Soft Robotics Hack Chat

October 25, 2021 by Dan Maloney No comments

Join us on Wednesday, October 27 at noon Pacific for the Soft Robotics Hack Chat with Ali Shtarbanov!

By this point in technological history, we’ve all been pretty well trained in how to think about robots. Designs vary wildly, but to achieve their goals, most robots have one thing in common: they’re rigid. Whether it’s a robot arm slinging a spot welder on an assembly line or a robot dog on patrol, they’re largely made of stiff, strong, materials that, more often than not, are powered by electric motors of some sort.

But just because that’s the general design palette for robotics doesn’t mean there aren’t other ways. Robots, especially those that are intended to be used in close association with humans, can often benefit from being a little more flexible. And that’s where the field of soft robotics shines. Rather than a skeleton of machined aluminum and powerful electric actuators, these robots tend more toward silicone rubber construction with pneumatic activation. Some soft robots are even compliant and safe enough to be wearable, giving humans the ability to do things they never could before, or perhaps restoring functions that have been lost to the ravages of entropy.

Soft robotics is a fascinating field with the potential to really revolutionize things like wearables and collaborative robotics. To help us understand a little more about what’s going on in this space, we’re pleased to welcome Ali Shtarbanov to the Hack Chat. Ali is a Ph.D. student at MIT’s famed Media Lab, where he studies Human-Computer Interaction. He’s particularly interested in making soft robotics as fast and easy to prototype as traditional robotics have become, and to this end, he invented FlowIO, an open-source platform for pneumatic control. We’ll use this as a jumping-off point to discuss the whole field of soft robotics, especially where it is now and where Ali sees it going in the future.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, October 27 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

Expanding On The Creation Of Collapsible Containers

September 30, 2021 by Kristina Panos No comments

You might remember that industrial designer [Eric Strebel] tried to make a collapsible silicone container with 3D printed molds a few weeks ago, and was finally successful after dozens of attempts. Someone commented that commercial containers are molded in the collapsed position instead of the expanded position, so naturally, [Eric] had to try it once he saw the photographic proof of these molds.

This time around, [Eric] made things easier on himself by adding some handles to the mold and using both wax and spray mold release before pouring in the degassed silicone. The first one was a failure — he had let it cure the whole time in the collapsed mold, and it just didn’t want to stay expanded. On the second attempt, [Eric] decided to pull the piece while it was curing, about 5 1/2 hours into the process.

After carefully de-molding the piece, he pressed it into the grooves of one of the older molds from the days of molding containers in the expanded state. Then he filled it with sand and let it cure the rest of the way. That worked out quite well, but even so, [Eric] made a third attempt that he pulled after 3.5 hours or so when the silicone was still sticky. He did the sand trick again, but this time, he ran a piece of string up the wall and over the edge so that the air that gets trapped under the sand can escape. The final result looks great, albeit a little bit floppy, but [Eric] fits the final product into a frame that makes them much sturdier. Check out the process in the video after the break.

Did you miss the first installment? It’s worth a look into the science of creating collapsible walls.

Continue reading “Expanding On The Creation Of Collapsible Containers” →

Injection Molding Silicone Parts For Under $50

September 5, 2021 by Lewin Day 14 Comments

You’ve likely seen many tutorials on making silicone parts using 3D printed molds online. The vast majority of these methods use a simple pour method to fill the mold. This relies on careful degassing and gentle pouring to reduce the presence of bubbles in the final result. [Jan Mrázek] has been working on an alternative method however, that allows for injection molding at low cost in the home shop.

The process relies on the use of printed resin molds. [Jan] notes that this generally necessitates the use of condensation-cure silicones, as additive types don’t cure well in resin molds. The condensation silicone is mixed up, degassed, and poured into a standard cartridge. From there, it’s installed in a silicone delivery air gun, which uses compressed air to force the silicone out of the nozzle and into the waiting mold.

It’s basically using a bunch of home DIY gear to create a cheap injection molding solution for silicone parts. [Jan] notes that there are a few mods needed to mold design to suit the process, and that 400-800 kPa is a good pressure to inject the silicone at.

Having the silicone injected under pressure is great for complex mold designs, as it forces the material into all the little difficult nooks and crannies. Of course, we’ve seen other methods for making silicone parts before, too. Be sure to sound off in the comments with your own favored techniques for producing quality silicone parts. Video after the break.

Continue reading “Injection Molding Silicone Parts For Under $50” →

‘Quiet On The Set’ Goes For Objects, Too

September 4, 2021 by Kristina Panos 10 Comments

Unless you’re sonically savvy, trying to sleep, or simply on edge, you probably don’t realize just how noisy common items can be. Pretty much everything makes enough racket to ruin a sound man’s day, or at the very least, their chance of picking up the dialogue between two characters. What you need on a set are noiseless but realistic versions of common noisemakers like paper bags, ice cubes, and to a lesser extent, billiard balls.

