A 3D-Printed Calculator Does Addition and Multiplication with Gears Instead of Electronics
Designing A Fully 3D-Printed Mechanical Calculator
A fully FDM-printed mechanical calculator performs addition and multiplication by setting digits and turning a hand crank. It uses no electronics; rotations through printed gears perform the calculation, including a mechanical carry mechanism.
3D All Workshop spent about two months developing the design. Because FDM-printed gears are sensitive to tolerances, the mechanism went through roughly one hundred design iterations before it worked reliably.
A cheap calculator can produce the answer instantly, but this one required roughly a hundred mechanical redesigns just to make the gears cooperate. Building the calculator is vastly more work than doing the calculation.