Thermal management is becoming increasingly important as AI servers, high-performance computing systems, and data centers continue to develop. The traditional air cooling system is not sufficient to cool today's high power CPUs, GPUs and AI accelerators. Cold plate is a solution that can be used to cool CPUs, GPUs, and AI accelerators.

From the perspective of a precision part supplier, CNC Cold Plate Machining does not only involve cutting metal, but also involves manufacturing a functional component with high reliability that affects system performance, longevity, and stability.

This article explains how liquid cold plate work, why AI server cooling is essential, and how CNC machine quality affects the success or failure of an AI Server Cooling Plate.

What is a cold plate?

A cold plate is an exchanger that transfers heat directly from electronic components with high power to a coolant circulating. Cold plates are different from heat sinks that use air cooling. They rely on flow channels to carry liquid across a metal surface, typically water or dielectric cooler.

Cold plates are used widely in:

• AI servers and GPU Servers

• Data center liquid cooling systems

• High-power processors and accelerators

• Power electronics and energy systems

Liquid cold plates are more efficient at cooling because heat is removed from the source.

How does a liquid CPU cooler work?

It is important to understand how liquid CPU coolers work.

A cold plate is at the core of every liquid CPU cooler. This is how the process works:

1. The cold plate can be mounted directly on the GPU or CPU surface

2. The heat transfer from the chip to the metal cold plate is usually aluminum or copper.

3. Coolant is pumped through channels that are precision-machined.

4. The liquid absorbs heat and transports it to a heat exchanger or radiator

5. The liquid is cooled and circulated back to repeat the cycle

This system's effectiveness is heavily dependent on design of the flow channels, surface flatness and machining accuracy. CNC machining is therefore a crucial manufacturing step.

AI Server Coldplates Need Advanced CNC Machining

An AI Server Cold Plate operates under extreme conditions:

• High thermal density

• Continuous 24/7 operation

• No tolerance for leakage and flow imbalance

Cold plates are different from CNC parts on several levels.

• These are thermal functional components and not simply structural parts

• Micro-channels on the surface must be uniform.

• Surfaces must be flat and meet strict tolerances for dimensions

• A defect may cause system failure, overheating or leakage

Cold Plate Machining is a complex process that requires highly-skilled engineers and strict quality assurance systems.

Common Materials Used for Liquid Cool Plates

The right material selection is crucial for cooling and manufacturing efficiency.

Aluminum Cold Plates

• Cost-effective and lightweight

• Alloys 6061 and 6063

• Good corrosion resistance after surface treatment

• Data centers of large scale are widely used to store and process data

Copper Cold Plates

• Superior Thermal Conductivity

• Ideal for AI and HPC applications that require high-performance computing

• Due to material adhesion and tool wear, it is more difficult to machine.

Copper-Aluminum Hybrid Designs

• Performance and cost: a balance

• Precision CNC machining is required to ensure proper bonding, alignment and bonding.

Cold Plate CNC Machining: Key Processes

1. Precision Milling Flow Channels

Internal structure determines cooling performance. Channel widths typically range between 0.3mm and 2.0mm with complex patterns like serpentine, parallel or pin-fin designs.

The following are the key machining requirements:

• Tight dimensional tolerance (+-0.02 mm)

• Internal surfaces with smooth internal surfaces reduce flow resistance

• Edges without burrs to prevent clogging

2. Surface Machining with Thermal Contact

To ensure heat transfer, the surface of the CPU or GPU should be flat.

Standard requirements

• Flatness =0.05 mm

• Surface roughness is important for thermal interface performance.

3. Drilling and Threading

Cold plates need precise mounting holes and inlet/outlet port. CNC machining assures:

• Accurate hole positioning

• Consistent thread quality

• Protecting thin-wall surfaces from deformation

Sealing Methods with their CNC requirements

Cold plates are sealed by one of the methods listed below:

• O-ring + Bolted Assembly - requires high-precision groove machining

• Vacuum brazing- requires excellent surface consistency prior to joining

• Laser Welding or Friction Welding- Relies on strict Dimensional Control

The accuracy and repeatability of CNC machining is affected by the sealing method.

Quality Control for AI Servers Cold Plates

Dimensional inspection is not sufficient for liquid cooling components. Functional validation must be performed by a professional supplier, which includes:

• Tests for pressure and leakage

• Tests for Flow Resistance

• Thermal performance measurement

• Surface Treatment Inspection

This ensures that cooling plates perform reliably in real server environments.

Liquid Cooling Systems: Why CNC Machining Quality is Important

A cooling failure in AI servers can cause:

• Reduced computing performance

• Hardware damage

• System downtime can be costly

It is for this reason that OEMs and system integrators are increasingly working with CNC suppliers, who have a good understanding of not only basic metal processing but also thermal engineering.

YIXIN PRECISION: Your Cold Plate CNC Machining partner

YIXIN PRECISION is a Shenzhen-based precision CNC machining provider with over 20 years' experience in manufacturing high-precision metal components and plastic parts for industries that demand the highest quality.

Our advantages with Cold plate CNC Machining includes:

• Advanced CNC milling centres for micro-channel machining

• Aluminium and copper thermal components expertise

• Quality control and functional tests

• Support for small-batch production, prototypes and large-scale production

• All-in-one service including surface treatment, assembly and other services

We work closely with thermal and mechanical engineers to optimize cold plate designs in terms of cost, performance and manufacturability.

The conclusion of the article is:

Cold Plate is becoming more important as liquid cooling becomes the norm for AI servers and High-Performance Computing. Every reliable liquid cooling system relies on a precision-machined cooling plates. This is achieved through Cold plate CNC Machining.

It is important to choose the right CNC machining partners for long-term stability and performance.