead screws, and is a whole lot more useful than what we see here. Also a lot more rigid, which is the name of the game. Anybody who’s ever used a Dremel knows that the bit will always try to move in a direction other than that which you intend, and in a CNC, the machine’s stiffness is the only thing preventing this. Solid leadscrews are both stiffer and far more precise than cog belts. A PCB mill is NOT a 3D printer – even at super-low feed speeds, there are forces on the tool!

Sandvik Coromant has also released a PVD coating, Zertivo, that follows the same principle. Again, Tucker said the differentiating factor is Sandvik Coromant’s ability to “add greater strength at the micro level or the nano level of the edge line. We’re able to bring strong particles up to the edge line where we need them, and keep other material behind that where we need toughness.” He also emphasized that 90 percent of the company’s coatings are done in-house, with specialized processes, and include secret edge preparation.

I’ve not measured repeatability properly though. Is there a standard measurement for it? I imagine running it round in circles or back and forth for 10 mins then checking against the start location?

My commercial equivalent has something like this. It has an enclosure around the cutting head that drops down and rides on the copper, which both establishes the tool height (as an offset from the cutting head lip) and provides a complete vacuum enclosure for the head, attached to a filtered vacuum system. It’s a nice solution because it automatically tracks variations in the copper thickness or board flatness. I haven’t yet found a silent vacuum cleaner, but would love one.

But what would that save? You’d still have the relative mess of photoresist and etching acid. It’d be slower than overlaying a negative and might result in fuzzy edges.

Ceramic tooling is a large part of Greenleaf’s business. For these tools it does not recommend liquid cooling, owing to the thermal shock and the resulting loss of tool life. Interestingly, in its testing Greenleaf has found no need to design toolholders any differently for air coolant than it would for liquid coolant. Many of its holders can use either ceramic or carbide inserts.

2. It might not be relevant for light etching, but if you want to get the rpm’s as ideal as possible then look at “speeds and feeds” for copper, Usually when milling metal lower rpm’s are better, you might be able to lower the rpm’s by using a pulley / driving a separate spindle as above

When I bought my 3018, I was really looking for components to build one of my own design, but discovered that there was no way to buy the parts for the price of the whole kit, which settled it for me – if I didn’t like the machine, I would still have all of the components to build it my own way. A YouTube search for “cnc upgrade” indicates that many people have had the same idea. But I have not been disappointed – what I got was better than I probably would have built, and it’s good for more than just tiny PCBs. And no, a CCCNC is not a real CNC machine – you can’t expect something made out of aluminum and ABS to hog out serious metal all day – but for carving wood and plastics, and engraving soft metals (like copper on FR-4), they are adequate. And better than “The Ant”.

Martin Dillaman, manager of applications engineering/project manager for Greenleaf Corp., Saegertown, Pa., observed that improved CAM software has done a lot to improve tool life. “The increased focus on maintaining consistent chip thickness helps promote longer tool life and controlled wear over the length of the tool. That helps whether it’s indexable or solid tooling.”

I would make a solid (transparent?) case for it, though. Or maybe just run it in the basement. I hate the dust that comes off of epoxy/fiberglass when it’s cut/milled/drilled. Anyone have a good solution for the dust extraction and filtering?

I’ve read nothing good about those Chinese PCB cncs. The idea of an easy home one off solution is pretty awesome.

Optical alignment for double-sided boards is achieved using a USB micro camera and the bCNC software, while the cost for materials is said to be quite inexpensive when compared with commercial solutions

Dillaman said Greenleaf has also concentrated on developing insert tools with coolant lines in order to extend life. “Whether it’s used for liquid or air coolant, you need a controlled flow out to the cutting edge to help prevent chips from building up and also for evacuating the chips out of the area where the next insert will be coming through to cut. That prevents possible recutting or packing of chips into the flutes and helps overall performance and finish.”

If anyone else is curious about speed. Watching one of the vids on their channel it looks like it took about 40 minutes, plus setup time and tool changes, to produce a 30mm x 30mm single sided board with 15-20 holes and about 6 traces.

Greenleaf also offers a tooling family with indexable nests for the inserts. Called C4 and CP4 cutters, Dillaman explained that they enable the user to easily switch between completely different insert geometries. “Whether it is a round insert, or a square, or an 80° diamond, you can change out the nests, depending on the geometry of the part being machined.”

