Everything You Wanted To Know About 3D Printing Support But Were Afraid To Ask

February 18, 2020 by Al Williams 6 Comments

At the dawn of 3D printing, support structures were something to avoid. ABS is a hard substance to clear off, and the slicers did a comparatively poor job of making structures that were easy to remove. Today, supports are not a big deal and most of the slicers and materials allow for high-quality prints with supports. We were printing something with supports the other day and noticed that Cura has a support floor and roof function. Curious, we did a quick search and found this very comprehensive post about the current state of support.

With 25 topics in the table of contents, this isn’t a 3-minute read. Of course, you might wish to skip over some of the first parts if you get why you need support and understand the basic ideas. We became more interested when we reached the geometry section.

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$200 Resin Printer Reviewed

February 14, 2020 by Al Williams 29 Comments

[3DPrintFarm] got an early version of the Phrozen Sonic Mini resin printer. If you look at the video below, he was very impressed with its build quality and results. The price is reported to be $200, although we have seen it on some web sites for a bit more. The build quality does look good, although you have to admit, the motion mechanism on a resin printer is pretty simple, since you just need to move up and down.

The printer uses a monochrome LCD which allows it to cure layers very fast (apparently, monochrome panels pass more ultraviolet light through). The panel also has a higher-rated lifetime than color LCDs

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Welcome To McDonald’s; Would You Like 3D Printing Resin With That?

February 10, 2020 by Al Williams 33 Comments

University of Toronto researchers have succeeded in converting used cooking oil — from McDonald’s, no less — into high-resolution 3D printing resin. Your first response might be: “Why?”, but thinking about it there are several advantages. For one thing, waste oil is a real problem for the food industry, and thus it can be acquired rather cheaply. An even bigger benefit is that the plastic that originates from this oil is biodegradable. Their 3d-printed butterfly, of course, is made from the recycled resin.

We aren’t chemists, but apparently 3D resin has a lot in common with cooking oil already. The team used a one-step chemical process to convert one liter of McDonald’s greasiest into a little more than 400 milliliters of resin.

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3D Printing For Wire Paths Yields An Arduboy Minus The PCB

February 8, 2020 by Jenny List 23 Comments

What is part way between a printed circuit board and a rats-nest of point-to-point wiring? We’re not sure, but this is it. [Johan von Konow] has come up with an inspired solution, 3D printing an Arduboy case with channels ready-made for all the wires. The effect with his 3DPCBoy is of a PCB without the PCB, and allows the console to be made very quickly and cheaply.

The Arduboy — which we originally looked at back in 2014 — is a handheld gaming console in a somewhat Gameboy-like form factor. Normally a credit-card sized PCB hosts all the components, including a microcontroller, display, and buttons. Each has a predictable footprint and placement so they can simply be wired together with hookup wire, if you don’t mind a messy result.

Here the print itself has all the holes ready-created for the components, and the path of the wires has a resemblance to the sweeping traces of older hand-laid PCBs. The result is very effective way to take common components — and Arduino pro micro board for the uC, an OLED breakout board, and some buttons — and combine them into a robust package. This technique of using 3D prints as a combination of enclosure and substrate for components and wiring has an application far beyond handheld gaming. We look forward to seeing more like it.

[Via the Arduboy community forum, thanks Kevin Bates for the tip.]

Can You Help 3D Print A Selectric Ball?

January 26, 2020 by Al Williams 63 Comments

The IBM Selectric changed typewriters as we knew them. Their distinctive ball element replaced the clunky row of typebars and made most people faster typists. When [Steve Malikoff] thought about 3D printing a type ball — colloquially known as a golf ball — it seemed like a great idea.

The problem? It just doesn’t work very well. According to [Steve], it is likely because of the low resolution of the printer. However, it isn’t clear the latitudes of the characters are correct. and there are a few other issues. It is possible that a resin printer would do better and there’s a call for someone out there to try it and report back. We are guessing a finer nozzle and very low layer height might help on an FDM printer.

