External Buffer Boosts 3D Printer Filament Splicing On The Palette 2

July 21, 2019 by Tom Nardi 15 Comments

There was a time when most of us thought the next logical step for desktop 3D printing was to add additional extruders and hotends, allowing the machine to print in multiple colors or materials. Unfortunately such arrangements quickly become ungainly, and even with just two extruders, calibration can be a nightmare. Because of this, development has been trending towards systems that use just one hotend and simply alternate the filament being fed into it. But such systems have their own problems.

Arguably the biggest issue is how long it takes to switch filaments. The Palette 2 uses a physical buffer of spliced filament to try and keep ahead of the printer, but as [Kurt Skauen] demonstrates, there are considerable performance gains to be had by building a bigger buffer. He says there’s still some calibration issues to contend with, but judging by the video after the break, we’d say he is certainly on the right track.

The buffer is necessary to give the spliced filament time to cool and bond before being fed into the printer, but as currently designed, the machine simply can’t store enough of it to keep up with high print speeds. The stock buffer area holds 125mm worth of spliced filament, but the modification [Kurt] has designed adds a whopping 280mm on top of that to reach more than three times the stock capacity.

He’s successfully tested printing at speeds as high as 200mm/s with his upgraded buffer, a big improvement over what he was seeing with the original buffer area. This despite the fact that Mosaic (the company that produces the Palette) claim the original buffer size was already more than sufficient. It seems we’ve found ourselves in the middle of a debate between Mosaic and some very vocal members of the community, and while we don’t want to take sides, it’s hard to ignore [Kurt]’s findings.

Want to make your own? [Kurt] has released all the information necessary for others to duplicate his work, including the STLs for all printed parts and a list of the bearings, springs, and fasteners you’ll need to put it together. It looks like a fairly large undertaking, but with the potential for such a considerable speed boost, we don’t doubt others will be willing to take the plunge. One person who printed and assembled an earlier version of the buffer upgrade reports their print speeds with a 0.8 mm nozzle have more than doubled.

The Palette has come a long way from we first saw it in 2016, and since then, Prusa has thrown their orange hat into the ring with their own filament-switching upgrade. Neither machine is without its niggling issues, but they’re still probably our best shot at taking desktop 3D printing to the next level.

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Syringe Pump Turns CNC Machine Into A Frosting Bot

June 28, 2019 by Dan Maloney 3 Comments

“Amazing how with only the power of 3D-printing, two different computers, hundreds of dollars in CNC machinery, a lathe, and modern microcontroller magic, I can almost decorate a cupcake as well as a hyperactive ten-year-old.” We can think of no better way to sum up [Justin]’s experiment in CNC frosting application, which turns out to only be a gateway to more interesting use cases down the road.

Granted, it didn’t have to be this hard. [Justin] freely admits that he took the hard road and made parts where off-the-shelf components would have been fine. The design for the syringe pump was downloaded from Thingiverse and does just about what you’d expect – it uses a stepper motor to press down on the plunger of a 20-ml syringe full of frosting. Temporarily attached in place of the spindle on a CNC router, the pump dispenses onto the baked goods of your choice, although with an irregular surface like a muffin top the results are a bit rough. The extruded frosting tends to tear off and drop to the surface of the cake, distorting the design. We’d suggest mapping the Z-height of the cupcake first so the frosting can dispense from a consistent height.

Quality of the results is not really the point, though. As [Justin] teases, this hardware is in support of bioprinting of hydrogels, along with making synthetic opals. We’re looking forward to those projects, but in the meantime, maybe we can all just enjoy a spider silk beer with [Justin].

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Assessing Nozzle Wear In 3D-Printers

June 6, 2019 by Dan Maloney 15 Comments

How worn are your nozzles? It’s a legitimate question, so [Stefan] set out to find out just how bad 3D-printer nozzle wear can get. The answer, as always, is “It depends,” but exploring the issue turns out to be an interesting trip.

Reasoning that the best place to start is knowing what nozzle wear looks like, [Stefan] began by printing a series of Benchies with brand-new brass nozzles of increasing diameter, to simulate wear. He found that stringing artifacts, interlayer holes, and softening of overhanging edges and details all worsened with increasing nozzle size. Armed with this information, [Stefan] began a torture test of some cheap nozzles with both carbon-fiber filament and a glow-in-the-dark filament, both of which have been reported as nozzle eaters. [Stefan] found that to be the case for at least the carbon-fiber filament, which wore the nozzle to a nub after extruding only 360 grams of material.

Finally, [Stefan] did some destructive testing by cutting used nozzles in half on the mill and looking at them in cross-section. The wear on the nozzle used for carbon-fiber is dramatic, as is the difference between brand-new cheap nozzles and the high-quality parts. Check out the video below and please sound off in the comments if you know how that peculiar spiral profile was machined into the cheap nozzles.

Hats off to [Stefan] for taking the time to explore nozzle wear and sharing his results. He certainly has an eye for analysis; we’ve covered his technique for breaking down 3D-printing costs in [Donald Papp]’s “Life on Contract” series.

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A Better Bowden Drive For Floppy Filaments

May 16, 2019 by Dan Maloney 7 Comments

You might not think to use the word “rigid” to describe most 3D-printer filaments, but most plastic filaments are actually pretty stiff over a short length, stiff enough to be pushed into an extruder. Try the same thing with a softer plastic like TPE, though, and you might find yourself looking at this modified Bowden drive for elastomeric filaments.

