For most CNC machining RFQs, STEP (.stp / .step) is preferred because it carries solid model geometry without the ambiguity of older 2D-only workflows. IGES is acceptable for many parts, though surface trims and translations can occasionally introduce gaps that require cleanup.
Please also include 2D drawings (PDF) when tolerances, GD&T, threads, surface finish, or inspection requirements are not fully modeled. For turned parts, a drawing with section views and thread callouts is especially helpful.
If you only have mesh formats (STL), we can review feasibility, but prismatic and tolerance-critical parts are best quoted from precise B-rep solids. ZIP archives with multiple revisions should include a short note indicating which revision is current.
