Phosphor-based displays like CRTs rely on the phosphor to emit light for a set amount of time after being activated, allowing them to display a seemingly persistent image with one drawing beam per color. Translated to UV-sensitive PLA filament, this means that you can totally use a printed sheet of this material in combination with a 405 nm laser diode to create a display that doesn’t look dissimilar to an early CRT. This is exactly what [bitluni] did in a recent video, meshing together said laser diode, UV-sensitive PLA, stepper motors and two mirrors with an Arduino-based controller to create a rather interesting vector display.

In the video, [bitluni] goes over the development steps, including a range of improvements like being able to turn off the laser when moving between the end of a line and the beginning of a new one. While the Arduino Nano board does the driving of the stepper motor controllers, an ESP32 provides the drawing instructions. The STL and other project files including Nano & ESP32 firmware can be found on the GitHub project page.

While far from being a practical display with a single-digit Hz refresh rate, it does provide an interesting demonstration of these types of persistence of vision based displays, and without the use of exotic MEMS mirror modules or the like.

Magnetic skyrmions are an interesting example of solitons that occurs in ferromagnetic materials with conceivable solutions in electronics, assuming they can be created and moved at will. The creation and moving of such skyrmions has now been demonstrated by [Yubin Ji] et al. with a research article in Advanced Materials. This first ever achievement by these researchers of the Korea Research Institute of Standards and Science (KRISS) was more power efficient than previously demonstrated manipulation of magnetic skyrmions in thicker (3D) materials.

Magnetic skyrmions are sometimes described as ‘magnetic vortices’, forming statically stable solitons. In a broader sense skyrmions are a topologically stable field configuration in particle physics where they form a crucial part of the emerging field of spintronics. For magnetic skyrmions their stability comes from the topological stability, as changing the atomic spin of the atoms inside the skyrmion would require overcoming a significant energy barrier.

In the case of the KRISS researchers, electrical pulses together with a  magnetic field were used to create magnetic skyrmions in the ferromagnetic  (Fe₃GaTe₂, or FGaT) film, after which a brief (50 µs) electric current pulse was applied. This demonstrated that the magnetic skyrmions can be moved this way, with the solitons moving parallel to the electron flow injection, making them quite steerable.

While practical applications of magnetic skyrmions are likely to be many years off, it is this kind of fundamental research that will enable future magnetic storage and spintronics-related devices.

Featured image: Direct imaging of the magnetic skyrmions. The scale bars represent 300 nm. (Credit:Yubin Ji et al., Adv. Mat. 2024)

Recently China’s new CHIEF hypergravity facility came online to begin research projects after beginning construction in 2018. Standing for Centrifugal Hypergravity and Interdisciplinary Experiment Facility the name covers basically what it is about: using centrifuges immense acceleration can be generated. With gravity defined as an acceleration on Earth of 1 g, hypergravity is thus a force of gravity >1 g. This is distinct from simple pressure as in e.g. a hydraulic press, as gravitational acceleration directly affects the object and defines characteristics such as its effective mass. This is highly relevant for many disciplines, including space flight, deep ocean exploration, materials science and aeronautics.

While humans can take a g-force (g₀) of about 9 g₀ (88 m/s²) sustained in the case of trained fighter pilots, the acceleration generated by CHIEF’s two centrifuges is significantly above that, able to reach hundreds of g. For details of these centrifuges, this preprint article by [Jianyong Liu] et al. from April 2024 shows the construction of these centrifuges and the engineering that goes into their operation, especially the aerodynamic characteristics. Both air pressure (30 – 101 kPa) and arm velocity (200 – 1000 g) are considered, with the risks being overpressure and resonance, which if not designed for can obliterate such a centrifuge.

The acceleration of CHIEF is said to max out at 1,900 gravity tons (gt, weight of one ton due to gravity), which is significantly more than the 1,200 gt of the US Army Corps of Engineers’ hypergravity facility.

Who doesn’t like dial-up internet? Even if those who survived the dial-up years are happy to be on broadband, and those who are still on dial-up wish that they weren’t, there’s definitely a nostalgic factor to the experience. Yet recreating the experience can be a hassle, with signing up for a dial-up ISP or jumping through many (POTS) hoops to get a dial-up server up and running. An easier way is demonstrated by [Minh Danh] with a Viking DLE-200B telephone line simulator in a recent blog post.

