Better Car Hinges By 3D Printing

January 25, 2022 by Al Williams 30 Comments

We often use 3D printing to replicate items we might otherwise make with traditional machining methods. Fraunhofer’s new door hinge for a sports car takes a different tack: it tries to be better than the equivalent machined part. The company claims that the new part is half the cost and weighs 35% less than the normal hinge.

Using tools in their 3D Spark software, the team analyzed different factors that led to manufacturing cost. Some of these were specific to the part while others were specific to the process. For example, orienting the part to minimize support and maximize the quantity that fit on the build surface.

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Printing In Silicone

January 22, 2022 by Al Williams 22 Comments

When you think of making something out of silicone, you usually think of using a mold and injecting it with the material. Can you 3D print it? [Kimberly Beckett] answers that very question in a recent post. The short answer is yes, but you need specialized printing equipment.

Most consumer or hobby printers use either filament deposition or photoresin. Neither of these processes are good for printing silicone. For one thing, silicone doesn’t melt and reform like a thermoplastic. After all, that is why we like making hotend socks and oven utensils with the material. If you do melt silicone, you get a gooey mess, not a nice fluid you can push through an extruder nozzle. As for resin printing, silicone is resistant to UV so the chances of coming up with UV curable silicone are pretty small.

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Monowheel Mayhem: When Good Gyroscopic Precession Goes Bad

January 19, 2022 by Ryan Flowers 11 Comments

Since the dawn of the age of the automobile, motorheads have been obsessed with using as few wheels as possible. Not satisfied with the prospect of being incompletely maimed by a motorcycle, the monocycle was born. Gracing the covers of Popular magazines and other periodicals, these futuristic wheels of doom have transfixed hackers of all kinds. [James Bruton] is one such hacker, and in the video below the break you can see his second iteration of a 3d printed monowheel.

[James]’ wonderful monowheel is beautifully engineered. Bearing surfaces, gears, idlers, motors, and yes, twin gyroscopes are all contained within the circumference of the tire. The gyroscopes are actuated by a rather large servo, and are tied together by a gear that keeps their positions in sync. Their job is to keep the monowheel balanced at all times.

But as [James] discovered, the chief difficulty of only having one wheel isn’t lateral balancing. Ask any monocyclist and they’ll assure you that it’s possible. The real trick is balancing the machine fore and aft. Unlike a two wheeled velocipede, the monowheel has nothing to exert torque against save for a bit of gravity.

As [James] found out the hard way, it was within this fore-aft balancing act that the gyroscopic precession reared its ugly head. The concept is explained well in the video. We won’t spoil the surprise ending because the explanation and conclusion are quite good so make sure to watch to the end!

If you’d like to look at [James]’ first version, we covered it here. And if you’re the daredevil type, perhaps we can interest in you in a two stroke human sized monowheel that will probably end in an ER visit. At least they wore a helmet. Thanks to [Baldpower] for the tip!

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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.

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