Injection Molding Using A 3D Printer

June 25, 2024 by Maya Posch 16 Comments

Recently [Stefan] of CNC Kitchen took a gander at using his gaggle of 3D printers to try injection molding (IM). Although the IM process generally requires metal molds and specialized machinery, 3D printers can be used for low-volume IM runs which is enough for limited production runs and prototyping before committing to producing expensive IM molds. In the case of [Stefan], he followed Form Labs’ guidance to produce molds from glass-infused Rigid 10K resin (heat deflection temperature of 218 °C). These molds are very rigid, as the ceramic-like noise when [Stefan] taps two together attests to.

Injection molded bolt, with imperfections on the head. (Credit: Stefan, CNC Kitchen)

The actual injection process is where things get more hairy for [Stefan], as he attempts to push the clamped-shut mold against the nozzle of the FDM printer to inject the molten plastic, rather than using an IM press. With PLA at standard extrusion temperature the plastic barely gets into the mold before solidifying, however. Following this, higher temperatures, different materials (PETG, TPU) and high flow-rate extruders are attempted, with varying results.

Many of the struggles would seem to be due to poor mold design, rather than fundamental issues with using an FDM. The Form Labs document details some of the basics, such as opening up the injection gate (to decrease pressure inside the mold), adding air vents to improve flow and so on. Commentators to the video with professional experience point out many of these issues as well, along with the benefits of preheating the mold.

With the caveat that most of the challenge is in making a good mold, we’ve even injection molding done with nothing more exotic than a hot glue gun. If you’ve got a friend, or a long enough lever, you can even inject the plastic by hand.

Continue reading “Injection Molding Using A 3D Printer” →

How The CD-ROM Lost The Multimedia Dream To The Internet

June 24, 2024 by Maya Posch 77 Comments

High-tech movie guides on CD-ROM; clearly the future had arrived in 1994.

In the innocent days of the early 90s the future of personal computing still seemed to be wide open, with pundits making various statements regarding tis potential trajectories. To many, the internet and especially the World Wide Web didn’t seem to be of any major significance, as it didn’t have the reach or bandwidth for the Hot New Thing^tm in the world of PCs: multimedia. Enter the CD-ROM, which since its introduction in 1985 had brought the tantalizing feature of seemingly near-infinite storage within reach, and became cheap enough for many in the early 90s. In a recent article by [Harry McCracken] he reflects on this era, and how before long it became clear that it was merely a bubble.

Of course, there was a lot of good in CD-ROMs, especially when considering having access to something like Encarta before Wikipedia and broadband internet was a thing. It also enabled software titles to be distributed without the restrictions of floppy disks. We fondly remember installing Windows 95 (without Internet Explorer) off 13 1.44 MB floppies, followed by a few buckets of Microsoft Office floppies. All pray to the computer gods for no sudden unreadable floppy.

Inevitably, there was a lot of shovelware on CD-ROMs, and after the usefulness of getting free AOL floppies (which you could rewrite), the read-only CD-ROMs you got in every magazine and spam mailing were a big disappointment. Although CD-ROMs and DVDs still serve a purpose today, it’s clear that along with the collapse of the Internet Bubble of the late 90s, early 2000s, optical media has found a much happier place. It’s still hard to beat the sheer value of using CD-R(W)s and DVD-/+R(W)s (and BD-Rs) for offline backups, even if for games and multimedia they do not appear to be relevant any more.

If you’re interested in another depiction of this period, it’s somewhere we’ve been before.

Testing Large Language Models For Circuit Board Design Aid

June 24, 2024 by Maya Posch 27 Comments

Beyond bothering large language models (LLMs) with funny questions, there’s the general idea that they can act as supporting tools. Theoretically they should be able to assist with parsing and summarizing documents, while answering questions about e.g. electronic design. To test this assumption, [Duncan Haldane] employed three of the more highly praised LLMs to assist with circuit board design. These LLMs were GPT-4o (OpenAI), Claude 3 Opus (Anthropic) and Gemini 1.5 (Google).