This little device does all the work of making two telephones (or modems) think that they’re communicating via a regular old POTS network. After picking up one of these puppies for a mere $5 at a flea market, [Minh Danh] tested it first with two landline phones to confirm that yes, you can call one phone from the other and hold a conversation. The next step was thus to connect two PCs via their modems, with the other side of the line receiving the ‘call’. In this case a Windows XP system was configured to be the dial-up server, passing through its internet connection via the modem.

With this done, a 33.6 kbps dial-up connection was successfully established on the client Windows XP system, with a blistering 3.8 kB/s download speed. The reason for 33.6 kbps is because the DLE-200B does not support 56K, and according to the manual doesn’t even support higher than 28.8 kbps, so even reaching these speeds was lucky.

As impractical as most overclocking of computers is these days, there is still a lot of fun to be had along the way. Case in point being [Pieter-Jan Plaisier]’s recent liquid nitrogen-aided overclocking of an unsuspecting Raspberry Pi 5 and its BCM2712 SoC. Previous OCing attempts with air cooling by [Pieter] had left things off at a paltry 3 GHz from the default 2.4 GHz, with the power management IC (PMIC) circuitry on the SBC turning out to be the main limiting factor.

The main change here was thus to go for liquid nitrogen (LN₂) cooling, with a small chipset LN₂ pot to fit on the SBC. Another improvement was the application of a NUMA (non-uniform memory addressing) patch to force the BCM2712’s memory controller to utilize better RAM chip parallelism.

With these changes, the OC could now hit 3.6 GHz, but at 3.7 GHz, the system would always crash. It was time to further investigate the PMIC issues.

The PMIC imposes voltage configuration limitations and turns the system off at high power consumption levels. A solution there was to replace said circuitry with an ElmorLabs AMPLE-X1 power supply and definitively void the SBC’s warranty. This involves removing inductors and removing solder mask to attach the external power wires. Yet even with these changes, the SoC frequency had trouble scaling, which is why an external clock board was used to replace the 54 MHz oscillator on the PCB. Unfortunately, this also failed to improve the final overclock.

We covered the ease of OCing to 3 GHz previously, and no doubt some of us are wondering whether the new SoC stepping may OC better. Regardless, if you want to get a faster small system without jumping through all those hoops, there are definitely better (and cheaper) options. But you do miss out on the fun of refilling the LN₂ pot every couple of minutes.

Thanks to [Stephen Walters] for the tip.

On today’s installment of UE1 vacuum tube computer construction, we join [David Lovett] once more on the Usagi Electric farm, as he determines just how much work remains before the project can be called done. When we last left off, the paper tape reader had been motorized, with the paper tape being pulled through smoothly in front of the photodiodes. This left [David] with the task to create a PCB to wire up these photodiodes, put an amplification circuit together (with tubes, of course) to amplify the signal from said photodiodes, and add some lighting (two 1-watt incandescents) to shine through the paper tape holes. All of this is now in place, but does it work?

The answer here is a definite kinda, as although there are definitely lovely squiggles on the oscilloscope, bit 0 turns out to be missing in action. This shouldn’t have come as a major surprise, as one of the problems that Bendix engineers dealt with back in the 1950s was effectively the same one: they, too, use the 9th hole on the 8-bit tape as a clock signal, but with this whole being much smaller than the other holes, this means not enough light passes through to activate the photodiode.

Here, the Bendix engineers opted to solve this by biasing the photodiode to be significantly more sensitive. This seems to be the ready-made solution for the UE1’s tape reader, too. After all, if it worked for Bendix for decades, surely it’ll work in 2024.

Beyond this curveball, the rest of the challenges involve getting a tape punched with known data on it so that the tape reader’s output can actually be validated beyond acknowledging the presence of squiggles on the scope display. Although the tape guiding mechanism seems more stable now, it also needs to be guided around in an endless loop due to the way that the UE1 computer will use the tape. Much like delay line memory, the paper tape will run in an endless loop, and the processor will simply skip over sections until it hits the next code it needs as part of a loop or jump.

With semi-modern components, paper tape is easy to handle. Automatic tape feed only adds a little complexity.

Formerly known as Unidentified Flying Objects, Unidentified Anomalous Phenomena (UAP) is a category of observations that are exactly what the UAP label suggests. This topic concerns the US military very much, as a big part of national security involves knowing everything that appears in the skies. This is the reason for the development of a new sensor suite by the Pentagon called GREMLIN. Recently, a new report has provided more details about what this system actually does.

