Design and Testing of the Form 2

Formlabs makes a pretty dang good SLA printer by all accounts. Though a bit premium in the pricing when compared to the more humble impact of FDM printers on the wallet, there’s a bit more to an SLA printer. The reasoning becomes a bit more obvious when reading through this two part series on the design and testing of the Form 2.

It was interesting to see what tests they thought were necessary to ensure the reliable operation of the machine. For example the beam profile of every single laser that goes into a printer is tested to have the correctly shaped spot. We also thought the Talcum powder test was pretty crazy. They left a printer inside a sandblast cabinet and blasted it with Talcum powder to see if dust ingress could cause the printer to fail; it didn’t.

The prototyping section was a good read. Formlabs was praised early on for the professional appearance of their printers. It was interesting to see how they went from a sort of hacky looking monstrosity to the final look. They started by giving each engineer a Form 1 and telling them to modify it in whatever way they thought would produce a better layer separation mechanism. Once they settled on one they liked they figured out how much space they’d need to hold all the new mechanics and electronics. After that it was up to the industrial designer to come up with a look that worked.

They’re promising a third part of the series covering how the feedback from beta testing was directed back into the engineering process. All in all the Form 2 ended up being quite a good printer and the reviews have been positive. The resin from Formlab is a little expensive, but unlike others they still allow users to put the printer in open mode and use other resin if they’d like. It was cool to see their engineering process.

BuildTak, PEI, and Early Adopter Syndrome

I’m guessing most of the members of the Hackaday community are what most people would consider early adopters. Sure, there’s variation among us, but compared to the general population we probably all qualify. I’ve spent many years being an early adopter. I owned a computer, a TiVO, a digital camera, a 3D printer, a drone, and many other gadgets before they became well known. I’ve avoided the self-balancing conveyance craze (I’ll stick with my motorcycle).

Of course, you know if you are an early adopter, you will overpay. New has a premium, after all. But there is another price: you often have the first, but not the optimum. My first digital camera took 3.5 inch floppies. My TiVO has an analog tuner.

I was reminded of this last week. A number of years ago, I built a 3D printer. A lot of printers back then didn’t have heated build plates, so printing ABS required rafts and ABS juice and frustration. I made sure to get a heated bed and, like most people in those days, I had a glass print surface covered in Kapton.

That works pretty well with ABS, but it isn’t perfect. Aqua Net hair spray makes it stick better, but large flat prints still take a little work. With a little practice, it isn’t bad. I eventually switched to an aluminum bed and didn’t have to level the head quite as often, but it didn’t really make things any better, just more repeatable.

The years pass and other gadgets beckon. I use the printer about like I use a drill press. I don’t use it every day, but when you need it it is handy. I have to admit, I’ve been getting partial to PLA since it doesn’t warp. But PLA in the hot Houston sun isn’t always a good mix, so I still print a fair amount of ABS.

The other day I noticed a product called BuildTak. I also heard some people are printing on PEI sheets. I decided to try the BuildTak. Wow! What a difference.

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Robots With 3D Printed Shock Absorbing Skin

MIT’s Computer Science and Artificial Intelligence Laboratory, CSAIL, put out a paper recently about an interesting advance in 3D printing. Naturally, being the computer science and AI lab the paper had a robotic bend to it. In summary, they can 3D print a robot with a rubber skin of arbitrarily varying stiffness. The end goal? Shock absorbing skin!

They modified an Objet printer to print simultaneously using three materials. One is a UV curing solid. One is a UV curing rubber, and the other is an unreactive liquid. By carefully depositing these in a pattern they can print a material with any property they like. In doing so they have been able to print mono body robots that, simply put, crash into the ground better.  There are other uses of course, from joints to sensor housings. There’s more in the paper.

We’re not sure how this compares to the Objet’s existing ability to mix flexible resins together to produce different Shore ratings. Likely this offers more seamless transitions and a wider range of material properties. From the paper it also appears to dampen better than the alternatives. Either way, it’s an interesting advance and approach. We wonder if it’s possible to reproduce on a larger scale with FDM.

Hello 3D Printed Dolly

[Ivan] likes to take time lapse videos. Using his 3D printer and a stepper motor he fashioned a rig that allows him to control the camera moving any direction on a smooth floor.

The dolly has a tripod-compatible mounting plate and scooter wheels. An Arduino runs the thing and a cell phone battery provides power. A pot sets the speed and [Ivan] provides code for both a linear pot, which he suggests, and for a logarithmic pot, which he had on hand. You can see a video of the results below.

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3D Printering: Trinamic TMC2130 Stepper Motor Drivers

Adjust the phase current, crank up the microstepping, and forget about it — that’s what most people want out of a stepper motor driver IC. Although they power most of our CNC machines and 3D printers, as monolithic solutions to “make it spin”, we don’t often pay much attention to them.

In this article, I’ll be looking at the Trinamic TMC2130 stepper motor driver, one that comes with more bells and whistles than you might ever need. On the one hand, this driver can be configured through its SPI interface to suit virtually any application that employs a stepper motor. On the other hand, you can also write directly to the coil current registers and expand the scope of applicability far beyond motors.

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The Hackaday Prize: An Open Electric Wheelchair

[Irene Sans] and [Alvaro Ferrán Cifuentes] feel that electric wheelchairs are still too expensive. On top of that, as each person’s needs are a little different, usually don’t exactly fit the problems a wheelchair user might face. To this end they’ve begun the process of creating an open wheelchair design which they’ve appropriately dubbed OpenChair.

As has been shown in the Hackaday Prize before, there’s a lot of things left to be desired in the assistive space. Things are generally expensive. This would be fine, but often insurance doesn’t cover it or it’s out of the range of those in developing nations.  As always, the best way to finish is to start, so that’s just what [Irene] and [Alvaro] has done.

They based their initial design on the folding wheel chair we all know. It’s robust enough for daily use and is fairly standard around the world. They designed a set of accessories to make the wheelchair more livable for daily use as well as incorporating the controls.

The next problem was locomotion. Finding an off-the-shelf motor that was powerful enough without breaking the budget was proving  difficult, but they had an epiphany. Why not use mass production toy crap to their advantage. The “hoverboards” that were all the rage this past commerical holiday season were able to roll a person around, so naturally a wheelchair would be within the power range.

They extracted the two 350 watt hub motors, batteries, and control boards. It took a bit of reverse engineering but they were able to get the hub drive motors of the hoverboard integrated with the controls on their wheelchair.

In the end they were able to cut the price of a regular electric wheelchair in half with their first iteration and set the foundation for future work on an open electric wheelchair system. Certainly more work could bring even better improvements.

The Healthy Maker: Tackling Vapors, Fumes And Heavy Metals

Fearless makers are conquering ever more fields of engineering and science, finding out that curiosity and common sense is all it takes to tackle any DIY project. Great things can be accomplished, and nothing is rocket science. Except for rocket science of course, and we’re not afraid of that either. Soldering, welding, 3D printing, and the fine art of laminating composites are skills that cannot be unlearned once mastered. Unfortunately, neither can the long-term damage caused by fumes, toxic gasses and heavy metals. Take a moment, read the material safety datasheets, and incorporate the following, simple practices and gears into your projects.

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