Case Study: Container Spray Painting Line, Qingdao
Summary
A spray painting line for the Qingdao base of a major container group, which builds refrigerated and special containers and is one of the group's energy-storage production bases. The line is built around rail transfer carts that move refrigerated, special and energy-storage boxes between booths and drying rooms without re-rigging, with booths sized for full container bodies, drying rooms with forced cooling and exhaust treatment integrated into the line. The page's reference configuration shows a current 20-ft energy-storage box line design. The line is in production in 2026.
Project Background
The client’s Qingdao base, part of a major container group, builds refrigerated and special containers and is one of the group’s energy-storage production bases. MUSI supplied a container spray painting line to the Qingdao operation.
The group's customers are ocean carriers and container leasing companies, Evergreen Marine among them; the Qingdao base is also one of its energy-storage production sites.
The Challenge
Refrigerated, special and energy-storage boxes differ in size and fittings, so the line has to move different box types between stations without re-rigging, and paint each one to a finish that survives marine and outdoor exposure.
MUSI's Solution
MUSI supplied a spray painting line built around rail transfer carts, which move each box between the booths and drying rooms, with booths sized for full container bodies and exhaust treatment integrated into the line.
Equipment Scope
- Rail transfer carts
- Container-scale spray booths
- Drying rooms and forced cooling
- Exhaust ducting and VOC treatment
Reference Configuration: 20-ft Energy-Storage Box Line
The figures below come from a current 20-ft energy-storage box line design. They show how a line of this type is typically configured; each plant’s line is sized to its own product mix and output.
| Workpiece | 20-ft box, 6,058 × 2,438 × 2,591 mm, up to 2,500 kg |
|---|---|
| Conveyor | Box-pulling chain (32A roller chain), approx. 280 m |
| Surface preparation | Automatic shot blasting room (10 × 6.6 × 5 m) with servo reciprocators on both sides and top; cleaning room with automatic blow-off; abrasive recovery and cartridge dust collector |
| Liquid paint booths | Primer, intermediate and topcoat booths, 10 × 6.6 × 5.2 m, reciprocators on both sides, top and bottom; interior-cavity primer applied by robot |
| Robots | Yaskawa 7-axis explosion-proof, 15 kg payload, 2,700 mm reach, on travel rails |
| Paint supply | Graco high-pressure airless automatic guns; 2K automatic mixing for primer, intermediate and topcoat |
| Powder booth | Automatic, 9.8 × 4.9 × 4.2 m; cyclone and cartridge recovery; explosion isolation valves and flameless venting |
| Ovens | Paint drying 80–120 °C; powder curing 200–220 °C; direct natural-gas heating (280,000 and 440,000 kcal/h burners); forced cooling after each oven |
| Quality check | Rain test chamber, 10 × 6 × 5 m |
| VOC treatment | 160,000 m³/h dry filtration + activated carbon adsorption + catalytic combustion |
| Output | Reference layout: 20 boxes per 12 hours. MUSI’s fastest energy-storage box lines release one finished box per minute. |
Results
The line is in production at the Qingdao plant, handling its mix of container and energy-storage box types.
Selection logic: why this configuration
Rail transfer carts were chosen over a continuous floor chain because the Qingdao plant runs box types that differ in length, fittings and coat count; carts let each box follow its own route between booths and drying rooms. Booths were sized for the largest box type so the mix runs without changeover, and exhaust treatment was integrated so every booth discharges to one system.
Scope of supply and key components
| Item | Specification | Notes |
|---|---|---|
| Rail transfer carts | Between booths and drying rooms | |
| Spray booths | Container-scale | |
| Drying rooms | With forced cooling | |
| Exhaust and VOC treatment | Integrated |
Key components
Key components are available from international brands, configurable per customer specification, so that spare parts can be sourced locally over the life of the line. Brand names below are the usual options for this type of equipment; the brands actually fitted are fixed in the contract specification.