Managed by the All-domain Anomaly Resolution Office (AARO) within the DoD, GREMLIN blends many different sensors, ranging from radar to ADS-B and RF monitors, together to establish a baseline and capture any anomalies within the 90-day monitoring period to characterize them.

UAPs were a popular topic even before the 1950s when people began to see them everywhere. Usually taking the form of lights or fast-moving objects in the sky, most UAP reports can be readily classified as weather balloons, satellites like Starlink, airplanes, the Northern Lights, the ISS, or planets like Mars and Venus. There are also curious phenomena such as the Hessdalen lights, which appear to be a geological, piezoelectric phenomenon, though our understanding of such natural lighting phenomena remains limited.

But it is never aliens, that’s one thing we know for sure. Not that UFO’s don’t exist. Really.

At first glance, trying to play chess against a large language model (LLM) seems like a daft idea, as its weighted nodes have, at most, been trained on some chess-adjacent texts. It has no concept of board state, stratagems, or even whatever a ‘rook’ or ‘knight’ piece is. This daftness is indeed demonstrated by [Dynomight] in a recent blog post (Substack version), where the Stockfish chess AI is pitted against a range of LLMs, from a small Llama model to GPT-3.5. Although the outcomes (see featured image) are largely as you’d expect, there is one surprise: the gpt-3.5-turbo-instruct model, which seems quite capable of giving Stockfish a run for its money, albeit on Stockfish’s lower settings.

Each model was given the same query, telling it to be a chess grandmaster, to use standard notation, and to choose its next move. The stark difference between the instruct model and the others calls investigation. OpenAI describes the instruct model as an ‘InstructGPT 3.5 class model’, which leads us to this page on OpenAI’s site and an associated 2022 paper that describes how InstructGPT is effectively the standard GPT LLM model heavily fine-tuned using human feedback.

Ultimately, it seems that instruct models do better with instruction-based queries because they have been programmed that way using extensive tuning. A [Hacker News] thread from last year discusses the Turbo vs Instruct version of GPT 3.5. That thread also uses chess as a comparison point. Meanwhile, ChatGPT is a sibling of InstructGPT, per OpenAI, using Reinforcement Learning from Human Feedback (RLHF), with presumably ChatGPT users now mostly providing said feedback.

OpenAI notes repeatedly that InstructGPT nor ChatGPT provide correct responses all the time. However, within the limited problem space of chess, it would seem that it’s good enough not to bore a dedicated chess AI into digital oblivion.

If you want a digital chess partner, try your Postscript printer. Chess software doesn’t have to be as large as an AI model.

When Apple recently announced the hearing aid feature on their new AirPods Pro 2, it got the attention of quite a few people. Among these were [Rithwik Jayasimha] and friends, with [Rithwik] getting a pair together with his dad for use by his hard-of-hearing grandmother. That’s when he found out that this feature is effectively limited to the US and a small number of other countries due them being ‘regulated health features’, per Apple. With India not being on the approved countries list and with no interest in official approval legalities, [Rithwik] set to work to devise a way to bypass this restriction.

As noted in the blog post, the primary reason for using AirPods here instead of official hearing aids is due to the cost of the latter, which makes them a steal for anyone who is dealing with mild to moderate hearing loss. Following the official Hearing Aid feature setup instructions requires that your location is detected as being in an approved country. If it is, the Health App (on iOS 18.1) will popup a ‘Get Started’ screen. The challenge was thus to make the iOS device believe that it was actually in the FDA-blessed US and not India.

Merely spoofing the location and locale didn’t work, so the next step was to put the iOS device into a Faraday cage along with an ESP32 that broadcast California-based WiFi SSIDs. Once the thus treated iPad rebooted into the US, it could be used to enable the hearing aid feature. Next [Rithwik] and friends created a more streamlined setup and procedure to make it possible for others to replicate this feat.

As also noted in the blog post, the Hearing Aid feature is essentially a specially tuned Transparency mode preset, which is why using AirPods for this feature has been a thing for a while, but with this preset it’s much better tuned for cases of hearing loss.

It’s not much of a secret that in the world of ‘audiophile gear’ there is a lot of snake oil and deception, including many products that are at best of questionable value. The Tom Evans Mastergroove SR mkIII preamplifier is one example of this, as [Mark] from the Mend it Mark YouTube channel found in a recent video when he got one to repair which the manufacturer claimed ‘could not be fixed’. This marvel of audio engineering provides amplification for record players, for the low-low price of only twenty-five thousand quid, or about 29.000 US bucks. So what’s inside one of these expensive marvels?

