Dynamic Build Platforms For 3D Printers Remove Supports And Save Material

April 10, 2021 by Bob Baddeley 31 Comments

We’re all too familiar with the 3D printing post-processing step of removing supports, and lamenting the waste of plastic on yet another dwindling reel of filament. When the material is expensive NinjaFlex or exotic bio-printers, printing support is downright painful. A group at USC has come up with a novel way of significantly reducing the amount of material that’s 3D printed by raising portions of the bed over time, and it makes us wonder why a simpler version isn’t done regularly.

In the USC version, the bed has a bunch of square flat metal pieces, with a metal tube underneath each. The length of the tube determines the eventual height of that square. Before the print is made, the bed is prepared by inserting the appropriate length tubes in the correct squares. Then, during the print, a single motor pushes a platform up, and based on the height of the pin, that portion of the bed raises appropriately, then stops at the right height.

This is a significant savings over having a matrix of linear motors or servos to control each square, at the cost of having to prepare the pins for each print.

But it has us wondering; since CURA and other slicing software have the ability to pause at height, what if the slicing software could allow for the placement of spacer blocks of a known size? The user would have a variety of reusable spacer blocks, and position them in the software, and the slicer would build the support material starting on top of the block. It could print a rectangle on the base layer to aid in proper placement of the blocks during printing, and pause at the correct heights to let the user insert the blocks. At the end of the print a lot less support material has been used.

For situations where you want to leave your print to run unattended, or if the cost of the material is low enough that it doesn’t justify the effort, then maybe this isn’t worth it. Another problem might be heating that platform, though since only support material will be printed on it, some curling won’t matter much. What do you think?

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Solid Tips For Casting Colored Silicone Tires

April 5, 2021 by Donald Papp 13 Comments

For people who work with wheeled robots or RC vehicles, sooner or later one gets interested in making custom tires instead of dealing with whatever is available off the shelf. [concreted0g]’s preferred method is to design and 3D print wheel hubs, then cast some custom silicone tires to fit over them. Of course, the devil is in the details and this process can be a bit messy, so he’s shared useful tips on how to get reliable results with simple materials.

The casting material is cheap silicone caulking from a hardware store, and color can be added with a small amount of cheap acrylic paint. A few drops of glycerin added to the silicone thins it out slightly and helps it flow into a mold better. Mix well (the paint will also serve as a visual indicator of how well it is mixed), then scoop the mixture into the mold while trying to avoid creating air pockets. If your mold is in two pieces, assemble the mold and remove any overflow, then let it sit undisturbed for at least several hours while it cures.

Mounting the resulting tire to a wheel hub can be done with a thin film of super glue, which seems to work perfectly well for small tires and is easy to apply.

The rules are going to be a bit different for big objects. We know that silicone caulking can have difficulty fully curing when it’s applied thickly, especially when sealed into a mold with little to no airflow. In such cases, adding cornstarch (in about a 5:1 ratio of silicone to cornstarch by volume) is all that it takes to cure even thick wads of goop in less than an hour. Stirring cornstarch in tends to introduce more air bubbles into the mixture, but for larger pieces that can be an acceptable tradeoff. Cheap silicone caulking is versatile stuff, one just needs to know what to expect, and take a few steps to deal with the messiness.

Need something tougher? Maybe check out using slices of automotive silicone hose for robot wheels to get something that works just as well, but is a lot more durable.

3D Printer As Robot: The Functograph

April 3, 2021 by Al Williams 12 Comments

A 3D printer is really a specialized form of robot. Sure, it isn’t exactly Data from Star Trek, but it isn’t too far from many industrial robots. Researchers from Meiji University made the same observation and decided to create a 3D printer that could swap a hot end for other types of robotic manipulators. They call their creation the Functgraph. (Video, embedded below.)

Some of the tasks the Functgraph can do including joining printed parts into an assembly, breaking support material, and more. The surprise twist is that — unlike traditional tool change schemes — the printer prints its own end effectors together with the print job and picks them up off the build plate.

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Micro Quadcopter Designed In OpenSCAD

April 2, 2021 by Lewin Day 20 Comments

Quadcopters are fantastical things, and now come in a huge variety of flavours, from lithe featherweight racers to industrial-grade filming rigs worth tens of thousands of dollars. The Beatle-1 from [masterdezign] comes in at the smaller scale, and its body was created entirely in code.

