Sheet Metal Forming With 3D Printed Dies

January 9, 2025 by Maya Posch 16 Comments

Sheet metal is very easy to form, including the pressing in of intricate shapes with dies and a hydraulic press, but the dies themselves are slightly harder to come by. What if we could 3D print custom dies to stamp logos and more into sheet metal? This is the premise of a recent video by the Stick Shift Garage channel on YouTube in which dies are printed in PLA+ (solid infill) and used to stamp 1 and 2 mm thick sheet metal with the channel’s logo.

As can be observed in the video, the results aren’t bad at all after a couple of tweaks and adjustments to the pressure, but of course there is room for improvement. Some helpful commentators suggest improving the dies with properly rounded edges on the die’s shape and paying attention to K-factors and kin so as not to overstress or tear the sheet metal. In terms of die longevity, the PLA+ dies began to wear out after about a dozen tries but not the point of failure. Here other filament types might work even better, maybe even to the point of competing with a CNCed metal die.

Considering that this was a first attempt without a lot of pre-existing knowledge it went pretty well, and a future video was promised in which improvements will be shown off.

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Front panel of a GPO Brooklyn with cassette player (Credit: VSchagow, Wikimedia)

Physical Media Is Dead, Long Live Physical Media

January 9, 2025 by Maya Posch 126 Comments

Much has been written about the demise of physical media. Long considered the measure of technological progress in audiovisual and computing fields, the 2000s saw this metric seemingly rendered obsolete by the rise of online audiovisual and software distribution services. This has brought us to a period in time where the very idea of buying a new music album, a movie or a piece of software in a physical, or even online, retail store has become largely impossible amidst the rise of digital-only media.

Even so, not all is well in this digital-only paradise, as the problems with having no physical copy of the item which you purportedly purchased are becoming increasingly more evident. From increases in monthly service costs, to items being removed or altered without your consent, as well as concerns over privacy and an inability to resell or lend an album or game to a buddy, there are many reasons why having the performance or software on a piece of off-line, physical media is once again increasing in appeal.

Even if the demise of physical data storage was mostly a trick to extract monthly payments from one’s customer base, what are the chances of this process truly reverting, and to what kind of physical media formats exactly?

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3DBenchy Starts Enforcing Its No Derivatives License

January 9, 2025 by Maya Posch 104 Comments

[Editor’s note: A few days later, it looks now like Prusa pulled the models of their own accord, because of their interpretation of the copyright law. Creative Tools and NTI claim that they were not involved.]

Nobody likes reading the fine print, least of all when you’re just downloading some 3D model. While printing a copy for personal use this is rarely an issue, things can get a lot more complicated when you make and distribute a derived version of a particular model.

Case in point the ever popular 3DBenchy model, which was intended to serve as a diagnostic aid by designer [Creative Tools] (recently acquired by [NTI Group] ). Although folks have been spinning up their own versions of this benchmark print for years, such derivative works were technically forbidden by the original model’s license — a fact that the company is now starting to take seriously, with derivative models reportedly getting pulled from Printables.

The license for the 3DBenchy model is (and always has been) the Creative Commons BY-ND 4.0, which requires attribution and forbids distributing of derivative works. This means that legally any derived version of this popular model being distributed on Thingiverse, Printables, etc. is illegal, as already noted seven years ago by an observant user on Reddit. According to the message received by a Printables user, all derived 3DBenchy models will be removed from the site while the license is now (belatedly) being enforced.

Although it’s going to be a bit of an adjustment with this license enforcement, ultimately the idea of Creative Commons licenses was that they set clear rules for usage, which become meaningless if not observed.

Thanks to [JohnU] for the tip.

Deteriorating section of the UCIL plant near Bhopal, India. (Credit: Luca Frediani, Wikimedia)

Cleaning Up Bhopal: The World’s Worst Industrial Disaster

January 7, 2025 by Maya Posch 44 Comments

Forty years ago, on the night of Sunday 2 December of 1984, people in the city of Bhopal and surrounding communities were settling in for what seemed like yet another regular night. The worst thing in their near future appeared to be having to go back to school and work the next day. Tragically, many of them would never wake up again, and for many thousands more their lives would forever be changed in the worst ways possible.

