Mechanical & Thermal Packaging

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Reliable power electronics demand more than electrical performance — they require optimized enclosures, thermal paths, and stress-tested integration.

Thermal stress is a leading cause of premature power-electronics field returns. Poor packaging leads to warping, vibration issues, delamination, or accelerated aging of components. At MarSum Solutions, mechanical and thermal packaging is treated as a core design pillar — not a constraint to fix downstream.

We model, design, and validate heat dissipation and structural robustness from the start. Whether you’re deploying in high-vibration environments, sealed housings, or high-power density systems, we ensure electronics remain within spec over their full service life.

Every thermal path in our systems is mapped, simulated, and validated — from die to ambient.

Thermal Strategy Layers:

• Junction-to-case modeling: Based on datasheet, FEM, and application-specific cooling
• Case-to-sink interface: TIM selection, flatness analysis, and contact pressure modeling
• Sink-to-ambient optimization:
  • Natural convection, forced air, liquid cooling
  • Heat pipe integration, cold plate design
  • Fan sizing via P–Q curves, altitude- and temperature-derated performance
• Thermal margin modeling: <6 °C junction rise at 30 A RMS with 250 LFM forced air
  

Tools Used:

• ANSYS® Icepak
• Siemens® Simcenter Flotherm™
• Ansys® Sherlock® (physics-of-failure reliability)
• SolidWorks® Flow Simulation
• Ambient profile modeling for power-stage dissipation
  

We quantify:

• RθJC, RθCS, and RθSA under all mounting orientations
• Hot spot localization and mitigation
• Transient thermal and power-cycling fatigue for wire-bond and solder joint durability

We design enclosures that protect electronics from vibration, contamination, mechanical shock, and environmental exposure.

Key Enclosure Elements:

• Custom-machined and die-cast enclosures (aluminum, composite, hybrid)
• Injection-molded plastic housing with integrated standoffs and seals
• Internal standoff, PCB mounting, and strain relief design
• Connector selection and panel-mount mechanics
• Gasket sealing for IP-rated ingress protection (IP54–IP67, IP6K9K, NEMA 4X/6P when required)
• Screw torque analysis and retention features (e.g., thread-lockers, captive fasteners)
• Shock-absorbing layouts and thermal-expansion buffers
  

We deliver:

• 3D CAD models with critical dimensions and tolerancing
• Manufacturing drawings for CNC, molding, or extrusion
• Assembly instructions and interface callouts
• Cable routing and connector strain relief documentation

We build ruggedization into the packaging — not as an afterthought, but as a requirement.

Ruggedization & Reliability Techniques:

• Thermal cycling accommodation: expansion joints, compliant interfaces
• Vibration isolation: elastomer mounts, floating boards, mass damping
• Shock mitigation: fastener strategy and housing mass distribution
• Sealing and protection: potting, conformal coating, ePTFE/PP membrane vents for pressure equalisation
• Material selection for chemical, UV, and corrosion resistance (ASTM B117 salt-fog, UL 94 V-0)
• Reliability growth planning, FMEA, and accelerated life testing
  

Validation Tools & Standards:

• Ansys® Sherlock reliability prediction
• FEA for stress and fatigue analysis
• SAE J1455, ISO 16750-3/-4, IEC 60068-2-6/-14, MIL-STD-810H compliance testing
• Passed ISO 16750-3 random vibration: 10 g RMS, 8 hr/axis with no resonance shift

Mechanical integration must align with thermal paths and electrical constraints.

Integrated Design Elements:

• PCB stackup and stiffening for high-G environments
• Power module-to-heatsink interface detailing
• Clearance and creepage management
• Connector breakout boards and interface shields
• Heat spreading layers, copper coin insertion, and IMS baseplates for board-level spreading
• EMI shielding tied to mechanical ground through low-impedance paths
  

We provide:

• Assembly stack-up drawings with allocated tolerances
• CAD-native models for supplier and fab coordination
• Cross-domain simulation data (thermal + structural + electrical)

We design for manufacturability, assembly, and repeatability from day one.

Production-Ready Deliverables:

• DFM reviews with CNC, injection mold, or casting vendors
• GD&T-based drawing generation
• Assembly fixture and QC point planning
• Machining specs: flatness, surface roughness, anodizing finish
• TIM application maps and torque specs for mounting hardware
• BOMs for thermal/mechanical parts and custom fixtures
• Prototype and tooling support for rapid iteration