| Component | Brands available on request |
|---|---|
| Automatic liquid guns, pumps and 2K proportioners | Graco ProMix 2KS, Sames Airmix, WAGNER AirCoat, Nordson, Binks (Carlisle Fluid Technologies) |
| Painting robots | ABB IRB 5500, FANUC P-350iA, Yaskawa MOTOMAN MPX series, KUKA, Kawasaki |
| Oven and dryer gas burners | Riello RS series, Weishaupt monarch WM-G, Baltur TBG, Honeywell Maxon OVENPAK, Eclipse |
| PLC and HMI | Siemens SIMATIC S7-1500, Mitsubishi Electric MELSEC iQ-R, Schneider Electric Modicon, OMRON NX, Rockwell Automation Allen-Bradley |
| Variable-frequency drives | ABB ACS580, Siemens SINAMICS G120, Danfoss VLT, Schneider Electric Altivar, Yaskawa, Mitsubishi Electric |
| Booth ceiling and intake filter media | Freudenberg Viledon, AAF SureStop, Camfil, MANN+HUMMEL |
| RTO ceramic media and burners | Lantec MLM, Honeywell Maxon line burners, Riello RS, Eclipse |
| Conveyor gear motors | SEW-EURODRIVE, NORD DRIVESYSTEMS, Bonfiglioli, Siemens, Sumitomo Drive Technologies |
Not included in the scope of supply
- Civil works, foundations and pits
- Building services up to the battery limit: power supply, gas, compressed air, water and drainage
- Local permits, emission approvals and third-party inspections
- Paint or powder supply, unless stated in the contract
Services included with every line: engineering design, manufacturing, shipping documentation, installation supervision, commissioning, operator training, warranty and spare parts.
Typical programme
The durations below are typical for equipment of this class and are given for planning; they are not the recorded schedule of this project. A complete line usually runs 90–180 days from contract to acceptance, a single unit 30–60 days.
| Stage | Typical duration | What happens |
|---|---|---|
| Site survey and workpiece review | 5–10 days | Remote review of drawings and photos, or an engineer visit |
| Layout and detail design | 15–30 days | Layout drawing, utilities list and specification sign-off |
| Manufacturing | 45–90 days | Booths, ovens, conveyor, pretreatment and controls built and pre-assembled at the works |
| Shipping | 20–45 days | Sea freight; equipment shipped in sections for on-site assembly |
| Installation | 15–40 days | MUSI supervision with the client's installation crew or MUSI crew |
| Commissioning, training and acceptance | 7–15 days | Trial runs on the client's parts, operator training, acceptance record |
Applicability and limits
Transfer carts suit plants with a mixed box programme; a plant running one box type at high takt is usually faster on a continuous chain. Refrigerated containers have insulated panels and fittings whose coating is set by the box specification and may need masking steps not shown in the reference configuration.
Results shown in this case study reflect the stated operating conditions and should not be interpreted as guaranteed performance under different feed, production, environmental, or site conditions.
After-sales and spare parts
Warranty on a MUSI coating line runs from acceptance: 12 months on the complete line excluding consumables, 36 months on critical components such as motors, drives and the PLC, and 60 months on structural parts such as steel structure, ducting and oven bodies. Failures within warranty, excluding misuse, are repaired free of charge.
Support starts remotely: the service line is staffed around the clock, a preliminary diagnosis with recommendations is given within 2 hours, and where a site visit is needed an engineer reaches any major city within 72 hours. A spare-parts inventory is held at the Changzhou headquarters with same-day shipping, and customers can keep a dedicated parts stock at MUSI for emergencies. Details are on the after-sales service page.
FAQ
Why use transfer carts instead of a chain conveyor for containers? A mixed programme of refrigerated, special and energy-storage boxes needs different routes and coat counts; carts move each box where it needs to go without re-rigging the line.
Can refrigerated containers be painted on the same line as dry boxes? Yes, with booths sized for the largest type and recipes per box type; fittings and insulated panels are masked per specification.
How is exhaust handled across several booths? All booths discharge to one integrated exhaust and VOC treatment system sized for the combined flow.
What does the reference configuration show? A current MUSI design for a 20-ft energy-storage box line: blasting, three paint booths, robots for cavities, powder booth, ovens, rain test and VOC treatment.
Is the line running? Yes, at the Qingdao plant, handling its mix of container and energy-storage box types.
Next step: a configuration proposal for a similar line
If your parts, volumes or plant conditions are close to this project, MUSI can return a line configuration and layout proposal. To prepare it we need four things:
- Photos and dimensions of the workpieces, with weight and material
- Required output (pieces per hour or per day, and shifts)
- Number of colours and how often colour changes are needed
- Available floor space and ceiling height, with the utilities on site
Message us on WhatsApp with these details, or use the quotation form.
Published 2026-09-26 · Updated 2026-09-30 · Last technical review: 2026-09-30
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Provided by Lin Cong, Technical Director, MUSI Technology