Machining Solutions for Pure Aluminum Heat Sink Parts

In the world of automotive headlamp components, the heat sink plays a crucial role. Today, WayKen shares a project about the machining process of heat sink products and the solutions we implemented.

Project Overview

This project involved custom manufacturing 1,000 heat sinks for a client. The overall dimensions of the heat sink are 74×44×34mm, with fin thickness as thin as 0.5mm. Given the high-temperature working environment, thermal conductivity and heat dissipation performance are the key indicators of this product.

In this heat sink part, the aluminum content requirement for the material is between 99.5% and 99.7%, with the base plate and fins requiring thermal conductivity values of at least 210 W/m·K and 130 W/m·K, respectively.

Part Structure Analysis

The heat sink is assembled from four separate sets of fins and a base plate, a design approach akin to breaking down a complex puzzle into smaller pieces for reassembly. This method ensures optimal performance while effectively controlling production costs.

Based on this structure, we quickly determined the overall process: the base plate is CNC machined, the fins are fabricated using sheet metal processing, and all components are then riveted together to form a complete unit.

Here, we will focus on the machining challenge during the production of the base plate.

Challenges and Solutions in Machining Heat Sink Base Plate

Manufacturing the heat sink base plate involved multiple steps, including maintaining precision, preventing deformation, and improving machining efficiency. Here’s how we achieved these issues.

CNC Machining Strategy for the Base Plate

After analysis, we identified that the main machining features of the base plate are located on both its top and bottom surfaces. Therefore, we designed a vacuum fixture and adopted a 1-out-of-6 panel layout, allowing both sides of the part to be processed within the same fixture.

Although this method slightly extended the machining cycle per unit, it offered the advantage of simplified operator handling, saving both time and labor while enabling six parts to be completed in a single setup.

Machining Challenge for Pure Aluminum Parts

Processing nearly pure aluminum presents material deformation and tool sticking, requiring specialized strategies for effective machining.

Deformation of the Plate Blank

During the prototype stage, we met the challenges. The base plate blank was made from AL1060, which is nearly pure aluminum with low strength and hardness, making the flatness highly prone to warping and deformation.

To address this issue, we promptly communicated with our material supplier. Fortunately, after process optimization, the supplier was able to provide batch materials (280×160×6mm) with improved flatness, keeping deformation within 0.05mm, laying a solid foundation for subsequent machining.

Tool Sticking Issue

The next challenge was tool sticking. With an aluminum content of 99.6%, AL1060 is highly ductile and soft, causing chips to adhere to the cutting tools like sticky gum. Upon further research, we learned that AL1060 comes in different tempers: O, H, and T, each with distinct hardness levels.

• O Temper: Fully annealed state, with a Vickers hardness (HV) of typically 30-40.
• H Temper: a hardening process that offers higher strength and hardness than O temper.
• T Temper: Solution heat-treated and naturally aged, with a Vickers hardness of 65-85, which can reach 95-120 after artificial aging.

After careful evaluation and discussions with our client, we determined that the core requirements for the heat sink base plate were thermal conductivity and positional accuracy of the holes as per the drawings. As a result, we selected AL1060-H24.

This choice significantly solved the tool sticking problem while maintaining the required material composition. It successfully met product specifications while also accommodating cutting performance. Since this material remains relatively soft overall, machining stress had minimal impact on part deformation, allowing us to easily control flatness within 0.05mm. Additionally, hole positioning accuracy was maintained within ±0.01mm, achieving excellent results.

Riveting and Testing

After completing the CNC machining of the base plate, the test results of the finished products for the riveting of the base plate and fins proved equally satisfactory: the base plate achieved a thermal conductivity of 215.6 W/m·K, while the fins reached 138.3 W/m·K. The product successfully passed all testing and received high praise from the client.

Expert Solutions for Soft Metal Machining

If you encounter challenges when machining soft metal materials, feel free to contact WayKen. With our professional team and extensive experience, we can provide effective CNC machining solutions and competitive pricing, helping you overcome manufacturing difficulties!