The tasks ranged from ‘stupid questions’, like asking the delay per unit length of a trace on a PCB, to finding parts for a design, to designing an entire circuit. Of these tasks, only the ‘parsing datasheets’ task could be considered to be successful. This involved uploading the datasheet for a component (nRF5340) and asking the LLM to make a symbol and footprint, in this case for the text-centric JITX format but KiCad/Altium should be possible too. This did require a few passes, as there were glitches and omissions in the generated footprint.

When it came to picking components for a design, it’s clear that you’re out of luck here unless you’re trying to create a design that a million others have made before you in exactly the same way. This problem got worse when trying to design a circuit and ultimately spit out a netlist, with the best LLM (Claude 3 Opus) giving nonsensical suggestions for filter designs and mucking up even basic amplifier designs, including by sticking decoupling capacitors and random resistors just about everywhere.

Effectively, as a text searching tool it would seem that LLMs can have some use for engineers who are tired of digging through yet another few hundred pages of poorly formatted and non-indexed PDF datasheets, but you still need to be on your toes with every step of the way, as the output from the LLM will all too often be slightly to hilariously wrong.

Rescued IMac G4 Restored And Upgraded With Mac Mini M1 Guts

June 23, 2024 by Maya Posch 12 Comments

Three abandoned iMac G4s, looking for a loving home... (Credit: Hugh Jeffreys) — Three abandoned iMac G4s, looking for a loving home… (Credit: Hugh Jeffreys)

The Apple iMac G4 was also lovingly referred to as the ‘Apple iLamp’ due to its rather unique design with the jointed arm on which the display perches. Released in 2002 and produced until 2004, it was the first iMac to feature an LCD. With only a single-core G4 PowerPC CPU clocked at around 1 GHz, they’re considered e-waste by the average person.

That’s how [Hugh Jeffreys] recently found a triplet of these iMacs abandoned at an industrial site. Despite their rough state, he decided to adopt them on the spot, and gave one of them a complete make-over, with a good scrub-down and a brand-new LCD and Mac Mini M1 guts to replace the broken G4 logic board.

The chosen iMac had a busted up screen and heavily corroded logic board that looked like someone had tried to ‘fix’ it before. A new (used) 17″ LCD was installed from a MacBook Pro, which required the use of a Realtek RTD2660-based display controller to provide HDMI to LVDS support. The new logic board and power supply were sourced from a Mac Mini featuring the M1 SoC, which required a 3D printed adapter plate to position everything inside the iMac’s base. Wiring everything up took some creative solutions, with routing the wires through the flexible monitor arm the biggest struggle. The WiFi antenna on the Mac Mini turned out to be riveted and broke off, but the iMac’s original WiFi antenna could be used instead.

Although some clean-up is still needed, including better internal connector extensions, the result is a fully functional 2024 iMac M1 that totally wouldn’t look out of place in an office today. Plus it’s significantly easier to adjust the monitor’s angle and height compared to Apple’s official iMac offerings, making it the obviously superior system.

Continue reading “Rescued IMac G4 Restored And Upgraded With Mac Mini M1 Guts” →

TSMC’s Long Path From Round To Square Silicon Wafers

June 23, 2024 by Maya Posch 45 Comments

Most of us will probably have seen semiconductor wafers as they trundle their way through a chip factory, and some of us may have wondered about why they are round. This roundness is an obvious problem when one considers that the chip dies themselves are rectangular, meaning that a significant amount of the dies etched into the wafers end up being incomplete and thus as waste, especially with (expensive) large dies. This is not a notion which has escaped the attention of chip manufacturers like TSMC, with this particular manufacturer apparently currently studying a way to make square substrates a reality.

