The White House’s proposed budget for 2020 is out, and with it comes cuts to NASA. The most important item of note in the proposed budget is a delay of the Space Launch System, the SLS, a super-heavy lifting launch vehicle designed for single use. The proposed delay would defer work on the enhanced version of the SLS, the Block 1B with the Exploration Upper Stage.
The current plans for the Space Launch System include a flight using NASA’s Orion spacecraft in June 2020 for a flight around the moon. This uncrewed flight, Exploration Mission 1, or EM-1, would use the SLS Block 1 Crew rocket. A later flight, EM-2, would fly a crewed Orion capsule around the moon in 2022. A third proposed flight in 2023 would send the Europa Clipper to Jupiter. The proposed 2020 budget puts these flights in jeopardy.
As [Glen] describes it, the only real goal in his decision to design his single-key USB keyboard was to see how small he could build a functional keyboard using a Cherry MX key switch, and every fraction of a millimeter counted. Making a one-key USB keyboard is one thing, but making it from scratch complete with form-fitting enclosure that’s easy to assemble required careful design, and luckily for all of us, [Glen] has documented it wonderfully. (Incidentally, Cherry MX switches come in a variety of qualities and features, the different models being identified by their color. [Glen] is using a Cherry MX Blue, common in keyboards due to its tactile bump and audible click.)
[Glen] steps though the design challenges of making a device where seemingly every detail counts, and explains problems and solutions from beginning to end. A PIC16F1459, a USB micro-B connector, and three capacitors are all that’s needed to implement USB 2.0, but a few other components including LED were added to help things along. The enclosure took some extra care, because not only is it necessary to fit the board and the mounted components, but other design considerations needed to be addressed such as the depth and angle of the countersink for the screws, seating depth and clearance around the USB connector, and taking into account the height of the overmold on the USB cable itself so that the small device actually rests on the enclosure, and not on any part of the cable’s molding. To top it off, it was also necessary to adhere to the some design rules for minimum feature size and wall thicknesses for the enclosure itself, which was SLS 3D printed in nylon.
PCB, enclosure, software, and bill of materials (for single and triple-key versions of the keyboard) are all documented and available in the project’s GitHub repository. [Glen] also highlights the possibility of using a light pipe to redirect the embedded LED to somewhere else on the enclosure; which recalls his earlier work in using 3D printing to make custom LED bar graphs.
Form Labs recently announced the launch of the Fuse 1, a desktop SLS printer that will print all your parts using nylon powder and a laser. This a fundamentally different method of 3D printing as compared to filament-based machines, and the best way to use a Fuse 1 is to fill the entire volume of the machine with 3D printed parts. [Michael Fogelman] decided to investigate the 3D packing problem, and managed to fill this printer with the maximum number of 3D printed tugboats. If you’re wondering, it’s 113, as compared with 82 tiny Benchies using naive bin packing.
The formal definition of this sort of problem is the bin packing problem, or simply calculating the maximum number of items can be packed into a finite volume. There is no general solution to this problem, and it’s probably impossible to create an algorithm that will solve this problem for any collection of 3D models. Nevertheless, it’s possible to create a solution that shows marked improvement over a naive solution.
[Michael]’s solution involves simulated annealing. This algorithm begins by randomly placing tugboats, then mutating the position or rotation of one of the boats for each iteration. The code is less than 1000 lines of Go and is available on GitHub if you already have an SLS printer at your disposal.
It should be noted this type of problem isn’t particularly new to the world of 3D printers. There have been a few tools to solve the bin-packing problem for filament-based printers, but the solutions to these problems are two-dimensional; since filling a bed is a problem that only uses the ‘shadow’ of the Z-axis of each part, it’s a slightly easier problem to solve.
Now that Form Labs’ Fuse 1 SLS printer has been announced, there is a new application for this type of problem in the space of 3D printers. It’s not a perfect solution — and it’s doubtful there will ever be a perfect solution — but if you’re looking for a way to fill the volume of your powder printer with parts, this is the best you’re going to do.