Claiming to be a high-end unit, with only ten units produced per year, you’d expect a gold-plated PCB with excellent noise isolation. The unit does come with an absolutely massive external power supply that dwarfs the preamplifier itself, but the real surprise came after opening up the unit itself to take a peek at the damage, some of which was caused by transport.

As it turns out, the inside of the preamplifier consists out of four stacks of rather cheap, home-made looking boards with what looks like improvised RF shielding in the form of bare PCBs and filed-off markings on many parts. In between the rat’s nest of wiring running everywhere, [Mark] had to trace the broken channel’s wiring, creating a full repair manual in the process. Along the way one of the opamp boards was found to be defective, courtesy of a single shorted tantalum capacitor.

With the tantalum capacitor replaced, [Mark] had repaired the unit, but even though the preamplifier isn’t terribly designed, the illusion of its price tag has been shattered worse than the contents of a parcel kicked across the parking lot by the Royal Mail.

Thanks to [Jim] for the tip.

It’s not much of a secret that Texas’ nearly completely isolated grid is in a bit of a pickle, with generating capacity often being handily outstripped during periods of extreme demand. In a latest bid to fight this problem, smart thermostats are being offered to customers, who will then participate in peak-shaving. The partnership between NRG Energy Inc., Renew Home LLC, and Alphabet Inc. will see about 650,000 of these thermostats distributed to customers.

For customers the incentive would be mostly financial, though the details on the potential cost savings seem scarce. The thermostats would be either a Vivint (an NRG company) or Google Nest branded one, which would be controlled via Google Cloud, allowing for thermostat settings to be changed to reduce the load on the grid. This is expected to save ‘300 MW’ in the first two years, though it’s not clear whether this means ‘continuously’, or intermittent like with a peaker natural gas plant.

Demand curtailment is not a new thing, with it being a big thing among commercial customers in South Korea, as we discussed within the topic of vehicle-to-grid energy storage. Depending on how it is implemented it can make a big difference, but it’ll remain to see how regular consumers take to the idea. It also provides more evidence for reducing grid load being a lot easier than adding grid-level storage, which is becoming an increasingly dire topic as more non-dispatchable solar and wind power is added to the grid.

In-space manufacturing is a big challenge, even with many of the same manufacturing methods being available as on the ground. These methods include rivets, bolts, but also welding, the latter of which was first attempted fifty years ago by Soviet cosmonauts. In-space welding is the subject of a recently announced NASA collaboration. The main aspects to investigate are the effects of reduced gravity and varying amounts of atmosphere on welds.

The Soviets took the lead in space welding when they first performed the feat during the Soyuz-6 mission in 1969. NASA conducted their own welding experiments aboard Skylab in 1973, and in 1984, the first (and last) welds were made in open space during an EVA on the Salyut-7 mission. This time around, NASA wants to investigate fiber laser-based welding, as laid out in these presentation slides. The first set of tests during parabolic flight maneuvers were performed in August of 2024 already, with further testing in space to follow.

Back in 1996 NASA collaborated with the E.O. Paton Welding Institute in Kyiv, Ukraine, on in-space welding as part of the ISWE project which would have been tested on the Mir space station, but manifesting issues ended up killing this project. Most recently ESA has tested in-space welding using the same electron-beam welding (EBW) approach used by the 1969 Soyuz-6 experiment. Electron beam welding has the advantage of providing great control over the weld in a high-vacuum environment such as found in space.

So why use laser beam welding (LBW) rather than EBW? EBW obviously doesn’t work too well when there is some level of atmosphere, is more limited with materials and has as only major advantage that it uses less power than LBW. As these LBW trials move to space, they may offer new ways to create structure and habitats not only in space, but also on the lunar and Martian surface.

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Featured image: comparing laser beam welding with electron beam welding in space. (Source: E. Choi et al., OSU, NASA)

Within the world of CAD there are the well-known and more niche big commercial players and there are projects like FreeCAD that seek to bring a OSS solution to the CAD world. As with other OSS projects like the GIMP, these OSS takes on commercial software do not always follow established user interactions (UX), which is where Ondsel sought to bridge the gap by giving commercial CAD users a more accessible FreeCAD experience. This effort is now however at an end, with a blog post by Ondsel core team member [Brad Collette] providing the details.

