Mechanical Multiplier (Compliant Mechanism)

This is my prototype of a fully functional one-piece mechanical multiplier made entirely as a compliant mechanism. No electronics or screws or assembly. It is just one 3D-printed part that can actually multiply numbers!

As far as I know this is the world's first fully functional, one-piece 3D-printed mechanical multiplier based entirely on compliant mechanisms.

How does it work?

The idea is inspired by the principle of a traditional slide rule. Instead of using gears or electronics the calculator uses two sliding inputs.

Each input can be set to 0, 1, 2 or 3. Their movements are mechanically combined and a pointer at the bottom indicates the result of the multiplication.

For example set A to 2 and B to 3 and the pointer indicates 6.

What makes this design cool in my opinion is that all the movement is achieved using flexible structures instead of conventional joints. Even the input positions are maintained by integrated flexible detents.

Some technical details:

• Dimensions: 100 × 100 × 4,8 mm

• One single part with no assembly required

• Two numerical inputs (0–3)

• 16 possible input combinations

• Multiplication results from 0 to 9

• Integrated flexible springs and detents

• Completely mechanical

How to use it

1. Set A: Hold the outer frame and move the large A handle sideways until the upper indicator points to your desired number (0–3).

2. Set B: Hold the A handle in place and move the B slider relative to it. The second indicator shows the selected number.

3. Read the result: The pointer at the bottom indicates the product on the result scale. The wider marked area represents zero.

4. Reset: Carefully return both sliders to the leftmost parking position (P). This is the resting position, not a numerical input.

That's it! You can now multiply two numbers without any electronics :)

How do you print it?

I recommend starting with the following settings:

• PLA

• Layer height: 0,2 mm

• Infill: 100%

Please also notice, that the distance between the elements that lock into each other is quite narrow when you print it. It is possible that it melts together, if that happens just seperate it with a razor blade or something similar.

Be careful when operating the mechanism for the first time and please don't pull directly on the thin flexible sections or force the sliders if they don't move freely!

Have fun experimenting!

If you print one yourself, I'd love to see your results! Feedback, suggestions and ideas for improvements are always welcome.

I hope you have as much fun with it as I had designing it :)