Hacking A 3D Pen For Better Performance

January 13, 2021 by Bryan Cockfield 9 Comments

When 3D pens first became available, many assumed them to be gimmicky or part of a general fad that would eventually die out. Like most revolutionary technologies, though, they’ve found a firm foothold, especially in the art community where the ability to 3D print in freehand is incredibly valuable. There are still some shortcomings with the technology, though, but [tterev3] recently tore into a 3doodler pen to make some necessary upgrades.

First, this pen has some design choices that are curious, to say the least. The cooling fan runs regardless of temperature, and it has pushbuttons for start and stop rather than a momentary button that controls the extrusion. To fix these issues, as well as change the filament size, improve the cooling, and provide greater control over the extrusion speed, [tterev3] completely rewrote the firmware, changed the microcontroller on the PCB, and made several hardware upgrades to accommodate these changes. He also went ahead and installed a USB-C port for charging, which should be standard practice on all low-voltage consumer electronics by now anyway.

The detail work on this project is impressive, given the small size of the pen itself and the amount of precision hardware needed to make the changes. Especially regarding the replacement of the microcontroller on the board itself, which is an impressive feat even without the incredibly small dimensions. The firmware upgrade is available on his GitHub page as well if you have your own 3doodler that needs modifications, and if you’re still struggling to find uses for these handy devices, we’ve seen them used with interesting effect to build drones.

3D Printing In Five Axes Makes The World Flat

January 12, 2021 by Al Williams 23 Comments

Just when you thought your 3D printer was hot stuff, along comes a 5D printer. Two doctoral students at Penn State want to add two more axes to get rid of overhangs. This means that instead of supports or breaking objects into pieces, the printer simply orients the print so each region of the part is printing as if it were flat. Of course, 5D printers aren’t really new, even though you don’t hear much about them. However, the paper details a new algorithm that eliminates manually defining print regions and rotations.

You do this all the time manually when you’re setting the print up. For example, if you want to print a letter T, you could print it with supports under the cross pieces or flip it upside down and print it with no support at all. The difference here is the printer can flip the workpiece itself to different angles and can change it on the fly during printing. The printer might print the shaft of the T, rotate it to draw half of the crossbar, then rotate it 180 degrees to print the other half. In all three zones, the print head is depositing materials flat with no overhang. In a simple case like a T that doesn’t really require a special machine or an algorithm, but in the general case, you often can’t just rotate a model to avoid using supports.

Continue reading “3D Printing In Five Axes Makes The World Flat” →

Xolography: A Method To Improve The Accuracy Of Volumetric 3D Printing

January 4, 2021 by Maya Posch 7 Comments

Over the past years, additive manufacturing (AM) has become a common tool for hackers and makers, with first FDM and now SLA 3D printers becoming affordable for the masses. While these machines are incredibly useful, they utilize a slow layer-by-layer approach to produce objects. A relatively new technology called Volumetric Additive Manufacturing (VAM) promises to change all that by printing the entire object in one go, and according to a recent article in Nature, it just got a big resolution boost.

The concept is similar to SLA printing, but instead of curing the resin by projecting a 2D image of the current layer into the container, VAM uses multiple lasers to create intersecting points within the liquid. After exposing the resin to this projection for several seconds, the 3D model is built all at once. Not only is this far faster, but it removes the need for support materials and even a traditional build plate is unnecessary.

Visualization of the dual-color printing process as used by Regehly et al. (Credit: Nature)

Up till now the resolution and maximum object size of VAM has left a lot to be desired, but in this new research by Regehly et al. claim to have accomplished a feature resolution of ‘up to 25 micrometers’ and a solidification rate of ‘up to 55 cm³/s’. They used two crossing laser beams of different wavelengths, one to form the ‘light sheet’ (blue in the graphic) and a second beam (in red) to project the slide onto this light sheet. They refer to this technique as ‘xolography’, as a mesh-up of ‘holo’ (Greek for ‘whole’) and the ‘X’ shape formed by the crossing laser beams.

Key to making this work is the chemistry of the resin: the first wavelength excites the molecules called DCPI (Dual-Color Photo Initiators) that are dissolved in the resin. The second wavelength when hitting the same molecules initiates the resin polymerization process. The object pictured at the top of the page was a test print; producing such a design on a traditional 3D printer would have required a considerable amount of difficult to remove support material.

While this is obviously not a technology hobbyists will be using to replace their FDM and SLA printers with any time soon, there are still many companies and institutes working on various VAM technologies and approaches. As more and more of the complexities and challenges are dealt with, who knows when VAM may become a viable replacement for at least some SLA applications?

Thanks to [Qes] for the tip.

More 3D Printed IKEA Hacks Make Life Better

December 29, 2020 by Al Williams 28 Comments

There’s an old joke that the CEO of IKEA is running to be Prime Minister of Sweden. He says he’ll be able to put together his cabinet in no time. We don’t speak Swedish, but [Adam Miklosi] tells us that the word “uppgradera” means “upgrade” in Swedish. His website, uppgradera.co has several IKEA upgrade designs you can 3D print.

There are currently six designs that all appear to be simple prints that have some real value. These are all meant to attach to some IKEA product and solve some consumer problem.

For example, the KL01 is a cup holder with a clip that snaps into the groove of a KLIPSK bed tray. Without it, apparently, your coffee mug will tend to slide around the surface of the tray. The CH01 adds a ring around a cheese grater. There are drains for a soap dish and a toothbrush holder, shoulder pads for coat hangers, and a lampshade.

