Office breaktime kit

The OBTK (Office Breaktime Kit) provides you with a construction toolkit that will turn idle time into a break that will improve productivity right after. It also allows organizing social activities and it therefore can contribute to team building if that is permitted and/or feasible under cover in your organization. You also can encourage trading and competition: Who can come up with a new toy / engine / exhibit or design a sliding game (tip: use whiteboard markers on your desk) ? Finally, squezzy elements can be used to prevent wrist tendinitis.

According to old-style management literature, most folks seem to "spend time inappropriately" at work, on a daily basis. Surfing on the Internet (either using work computers or private cell phones) seems to be most popular. Others rather defend the idea that workers need breaktime. In today's IT-intensive environments, idling on the Internet (e.g. worrying about FB status, new job opportunities and such) is not a good idea. Breaktime should be used to do something that is relaxing, fun and rather physical. Idle time should clear the mind, not clog it !

There are 6 elements which can be combined into various objects

- a half sphere with a hole, can also sit upside down

- an asymmetric wheel, can be used as support for a ball

- a beam with 4 + 3 holes, for constructing engines

- a short stick rounded on one side, for gluing, tip, and as handle

- a long stick rounded on one side, for gluing and as tip/handle

- a long stick that is thinner in the middle, i.e. an axle for the wheels

From these 6 elements people at your workplace can assemble various devices like spinning tops, table curling stones, bowling balls and pins, yoyos, wheels of fortune, racing cars, and more. Alternatively, they also could create stunning works of art (e.g. a black apple sandwich with a raspberry filling). This kit is also suitable for kids of an age where they stop swallowing little sticks.

The idea for creating this set came to me by "accident" after playing around with Arnitel (a very strong flexible filament) of which I bought a roll 2 years ago but had forgotten about (see http://edutechwiki.unige.ch/en/Arnitel for some information). I started playing with creating a squeezy half sphere and then wanted to make something that would allow playing with it. Since I also teach a bit of 3D printing and since it's always nice to be able to justify time spent on 3D printing in my office, I came up with the challenge of create a minimalist (but hopefully successful) construction kit that would allow to create cool little devices from just a few elements. Once I was done, I remembered that as a kid I played with "Matador" (http://en.wikipedia.org/wiki/Matador_(toy)).

All objects are very easy to print. There are only two challenges:

- Print as precisely and nicely as possible

- Prevent warping with plastics like ABS or Arnitel

Sticks: I suggest printing most sticks with flexible filament (e.g. Arnitel). Use strong fills for PLA (50%) and 10-50% for ABS or Arnitel. I used a raft for Arnitel stick printing, since it lessens the chance of having it ripped off the platform after some irregularity. With flexible plastic and PLA I suggest printing two sticks at a time. Else it may not cool enough between layers...

Wheels and half spheres: Print with any plastic and any fill (between 10-20% is probably best). Use only 5% filling for flexible plastic. Put "office" glue (e.g. "Pritt Power") on the platform for Arnitel or ABS, since the beam, half sphere and wheel will try to warp. Remove the glue before printing with PLA or it will stick too much !

Beam: I suggest either using ABS (or equivalent), or PLA with a strong fill (50%). ABS will have a strong tendency to warp, but the horizontal holes should help preventing this. Add more holes if you cannot use glue...

All-in-one: I don't suggest printing this because I'd change both plastic and slicer settings for sticks, the beam and the two larger objects...

Print speed and resolution can be anything. I suggest some kind of "medium 2.5mm layers" and 80mm/s for good quality. Printing much faster is also possible ....

Calibration:

Print a half-sphere, a beam and a long stick. If the long stick doesn't fit (after filing), make it smaller or larger. Creating construction kits with "normal" printers and slicers is quite difficult. Every setting (printer model, printer calibration, slicer settings, plastic, etc.) will produce slight variations. My models use the same width for holes and sticks that should fit inside since I observed that sticks somewhat shrink with my current setup...

OpenSCAD file:

It is somewhat parametrized code (disclaimer: I am not a programmer). You easily can calibrate the sticks. Making more radical changes, e.g. print everything on a smaller scale would require some re-coding or at least testing (which I did not).