Formlabs have just announced the Fuse 1 — a selective laser sintering (SLS) 3D printer that creates parts out of nylon. Formlabs is best known for their Form series of resin-based SLA 3D printers, and this represents a very different direction.
SLS printers, which use a laser to sinter together models out of a powder-based material, are not new but have so far remained the domain of Serious Commercial Use. To our knowledge, this is the first time an actual SLS printer is being made available to the prosumer market. At just under 10k USD it’s definitely the upper end of the prosumer market, but it’s certainly cheaper than the alternatives.
The announcement is pretty light on details, but they are reserving units for a $1000 deposit. A few things we can throw in about the benefits of SLS: it’s powder which is nicer to clean up than resin printers, and parts should not require any kind of curing. The process also requires no support material as the uncured powder will support any layers being cured above it. The Fuse 1’s build chamber is 165 x 165 x 320 mm, and can be packed full of parts to make full use of the volume.
In the past we saw a detailed teardown of the Form 2 which revealed excellent workmanship and attention to detail. Let’s hope the same remains true of Formlabs’ newest offering.
It’s tough times for 3D-printing. Stratasys got burned on Makerbot, trustful backers got burned on the Peachy Printer meltdown, I burned my finger on a brand new hotend just yesterday, and that’s only the more recent events. In recent years more than a few startups embarked on the challenge of developing a piece of 3D printing technology that would make a difference. More colors, more materials, more reliable, bigger, faster, cheaper, easier to use. There was even a metal 3D printing startup, MatterFab, which pulled off a functional prototype of a low-cost metal-powder-laser-melting 3D printer, securing $13M in funding, and disappearing silently, poof.
This is just the children’s corner of the mall, and the grown-ups have really just begun pulling out their titanium credit cards. General Electric is on track to introduce 3D printed, FAA-approved fuel nozzles into its aircraft jet engines, Airbus is heading for 3D-printed, lightweight components and interior, and SpaceX has already sent rockets with 3D printed Main Oxidizer Valves (MOV) into orbit, aiming to make the SuperDraco the first fully 3D printed rocket engine. Direct metal 3D printing is transitioning from the experimental research phase to production, and it’s interesting to see how and why large industries, well, disrupt themselves.
Filament style 3D printers are great, but typically are rather size limited. Laser sintering printers offer huge print beds, but also come with quarter million dollar price tags. What are we supposed to do? Well, thanks to OpenSLS, it might just be possible to turn your laser cutter into your very own SLS 3D printer.
The team has created the hardware to turn a laser cutter with a bed size of 60cm x 90cm into an SLS printer. The beauty? The majority of the hardware is laser cut which means you already have the means to convert your laser cutter into a 3D printer.
The design files are available on their GitHub. Hardware will likely cost you around $2000, which is peanuts compared to the commercial laser sintering printers. There is tons of info in their article — too much for us to cover in a single post. If you end up building one, please let us know!
Laser sintering works by laying down a thin layer of metal powder and then hitting it with a strong enough laser to sinter the particles together. (Sintering sticks the grains together without getting the metal hot enough to melt it.) The rapid local heating and cooling required to build up 3D objects expands and cools the metal, and can result in stresses inside the resulting object.
The Northwestern team still lays down layers of powder, but glues the layers together with a quick-drying polymer instead of fusing them with a laser. Once the full model is printed, they then sinter it in one piece in an oven.
3D-printed copper lattice. Credit: Ramille Shah and David Dunand
The advantages of adding this extra step are higher printing speed — squirting the liquid out of syringe heads can be faster than fusing metal particles with a laser — and increased structural integrity because the whole model is heated and cooled at one time. A fringe benefit is that the model is still a bit flexible before firing, opening up possibilities for printing a flat model and then bending it into shape before sintering.
And if that weren’t enough, the team figured that they’d add a third step to the procedure to allow it to be used with rust (iron oxide) as the starting powder. They print the rust and polymer model, then un-rust the iron using hydrogen, and then fire it as before. Why rust? Do you know anything cheaper to use as a raw material?
What do you think? The basic idea may even be DIYable — glue metal particles together and heat them up enough to stick. Not in my microwave oven, though. We’d love to see a more energy-efficient 3D metal printer.
