The slicing device is composed of a piston that pushes the potato through a blades system. But as simple as this mechanism may seem, we have been struggling to build it for almost a week, as it has been way more challenging than we initially thought and problems arose at every step.
The first issue was the fact that the Lego motors we used for moving the arm are not very powerful, and even with a reduction we weren’t able to use them to move the piston and press the potato through the blades. However the solution for this was quite obvious: we used a more powerful motor, with a reduction of 1:139 and 3.8 W.
Then we had a lot of problems with the blades system. We initially tried to build it ourselves with two sets of cutter blades, hold together by a piece printed with the 3D printer. But even though the smaller version we built for testing purposes (it only had about 5 blades per set) worked fine, the real one didn’t because the blades bent. Then we tried to remove one of the sets of blades and see what happens, but they still bent. Here is how it looked after removing one of the sets:
The problem was that the blades were too tall and didn’t had enough resistance. So after a lot of searching on the internet, we came across something for sale that seemed to better fit our needs (and happily it arrived in just one day):
Working on the piston was not very hard but rather time consuming. Because of it’s dimensions and the high level of accuracy needed, it was not possible to print it with the 3D printer, so we decided to make it from wood. Here is the initial version of it, with the motor and some touch sensors already attached:
And the whole mechanism, potato included 🙂
But of course that the pistons’s teeth, which were designed for the first blades system, didn’t match with the second one. So we had to cut all of them off and recreate them, which took us another couple of hours since we only had a saw available in the laboratory.
This time the testing went fine, but unfortunately we didn’t had the time to film it. But we promise to attach the whole mechanism to the robot and upload some videos as soon as we can.