Hasso-Plattner-Institut
Prof. Dr. Patrick Baudisch
  
 

Kerf-Canceling Mechanisms: Making Laser-Cut Mechanisms Operate Across Different Laser Cutters

Thijs Roumen, Ingo Apel, Jotaro Shigeyama, Abdullah Muhammad, and Patrick Baudisch

Getting laser-cut mechanisms, such as those in microscopes, robots, vehicles, etc., to work, requires all their components to be dimensioned precisely. This precision, however, tends to be lost when fabricating on a different laser cutter, as it is likely to remove more or less material (aka “kerf”). We address this with what we call kerf-canceling mechanisms. Kerf-canceling mechanisms replace laser-cut bearings, sliders, gear pairs, etc. Unlike their traditional counterparts, however, they keep working when manufactured on a different laser cutter and/or with different kerf. Kerf-canceling mechanisms achieve this by adding an additional wedge element per mechanism. We have created a software tool Kerf-Canceler that locates traditional mechanisms in cutting plans and replaces them with their kerf-canceling counterparts. 

This laser-cut microscope (based on thingiverse id: 31632) contains three types of mechanisms that allow the microscope to adjust focus. By using kerf-canceling mechanisms, the focus adjustment operates reliably, independent of how much material the laser cutter that produced the microscope removes (kerf).

(a) The kerf-canceling bearing. (b) when the model is cut with more kerf, the inset gets smaller while the cutout gets wider. (c) the resulting inset falls out (d), however the self-similar shape of the inset makes that it always jams when rotated in place, even as kerf gets bigger.

Kerf-canceling bearings fit their axle under variation of a wide range of kerf (by eroding the model). Even when cut on a milling machine with much more kerf.

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