The idea behind the Bowden drive favored by some 3D-printer designers is simple: clamp the filament between a motor-driven wheel and an idler to push it up a pipe into the hot end of the extruder. But with TPE and similar elastomeric filaments, [Tech2C] found that the Bowden drive on his Hypercube printer was causing jams and under-extrusion artifacts in finished prints. A careful analysis of the stock drive showed a few weaknesses, such as how much of the filament is not supported on the output side of the wheel. [Tech2C] reworked the drive to close that gap and also to move the output tube opening closer to the drive. The stock drive wheel was also replaced with a smaller diameter wheel with more aggressive knurling. Bolted to the stepper, the new drive gave remarkably improved results – a TPE vase was almost flawless with the new drive, while the old drive had blobs and artifacts galore. And a retraction test print showed no stringing at all with PLA, meaning the new drive isn’t just good for the soft stuff.

All in all, a great upgrade for this versatile and hackable little printer. We’ve seen the Hypercube before, of course – this bed height probe using SMD resistors as strain gauges connects to the other end of the Bowden drive.

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3D Printering: The Quest For Printable Food

April 24, 2019 by Tom Nardi 44 Comments

A video has been making the rounds on social media recently that shows a 3D printed “steak” developed by a company called NovaMeat. In the short clip, a machine can be seen extruding a paste made of ingredients such as peas and seaweed into a shape not entirely unlike that of a boot sole, which gets briefly fried in a pan. Slices of this futuristic foodstuff are then fed to passerby in an effort to prove it’s actually edible. Nobody spits it out while the cameras are rolling, but the look on their faces could perhaps best be interpreted as resigned politeness. Yes, you can eat it. But you could eat a real boot sole too if you cooked it long enough.

To be fair, the goals of NovaMeat are certainly noble. Founder and CEO Giuseppe Scionti says that we need to develop new sustainable food sources to combat the environmental cost of our current livestock system, and he believes meat alternatives like his 3D printed steak could be the answer. Indeed, finding ways to reduce the consumption of meat would be a net positive for the environment, but it seems his team has a long way to go before the average meat-eater would be tempted by the objects extruded from his machine.

But the NovaMeat team aren’t the first to attempt coaxing food out of a modified 3D printer, not by a long shot. They’re simply the most recent addition to a surprisingly long list of individuals and entities, not least of which the United States military, that have looked into the concept. Ultimately, they’ve been after the same thing that convinced many hackers and makers to buy their own desktop 3D printer: the ability to produce something to the maker’s exacting specifications. A machine that could produce food with the precise flavors and textures specified would in essence be the ultimate chef, but of course, it’s far easier said than done.

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Active Strain Relief For 3D-Printer Filament

February 19, 2019 by Dan Maloney 26 Comments

Buying 3D-printer filament is little like eating potato chips: you can’t stop at just one. You start with basic black PLA, then you need a particular color for a special project, then you start experimenting with different plastics, and before you know it, you’ve got dozens of reels lined up. Trouble is, unless you move the in-use reel right over the printer, the filament can get a bit unruly as the printer sucks it up. What to do?

How about building an active strain relief system for your filament collection? That what [Daniel Harari] chose to do, and we have to say that it looks pretty slick. The idea is to keep the filament slack before it enters the printer’s extruder no matter where the reel is positioned relative to the printer. The active bit is a little like a low-force extruder, using a couple of pinch rollers from an old 2D-printer to pay out filament when needed. A clever sensor, consisting of a 3D-printed funnel and a copper wire contact loop, detects when the printer has taken up all the slack in the filament and triggers a payout from the feeder. In a nice touch, the feeder motor is controlled by a couple of 555s rather than a microcontroller. The short clip below shows the feeder being triggered and paying out a little more slack.

In the final analysis, this is just another in a long series of filament management projects, from dry-boxes to filament meters to end-of-spool alarms. It may be overkill, but [Daniel] put a lot of thought into it, which we always appreciate.

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3D-Printer Extrudes Paper Pulp Instead Of Plastic

November 11, 2018 by Dan Maloney 33 Comments

We’ve seen all sorts of 3D-printers on these pages before. From the small to the large, Cartesians and deltas, and printers that can squeeze out plastic, metal, and even concrete. But this appears to be the first time we’ve ever featured a paper-pulp extruding 3D-printer.

It’s fair to ask why the world would need such a thing, and its creator, [Beer Holthuis], has an obvious answer: the world has a lot of waste paper. Like 80 kg per person per year. Thankfully at least some of that is recycled, but that still leaves a lot of raw material that [Beer] wanted to put to work. Build details on the printer are sparse, but from the photos and the video below it seems clear how it all went together. A simple X-Y-Z gantry moves a nozzle over the build platform. The nozzle, an order of magnitude or two larger than the nozzles most of us are used to, is connected to an extruder by a plastic hose. The extruder appears to be tube with a stepper-driven screw that lowers a ram down onto the pulp, squeezing it into the hose. [Beer] notes that the pulp is mixed with a bit of “natural binder” to allow the extruded pulp to keep its shape. We found the extrusion process to be just a wee bit repulsive to watch, but fascinating nonetheless, and the items he’s creating are certainly striking in appearance.

This may be the first pulp printer to grace our pages, but it’s not the first pulp hack we’ve featured. Pulp turns out to be a great material to keep your neighbors happy and even makes a dandy fuel.

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