Making An Injection Mold For Yourself

Injection molding is the obvious onward step from 3D printing when the making of a few plastic parts becomes their series manufacture. The problem with injection molding is though, that making a mold can be prohibitively expensive. Has the advent of affordable CNC machining changed that? [Teaching Tech] takes a look, and machines a mold for part of a bicycle bracket.

With a diversion into home-made silicone seals for the injection molding machine, he proceeds to machine the mold itself from a block of aluminium. It’s a basic introduction to mold construction for those of us who’ve never ventured in this direction before, and it provides some interesting lessons. As we’d expect he does a rough machining pass before returning with a ball-end tool to smooth off those curves, but there’s a lesson in measuring rather than believing the paperwork. The tool he used was a bit smaller then the spec, so his path left some rough edges that had to be returned to. Otherwise the use of a removable pair of bolts to form holes in the finished part is we guess obvious after watching the video, but it’s something we learned as injection molding newbies.

This video follows on from a previous one we also covered, in which we’re introduced to the machine itself.

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

[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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Pen Plotter Uses Polar Coordinates

To keep track of a location in a two-dimensional space, two measurements are needed. Most of the time, we would naturally think to do this by the Cartesian method, measuring position along one axis and then again along a second axis. But this isn’t the only way of keeping track of position. Polar coordinates, where the distance from the origin and an angle are used as the two measurements, works just as well, and sometimes can be a preferred method. This pen plotter tosses the expected Cartesian methodology we would typically expect in favor of this polar system.

The first prototype that [André] built was a good proof of concept. A pen attached to a movable carriage on a single rotating arm produced passable drawings, but as all prototypes go this one needed some refinement. Limit switches at the ends of the table, as well as within the arm, served to orient the plotter so that it didn’t manually need to be zeroed out every time. A linear actuator was added to give finer control over the pen’s pressure on the table, and finally an encoder was added to the base of the plotter to more accurately correct positional errors in the rotating arm mechanism.

With everything said and done, the polar coordinate plotter seems to work just as well as its Cartesian cousins might, orienting it like this has some advantages as well. Specifically, it is more adapted to drawing curves or circles than an X-Y device might be able to, like we saw with this similar sand-drawing plotter. Also, if allowed to rotate its entire 360-degree reach instead of just the 90 degrees shown in the video, a machine like this could theoretically reach a wider workspace more easily than other plotters.

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Hackaday Prize 2023: Circuit Scout Lends A Hand (Or Two) For Troubleshooting

Troubleshooting a circuit is easy, right? All you need is a couple of hands to hold the probes, another hand to twiddle the knobs, a pair of eyes to look at the schematic, another pair to look at the circuit board, and, for fancy work, X-ray vision to see through the board so you know what pads to probe. It’s child’s play!

In the real world, most of us don’t have all the extra parts needed to do the job right, which is where something like CircuitScout would come in mighty handy. [Fangzheng Liu] and [Thomas Juldo]’s design is a little like a small pick-and-place machine, except that instead of placing components, the dual gantries place probes on whatever test points you need to look at. The stepper-controlled gantries move independently over a fixture to hold the PCB in a known position so that the servo-controlled Z-axes can drive the probes down to the right place on the board.

As cool as the hardware is, the real treat is the software. A web-based GUI parses the PCB’s KiCAD files, allowing you to pick a test point on the schematic and have the machine move a probe to the right spot on the board. The video below shows CircuitScout moving probes from a Saleae logic analyzer around, which lets you both control the test setup and see the results without ever looking away from the screen.

CircuitScout seems like a brilliant idea that has a lot of potential both for ad hoc troubleshooting and for more formal production testing. It’s just exactly what we’re looking for in an entry for the Gearing Up round of the 2023 Hackaday Prize.

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GrblHAL CNC Controller Based On RP2040 Pico

[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.

Laser Engraver Uses All Of The DVD Drive

For the last ten to fifteen years, optical drives have been fading out of existence. There’s little reason to have them around anymore unless you are serious about archiving data or unconvinced that streaming platforms will always be around. While there are some niche uses for them still, we’re seeing more and more get repurposed for parts and other projects like this tabletop laser engraver.

The build starts with a couple optical drives, both of which are dismantled. One of the shells is saved to use as a base for the engraver, and two support structures are made out of particle board and acrylic to hold the laser and the Y axis mechanism. Both axes are made from the carriages of the disassembled hard drives, with the X axis set into the base to move the work piece. A high-output laser module is fitted to the Y axis with a heat sink, and an Arduino and a pair of A4988 motor controllers are added to the mix to turn incoming G-code into two-dimensional movement.

We’ve actually seen a commercial laser engraver built around the same concept, but the DIY approach is certainly appealing if you’ve got some optical drives collecting dust. Otherwise you could use them to build a scanning laser microscope.

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

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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