Judging from the images, it looks like some of the balls do pretty well, but don’t get a full strike at the tilt angle. So it could be something else. However, it does sound like cleaning up the print so it fits is a major problem.

The Selectric was notable for several reasons — you can see an ad for the machine in the video below. The type ball meant you couldn’t jam keys. Since you didn’t have to unjam keys and you had the ribbon in a cartridge, you would have to work really hard to get ink on your fingers, even if you used the cloth ribbon instead of the arguably better carbon film ribbon. The Selectric II could even use a special tape to lift the carbon ribbon off the paper for correcting mistakes. No white-out liquid or fussing with little strips of correction paper. The fact that the ball moves means you don’t have to clear space on the side of the machine for the platen to travel back and forth.

Can you help? If you have a Selectric I or II and a high-quality printer, this would be a fun project to try and report back your results to [Steve]. If you are familiar with the later issue typeballs, you might not have seen the wire clip that [Steve] uses to hold the ball in place. However, you can see them in the video ad below. More modern balls use a plastic lever that acts as a handle so even with cloth ribbons you have less chance of getting ink on your hands.

Although there were Selectrics meant to interface with a computer, you can refit any of them to do it with some work. The Selectric also has a role in one of the great techno spy stories of all time: The GUNMAN project.

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Form 3 SLA Printer Teardown, Bunnie Style

January 21, 2020 by Donald Papp 15 Comments

[Bunnie Huang] has shared with all of us his utterly detailed teardown on the Form 3 SLA printer from Formlabs (on the left in the image above) and in it he says one of the first things he noticed when he opened it to look inside was a big empty space where he expected to see mirrors and optics. [Bunnie] had avoided any spoilers about the printer design and how it worked, so he was definitely intrigued.

Not only does the teardown reveal the kind of thoughtful design and construction that [Bunnie] has come to expect of Formlabs, but it reveals that the Form 3 has gone in an entirely new direction with how it works. Instead of a pair of galvanometers steering a laser beam across a build surface (as seen in the Form 1 and Form 2 printers) the new machine is now built around what Formlabs calls an LPU, or Light Processing Unit, which works in conjunction with a new build tank and flexible build surface. In short, the laser and optics are now housed in a skinny, enviromentally-sealed unit that slides left and right within the printer. A single galvo within steers the laser vertically, as the LPU itself moves horizontally. Payoffs from this method include things such as better laser resolution, the fact that the entire optical system is no longer required to sit directly underneath a vat of liquid resin, and that build sizes can be bigger. In addition, any peeling forces that a model is subjected to are lower thanks to the way the LPU works.

Details about exactly how the Form 3 works are available on Formlabs’ site and you can also see it in action from a practical perspective on Adam Savage’s Tested (video link), but the real joy here is the deeply interesting look at the components and assembly through the eyes of someone with [Bunnie]’s engineering experience. He offers insights from the perspective of function, supply, manufacture, and even points out a bit of NASA humor to be found inside the guts of the LPU.

[Bunnie] knows his hardware and he’s certainly no stranger to Formlabs’ work. His earlier Form 2 teardown was equally detailed as was his Form 1 teardown before that. His takeaway is that the Form 3 and how it works represents an evolutionary change from the earlier designs, one he admits he certainly didn’t see coming.

Gradient Infill Puts More Plastic Where You Want It

January 20, 2020 by Al Williams 13 Comments

It is always tricky setting the infill for a 3D printed part. High infill parts are strong but take longer to print, while low infill prints take less time, but are weaker internally and in danger of surface layer droop between the infill pattern. [Stephan] has a better answer: gradient infill. You can see a video below and find his Python code on GitHub.

The idea is simple enough. In most cases, parts under stress see higher stress near the surface. Putting more material there will make the part stronger than adding plastic in places where the stress is lower. [Stephan] has done finite element analysis to determine an optimal infill pattern before, but this is somewhat difficult to do. Since the majority of parts can follow the more at the edges and less at the center rule, gradient infill makes sense except for a few special cases.

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