BIQU has released a new line of low-temperature build plates that look to be the next step in 3D printing’s iteration—or so YouTuber Printing Perspective thinks after reviewing one. The Cryogrip Pro is designed for the Bambu X1, P1, and A1 series of printers but could easily be adapted for other magnetic-bed machines.

The idea of the new material is to reduce the need for high bed temperatures, keeping enclosure temperatures low. As some enclosed printer owners may know, trying to print PLA and even PETG with the door closed can be troublesome due to how slowly these materials cool. Too high an ambient temperature can wreak havoc with this cooling process, even leading to nozzle-clogging.

The new build plate purports to enable low, even ambient bed temperatures, still with maximum adhesion. Two versions are available, with the ‘frostbite’ version intended for only PLA and PETG but having the best adhesion properties.  A more general-purpose version, the ‘glacier’ sacrifices a little bed adhesion but gains the ability to handle a much wider range of materials.

An initial test with a decent-sized print showed that the bed adhesion was excellent, but after removing the print, it still looked warped. The theory was that it was due to how consistently the magnetic build plate was attached to the printer bed plate, which was now the limiting factor. Switching to a different printer seemed to ‘fix’ that issue, but that was really only needed to continue the build plate review.

They demonstrated a common issue with high-grip build plates: what happens when you try to remove the print. Obviously, magnetic build plates are designed to be removed and flexed to pop off the print, and this one is no different. The extreme adhesion, even at ambient temperature, does mean it’s even more essential to flex that plate, and thin prints will be troublesome. We guess that if these plates allow the door to be kept closed, then there are quite a few advantages, namely lower operating noise and improved filtration to keep those nasty nanoparticles in check. And low bed temperatures mean lower energy consumption, which is got to be a good thing. Don’t underestimate how much power that beefy bed heater needs!

Ever wondered what mini QR-code-like tags are on the high-end build plates? We’ve got the answer. And now that you’ve got a pile of different build plates, how do you store them and keep them clean? With this neat gadget!

Some inventions are so simple that it’s hard to improve them. The magnetic compass is a great example — a magnetized needle, a bit of cork, and a bowl of water are all you need to start navigating the globe. So why in the world would you want to over-complicate things with something like this Earth inductor compass? Just because it’s cool, of course.

Now, the thing with complication is that it’s often instructive. The simplicity of the magnetic compass masks the theory behind its operation to some degree and completely fails to deliver any quantitative data on the Earth’s magnetic field. [tsbrownie]’s gadget is built from a pair of electric motors, one intact and one stripped of its permanent magnet stators. The two are mounted on a 3D printed frame and coupled by a long shaft made of brass, to magnetically isolate them as much as possible. The motor is powered by a DC supply while a digital ammeter is attached to the terminals on the stator.

When the motor spins, the stator at the other end of the shaft cuts the Earth’s magnetic lines of force and generates a current, which is displayed on the ammeter. How much current is generated depends on how the assembly is oriented. In the video below, [tsbrownie] shows that the current nulls out when oriented along the east-west axis, and reaches a maximum along north-south. It’s not much current — about 35 microamps — but it’s enough to get a solid reading.

Is this a practical substitute for a magnetic compass? Perhaps not for most use cases, but a wind-powered version of this guided [Charles Lindbergh]’s Spirit of St. Louis across the Atlantic in 1927 with an error of only about 10 miles over the trip, so there’s that. Other aircraft compasses take different approaches to the problem of nulling out the magnetic field of the plane.

A few years back NVIDIA created a dedicated cryptocurrency mining GPU, the CMP 170HX. This was a heavily restricted version of its flagship A100 datacenter accelerator, using the same GA100 chip. It was intended for accelerating Ethash, the Etherium proof-of-work algorithm, and nothing else. [niconiconi] bought one to use for accelerating PCB electromagnetic simulations and put a lot of effort into repairing the card, converting it to water-cooling, and figuring out how best to use this nobbled GPU.

Typically, the GA100 silicon sits in the center of the mighty A100 GPU card and would be found in a server rack, cooled by forced air. This was not an option at home, so an off-the-shelf water-cooling block was wedged in. During this process, [niconconi] found that the board wouldn’t power on, so they went on a deep dive into the power supply tree with the help of a leaked A100 schematic. The repair and modifications can be found in the appendix, right down to the end of the article. It is a long read to get there.

NVIDIA has a history of deliberately restricting silicon in consumers’ hands to justify the hefty price tags of its offerings to big businesses, and this board is no different. The plan was to restrict the peak performance of the board to only applications with the same compute requirements as Ethash, specifically memory-intensive algorithms. The FP64 performance was severely limited, but instructions were not removed. This meant the code would run really badly, considering what the GPU is capable of.

The memory was limited to 8 GB, despite some A100 cards hosting a whopping 80 GB. The strategy was to use fuses to limit the crucial instructions, particularly the FP32 FMA and MAD instructions, which are used for multiply-add operations and are crucial for general computing applications. Finally, the PCIe bus was nobbled to run only as a Gen 1 interface with a single lane. They reduced the lane count by removing the coupling capacitors on the PCB, which meant they could just be added later, but it’s still only a slow interface.

[niconconi] went into great detail benchmarking the instruction types, keeping their EM simulation application in mind. After a few tweaks to make it work, they determined it was a good purchase. This article is worth reading for all those hardcore GPU nerds!

If you need a primer on GPU mining, we’ve got you covered. Once you’ve understood proof-of-work crypto, perhaps take a look at Chia?

Thanks to [gnif] for the tip!