We worry a little about the safety of the cheese grater and the toothbrush because you will presumably put the cheese and the toothbrush into your mouth. Food safe 3D printing is not trivial. However, the other ones look handy enough, and we know a lot of people feel that PLA is safe enough for things that don’t make a lot of contact with food.

Honestly, none of these are going to change your life, but they are great examples of how simple things you can 3D print can make products better. People new to 3D printing often seem to have unrealistic expectations about what they can print and are disappointed that they can’t easily print a complete robot or whatever. However, these examples show that even simple designs that are easily printed can be quite useful.

If you don’t have a printer, it looks like as though site will also sell you the pieces and they aren’t terribly expensive. We don’t know why IKEA invites so many hacks, but even they provide 3D printer files to improve the accessibility of some products.

Control Theory Spellcasting Banishes The 3D Printing Ghosts

December 24, 2020 by Sonya Vasquez 43 Comments

It seems as though we still can’t hit the ceiling on better control schemes for 3D Printers. Input Shaping is the latest technique to land on our radar, a form of resonance compensation that all but eliminates the ghosting (aka: vertical ringing) artifacts we see on the walls of printed parts. While the technique has been around for decades, only recently did [Dmitry Butyugin] both apply it to 3D printer control and merge their hard work into the open source firmware package Klipper. Once tuned, the results are simply astonishing–especially since this scheme can augment the print quality of even the most budget printer.

A Split A/B Test with and without Klipper’s Input Shaping feature courtesy of [@LukesLaboratory]

Assuming your 3D printer isn’t infinitely stiff, when your nozzle moves from point to point or changes direction, it vibrates in response to having its speed altered. The result is that the nozzle wobbles along the ideal path it’s trying to track. The result is ghosting, an aesthetic blemish that looks like vertical waves on the sides of your printed part.

Input Shaping is a feed-forward controls technique for cancelling the mechanical vibrations that create ghosting. The idea is that, if we wanted to move the machine from point to point, we send it two impulses. The first impulse kicks the machine into moving and the second impulse follows up at a precise time to cancel the vibrations we would see when the machine comes to a stop. Albeit, moving any machine by sending it two impulses is pretty crude, so we take these impulses, adjust their amplitudes so that they sum to 1, and convolve them with a control input signal that we’d actually like to send it. The result is that the resonance cancellation part of the signal seamlessly “mixes” into the control input signal, and the machine moves from point to point with significantly less vibration at the end of the travel move. For more info on the maths behind this process, have a look at the first four pages of this paper from [Singh and Singhose].

The only hiccup is that you need to do some up-front system characterization of your 3D Printer running Klipper before you can take advantage of this technique. Thankfully the Klipper update comes with a set of step-by-step instructions for characterizing your machine up-front. After a couple test prints to measure the periodicity of your ringing, you can simply apply your measurement results to your config file, and you’re set.

Input Shaping is a prime example of “just wrap a computer around it!“–fixing hardware by characterizing and cancelling unwanted behaviors with software. If you’re hungry for more clever, characterized hardware control schemes, look no further than this Anti-Cogging algorithm for BLDC Motors. And for a video walkthrough of the Klipper implementation, have a look at [eddietheengineer]’s breakdown after the break.

Does your 3D Printer run Klipper? We’d love to see some of your Input Shaping results in the comments.

Continue reading “Control Theory Spellcasting Banishes The 3D Printing Ghosts” →

Hackaday Links: December 20, 2020

December 20, 2020 by Dan Maloney 11 Comments

If development platforms were people, Google would be one of the most prolific serial killers in history. Android Things, Google’s attempt at an OS for IoT devices, will officially start shutting down on January 5, 2021, and the plug will be pulled for good a year later. Android Things, which was basically a stripped-down version of the popular phone operating system, had promise, especially considering that Google was pitching it as a secure alternative in the IoT space, where security is often an afterthought. We haven’t exactly seen a lot of projects using Android Things, so the loss is probably not huge, but the list of projects snuffed by Google and the number of developers and users left high and dry by these changes continues to grow. Continue reading “Hackaday Links: December 20, 2020” →

Creality WiFi Takes On Octoprint

December 13, 2020 by Al Williams 78 Comments

A very common hack to a 3D printer is to connect a Raspberry Pi to your printer and then load Octoprint or a similar program and send your files to the printer via the network. [Teaching Tech] noticed that Creality now has an inexpensive WiFi interface that promises to replace Octoprint and decided to give it a quick review.

You might wonder why you’d want this system when Octoprint exists? Mainly, the value proposition is the price. You can buy the Creality box for about $20. A Raspberry Pi with a similar case would be at least twice that price. In addition, the box integrates with a Thingiverse-like library and does cloud slicing, which is attractive when you have a very small computer connected to your printer.

However, [Teaching Tech] found some issues. The box was pretty picky about connecting to printers and there were many other problems. The 3D model library wasn’t very comprehensive, although that could change if the thing got very popular. Worse, the slicer didn’t really produce stellar results.

We have to admit, an attractive network interface for $20 would be of interest. But it is hard to see how this would be a better value than Octoprint unless you were very short on cash and had no Raspberry Pi surplus laying around. You still need an SD card and a power supply, so those extras are a wash.

On the other hand, if Creality fixes the problems and expands the 3D model library, we’d buy one. But it remains to be seen if either of those things will happen, much less both of them. We do wish [Teaching Tech] had opened the thing up for us. Maybe next time.

Continue reading “Creality WiFi Takes On Octoprint” →