Case Study: Tower Crane Mast Section Coating Line, Zhangjiagang
Summary
A coating line for a construction machinery manufacturer in Zhangjiagang, Jiangsu, producing tower crane mast sections, construction hoists, anchorages and adapters, with spray booths fitted with two-level steel platforms and ladders so operators reach the upper and inner faces of each lattice section. Pretreatment and curing are sized for large welded structures, on a heavy-duty conveyor with exhaust treatment. The line is in regular production in 2026; MUSI also supplied the client's energy-storage box painting line.
Project Background
The client, based in Zhangjiagang, Jiangsu, makes tower crane mast sections, construction hoists, anchorages and adapters: large welded steel structures used on building sites.
The Challenge
Mast sections are big lattice structures with a lot of surface area, internal bracing and weld joints. Operators need to reach every face, and the finish has to protect the steel through years of outdoor use and repeated assembly on site.
MUSI's Solution
MUSI built the line around working access: spray booths with two-level steel platforms and ladders, so operators can reach the upper and inner faces of each section, with pretreatment and curing sized for large welded structures.
Equipment Scope
- Pretreatment for large welded structures
- Spray booths with two-level working platforms
- Heavy-duty conveyor
- Curing oven
- Exhaust treatment
Results
The line is in regular production, giving the client a coating process sized for full mast sections. MUSI also supplied the client’s energy-storage box painting line (see related cases).
Selection logic: why this configuration
Booths with two-level working platforms were chosen over automatic reciprocators because a lattice mast section has bracing and joints on every face that fixed guns cannot follow, and the volume did not justify robots. The platforms put operators at the right height for the upper faces without ladders inside the spray zone, which is where coverage on mast sections is usually lost.
Scope of supply and key components
| Item | Specification | Notes |
|---|---|---|
| Pretreatment | For large welded structures | |
| Spray booths | Two-level steel working platforms and ladders | |
| Conveyor | Heavy-duty | |
| Curing oven | Sized for mast sections | |
| Exhaust treatment |
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) |
| 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 |
| Conveyor gear motors | SEW-EURODRIVE, NORD DRIVESYSTEMS, Bonfiglioli, Siemens, Sumitomo Drive Technologies |
| Booth ceiling and intake filter media | Freudenberg Viledon, AAF SureStop, Camfil, MANN+HUMMEL |
| Pretreatment pumps and chemistry | Grundfos CR, KSB Etanorm, Xylem; Henkel BONDERITE, Chemetall Gardobond, PPG Zircobond, Nippon Paint |
| Compressed air for powder feed and instruments | Atlas Copco GA, Ingersoll Rand RS, KAESER ASD, Sullair |
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
Manual spraying from platforms suits large lattice structures in medium volume; plants producing simple box sections in high volume are better served by reciprocators. The finish specification for site-assembled steel is set by the crane maker and the line applies it as specified.
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 are tower crane mast sections painted inside and out? From two-level platforms inside the booth, so operators reach the upper chords and inner bracing at working height while the section stands on the conveyor.
Why not automatic spraying for mast sections? Lattice bracing and joints face every direction; fixed guns leave shadows and the volume does not justify robots. Platforms give full coverage at lower cost.
What pretreatment do welded structures need? Blast cleaning or chemical pretreatment sized for heavy sections, so weld spatter, scale and rust are removed before the primer.
Does the line handle hoist parts too? Yes; construction hoists, anchorages and adapters share the booths and oven with the mast sections.
Did MUSI supply anything else to this client? Yes, the client's energy-storage box painting line, described in a separate case study.
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