Design decisions

Cross-cutting rationale. Module-specific rationale lives on each module page. Documenting why is what makes this replicable rather than merely imitable — if your constraints differ from ours, these are the decisions to re-evaluate.

The registration-critical path contains no moving optics

The laser serves two functions: mask micromachining (via galvo) and target ablation (via the ablation scanner). Path switching is done by a mirror inserted into the beam to divert it to the scanner. The asymmetry is deliberate: the galvo path — which defines the mask coordinate frame and therefore the registration of every layer — is optically static during a full fabrication run. Switch-mirror insertion repeatability only perturbs the ablation path, where beam pointing is uncritical because the scanner rasters over the target anyway.

One laser, two jobs (and a third)

A single 1064 nm fibre source performs machining and ablation, which halves the cost of the most expensive subsystem at the price of the switching optics and of accepting an ablation wavelength/pulse regime that is not ideal for all target materials (). Additionally, with the galvo slid aside on its rails, the machine works as a conventional laser engraver for substrate cutting and general fabrication.

Mechanism-in-chamber, dumb chamber

All motion and registration intelligence lives in the removable main mechanism; the chamber provides only environment and wall crossings. This makes the vacuum system substitutable (see its procurement guide) and the mechanism serviceable on the bench.