During that night, clouds of highly toxic methyl isocyanate (MIC) gas rolled through the streets and into houses, venting from the Bhopal pesticide plant until the leak petered out by 2 AM. Those who still could wake up did so coughing, with tearing eyes and stumbled into the streets to escape the gas cloud without a clear idea of where to go. By sunrise thousands were dead and many more were left severely ill.

Yet the worst was still to come, as the number of casualties kept rising, legal battles and the dodging of responsibility intensified, and the chemical contamination kept seeping into the ground at the crippled plant. Recently there finally seems to be progress in this clean-up with the removal of 337 tons of toxic waste for final disposal, but after four decades of misgivings and neglect, how close is Bhopal really to finally closing the chapter on this horrific disaster?

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Schematic for progress of 3D integration. a, Schematic showing conventional 3D integration by TSV through wafers. b, M3D integration of single-crystalline Si devices by transfer, c, Growth-based M3D integration of polycrystalline devices. d, Growth-based seamless M3D integration of single-crystalline devices. (Credit: Ki Seok Kim et al., 2024, Nature)

Growing Semiconductor Layers Directly With TMDs

January 6, 2025 by Maya Posch 5 Comments

Transition-metal dichalcogenides (TMDs) are a class of material that’s been receiving significant attention as a possible successor of silicon. Recently, a team of researchers has demonstrated the use of TMDs as an alternative to through-silicon-vias (TSV), which is the current way that multiple layers of silicon semiconductor circuitry are stacked, as seen with, e.g., NAND Flash ICs and processors with stacked memory dice. The novelty here is that the new circuitry is grown directly on top of the existing circuitry, removing the need for approaches like TSV to turn 2D layers into 3D stacks.

As reported in the paper in Nature by [Ki Seok Kim] and colleagues (gift article), this technique of monolithic 3D (M3D) integration required overcoming a number of technological challenges, most of all enabling the new TMD single-crystals to grow at low enough temperatures that it doesn’t destroy the previously created circuitry. The progress is detailed in the paper’s schematic (pictured above): from TSV to M3D by transfer of layers and high- and low-temperature growth of single-crystal layers.

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One Small Step: All About Stepper Motors

January 6, 2025 by Maya Posch 12 Comments

The primary feature of stepper motors is listed right within their name: their ability to ‘step’ forwards and backwards, something which they (ideally) can do perfectly in sync with the input provided to their distinct coils. It’s a feature that allows the connected controller to know the exact position of the stepper motor, without the need for any sensor to provide feedback after a movement, saving a lot of hardware and effort in the process.

Naturally, this is the optimal case, and there are a wide number of different stepper motor configurations in terms of coil count, types of rotors and internal wiring of the coils, as well as complications such as skipped steps due to mechanical or driver issues. Despite this, in general stepper motors are quite reliable, and extremely versatile. As a result they can be found just about anywhere where accurate, step-based movement is desirable, such as (3D) printers and robotics.

For each application the right type of stepper motor and driving circuit has to be determined, of course, as they also have many reasons why you’d not want to use them, or just a particular type. When diving into a new stepper motor-based project, exactly what are the considerations to pay attention to?

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Reverse-Engineering The Polynomial Constants In The Pentium’s FPU

January 5, 2025 by Maya Posch 5 Comments

Die photo of the Intel Pentium processor with the floating point constant ROM highlighted in red. (Credit: Ken Shirriff)

Released in 1993, Intel’s Pentium processor was a marvel of technological progress. Its floating point unit (FPU) was a big improvement over its predecessors that still used the venerable CORDIC algorithm. In a recent blog post [Ken Shirriff] takes an up-close look at the FPU and associated ROMs in the Pentium die that enable its use of polynomials. Even with 3.1 million transistors, the Pentium die is still on a large enough process node that it can be readily analyzed with an optical microscope.

In the blog post, [Ken] shows how you can see the constants in each ROM section, with each bit set as either a transistor (‘1’) or no transistor (‘0’), making read-out very easy. The example looks at the constant of pi, which the Pentium’s FPU has stored as a version with no fewer than 67 significand bits along with its exponent.

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