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THE UN-
DEFINED

The Problem

A robotics OEM was developing an outdoor autonomous platform. Their existing embedded controller was housed in a commercial off-the-shelf ABS box that couldn't meet IP67, had no EMI mitigation, and was running 18°C above the controller's maximum ambient specification at 40°C outdoor temperature.

They needed a custom housing designed for die casting in aluminium — IP67 sealed, with integrated heat spreader features, cable gland bosses, and EMI shielding slots — within 8 weeks to meet their pilot build schedule.

Engineering Approach

We started with a thermal model using ANSYS Steady-State Thermal to establish the heat flux path from the PCB through the housing to ambient. This drove the placement of cast-in fin features on the base and the selection of AL6061-T6 for its thermal conductivity (167 W/m·K).

For IP67 sealing, we designed a precision machined groove on the lid parting line for a silicone O-ring (shore A 70), with a compression ratio of 18–22% — verified against Parker O-ring design guidelines. Cable gland bosses were designed with a 2° draft for casting and a secondary CNC op for the M20 PG thread.

EMI shielding was achieved through four interlocking boss features at the corners of the lid seam, providing a continuous conductive path when torqued to specification. GD&T datum scheme was set to the machined base face (Datum A) and two tooling holes.

Outcome

The design passed IP67 ingress testing on first-article. Peak PCB temperature reduced from the OEM's existing 62°C to 44°C in 40°C ambient — an 18°C improvement. The casting was first-time good from the tool, with no ECOs required after initial sampling. Total design to production-ready drawing: 7.5 weeks.

The Problem

A robotics startup was developing a 6-DOF collaborative robot arm for light industrial pick-and-place. Their baseline concept — a welded mild steel frame — passed static load cases but the fatigue simulation showed failure at 280,000 cycles against a 1M cycle target. The frame was also 3.2kg overweight for the payload-to-weight ratio requirement.

Engineering Approach

We performed a full ANSYS Static Structural analysis of the baseline design under worst-case loading — maximum payload at full reach at 90° from vertical. Stress concentration at the joint between link 2 and the shoulder was identified as the primary failure location (σ_max = 248 MPa, SF = 0.82 against endurance limit).

Redesign focused on three areas: gusset geometry at the shoulder joint to redistribute load; wall thickness optimisation through parametric sweep to reduce mass while maintaining stiffness; and material upgrade from mild steel to 4130 CrMo for the primary links — improving fatigue strength from 310 MPa to 460 MPa.

Outcome

Final design achieved σ_max = 142 MPa with a fatigue safety factor of 1.62 at 1M cycles. Total frame mass reduced by 18% (580g) relative to baseline. All weld joints designed to AWS D1.1 standards with full penetration specification on primary load paths.

The Problem

A laser instrumentation company needed to replace a friction-clamped lens mount that showed 4–8μm position drift after each removal and reinstallation. Their process required frequent lens swaps, and the drift was introducing misalignment in their beam path.

Engineering Approach

The solution was a three-ball kinematic coupling — a classic precision engineering approach where three balls seat against three V-grooves to provide deterministic, repeatable location. We designed the mount in SS316L for low thermal expansion and corrosion resistance, with the ball-groove geometry calculated to achieve the theoretical repeatability of under 0.5μm.

The outer thread was designed as a standard M60×1.0 to match the company's existing C-mount infrastructure. Spring preload was selected to ensure positive seating under vibration without inducing Hertzian contact stress beyond 40% of material yield.

Outcome

Measured repeatability on first prototype: 0.3μm RMS over 50 removal/reinstallation cycles. The customer reported zero beam path realignment required after lens swaps — eliminating a 25-minute recalibration step from their process.

The Problem

A drives manufacturer's existing 22kW VFD chassis had two critical issues: a thermal hotspot at 108°C on the IGBT mounting interface (8°C above the component's maximum junction temperature derating point), and a 32-screw assembly that was adding 14 minutes to their production line cycle time.

Engineering Approach

Thermal redesign focused on the IGBT mounting surface — replacing a flat bolted interface with an integrated cold-plate channel design that directs airflow across the component. Fin geometry was optimised for the available 80mm fan airflow using CFD analysis, adding 340cm² of effective surface area.

DFA rationalisation replaced 24 M3 screws with a snap-fit rail system requiring only 8 M4 captive screws for final torque-critical connections. The snap-fit geometry was designed for 10,000 cycle fatigue life and 3mm deflection during assembly without permanent set.

Outcome

Peak IGBT interface temperature reduced from 108°C to 94°C — 14°C improvement, well within the derating threshold. Assembly time reduced from 22 minutes to 8 minutes. The sheet metal design was fully DFM-checked for laser cutting and brake pressing with zero secondary ops required.