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Welcome back for the final time,
First of all, thank you for staying tuned this long. It has been quite a ride and we hope we have been able to give you a good (and not dreadfully boring) insight in our research. This will be our final post on the weblog, all that is left is the science fair next Tuesday.
That brings me to some very exciting news! We have succeeded in both UltiCasting and NinjaFlex printing. Next Tuesday we will have our UltiCaster running at the science fair, as well as a working prototype of the 3D printed exoskeleton for you to try out! If you are interested our process but have questions that are not answered in the weblog, we will be more than happy to share our knowledge next Tuesday.
In case you missed them, here are the details for the science fair.
Date: November 1st 2016, 12:30 – 16:00
Location: “De Tribune”, Central hall, Faculty of Industrial Design Engineering, TU Delft.
We have got a time lapse of the actual UltiCasting made in the picture above. Apart from that we don’t want to spoil to much just yet, so all that’s left for now is signing off.
Hope to see you next Tuesday flexi-friends!
Kind regards from Silicone Valley
Credits for this pun go to Jouke Verlinden
At Thursday 9.30 pm, we have concluded our first, complete, UltiCast. As our emotions of joy welled up like the silicons did in the overflow valve, we were tossed into an historical perspective that only Neil Armstrong could adeptly describe. This is a small step for one hacked UltiMaker 2+, but a huge step for UltiCast.
In all seriousness, we are stoked that we finally made UltiCasting work. Previously we have had major issues with the silicons curing inside the system, and consequently blowing up the tubing and covering our print head in silicons. This is why we redesigned the entire set up all over.
We have removed the right fan of the print head, to use that space for the nozzle. We had concluded that the mixed silicons settle faster when subjected to heat and one of the main reasons for our system to get clogged was the fact that our casting nozzle was right next to the heating element of the first extruder. Also we have once more increased the diameter of the mixing nozzle, and seeing we can now start mixing closer to the bed, we have shortened the mixing nozzle as well.
Not only the silicons proved to be though to work with, also the PVA had a will of its own. Getting the PVA to stick to the print bed proved to be a really big deal. After trying alcohol, window cleaner, vinegar and prayer, we found ye good old Pritt stick. The rest is history, we finished our first print and are waiting for the PVA to dissolve in water to see the final result. All in all, we did it, and we’ve got it on film.
To show the possibilities of FDM printing and UltiCasting soft robotics, we have looked for interesting fields in which the possibility for cheap 3D printing could prove valuable. This could be the case in the medical sector, especially with aided movement. Reducing the cost of treatment and support utilities is a goal that inspires us all, and soft robotics could, in the long term, be a big player in this progress.
This is why we have chosen to develop a 3D printed hand exoskeleton. This is in short a glove with soft robotics actuators to help move you fingers, visible in the concept drawing below. Possible applications in a completely developed product could be to assist people with arthritis, local paralysis, limited hand function or as supporting tool in rehabilitation. Our goal is not to create a finished product for next week, but rather to give a proof of concept showing the possibilities of 3D printing for soft robotics.
Good to see you again!
We are still quite unsure whether to call week 3 a success or a failure. Well at least there was some sort of progress. We didn’t quite meet last weeks goals due to some minor set backs including our UltiCast set up exploding, some burnt plastic and some broken parts. That being said, we are now ready to start UltiCasting again.
As you might have read in some of our earlier posts, we had to redesign the entire UltiCast set up to allow for bigger tubing and wider nozzles. After some cups of coffee and some flexible hours this seems to be about done. In the picture above Max is laying the final hand to the UltiCaster Mk. 2. This one is stylishly equipped with green aquarium tubing and features a new deposition system.
Due to the larger nozzle and tube size we are unable to do the static mixing inside the printer head. That is why we now mix our components before they reach the printer head, then feed them trough using a tube, and deposit them with a changeable nozzle. The advantages of this are the possibility to change nozzle diameter and the allowance of bigger tubing and nozzles. The disadvantages are that we still experience some leaking of silicons from the nozzle and we need to replace more parts after each print.
