# RPS / Max - fabrication request and scope

Please review the frozen Concept 28 R3.1 finished-part CAD for a first urethane-cast prototype set, with separately made metal, flexible, optical and sheet components. Preserve the approved exterior and core 78 x 150 x 24 mm shell size. Confirm proposed process/material substitutions and any geometry changes before fabrication; quote quantity and lead time separately because no casting order quantity is set here.

The supplied 93 STEP files are finished nominal part geometry, not compensated mold masters. Do not apply R1 shrink masters to R3.1. RPS should recommend resin grade, casting shrink allowance, parting, gates/vents, moldability/draft, minimum walls, attainable tolerances and finishing for this exact revision. Any finished-part changes become R3.2. Process-only tooling geometry should carry its own tooling identifier and identify R3.1 as its finished-part source.

Rigid shell/carrier/keeper intent is an impact-tough rigid urethane prototype; agree hardness and dimensional capability with RPS. The warm-grey rim and smooth ember grip require a compatible flexible elastomer (85A is the inherited starting target, not an approved resin grade). Soft pads/contacts require measured free/installed thickness and compression/attachment trials. The local 0.40 mm volume-holder lip, small pins, blind screw floors, side openings and lens seat need explicit process review. Do not infer production tolerances from decimal precision in CAD.

Separate 304 stainless play cap/bezel, natural satin 6061 aluminium volume caps, purchased graphite woven mesh/scrim and clear optical polymer are not opaque urethane/PLA jobs. Confirm finishing and edge treatment on samples. The mesh CAD rods illustrate bought-in stock, not 92 individual rod jobs. Shell metallic appearance, if explored, is a finish study subject to RF checks; default frozen appearance is Chalk Ember.

The print demonstrates shape only to the extent reported by the owner. Before a repeat casting batch, use the first article to establish closed-shell button return/travel, screw retention, PCB/U6/battery/wiring clearances, optical output, acoustic response and cellular RF/thermal performance. The inspection form records acceptance rather than assuming it.