The idea of commercializing OSS is by no means novel, as this is what Red Hat and many others have done for decades now. In our article on FOSS development bounties we touched upon the different funding models for FOSS projects, with the Linux kernel enjoying strong commercial support. The trick is of course to attract such commercial support and associated funding, which is where the development on the UI/UX and feature set of the core FreeCAD code base was key. Unfortunately the business case was not strong enough to attract such commercial partners and Ondsel has been shutdown.

As also discussed on the FreeCAD forum, the Ondsel codebase will likely be at least partially merged into the FreeCAD code, ending for now the prospect of FreeCAD playing in the big leagues with the likes of AutoCAD.

Thanks to [Brian Harrington] for the tip.

In a new installment on computer history, [Bradford Morgan White] takes us through the sordid history of Cyrix, as this plucky little company created the best math co-processors (FasMath) and then a range of interesting x86-compatible CPUs that would give competing x86 CPUs a run for their money. Even though Cyrix played by the rules of licensing agreements, Intel would keep suing Cyrix repeatedly since the 1980s well into 1990s, for a total of seventeen times until Cyrix counter-sued for patent violations in May of 1997.

This case was settled between Cyrix and Intel, with a cross-licensing agreement established. Unfortunately these mounting legal costs and the stresses of keeping up with the competition (i.e. Intel) was proving too much and Cyrix was sold off to National Semiconductor, who wasn’t enthusiastic about competing with Intel. After this Cyrix got split up into Geode (sold to AMD) and Cyrix Technologies (sold to VIA). Interestingly, VIA’s x86 patent licenses and patents ended up being the foundation of Zhaoxin: a joint venture between VIA and Shanghai’s government which produces x86 CPUs for primarily the Chinese market.

We looked at the Cyrix Cx486DLC processor a while ago, and why their 386 upgrade options were perhaps not that great. Their later CPUs have however left a strong legacy that seems to endure in some way to this day.

On November 5th, the United States launched an LGM-30G Minuteman III ICBM from Vandenberg Space Force Base in California. Roughly 30 minutes later the three warheads onboard struck their targets 4,200 miles (6,759 km) away at the Reagan Test Site in the Marshall Islands. What is remarkable about this test is not that one of these ICBMs was fired — as this is regularly done to test the readiness of the US’ ICBMs — but rather that it carried three warheads instead of a single one.

Originally the Minuteman III ICBMs were equipped with three warheads, but in 2014 this was reduced to just one as a result of arms control limits agreed upon with Russia. This New Start Treaty expires in 2026 and the plan is to put three warheads back in the 400 operational Minuteman III ICBMs in the US’ arsenal. To this end a validation test had to be performed, yet a 2023 launch failed. So far it appears that this new launch has succeeded.

Although the three warheads in this November 5 launch were not nuclear warheads but rather Joint Test Assemblies, one of them contained more than just instrumentation to provide flight telemetry. In order to test the delivery vehicle more fully a so-called ‘high-fidelity’ JTA was also used which is assembled much like a real warhead, including explosives. The only difference being that no nuclear material is present, just surrogate materials to create a similar balance as the full warhead.

Assuming the many gigabytes of test data checks out these Minuteman III ICBMs should be ready to serve well into the 2030s at which point the much-delayed LGM-35 Sentinel should take over.

We usually think of a hydraulic system as fully self-contained, with a hydraulic pump, tubing, and actuators filled with a working fluid. This of course adds a lot of weight and complexity that can be undesirable in certain projects, with the Saturn V Moon rocket demonstrating a solution to this which is still being used to this day. In a blast-from-the-past, a December 1963 article originally published in Hydraulics & Pneumatics details the kerosene-based hydraulics (fueldraulics) system for the S-1C stage’s gimbal system that controlled the four outer engines.

Rather than a high-pressure, MIL-H-5606 hydraulic oil-based closed loop as in the Saturn I, this takes kerosene from the high-pressure side of the F1 rocket engine’s turbopump and uses it in a single-pass system. This cuts out a separate hydraulic pump, a hydraulic reservoir, which was mostly beneficial in terms of reducing points of failure (and leaks), ergo increasing reliability. Such was the theory at the time at least, and due to issues with RP-1 kerosene’s relatively low flash point and differences in lubricity properties, ultimately RJ-1, RP-1 and MIL-H-5606 were used during checkout leading up to the launch.

In hindsight we know that this fueldraulic system worked as intended with all Saturn V launches, and today it’s still used across a range of aircraft in mostly jet engines and actuators elsewhere of the Boeing 777 as well as the F-35. In the case of the latter it only made the news when there was an issue that grounded these jets due to badly crimped lines. Since fueldraulics tends to be lower pressure, this might be considered a benefit in such cases too, as anyone who has ever experienced a hydraulic line failure can attest to.

