How We Helped a Metal Furniture Factory Increase Output by 40% with a New Coating Line

Client Background and Challenges

A mid-sized metal furniture manufacturer in South China primarily produces office chairs, filing cabinets, and metal desk frames, with an annual output of approximately 800,000 pieces. Its existing coating line was a semi-automatic liquid coating line that had been in operation for 12 years, with the following pain points:

• Capacity bottleneck: Spraying stations relied on manual operation, resulting in unstable cycle times and a daily output of only about 2,200 pieces, failing to meet growing order demand
• Quality fluctuations: Frequent defects such as orange peel, sagging, and uneven film thickness led to a rework rate as high as 12%, severely impacting delivery schedules and customer satisfaction
• High costs: Coating material utilization was below 45%, labor costs accounted for 30% of operating expenses, and frequent rework resulted in double waste of materials and labor hours
• Environmental non-compliance: Solvent-based coatings caused VOC emissions to exceed limits, and the client had already received a rectification notice from environmental authorities

After evaluation, the client concluded that retrofitting the old line could no longer meet capacity and environmental requirements for the next five years and decided to invest in a brand-new automatic metal furniture coating line.

Our Solution

After in-depth discussions with the client, Attractivechina designed and delivered a brand-new intelligent coating line on a turnkey basis, from process planning to equipment installation and commissioning.

Step 1: Overall Process Planning

Based on the client's product characteristics (high mix, medium-to-small batch sizes, metal substrates), we recommended a hybrid process route with "powder coating as the main process, liquid coating as a supplement":

• Main process: Electrostatic powder coating (environmentally friendly, efficient, high material utilization)
• Auxiliary station: Reserved liquid spray booth for special colors or high-gloss products

The line layout adopted a U-shaped design, with total length controlled within 45 meters, fitting the client's existing factory space.

Step 2: Core Equipment Configuration

• Pre-treatment system: Fully automatic spray-type 9-station system (pre-degrease - main degrease - rinse - surface conditioning - silanization - DI rinse - drying), stainless steel tanks, equipped with heat recovery
• Spraying system: Two 6-axis spraying robots with electrostatic bells and automatic color-change powder feed center; 3D vision guidance for automatic workpiece contour recognition
• Curing system: Gas-fired direct heating tunnel oven with zone temperature control and exhaust heat recovery
• Conveyor system: Intelligent power-and-free chain with VFD control; workpieces automatically routed to different spray stations
• Control system: Siemens PLC + SCADA, integrated energy monitoring and production data collection

Step 3: Process Parameter Setting and Commissioning

Using our process laboratory to pre-validate typical client workpieces, we determined optimal parameters:

• Electrostatic voltage: 65kV (balancing deep cavity coverage and surface quality)
• Powder film thickness: 60-80μm
• Curing temperature: 190°C for 12 minutes
• Color change time: ≤4 minutes (automatic cleaning by powder feed center)

Quantified Results

After the new coating line was delivered and operated stably for three months, the client achieved the following results:

The customer's annual production capacity has increased from 800,000 units to 1,120,000 units, adding 320,000 salable units directly. With an average profit of $2.07 per unit, the annual profit increases by approximately $662,400. The total investment in the new coating line is about $800,400, with an investment payback period of around 14.5 months.

Client Feedback

The factory's production manager said: "Investing in this new automated coating line was the best decision we have made in the past five years. Not only does the capacity fully meet peak season demand, but the coating quality has reached export standards for the EU. What impressed us even more was the professional full-process service from the Chuangzhi team from design to delivery — we hardly had to worry about anything."

Conclusion

This case demonstrates that for companies planning to expand coating capacity or replace aging facilities, investing in a brand-new automated coating line delivers step-change improvements across capacity, quality, cost, and environmental performance. Compared to patching up an old line, the total lifecycle cost of a new line is often lower and can adapt to technology trends for the next 5-10 years.

If you are planning a new coating line equipment installation, Attractivechina is a partner you can trust. As a professional turnkey integrator of coating lines, Attractivechina specializes in process design, equipment manufacturing, installation and commissioning, and training delivery for brand-new coating lines, with extensive successful cases in metal furniture, home appliances, automotive parts, building materials, and other industries.