There needs to be more metrology-wise truth-telling about tolerances in the precision manufacturing business. The strut width variation, as noted above, is typically +/- 5microns (0.0002”). But a true tolerance has to take into account measurement system error and operator error in addition to part variation. For this reason, we recommend setting a tolerance of +/- 15microns (0.0006”) for laser-cut parts and +/- 20microns (0.0008”) for laser-cut and electropolished parts.
Of course, error varies from design to design, so these are just general recommendations. Design engineers usually blanch at such “wide” tolerances on narrow features, but experience shows that most performance specifications can be met with tolerances in this general range. Moreover, manufacturing and quality assurance engineering demand taking all the sources of variation into account when setting tolerances.
Lumenous can help you craft a design verification study that justifies your tolerance-setting and gets all the viewpoints (design, manufacturing, and quality assurance) onboard.