Impulse Buying A 3040 CNC Machine, What Could Go Wrong?

August 26, 2023 by Donald Papp 46 Comments

[joekutz] made an impulse purchase of a CNC machine. It was a 3040 CNC that looked reasonably complete and had an attractive price, what could possibly go wrong? As it happens, [joekutz] really didn’t know what he was in for. Sometimes the price is good, but you pay in other ways. But where some would see defeat, [joekutz] sees an opportunity to document the restoration.

Dial indicators are useful tools for measuring how straight some parts aren’t.

The 3040 are relatively cheap and simple CNC machines that have been available from a variety of overseas retailers for years. They have 30 cm by 40 cm beds (hence the name) and while there are many variations, they all work about the same. [joekutz] expected that getting his up and running and converted to open source would be a fun weekend project, but it ended up taking far longer than that. In fact, it turns out that the machine was damaged in surprising and unexpected ways.

[joekutz] has a series of videos demonstrating the process of diagnosing and repairing the various things wrong with this device. In the first video, he dismantles the machine and discusses the next steps. In the second video, he takes some time to repair some dial indicators that will be critical for measuring the various things wrong with the CNC parts. Video number three delves into finding out the horrible things wrong with the machine, and the fourth is where repairs begin, including bending shafts and sanding blocks back into service.

Those videos are embedded below, and while the machine isn’t quite restored yet, progress is promising. We’ve seen easy and effective upgrades for such CNC machines before, but if you happen to be in more of a repair and restore situation, give [joekutz]’s work a look because it might just save you some time and frustration.

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Throw FreeCAD Some Curves

August 12, 2023 by Al Williams 43 Comments

[Mango Jelly] got a question from someone trying to model a phone box with a complex curved roof. We have to admit that when we saw it, we knew it would be hard to model well. Naturally, there are several ways it could be one, but [Mango Jelly] used the curves workbench in FreeCAD to produce a wireframe of the shape, and you can see how that works in the video below.

The curve bench didn’t sound familiar to us, and that’s because it is an add-on workbench. He starts with a sketch of a curve, constrained to be symmetrical. Then the draft workbench allowed a rotation to convert the curve into a nice skeleton of the curved roof.

The curves workbench can create a Gordon surface over that skeleton. You can extrude that into a solid object. There are still some details to add, though, and you’ll see how each part of the roof takes shape.

Watching videos like this reminds us that we use a small fraction of what FreeCAD can do. You’ll probably pick up at least one tip from this video. If you need a quick basic tutorial, try the one from [NovaSpirit]. Or, try a longer one.

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GrblHAL CNC Controller Based On RP2040 Pico

August 11, 2023 by Chris Lott 18 Comments

[Phil Barrett] designed a new CNC controller breakout board called the PicoCNC which uses the Raspberry Pi Pico RP2040 module and grblHAL. It packs a bunch of features typical of these controllers, and if you use the Pico W, you get WiFi connectivity along with USB. And if you don’t want connectivity, you can execute G-code directly from a micro SD card. The board is available in kit form, and schematics are posted on the GitHub repository above. Some of the features include four axes of motion, spindle control, limit switches, relay drivers, expansion headers, and opto-isolation.

This isn’t [Phil]’s first controller board. He also designed the grblHAL-based Teensy CNC controller breakout board, a step up from the usual Arduino-based modules at the time and boasting Ethernet support as well. According to the grblHAL site, nine different processors are now supported. There are well over a dozen CNC controller breakout boards listed as well. And don’t forget [bdring]’s 6-Pack grbl-ESP32 controller, a modular breakout board we covered a few years back. So pick your favorite board or roll your own and get moving.

Adding Two Axes Makes CNC Router More Than The Sum Of Its Parts

July 26, 2023 by Dan Maloney 20 Comments

The problem with building automated systems is that it’s hard to look at any problem and not see it in terms of possible automation solutions. Come to think of it, that’s probably less of a bug and more of a feature, but it’s easy to go overboard and automate all the things, which quickly becomes counterproductive in terms of time and money.

If you’re clever, though, a tactical automation solution can increase your process efficiency without breaking the budget. That’s where [Christopher Helmke] seems to have landed with this two-axis add-on fixture for his CNC router. The rig is designed to solve the problem of the manual modification needed to turn off-the-shelf plastic crates into enclosures for his line of modular automation components, aspects of which we’ve featured before. The crates need holes drilled in them and cutouts created in their sides for displays and controls. It’s a job [Christopher] tackled before with a drill and a jigsaw, with predictable results.

To automate the job without going overboard, [Christopher] came up with a tilting turntable that fits under the bed of the CNC router and sticks through a hole in the spoil board. The turntable is a large, 3D printed herringbone gear driven by a stepper and pinion gear. A cheap bearing keeps costs down, while a quartet of planetary gears constrain the otherwise wobbly platform. The turntable also swivels 90 degrees on a herringbone sector gear; together, the setup adds pitch and roll axes to the machine that allow the spindle access to all five sides of the crates.

Was it worth the effort? Judging by the results in the video below, we’d say so, especially given the number of workpieces that [Christopher] has to process. Add in the budget-conscious construction that doesn’t sacrifice precision too much, and this one seems like a real automation win.

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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.

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Mat Boards Are Spendy, So DIY CNC Tool To The Rescue

May 29, 2023 by Donald Papp 22 Comments

Mats are flat pieces of paper-based material that fill the space between a frame and the art within. They perform a number of aesthetic and practical functions, and they can also be expensive to purchase. Making them by hand is an option, but it’s an exacting process. [wooddragon48] felt that a CNC solution would serve this need nicely, and began designing a DIY CNC tool to do exactly that.

One of the tricky parts about cutting mat boards is that cuts are at an angle, and there is really no tolerance for overcuts or any kind of visual blemish. CNC control would seem to offer a great solution to both the need for precisely straight cuts, as well as fine control over where cuts begin and end in a way that opens the door to complex designs that would be impractical to do by hand.

[wooddragon48]’s design has an angled cutter designed to plunge perfectly on demand, surrounded by a ring — similar to that on a router — which ensures the cutting tool is always consistently positioned with the material. It’s still in the design phase, but this is a type of tool that doesn’t yet exist so far as we can tell. The ability to CNC cut mat board, especially in complex designs, would be a huge timesaver.

Art and DIY CNC have a long history of happy intersection, as we have seen with a CNC router repurposed for string art, a CNC painting robot, and even an interactive abstract sculpture generator.