What is the accuracy on a 3018-size mill? Spindle runout? Repeatability/accuracy of locating the head? Overall backlash in a PCB-milling/very-light-duty application?

The basic accuracy seems good. First job I did, I milled a 6” ruler, and then measured it with an actual ruler; it was as close as I could measure, which was far better than I expected – I’d expected it’d need calibration of the GRBL params.

I’m not sure what Micahel was talking about. I only see the bed leveling video here too. That said, Bed Leveling is in the title so it’s all I would expect from that video.

Use the laser and mirror assembly from a junk laser printer. Swap the laser with an IR diode laser. Think something akin to a laminator for feeding the copper clad past the mirror assembly. Quality should be able to at least match the original printer capabilities if done well.

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Dillaman pointed to the fact that Greenleaf typically uses a round geometry, “because of the strength of the insert and the chip thinning capabilities of that shape in milling. It also lends itself to quicker and easier indexing of the inserts, because you can loosen the screw and index to the next good edge by simply rotating the insert. Whether you’re rotating by 20˚ or up to 90˚, it’s just a simple rotation, lock it back down, and you’re ready to go.” And as mentioned earlier, Greenleaf offers both ceramic and carbide inserts and toolholders that handle either one. “That way, you could use the same cutter, especially in job shops or places where they’re moving between multiple materials, multiple hardnesses. One cutter could be used with a number of different grades, whether it’s carbide or ceramic.”

I’ve seen an Ant running, and if all you want is PCB milling, it’s small and solidly constructed. It does PCB-specific things, like bed levelling. (Granted, a matter mostly of software.) I think it’s more of a single-purpose device, and that’s a strength.

Agreed. In fact, you can get better (more precise) results with photoresist, but there are a lot more steps involved, some of which are messy. And even when you’re done, if you have more than a couple holes to drill, or need to route any kind of outline other than rectangular, you need a CNC machine setup anyway. So for prototypes, a “PCB mill” is usually the simplest solution.

The Othermill/Bantam Tools comes with a little attachment with round brush that fits around the tool with a hose that goes to the back of the machine where you can plug a vacuum cleaner. I’ve milled some 16 PCBs so far and the machine looks clean as new. The only issue is the noise of the vacuum cleaner, I want to get a silent one but haven’t checked yet.

Pollock cited customized insert shapes for crankshaft machining. “It’s one of the most expensive components in an internal combustion engine and machining them consumes a lot of inserts, so this area gets a lot of attention.” Both the shape of the insert and the geometry on the face are critical, explained Pollock, “in order to machine carbon steel that’s going to produce a long chip and be able to control it.” He added that the ability to press unique insert shapes and hold them to tight tolerances in the sintering process is “probably the biggest innovation” in creating these form tools. “The tolerances are good enough right from the sintering furnace. You don’t have to come back and grind them, which makes complex geometries more possible. If it had to be ground then there is more of a limit to the shapes that could be produced.”

Many of the recent advances in the brutally competitive world of indexable tooling may seem incremental. The details of others are shrouded in secrecy. But since cutting tool choices can have outsized impacts on productivity, it’s always worth asking the experts what’s new.

Dan Tucker, manager for the product management group and milling specialist for the western U.S. at Sandvik Coromant, Fair Lawn, N.J., quantified the trade off by saying solid-carbide surpasses indexable milling tools for diameters of 5/8" (15.88 mm) and below and “you could even make the argument that ¾" [19.05 mm] diameter solid carbide might surpass indexable as far as productivity. It is often hard to get enough indexable inserts into a smaller tool to compete, not only in terms of how many are put in the cutter, but also the length of the inserts to match up to a solid carbide.” Tucker’s colleague, Joe DeRoss, milling specialist for the eastern U.S., said there are rare cases in which it’s more cost-effective to rough with a small-diameter indexable tool, even though it would have fewer teeth than a solid tool of the same size. That’s because it’s less expensive (at least from a tooling standpoint) to chunk out material with a two-flute indexable mill and then switch out inserts when they wear.

Support and community interaction is mostly performed via the Reddit group for the project, where the diminutive machine finds a welcoming community as it continues to evolve. The machine itself is specified at this point as being able to built from commercially available and 3D printed parts, requiring no further tools for cutting or shaping. The precision is about 0.2 mm trace spacing.

