Case Study: Custom Gold Anodized Extruded Aluminum Enclosure for GSM Signal Repeater

📝 Brief Introduction

This case presents a custom aluminum enclosure project for a GSM signal repeater device (AT-980). The customer required a compact, heat-dissipating housing with a premium gold appearance that could accommodate RF connectors, indicator ports, and power input interfaces. PUMAYCASE delivered a complete solution using extruded aluminum profile as the base structure ⁴, combined with precision CNC machining and a striking gold anodizing finish — achieving both functional performance and strong visual branding identity.

📖 Detailed Content

Customer Background & Requirements

The customer manufactures wireless signal amplification equipment for the consumer and commercial telecom market. The AT-980 GSM Repeater required an enclosure that:

• Provided excellent passive heat dissipation for internal RF components
• Featured a distinctive gold appearance to differentiate the product on retail shelves
• Accommodated multiple interface cutouts including RF antenna connectors, LED indicator holes, and DC power input
• Was durable and corrosion-resistant for long-term field deployment
• Supported small-to-medium batch production with competitive per-unit pricing 

Our Solution

① Material & Profile Selection 6063-T5 extruded aluminum alloy was selected as the primary structural material. The extrusion process allows for complex cross-sectional profiles that integrate structural ribbing and heat dissipation fins directly into the body — eliminating the need for additional heatsink components.

Key material advantages:

• Excellent thermal conductivity for passive cooling
• High strength-to-weight ratio
• Superior anodizing compatibility for deep, uniform color absorption
• Lightweight for portable consumer device applications

② CNC Precision Machining — Interface Cutouts After extrusion, both end panels underwent CNC milling and drilling: ⁴

All cutout tolerances controlled to ±0.1mm for reliable connector fitment.

③ Surface Treatment — Brushing + Gold Anodizing The gold finish was achieved through a two-stage surface process:

Stage 1 — Wire Brushing:

• Linear brushing applied to all exterior surfaces
• Grit grade: 180# for fine uniform texture
• Creates a consistent metallic sheen before anodizing

Stage 2 — Gold Anodizing:

• Electrolyte: sulfuric acid bath, 18–20% concentration
• Voltage: 14–18V
• Temperature: 20–22°C
• Anodizing time: 25–35 minutes
• Gold color achieved via chemical dyeing with gold dye solution
• Oxide film thickness: 8–10μm
• Hot water sealing at 90–95°C for 20 minutes to lock in color and enhance corrosion resistance

The result is the deep, rich gold tone visible in the product image — consistent across the entire enclosure body, end panels, and edges.

④ Assembly & Integration

• End panels secured to the extruded body via countersunk screws 
• Internal PCB mounting rails integrated into extrusion profile
• Rubber feet applied to base for vibration dampening
• Final product passed salt spray corrosion test (48 hours) and adhesion cross-cut test

Process Flow

Advantage Highlights

Customer Feedback

The customer was extremely pleased with the final result. The gold anodized finish gave the AT-980 a premium, high-value appearance that stood out significantly on the retail market. The precision CNC machining ensured all RF connectors and interface ports fitted perfectly without modification. The enclosure's passive heat dissipation performance exceeded the customer's thermal requirements, and the product successfully passed all required certifications.