The script for the UltiCaster is almost finalized to our goal stadium. With huge assistance from our good friend, Robin Sveningson, we have managed to automate the slicing process and thereby generate a g-code containing commands for the fills operations, that can be interpreted by the Marlin firmware on the UltiMainboard. (read more about this in Methods). As soon as the hardware is ready we can start UltiCasting and kick back and relax. Hopefully.
As for the Ninjaflex FDM printing, well just look at that. We’ve never had a print that looks this promising in terms of quality so the settings should be right about perfect. So all that’s left is experimenting with some different geometries to get that real feel finger going.
Our focus now is to get our setup up and running, and prepare something cool for the science fair.
Hope to see you next week!
This article was 3D printed in the IDE Applied Labs Delft
Well the experiment did not fail, but it sure did not provide the desired results. “An absolute mess” it has been called, but from the gooey remains of our set up we have build the foundations of our new set up.
So what happened? Our initial UltiCast fears were confirmed when we tried to cast the silicons in our first full scale test. Due to the high viscosity (18,000 cps) of our silicon components, we had a huge pressure buildup when trying to use the second extruder. In reality we tried to push molten chocolate through a 1 meter flexible tube with a diameter of 4 millimeters, but you could imagine it to be like pushing wet concrete through a garden hose.
Needless to say soon we were all covered in silicons. Our tubes had burst under the pressure that was being build up. Due to a then discovered syringe flaw that lead us unable to retract the plunger and release the pressure from the tube, we discovered that the only thing we had created was a ticking silicon bomb. Luckily the silicons are skin safe so the damage was contained to a bit of clean up.
To counter these problems we have redesigned the UltiCast set up. First of all we now use bigger tubes and static mixing nozzles to reduce the friction created by the highly viscous silicon components. We have tried mixing the silicons in these wider pipes and they proved very successful.
.To be able to reduce the pressure on the pipes if needed, we have remodeled a part on the plunger to enable it to retract. This part still has to be tested in a full scale test, but also seems to be functioning correctly.
We are currently waiting for our final components to finish printing so we can do a second cast with UltiCast.
From moment one we were experiencing problems with our valve fittings. Turns out: our valves were to big for our fingers to handle. In the picture below you can see our first type of valve rupturing one of our fingers.
But then christmas came early! Our expert Rob Scharff supplied us with a bunch of different kind of valves we could test. He even tossed in some glue to make the seal as airtight as possible.
Below you can see the smallest valves glued to test prints. It turns out that not only the material does not rupture, but the seal itself is also completely airtight. This leads to most of the air leaking through the valves themselves. Turns out it’s not all about size on this one.
And that’s what she said!
Last Tuesday, the midterm presentations were held, in which we presented our progress thus far. Having brought all the prints that we have printed so far, the other advanced prototyping colleagues were given a chance to get a feel for the kind of ‘soft robotics’ we are attempting to develop. At the end of the presentation we were given some valuable questions about the adhesion of two different layers of the casted silicone, in case there was a significant time in between the castings. As we knew the curing time of the silicone is approximately 40 minutes, and therefore adhesion should not be a problem when casting in our setup. The silicon adhesion has been investigated however, and we have concluded that adhesion will not cause problems in the future as the layer adhesion was near perfect with a 40 minutes gap between the subsequent castings.
Week 2 has been a week of breaking parts, burning capacitors and freezing Ultimakers. In short: Progress. Not only have we been able to bypass multiple “FATAL ERROR”s, as they are called, we have been able to build an actual UltiCasting setup that is ready for extensive testing next week. We are currently still doing small scale tests with water to confirm the setup but we will be able to test the actual resins and start to actually UltiCast.
While the software for the UltiCasting is almost finished and the hardware is being tested as I write this. We’ve also been making strives on the FDM printing project. Our latest prints are almost completely airtight and are already functional. We do experience some issues with the valve fitting and the filament feed that still cause minor problems but today Christmas came early when our supervisor Rob Scharff brought us a care package.
New valve geometries are already being printed to try out our new goodies as we are planning to set up a new experiment to experiment with different actuator geometries, materials and valve fittings.
Our goals for next week are to set up an experiment to measure the effectiveness of all our different tried methods and to start UltiCasting. We are ready, the silicons are ready, and our UltiCaster is almost there.
See you next week!
Ulti-broad-Casted from: IDE Applied Labs