Featured image: Gimbal systems proposed for the F-1, oxygen-kerosene engine with a fueldraulic system. (Source: Hydraulics & Pneumatics, 1963)

After extracting all the useful stuff from a mine, you are often left with a lot of empty subterranean space without a clear purpose. This was the case with the Bethany Falls limestone mine, near Kansas City, Missouri, which left a sprawling series of caverns supported by 16′ (4.9 meter) diameter pillars courtesy of the used mining method. As detailed by [Benjamin Hunting] in a recent article on the Hagerty site, this made it a fascinating place for a  business complex development now called SubTropolis that among other things is used for car storage by Ford and long-term stamp storage by the US Post Office. (Check out their cool period photos!)

The reason for this is the extremely stable climate within these man-made caverns, with relative humidity hovering around a comfortable 40% and temperatures stable year-round at about 21 °C (70 °F), making it ideal for storing anything that doesn’t like being placed outdoors, while saving a lot on airconditioning costs. With Ford one of the biggest companies in SubTropolis, this means that many companies providing customization services for vehicles have also moved operations inside the complex.

With the only negative being a lack of daylight, it seems like the perfect place for many businesses and (evil) lairs, assuming electrical power and constant air circulation are provided.

Featured image: “Subtropolis” by [ErgoSum88]

Building a paper tape reader by itself isn’t super complicated: you need a source of light, some photoreceptors behind the tape to register the presence of holes and some way to pull the tape through the reader at a reasonable rate. This latter part can get somewhat tricky, as Usagi Electric‘s [David Lovett] discovered while adding this feature to his vacuum tube-era DIY reader. This follows on what now seems like a fairly simple aspect of the photosensors and building a way to position said photosensors near the paper tape.

As the feed rate of the paper tape is tied to the reading speed, and in the case of [David]’s also contains the clock for the custom tube-based UE1 computer, it determines many of the requirements. With 8 bits per line, the tape forms the ROM for the system, all of which has to be executed and used immediately when read, as there is no RAM to load instructions into. This also necessitates the need to run the tape as an endless loop, to enable ‘jumping’ between parts of this paper-based ROM by simple masking off parts of the code until the desired address is reached.

For the motor a slot car motor plus speed-reduction gear was chosen, with a design to hold these then designed in FreeCAD. Courtesy of his brother’s hobby machine shop and a CAD professional’s help, producing these parts was very easy, followed by final assembly. Guides were added for the tape, not unlike with a cassette player, which allowed the tape to be pulled through smoothly. Next up is wiring up the photodiodes, after which theoretically the UE1 can roar into action directly running programs off paper tape.

It is a fact of life that 3D-printed parts from an FDM (fused deposition modeling) printer have weaknesses where the layers join. Some of this is due to voids and imperfect layer bonding, but you can — as [Geek Detour] shows us — work around some of this. In particular, it is possible to borrow techniques from brick laying to create a pattern of alternating blocks. You can check out the video below.

The idea of ‘brick layers’ with FDM prints was brought to the forefront earlier this year by [Stefan] of CNC Kitchen. Seven months after that video you still can’t find the option for these layers in any popular slicers. Why? Because of  a 2020 patent filed for this technique by a 3D printing company which offers this feature in its own slicer. But is this patent even valid?

Considering the obviousness and that FDM printing hardly began in the 2000s, it’s no surprise that prior art already exists in the form of a 1995 Stratasys patent. The above image shows an excerpt from the 1995 Stratasys patent, covering the drawings of FDM layers, including brick layers. This covered all such ways of printing, but the patent expired in 2016. In 2019, a PrusaSlicer ticket was opened, requesting this feature. So what happened? A second patent filed in 2020 assigned to Addman Intermediate Holdings: US11331848B2.

This 2020 patent turns out to cover effectively the same claims as the Stratasys patent. Hilariously, the 2020 patent references the Stratasys patent but proceeds to give the wrong patent ID, a pattern that persists with other referenced patents in the same text, making one question who wrote (and verified) the patent.

Clearly, the patent offices involved did not do due diligence, and this new patent is obviously invalid. Yet unless it is invalidated, presumably by challenging it in court, we will have to wait until 2040 before we, too, can print brick layers with our FDM machines.

This isn’t the first time patents have blocked 3D-printed innovation. Or given credit to the wrong inventor.