According to the information provided to Nikkei Asia by people with direct knowledge, currently 510 mm x 515 mm substrates are being trialed which would replace the current standard 12″ (300 mm) round wafers. For massive dies such as NVidia’s H200 (814 mm²), this means that approximately three times as many would fit per wafer. As for when this technology will go into production is unknown, but there exists significant incentive in the current market to make it work.

As for why wafers are round, this is because of how these silicon wafers are produced, using the Czochralski method, named after Polish scientist [Jan Czochralski] who invented the method in 1915. This method results in rod-shaped crystals which are then sliced up into the round wafers we all know and love. Going square is thus not inherently impossible, but it will require updating every step of the process and the manufacturing line to work with this different shape.

Nearly 30 Years Of FreeDOS And Looking Ahead To The Future

June 23, 2024 by Maya Posch 27 Comments

The first version of FreeDOS was released on September 16 of 1994, following Microsoft’s decision to cease development on MS-DOS in favor of Windows. This version 0.01 was still an Alpha release, with 0.1 from 1998 the first Beta and the first stable release (1.0, released on September 3 2006) still a while off. Even so, its main developer [Jim Hall] and the like-minded developers on the FreeDOS team managed to put together a very functional DOS using a shell, kernel and other elements which already partially existed before the FreeDOS (initially PD-DOS, for Public Domain DOS) idea was pitched by [Jim].

Nearly thirty years later, [Jim] reflects on these decades, and the strong uptake of what to many today would seem to be just a version of an antiquated OS. When it comes to embedded and industrial applications, of course, a simple DOS is all you want and need, not to mention for a utility you boot from a USB stick. Within the retro computing community FreeDOS has proven to be a boon as well, allowing for old PCs to use a modern DOS rather than being stuck on a version of MS-DOS from the early 90s.

For FreeDOS’ future, [Jim] is excited to see what other applications people may find for this OS, including as a teaching tool on account of how uncomplicated FreeDOS is. In a world of complicated OSes that no single mortal can comprehend any more, FreeDOS is really quite a breath of fresh air.

Uncovering ChatGPT Usage In Academic Papers Through Excess Vocabulary

June 22, 2024 by Maya Posch 23 Comments

Frequencies of PubMed abstracts containing certain words. Black lines show counterfactual extrapolations from 2021–22 to 2023–24. The first six words are affected by ChatGPT; the last three relate to major events that influenced scientific writing and are shown for comparison. (Credit: Kobak et al., 2024)

That students these days love to use ChatGPT for assistance with reports and other writing tasks is hardly a secret, but in academics it’s becoming ever more prevalent as well. This raises the question of whether ChatGPT-assisted academic writings can be distinguished somehow. According to [Dmitry Kobak] and colleagues this is the case, with a strong sign of ChatGPT use being the presence of a lot of flowery excess vocabulary in the text. As detailed in their prepublication paper, the frequency of certain style words is a remarkable change in the used vocabulary of the published works examined.

For their study they looked at over 14 million biomedical abstracts from 2010 to 2024 obtained via PubMed. These abstracts were then analyzed for word usage and frequency, which shows both natural increases in word frequency (e.g. from the SARS-CoV-2 pandemic and Ebola outbreak), as well as massive spikes in excess vocabulary that coincide with the public availability of ChatGPT and similar LLM-based tools.

In total 774 unique excess words were annotated. Here ‘excess’ means ‘outside of the norm’, following the pattern of ‘excess mortality’ where mortality during one period noticeably deviates from patterns established during previous periods. In this regard the bump in words like respiratory are logical, but the surge in style words like intricate and notably would seem to be due to LLMs having a penchant for such flowery, overly dramatized language.

The researchers have made the analysis code available for those interested in giving it a try on another corpus. The main author also addressed the question of whether ChatGPT might be influencing people to write more like an LLM. At this point it’s still an open question of whether people would be more inclined to use ChatGPT-like vocabulary or actively seek to avoid sounding like an LLM.