Title: Senior Mechanical Engineer (ME): Rugged DFM Enclosure & LSR Overmolding (Phase 1 Trial)

Project Context: We are upgrading the structural architecture of a high-speed electromagnetic actuator driver used in rugged industrial test rigs. The device consists of a central PCBA and a high-rate Lithium Polymer battery, which must be fully protected from extreme mechanical stress and drop impacts. We are implementing a "Dual-Layer Bento Box" architecture: 1. An internal rigid PC/ABS inner capsule (housing the battery, PCBA, and RTV potting). 2. An external, soft LSR (Liquid Silicone Rubber) overmolding jacket. Before awarding the full 3D CAD modeling contract, we require a Phase 1 Paid Trial ($50 - $100) to validate your DFM (Design for Manufacturability), structural mechanics, and injection molding expertise. The Phase 1 Trial Scope (Conceptual Design & Problem Solving): Challenge 1: The "Z-Axis Crush" Defense (Exoskeleton & Standoffs) * Context: The PC/ABS inner capsule must withstand a sudden 1,000 Newtons (approx. 100 kg) external vertical compressive force without deflecting and crushing the soft-pack battery inside. The battery thickness is 5.0mm. * Task: Sketch/describe your internal ribbing strategy for the top cover and the layout of internal load-bearing standoffs (pillars). How do you ensure the PCBA (which acts as the bottom floor) does not flex, and the 0.4mm air clearance above the battery is never breached? Challenge 2: The FPC Gateway & RTV Sealing * Context: The PCBA inside the hard capsule needs to connect to two external copper coils (embedded in the outer LSR silicone) via FPCs (Flexible Printed Circuits). The inner capsule will be potted with liquid RTV silicone (which cures at room temp) before the final LSR overmolding. * Task: How do you design the FPC exit gateway on the PC/ABS side wall to ensure zero RTV leakage during the potting process, while preventing FPC sheer stress? (e.g., labyrinth seal, stepped groove, etc.) Challenge 3: Z-Axis Stack-up Audit * Context: The absolute maximum thickness of the entire assembly at the center ridge is strictly 11.0mm. * Task: Review our provided 12.0mm layer-by-layer stack-up list (will be shared upon hiring) and identify any unrealistic injection molding wall thicknesses or LSR tolerance risks. Challenge 4: The "Optical Illusion" Surfacing (Aesthetic DFM) * Context: While the central ridge is allowed to reach 12.0mm thick to accommodate the battery and standoffs, the user's perception of thickness must be defined by the edges. * Task: How do you approach the CAD surfacing (e.g., G2/G3 continuity) to transition from a razor-thin 1.5mm LSR edge to the 12.0mm central hub? Briefly explain how you would handle the draft angles and parting lines for the LSR overmolding to maintain this "Apple-style" seamless edge illusion. To Apply: Start your proposal with the word "EXOSKELETON". Briefly explain your approach to Challenge 2 (The FPC RTV Seal). Generic responses will be instantly declined. If your DFM logic aligns with factory realities, we will fund the Phase 1 milestone immediately.