EMC Upgrade Cuts Specific Power 26.6% at a Dongguan CNC Machining Plant

The client is a precision CNC machining company in Dongguan, Guangdong. It produces 3C hardware trim parts, copper and aluminium components and AI-server hardware parts. With several hundred multi-spindle machining centres running continuously, compressed air is a critical utility for tool changes, chip blow-off and fixtures.

The plant’s existing air system had a specific power of 0.124 kWh/m³. Electricity costs were high, and maintenance and repair of the older imported compressors added to the burden. Electricity and maintenance costs were also mixed together in the plant’s accounts, so the true cost of compressed air was not visible.

The project was delivered under an energy management contract (EMC). Diagnosis, design and equipment investment were covered under the contract, and the plant shares the savings according to the agreement, with no capital outlay or technical risk.

Rather than simply adding more compressors, the upgrade optimised the whole chain from compression through purification and storage to distribution. It was matched to the plant’s load fluctuations and production patterns so that the system runs efficiently under all operating conditions. A control system with remote real-time monitoring allows unattended operation, and lifecycle inspection and maintenance are included in the contract.

The station passed Grade-1 energy-efficiency certification.

After the upgrade, the station was measured on site:

• Specific power reduced from 0.124 to 0.091 kWh/m³, a 26.6% improvement in overall efficiency.
• About CN¥1,000,000 (≈US$140,800 at CN¥7.1/US$) saved in electricity costs per year.
• No capital investment and minimal management workload for the plant.
• Transparent cost per cubic metre of air, supporting production scheduling and cost accounting.

The result shows that system-level optimisation, not individual machine upgrades alone, is what brings a compressed air station to high efficiency.