Origami has become known as a miracle technique for designers. Elegant compliant mechanisms can leverage the material properties of a single geometry in ways that are sometimes stronger than those of more complicated designs. However, we don’t generally see origami used directly in 3D printed parts. [matthew lim] decided to explore this uncharted realm with various clever designs. You can check out the video below.
Continue reading “Origami On Another Level With 3D Printing”
If you’ve ever experimented with a microprocessor at the bare metal level, you’ll know that when it starts up, it will look at its program memory for something to do. On an old 8-bit machine, that program memory was usually an EPROM at the start of its address space, while on a PC, it would be the BIOS or UEFI firmware. This takes care of initialising the environment in both hardware and software, and then loading the program, OS, or whatever the processor does. The Raspberry Pi, though, isn’t like that, and [Patrick McCanna] is here to tell us why.
The Pi eschews bringing up its ARM core first. Instead, it has a GPU firmware that brings up the GPU. It’s this part of the chip that then initialises all peripherals and memory. Only then does it activate the ARM part of the chip. As he explains, this is because the original Pi chip, the BCM2835, is a set-top-box chip. It’s not an application processor at all, but a late-2000s GPU that happened to have an ARM core on a small part of its die, so the GPU wakes first, not the CPU. Even though the latest versions of the Pi have much more powerful Broadcom chips, this legacy of their ancestor remains. For most of us using the board it doesn’t matter much, but it’s interesting to know.
Fancy trying bare metal Pi programming? Give it a go. We’ve seen some practical projects that start at that level.
It’s amazing how fragile our digital lives can be, and how quickly they can fall to pieces. Case in point: the digital dilemma that Paris Buttfield-Addison found himself in last week, which denied him access to 20 years of photographs, messages, documents, and general access to the Apple ecosystem. According to Paris, the whole thing started when he tried to redeem a $500 Apple gift card in exchange for 6 TB of iCloud storage. The gift card purchase didn’t go through, and shortly thereafter, the account was locked, effectively bricking his $30,000 collection of iGadgets and rendering his massive trove of iCloud data inaccessible. Decades of loyalty to the Apple ecosystem, gone in a heartbeat.
3D Printing is great, but it is pretty much the worst way to make any given part– except that every other technique you could use to make that part is too slow and/or expensive, making the 3D print the best option. If only the prints were stiffer, stronger, more durable! [JanTech Engineering] feels your plight and has been hacking away with the M601 command to try embedding different sorts of hardware into his prints for up to 10x greater strength, as seen in the video embedded below.
It’s kind of a no-brainer, isn’t it? If the plastic is the weak point, maybe we could reinforce the plastic. Most concrete you see these days has rebar in it, and fiber-reinforced plastic is the only way most people will use resin for structural applications. So, how about FDM? Our printers have that handy M601 “pause print” command built in. By creatively building voids into your parts that you can add stronger materials, you get the best of all possible worlds: the exact 3D printed shape you wanted, plus the stiffness of, say, a pulltruded carbon-fiber rod.
[JanTech] examines several possible inserts, including the aforementioned carbon rods. He takes a second look at urethane foam, which we recently examined, and compares it with less-crushable sand, which might be a good choice when strength-to-weight isn’t an issue. He doesn’t try concrete mix, but we’ve seen that before, too. Various metal shapes are suggested — there are all sorts of brackets and bolts and baubles that can fit into your prints depending on their size — but the carbon rods do come out ahead on strength-to-weight, to nobody’s surprise.
You could do a forged carbon part with a printed mold to get that carbon stiffness, sure, but that’s more work, and you’ve got to handle epoxy resins that some of us have become sensitized to. Carbon rods and tubes are cheap and safer to work with, though be careful cutting them.
Finally, he tries machining custom metal insets with his CNC machine. It’s an interesting technique that’s hugely customizable, but it does require you to have a decent CNC available, and, at that point, you might want to just machine the part. Still, it’s an interesting hybrid technique we haven’t seen before.
Shoving stuff into 3D-printed plastic to make it a better composite object is a great idea and a time-honored tradition. What do you put into your prints? We’d love to know, and so would [Jan]. Leave a comment and let us know.
Continue reading “Pause Print, Add Hardware, And Enjoy Strength”
A lot of claims have been made about the purported benefits of adding chopped carbon fiber to FDM filaments, but how many of these claims are actually true? In the case of PLA at least, the [I built a thing] channel on YouTube makes a convincing case that for PLA filament, the presence of chopped CF can be considered a contaminant that weakens the part.
Using the facilities of the University of Basel for its advanced imaging gear, the PLA-CF parts were subjected to both scanning electron microscope (SEM) and Micro CT imaging. The SEM images were performed on the fracture surfaces of parts that were snapped to see what this revealed about the internal structure. From this, it becomes apparent that the chopped fibers distribute themselves both inside and between the layers, with no significant adherence between the PLA polymer and the CF. There is also evidence for voids created by the presence of the CF.
To confirm this, an intact PLA-CF print was scanned using a Micro CT scanner over 13 hours. This confirmed the SEM findings, in that the voids were clearly visible, as was the lack of integration of the CF into the polymer. This latter point shouldn’t be surprising, as the thermal coefficient of PLA is much higher than that of the roughly zero-to-negative of CF. This translates into a cooling PLA part shrinking around the CF, thus creating the voids.
Continue reading “Why Chopped Carbon Fiber In FDM Prints Is A Contaminant”
An oscilloscope is usually the most sensitive, and arguably most versatile, tool on a hacker’s workbench, often taking billions of samples per second to produce an accurate and informative representation of a signal. This vast processing power, however, often goes well beyond the needs of the signals in question, at which point it makes sense to use a less powerful and expensive device, such as [MatAtBread]’s ESP32 oscilloscope.
Continue reading “A Compact, Browser-Based ESP32 Oscilloscope”
Polaroid cameras have been very popular for a very long time and are especially hot gifts this year. Fresh film is easy to find but relatively expensive. In contrast, Fuji’s Instax line of instant film and cameras aren’t as well established, but the film is easy to find and cheap. You might like to shoot cheap Instax film in your Polaroid camera. Thankfully, [Nick LoPresti] figured out how to do just that.
You can’t just slam an Instax cassette in an old Polaroid camera and expect it to work. The films are completely different sizes, and there’s no way they will feed properly through the camera’s mechanisms at all. Instead, you have to get manual about things. [Nick] starts by explaining the process of removing Instax film sheets from a cassette, which must be done without exposure to light if you want the film to remain useful. Then, if you know what you’re doing, you can tape it in place behind the lens of an old-school Polaroid camera, and expose it as you would any other shot. The chemistry is close enough that you’ll have a fair chance of getting something with passable exposure.
Once exposed, you have to develop the film. Normally, a Polaroid camera achieves this by squeezing the film sheet out through rollers to release the developer and start the process. Without being able to rely on the camera’s autofeed system, you need to find an alternative way to squeeze out the chemicals and get the image to develop. [Nick] recommends a simple kitchen rolling pin, while noting that you might struggle with some uneven chemical spread across the sheet. Ultimately, it’s a fussy hack, but it does work. It might only be worthwhile if you’ve got lots of Instax film kicking around and no other way to shoot it.
Instant cameras can seem a little arcane, but they’re actually quite simple to understand once you know how they’re built. You can even 3D print one from scratch if you’re so inclined. Video after the break.
Continue reading “Shoot Instax Film In A Polaroid Camera With The Aid Of Tape”
