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🇺🇸 U.S. Oil & Gas Client | Integrated Welding and CNC Machining of Structural Frames for Offshore Skid Systems

Project Background

  Project Background

This case study highlights our expertise in copper heat sink machining for industrial power electronics.In Q4 2024, we were approached by a UK-based electronics manufacturer specializing in industrial power modules and rail inverter systems. The client was developing a new high-power rectifier system and urgently needed a precision-machined copper heat sink with tight tolerances, excellent thermal conductivity, and high structural integrity.After facing repeated issues with three previous suppliers—mainly deformation, surface tool marks, and poor assembly fit—the client contacted us via LinkedIn and our website. After technical discussions and reviewing our past capabilities in copper CNC machining and thermal component fabrication, they decided to move forward with a prototype order.

Client Requirements

The client provided 3D drawings and technical specifications for three aluminum alloy components, with the following key requirements:

 

Item

Description

Product Type

Welded structural steel frames + machined interfaces

Final Use

Subsea control module platform

Material

ASTM A36 plate + 4140 alloy inserts

Tolerance

±0.02 mm on bore centerlines, ≤0.15 mm flatness across span

Size (per frame)

1020 mm × 720 mm × 460 mm

Quantities

Pilot lot: 3 sets → Batch series: 12 sets / quarter

Surface Treatment

Blasted + epoxy coated (offshore marine coating)

Lead Time (Pilot Lot)

20 working days from drawing approval to dispatch

Documentation Required

Weld map, WPS/PQR, dimensional inspection, material certs

Key Technical Challenges

1️⃣ Large Welded Structure Flatness Control

Maintaining flatness across wide steel base plates is always challenging due to thermal distortion. The client required maximum deviation under 0.15 mm after welding and machining.

2️⃣ Precise Hole Positioning Over Welded Assemblies

Some interfaces required mounting hydraulic panels with multiple aligned through-holes—spanning from one steel sidewall to another. Hole-to-hole spacing tolerance was ±0.02 mm.

3️⃣ Repeatability Across Units

Unlike one-off fabrication, this project demanded consistent part-to-part accuracy across batches. Hole spacing, bolt pattern alignment, and base plate flatness needed to be identical across all units.

4️⃣ Minimizing Multi-vendor Communication Loops

The customer previously spent excessive time coordinating schedules and drawings between welders, heat treaters, machine shops, and coaters. They needed a single partner who could own and execute the whole process.

Challenges & Solutions

One-Stop Fabrication + Machining

All steel plates were cut and pre-machined in-house from ASTM A36 using CNC plasma and mill.

Welded frames were fabricated by ASME-certified welders using proprietary jigs to control deformation.

After welding, each unit was stress-relieved at 620°C in our local heat treatment facility.

Final precision machining was done in our double-column CNC center using Renishaw probing to set datums and align bores.

Critical dimensions—bolt hole positions, slot widths, bearing surfaces—were all CNC milled within target tolerances.

We created dedicated inspection jigs and datum fixtures to ensure identical setup conditions for each frame.

Inspection data was recorded and reviewed per unit for SPC (statistical process control) purposes.

Lessons from the first lot were locked into CAM and fixture setup, eliminating variance in the next production cycles.

The client noted that our one-source model saved them 3–4 days of handling and transport per unit, and simplified their quality management workload.

Ryan McAllister
Ryan McAllister— Senior Project Engineer, Offshore Controls Division
“These assemblies dropped right into our base platform with zero shimming or field corrections. The repeatability between units was the biggest win for us.”

Future Collaboration

This project transitioned into a recurring monthly order, with batch deliveries every two weeks. We’ve also helped the client set up batch traceability templates and inspection routines compatible with their CE and ISO9001 requirements.

Future projects include development of similar modules for a new inverter control platform. Learn more about our 5-axis CNC machining capabilities and how they support advanced copper heat sink machining.

The client especially recognized our strengths in

  • Holding tight machining tolerances after welding

  • Reliable delivery coordination and documentation

  • Consistent part-to-part accuracy across batches

  • Fast response time and organized technical communication

  • Professional document structure that meets their ISO9001 supplier requirements

Project Summary

Our ability to execute reliable and repeatable copper heat sink machining operations played a central role in this project.

This project demonstrates our strength in high-conductivity copper machining, heat sink structure control, and precision 5-axis workholding. While the core machining process was technically not highly complex, it required meticulous control over burrs, surface finish, and repeatable dimensional tolerances.

More importantly, it reflects our ability to understand the client’s real-world use cases and support them with full-cycle execution—from drawing to delivery.

We’re more than a machine shop. We offer expertise in copper heat sink machining, allowing customers to move from prototype to production with full confidence. We’re a problem-solving manufacturing partner.

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