Case Study: Container Spray Painting Line, Tianjin
Summary
A container-scale spray painting line for the Tianjin plant of one of the world's largest container manufacturers, painting container bodies inside and out, including the underside, on a production takt. Box bodies travel on floor rails through spray booths with grating floors and pits, followed by drying rooms, forced cooling and exhaust ducting with VOC treatment. The reference configuration for a 20-ft box line on this page is taken from a current MUSI design and shows the typical booth, oven, robot and VOC sizing. The line is in production at the Tianjin plant in 2026.
Project Background
The client is the Tianjin plant of one of the world’s largest container manufacturers, whose plants also build energy-storage boxes. MUSI supplied a spray painting line for the Tianjin operation.
The group's customers are ocean carriers and container leasing companies; Evergreen Marine, for example, has placed container orders with it. The Tianjin line is one of a series of container and energy-storage box lines MUSI has delivered to the group's plants.
The Challenge
A container is a large steel box that has to be painted inside and out, including the underside, and the finish has to survive years at sea. Painting a box of this size on a production takt needs the booth, conveyor and exhaust to work as one system.
MUSI's Solution
MUSI supplied a container-scale spray painting line: box bodies travel on floor rails through spray booths with grating floors and pits, so the underside can be painted from below, with drying and exhaust treatment built into the line.
Equipment Scope
- Floor rail conveyor for container bodies
- Spray booths with grating floor and pit
- Drying room 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 Tianjin plant, part of a series of container and energy-storage box lines MUSI has delivered to the same group.
Selection logic: why this configuration
Floor rails with grating floors and pits were chosen over an overhead conveyor because a container body is painted from below as well as from the sides, and its weight makes floor transfer the safer method. Booths with reciprocators on both sides, top and bottom, with robots for interior cavity primer, were specified because the flat faces are sprayed most evenly by reciprocators while cavities need a programmed path. VOC treatment was sized for the combined booth exhaust rather than per booth.
Scope of supply and key components
| Item | Specification | Notes |
|---|---|---|
| Floor rail conveyor | For container bodies | Box-pulling chain in the reference design |
| Spray booths | Grating floor and pit, underside access | Reciprocators on sides, top and bottom |
| Drying rooms | With forced cooling | |
| Exhaust and VOC treatment | Ducting and treatment for the booth group |
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 |
| Steel shot and grit | Ervin AMASTEEL, Winoa W Abrasives, Pometon |
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
The reference configuration is a design for 20-ft energy-storage boxes at 20 boxes per 12 hours; each plant's line is sized to its own product mix, takt and coating system. Marine-spec container paint systems and their VOC load are set by the paint supplier and the box owner's specification.
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
How is the underside of a container painted on a line? The body travels on floor rails over a grating floor with a pit beneath, so the underside is sprayed from below in the same booth as the sides and top.
How many booths does a container painting line have? Typically primer, intermediate and topcoat booths in sequence, each with its own drying room, as in the reference configuration on this page.
What handles the interior cavities? In the reference design, explosion-proof robots on travel rails apply the interior primer, while reciprocators cover the large flat faces.
What VOC treatment does a container line need? The reference design uses dry filtration, activated-carbon adsorption and catalytic combustion sized for 160,000 m³/h; the actual system follows the local permit.
Has MUSI built more than one line for this group? Yes, a series of container and energy-storage box lines at several of the group's plants; see the related case studies.
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