Since the start of the project, our team members have been working on building the individual sides of the fidget cube. We have designs for a ball bearing, buttons, slider, joystick,pen holder and some surface texture experiments. The first issue we have come across was the tolerances of the parts, especially with the ball bearing and slider design that include moving parts. With each iteration, we are increasing the sizes of the tolerances to prevent the fusing of the moving part to the side wall. The tolerancing will have to be adjusted for each moving component, but for now, we are making the spacing around .2 mm.
Bearing
This side of our fidget cube is meant to act like a ball bearing. It will give the user something to spin in their hand and keep busy. From previous iterations of this design, we have found that sloped supports work better than a curved housing for the desired spinning motion by having fewer contacting surfaces. Additionally, we are able to print this support structure without requiring the use of support material, further increasing surface finish and allowing for a better bearing surface. We have found from previous attempts that we will require a minimum of 0.2 mm of clearance between moving points. Therefore, this was design, with a minimum clearance of 0.28mm should provide adequate movement.
Slider
One surface of the cube will be a revolving dumbbell that freely slides insides of a circular path. This was attempted last week, but the smallest diameter of the dumbbell broke under a small force. This week, this diameter will be increased. Keys were also added to the sides of the part so that it can be mated into the final assembly.
Surface texture
One non-mechanical side of the Fidget Cube will serve as a textured element. 36 hemispheres will protrude from the surface. The final texture will be determined by the print speed and layer height, in addition to any post-processing such as sanding.
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Joystick
Another non-mechanical side is the joystick which will be printed out the flexible material to allow for movement of the joystick itself. While tolerance is not the issue, buckling of the material and flexibility of the joystick will have an impact in the final product in order to fulfill the “fidgety” behavior.
Buttons
The design below is targeted at those that like to click the button on a pen. The clicking noise can be very distracting and even irritating to some. The idea behind this design is to satisfy the desires of those who like to click the button on a pen while also pleasing those who are effected by the noise it creates by making the buttons completely silent when pressed.
Pen holder side
This side is supposed to be an adapter to a pens of different diameters. The pen goes inside the cube through the holes such that the cube can be rotated about the pen.
This side has 5 holes of different diameters. All dimensions are in inches.
The following are approximate dimensions in inches of the top and side views.
The dimensions are chosen so that the pen doesn’t clash with any other side.
Exoskeleton for Assembly
The next phase of our design will be to add the final touches to the assembly, making sure everything fits together nicely in the final cube assembly. While we have worked on each of the sides individually, we need to make sure that the sides will fit together in the cube holding structure that holds the individual sides of the cube together using the key and notch technique. While we are experimenting with printing the sides of the cube, we also are experimenting with the assembly to make sure it fits nicely together.