Honestly, after seeing the machine in action, wouldn’t you want to have a CNC machine that’s so small and good-looking on your desk? If there’s one thing one might want to add, it’s probably a way to deal with the copper dust that’s produced while creating PCBs. Having to clean that off the desk after each PCB manufacturing session would get a bit cumbersome, we imagine.

finding the right motors for this is hard, going with the common nema-17 motors used so commonly in 3d printers would save a fair bit of money (and I see there’s a post by someone who created new brackets to do this)

I lack a dial gauge, so haven’t taken proper measurements. Your reply has prompted me to test it properly, so I’ve literally just ordered one.

I’ve got a 3018, and it’s solid, repeatable, and precise. I think the weakest part on it is the spindle, which is still a lot beefier than this CNC. I think the steppers would happily handle a larger more powerful spindle, but I don’t know what the next step up is short of a trim router. Even still it’ll cut aluminium if you’re careful on feeds.

4. DiyouPCB tried using a blu-ray head for UV exposure of boards. I plan on trying something similar using Trinamic stepper drivers to get a smoother run

“If the periphery of the insert isn’t ground,” Walter USA’s Pollock added, “the variation will be on the order of ±0.001-0.0015" [0.0254-0.0381 mm]. This could result in a total runout of up to 0.003 [0.0762]" in the most extreme case.”

Repeatability / accuracy of locating the head is (anecdotally) excellent. I’ve killed power to it mid-job when the dust extraction came loose, and after re-homing it, it continued the job fine with no noticeable glitches. The only times I’ve seen issues is when it’s mis-stepped, usually due to too aggressive feeds & speeds, though occasionally due to hitting a fixture 😭

You’re using the wrong bit, if 0.1 mm in Z is the difference between pass and fail. The typical engraving bit has a 15 degree angle, which means that a 0.1 mm change in Z is only about a 0.025 mm change in diameter.

“Indexable” doesn’t have to mean “simple” or “standard.” For example, “gear milling used to require dedicated hobbing machines,” observed Horn USA’s Tonne. But advances in both CAM software and cutting tool technology have enabled the production of “even the most complex gear shapes and splines on standard lathes with C-axis synchronization. Horn also produces gear skiving tools on an indexable platform due to these advances.” DeRoss mentioned Sandvik Coromant’s indexable milling cutters for turbine root forms. They also make special tulip cutters in both indexable and solid carbide for the corresponding form in the ring the blades lock into. Railroad rails, which have a rounded edge, are another big application for special indexable tools.

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Let’s start with the age-old question of deciding between indexable and solid-carbide milling cutters. The first considerations, as Luke Pollock, product manager at Walter USA, Waukesha, Wis., put it, are “how much material needs to be removed and how much working space do you have?… When you have the room and a large amount of material to remove, I definitely think indexable tooling is the much better way to go. We even see use of indexable tools on small components for the first few operations, just to increase the material removal rate due to the tool’s size and number of teeth.”

I’ve not measured spindle runout or backlash. I think the spindle runout is very small as I’ve not noticed issues using a v-cutter (I assume it’d cut circles instead of a point if it was having problems?)

In addition to the above linked Bitbucket repository for the project, the ‘Ant Team’ has a YouTube channel on which they have a range of rather professionally edited videos on the project, ranging from constructing the little machine, to various updates and more  Also see the video that is attached after the link for a visual introduction to the project.

I saw it in person at Make Munich. given the size it seems slow, but to get a very accurate resuklt you want to give it time. fast feedrates will result in jiggyness. Given what it does the speed is not that bad and it is a viable alternative if you need to do pcbs in house right now.

From an applications standpoint, Edwin Tonne, training and technical specialist at Horn USA Inc., Franklin, Tenn., said slot milling or disk milling (face milling) are the best examples in which indexables beat solid tools. “Another example would be face milling in smaller closed pockets. With the Horn 304 mini mill, the bottom of a deeper pocket can be machined without the expense of a longer solid carbide tool,” he said.

Me too! It’s a sweet-looking design, mostly b/c it’s constrained to do only what it’s intended to — mill and drill PCBs. They were getting great results, and the design looks very thoroughly thought through, but also evolving/improving.