Giant 3D Prints Piece-by-Piece

January 16, 2022 by Al Williams 18 Comments

While FDM printers have gotten bigger lately, there’s almost always going to be a part that is bigger than your bed. The answer? Break your design into parts and assemble them after printing. However, the exact method to do this is a bit of a personal choice. A mechanical engineering student wrote:

After researching the state of the art as well as your ideas here on reddit, I realized, that there are almost no universal approaches to divide a large part and join the pieces which maintain mechanical strength, precisely position each segment, and also counteract tolerances due to the FDM-process.

Therefore I tried to develop a universal method to segment large trim parts, additively manufacture each segment and finally join those segments to form the desired overall part.

The result is a research paper you can download for free. The method focuses on thin parts intended as automotive trim, but could probably be applied to other cases.

You can read about the thought process, but the final result was a joggle — a joint made with a rabbet and tongue. Adhesive holds it together, but the joint offers advantages in constraining the final product and the transmission of force in the assembly. Judging by the picture, the process works well. It would be interesting to see slicer software develop the capability to segment a large model using this or a similar technique.

Of course, you can just build a bigger printer, at least to a point. It seems, though, that that point is pretty big.

3D Printering: Getting Started With Universal Bed Leveling

January 14, 2022 by Al Williams 10 Comments

Last time we talked about how Marlin has several bed leveling mechanisms including unified bed leveling or UBL. UBL tries to be all things to all people and has provisions to create dense meshes that model your bed and provides ways for you to adjust and edit those meshes.

We talked about how to get your printer ready for UBL last time, but not how to use it while printing. For that, you’ll need to create at least one mesh and activate it in your startup code. You will also want to correctly set your Z height to make everything work well. Continue reading “3D Printering: Getting Started With Universal Bed Leveling” →

3D Printed Sensor For Finding Wind Direction And Likely Much More

January 11, 2022 by Ryan Flowers 35 Comments

Have you ever wondered how an electronic wind vane translates a direction into a unique signal? It seems as though it might be very complicated, and indeed some of them are. [martinm] over at yoctopuce.com has an excellent writeup about measuring wind direction using just a single, easily printed disk and some phototransistors.

Commercial weather vanes often use complicated multi-tracked disks with magnets and reed switches, conductive traces and brushes, or some other means of getting a fine resolution. Unfortunately some of these are prone to wear or are otherwise more complicated than they need to be.

What makes [martinm]’s solution unique is that they have applied previous research on the subject to a simple and durable 3d printed wind vane that looks like it’ll be able to handle whatever global warming can throw at it. The encoder’s simplicity means that it could likely be used in a large number of applications where low resolution position sensing is more than enough- the definition of a great hack!

Adding more tracks or even more disks would enable higher resolution, but the 12 degree resolution seems quite good for the purpose. Such a neat wind vane design will surely be welcome if you want to 3d print your own weather station. Thanks to [Adrian] for the great tip!

3D Printering: One Bed Level To Rule Them All

January 5, 2022 by Al Williams 23 Comments

In an ideal world, your FDM 3D printer’s bed would be perfectly parallel with the print head’s plane of movement. We usually say that means the bed is “level”, but really it doesn’t matter if it is level in the traditional sense, as long as the head and the bed are the same distance apart at every point. Of course, in practice nothing is perfect.

The second best situation is when the bed is perfectly flat, but tilted relative to the print head. Even though this isn’t ideal, software can move the print head up and down in a linear fashion to compensate for the tilt. Things are significantly worse if the bed isn’t itself flat, and has irregular bumps up and down all over.

To combat that, some printer firmware supports probing the bed to determine its shape, and adjusts the print head up and down as it travels across the map. Of course, you can’t probe the bed at every possible point, so the printer will have to interpolate between the measured reference points. Marlin’s bilinear bed leveling is an example.

But if you have enough flash space and you use Marlin, you may want to try unified bed leveling (UBL). This is like bilinear leveling on steroids. Unfortunately, the documentation for this mode is not as plain as you might like. Everything is out there, but it is hard to get started and information is scattered around a few pages and videos. Let’s fix that.

Continue reading “3D Printering: One Bed Level To Rule Them All” →

3D Printing Gets Tiny

December 25, 2021 by Al Williams 6 Comments

Using a process akin to electroplating, researchers at the University of Oldenburg have 3D printed structures at the 25 nanometer scale. A human hair, of course, is thousands of time thicker than that. The working medium was a copper salt and a very tiny nozzle. How tiny? As small as 1.6 nanometers. That’s big enough for two copper ions at once.

Tiny nozzles are prone to every 3D printer’s bane: clogged nozzles. To mitigate this, the team built a closed-loop control that measured electrical current between the work area and inside the nozzle. You can read the full paper online.

Continue reading “3D Printing Gets Tiny” →

When Hacking And Biosensing Collide

December 24, 2021 by Elliot Williams 2 Comments

[Prof. Edwin Hwu] of the Technical University of Denmark wrote in with a call for contributions to special edition of the open-access scientific journal Biosensors. Along the way, he linked in videos from three talks that he’s given on hacking consumer electronics gear for biosensing and nano-scale printing. Many of them focus on clever uses of the read-write head from a Blu-ray disc unit (but that’s not all!) and there are many good hacks here.

For instance, this video on using the optical pickup for the optics in an atomic force microscope (AFM) is bonkers. An AFM resolves features on the sub-micrometer level by putting a very sharp, very tiny probe on the end of a vibrating arm and scanning it over the surface in question. Deflections in the arm are measured by reflecting light off of it and measuring their variation, and that’s exactly what these optical pickups are designed to do. In addition to phenomenal resolution, [Dr. Hwu’s] AFM can be made on a shoestring budget!

Speaking of AFMs, check out his version that’s based on simple piezo discs in this video, but don’t neglect the rest of the hacks either. This one is a talk aimed at introducing scientists to consumer electronics hacking, so you’ll absolutely find yourself nodding your heads during the first few minutes. But then he documents turning a DVD player into a micro-strobe for high speed microfluidics microscopy using a wireless “spy camera” pen. And finally, [Dr. Hwu’s] lab has also done some really interesting work into nano-scale 3D printing, documented in this video, again using the humble Blu-ray drive, both for exposing the photopolymer and for spin-coating the disc with medium. Very clever!

If you’re doing any biosensing science hacking, be sure to let [Dr. Hwu] know. Or just tear into that Blu-ray drive that’s collecting dust in your closet.

Continue reading “When Hacking And Biosensing Collide” →

Concrete With 3D Printed Foam Forms

December 20, 2021 by Al Williams 17 Comments

The latest 3D printing application? Forming concrete. That’s according to a team at ETH Zurich who claims that construction with foam forms cuts concrete usage up to 70%. It also offers improved insulation properties. You can see a video about the process, below.

Typical concrete work relies on a form often made with wood, steel, or plastic. That’s easy to do, but hard to make complex shapes. However, if you can create complex shapes you can easily put material where it adds strength and omit material where it doesn’t carry load. Using a robotic-arm 3D print technique, the researchers can lay out prefabricated blocks of foam that create forms with highly complex shapes. Continue reading “Concrete With 3D Printed Foam Forms” →