Tuesday the 1st of November we had presented our work at the Science Fair at Industrial Design Engineering Faculty at TUDelft.
We would like to thank all who visited our stand for the attention, the interest and the good advise. We had a great time spreading the word about how we think 3D-printing can contribute to the field of Soft Robotics.
If you still have questions, or want to contact us it can be done by sending an e-mail to firstname.lastname@example.org.
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!