If you’ve spent any time at all on Reddit, you’ve probably seen frustratingly short GIFs of [Tim Schultz] quickly explaining how this or that noiseless prop is made. Embedded below is a compendium of prop hacks with more information worked in along the way. Talk about dream job! Problem solving and then hacking together a solution for a living sounds terrifying and delightful all at once.

Speaking of terrifying and delightful hacks, there’s still plenty of time to enter our Halloween Hackfest contest, which runs through Monday, October 11th. Halloween is the best time to go all out, so show us what you can do!

Continue reading “‘Quiet On The Set’ Goes For Objects, Too” →

The BornHack Badge Gets A Bubble

September 3, 2021 by Jenny List 2 Comments

In a year of semiconductor shortages it’s a difficult task to deliver an electronic conference badge, so this year’s BornHack camp in Denmark had an SAO prototyping board as its badge. Some people made blinkies with theirs, but that wasn’t enough for [Inne] who had to go a step further with a light-up pneumatic bubble badge. It’s based upon a previous project producing silicone inflatable bubbles, but in a portable badge form.

On the front of the PCB is a multi-colour LED for illumination, while on the back is a small microcontroller board, a pressure sensor, and a motor driver circuit. A small air pump and battery sits in a pocket connected by a cable and a flexible tube, allowing the bubble to inflate at will. An interesting detail was the use of a cut-down hypodermic needle to carry the air through the silicone wall of the bubble. When seen up close at the camp it was an unnervingly organic effect, if there’s an uncanny valley of badges this is it.

We don’t see much in the way of soft robotics on these pages, so this happy crossover with BadgeLife is a special treat. It’s not entirely alone here though.

Casting Silicone Parts With 3D-Printed Inserts For Stiffness

August 17, 2021 by Donald Papp 8 Comments

Prolific maker [Jan Mrázek] shared his process for casting soft silicone parts that nevertheless have some added stiffness, which he accomplished by embedding porous, 3D-printed “ribs” into the pieces during the casting process. The 3D-printed inserts act as a sort of skeleton, and as a result, the parts have a soft silicone surface but gain structure and rigidity that simply wouldn’t be obtained if the part were cast entirely in silicone. The nice thing is that no new materials or tools were needed; [Jan] 3D printed both the molds for the parts as well as the structural inserts. It’s always nice when one can use the same tool and materials to accomplish different functions.

The parts [Jan] is making are interesting, as well. He observed that the process of swapping resin in his printer’s build tank was an unpleasant experience for a number of reasons, chief among them being that resin is sticky and messy, and the shape of the build tank doesn’t make pouring resin from it a clean job.

His solution was to design a pour spout that could be pressed onto the build tank, and some specially-designed squeegees to allow scraping the tank clean with ease. Silicone is the ideal material for the parts because it turns out that sticky resin beads nicely on silicone’s surface. Anywhere else, resin tends to spread out and form a sticky mess, but on silicone resin it forms tidy drops and is much easier to clean up.

It’s a technique worth keeping in mind, because one never knows when it could come in handy. Fabricating soft robots for example tends to involve silicone casting and clever techniques. See [Jan]’s parts in action in the video, embedded below.

Continue reading “Casting Silicone Parts With 3D-Printed Inserts For Stiffness” →

How To Make A Collapsible Container Without Breaking Down

July 5, 2021 by Kristina Panos 5 Comments

How hard could it be to make a collapsible silicone container? Turns out, it’s really, really hard — collapsible containers have rigid guidelines. Just ask [Eric Strebel], who failed dozens of times before finally getting it right (video, embedded below).

[Eric] started with an SLA-printed two-part mold and a silicone formulation with a Shore durometer of A 40 — this is the measure of hardness for silicone, polymers, and elastomers in the sense that the piece will resist indentation. The first twenty-four attempts all came out looking great, but not a single one of them would collapse and stay collapsed.

Eventually, [Eric] went back to the drawing board and played with the angles of the flex points, the thickness of the living hinges, and the wall thicknesses, which have to be strong enough to stay collapsed.

For attempt #25, [Eric] took the part out of the mold about three hours in and tried curing it in the collapsed state. Persistence paid off, and the part finally collapses and stays that way. Get yourself some popcorn and check out the fail-fest after the break. You know what we always say — fail fast, fail often.

[Eric] has made many molds both from silicone and for silicone. Some of them are really big!

Continue reading “How To Make A Collapsible Container Without Breaking Down” →