3D CAD Engineer — Precision Sacrificial Mold System (Patent-Stage)

Job Description I am developing a patent-stage consumer product that involves a precision two-component sacrificial foam mold system. The engineering is complete at the systems level. A detailed constraint brief, locked geometry, and full technical documentation are ready to hand over on day one under NDA. I have a solid background in 3D design and 5-axis CNC machining. I am not looking for someone to explain the basics. I am looking for a skilled solid modeler who can execute a well-defined engineering brief precisely — and who has the mechanical intuition to solve one genuinely novel geometry problem at the heart of this system. The core challenge in plain terms: One component of the mold system is a hollow curved foam shell that must be segmented into a three-dimensional jigsaw. The assembled jigsaw must be self-locking under inward compressive load during the casting process. After casting, every segment must be extractable through a constrained aperture — approximately 10 inches by 8.7 inches — without tools and without reaching inside the cast structure. The segmentation geometry, including a specific crown piece with a novel anti-uplift and wedge-free extraction geometry, is fully documented in the brief. The segmentation plan for the remaining shell segments is the open problem that requires spatial reasoning to solve in CAD. If that description made immediate sense to you and you already have a mental picture of the extraction sequence, we should talk. What You Will Receive After NDA A complete engineering brief package including all dimensions, functional requirements, geometric constraints, extraction aperture specifications, manufacturing tolerances, and reference drawings. The product category and application will be disclosed at that point. Phase 1 Deliverables 1. 3D solid model of the primary mold component — complete curved shell with solved segmentation geometry. All segments must pass through the extraction aperture in their optimal extraction orientation. The crown piece modeled to a specific documented geometry. Pull-cable attachment points and alignment features included. Drawn to final target dimensions — kerf compensation handled by the shop’s CAM software using a 3/8” cutter. 2. Interface option comparison — two interface options between mold sub-components to be modeled and assessed for machinability and shipping envelope. 3. Proportion renderings — scaled elevation views of three product sizes for design review. 4. Manufacturing file — STEP or IGES format ready for submission to a CNC foam pattern shop for quotation. Phase 2 (Contingent on Phase 1) Complete models for all three product sizes, secondary mold component models, full assembly model, exploded and section views for patent illustration, and bill of materials. Required Skills • Solid modeling in SolidWorks, CATIA, NX, or equivalent — complex curved surfaces, compound geometry, not prismatic parts • 5-axis CNC machining design experience — you understand witness marks, kerf compensation, draft angles, and what a foam shop can and cannot machine • Ability to evaluate extraction geometry — can a given segment clear a given aperture in a given orientation? This is the primary skill required for Phase 1 Preferred • Experience with EPS or soft material CNC machining design • Patent drawing or technical illustration experience Proposal Requirements I will only review proposals that directly answer these three questions: 1. Describe a specific complex geometry problem you have solved in 3D CAD — what made it difficult and how did you approach it. 2. Confirm your CAD platform and describe your 5-axis machining design experience specifically. 3. Based on the extraction geometry description above — what is your first question about how the segmentation problem should be approached? Proposals that do not answer all three will not be reviewed. I am not looking for the lowest bidder. I am looking for the right engineer. Terms • Hourly engagement — please quote your standard rate • Phase 1 is the initial commitment — Phase 2 follows on demonstrated performance • NDA required before any documentation is shared — this project is at the patent application stage and the product category will not be disclosed prior to NDA execution • Regular communication expected — screen shares and video calls to review geometry in progress This product has a clear commercial path and is being developed with patent counsel. The right engineer will have the opportunity to contribute to patent drawings and may have an ongoing role through prototyping and manufacturing.