To create the Beatle-1, [masterdezign] used OpenSCAD, a 3D modelling program that uses code rather than visual tools for producing geometry. Thus, with a series of Boolean operations, extrusions and rotations, a basic lightweight quadcopter frame is created in a handful of lines of text. Then, it’s just a simple job of 3D printing the parts, wiring up four Olimex F1607 motors and hooking up a flight controller and the little drone is ready for takeoff.

The Beatle-1 serves as not only a fun flying toy but also a great example of applying OpenSCAD modelling techniques to real-world applications. Parts are available on Thingiverse for those wishing to roll their own. 3D printed drone frames are popular, and we’ve seen a few around these parts before. Video after the break.

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Off-The-Shelf Parts Make A Tidy Heater For Resin Printer

April 1, 2021 by Lewin Day 6 Comments

Resin printers can offer excellent surface finish and higher detail than other 3D printing technologies, but they come with their own set of drawbacks. One is that they’re quite sensitive to temperature, generally requiring the resin chamber to be heated to 25-30 degrees Celsius for good performance. To help maintain a stable temperature without a lot of mucking around, [Grant] put together a simple chamber heater for his printer at home.

Rather than go for a custom build from scratch with a microcontroller, [Grant] was well aware that off-the-shelf solutions could easily do the job. Thus, a W1209 temperature control board was selected, available for under $5 online. Hooked up to a thermocouple, it can switch heating elements via its onboard relay to maintain the set temperature desired. In this case, [Grant] chose a set of positive-temperature coefficient heating elements to do the job, installing them around the resin chamber for efficiency.

The heater can preheat the chamber in under fifteen minutes, much quicker than other solutions using space heaters or heat mats. The time savings will be much appreciated by [Grant], we’re sure, along with the attendant increase in print quality. If you’re still not sure if resin printing is for you, have a read of our primer. And, if you’ve got your own workflow improvements for resin printing, drop us a line!

JIT Vs. AM: Is Additive Manufacturing The Cure To Fragile Supply Chains?

April 1, 2021 by Dan Maloney 46 Comments

As fascinating and frustrating as it was to watch the recent Suez canal debacle, we did so knowing that the fallout from it and the analysis of its impact would be far more interesting. Which is why this piece on the potential of additive manufacturing to mitigate supply chain risks caught our eye.

We have to admit that a first glance at the article, by [Davide Sher], tripped our nonsense detector pretty hard. After all, the piece appeared in 3D Printing Media Network, a trade publication that has a vested interest in boosting the additive manufacturing (AM) industry. We were also pretty convinced going in that, while 3D-printing is innovative and powerful, even using industrial printers it wouldn’t be able to scale up enough for print parts in the volumes needed for modern consumer products. How long would it take for even a factory full of 3D-printers to fill a container with parts that can be injection molded in their millions in China?

But as we read on, a lot of what [Davide] says makes sense. A container full of parts that doesn’t arrive exactly when they’re needed may as well never have been made, while parts that are either made on the factory floor using AM methods, or produced locally using a contract AM provider, could be worth their weight in gold. And he aptly points out the differences between this vision of on-demand manufacturing and today’s default of just-in-time manufacturing, which is extremely dependent on supply lines that we now know can be extremely fragile.

So, color us convinced, or at least persuaded. It will certainly be a while before all the economic fallout of the Suez blockage settles, and it’ll probably longer before we actually see changes meant to address the problems it revealed. But we would be surprised if this isn’t seen as an opportunity to retool some processes that have become so optimized that a gust of wind could take them down.

Moving Things With Electricity

March 29, 2021 by Al Williams 9 Comments

We use electricity to move things with the help of motors and magnets all the time. But if you have enough voltage, you can move things with voltage alone. As [James] found out, though, it works best if your objects — ping pong balls, in his case — are conductive.

He wanted to add a Van de Graaff generator to add to his “great ball machine” which already has some cool ways to move ping pong balls. However, to get the electrostatic motion, [James] had to resort to spraying the balls with RF shielding spray.

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