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How Truck Cargo Bodies Are Made: From Roll Forming to E-Coating

A truck cargo body has to survive years of loading, vibration and weather. How it is made decides how long it lasts. At Qingdao Hailong Machinery Group, cargo bodies go through one managed flow, from material preparation to warehousing. This article walks through the steps and explains why each one matters to the buyer.

Equipment behind the process

The process relies on equipment for long body panels and beams:

• Roll forming lines for side boards and profiles
• 8 m CNC bending and 8 m CNC shearing for long panels
• Stamping equipment, backed by group stamping lines up to 8,250 tons
• Dedicated welding fixtures for repeatable sub-assemblies
• E-coating and painting lines

Step 1: Floor assembly

Longitudinal beams, cross beams and bottom plates are positioned, welded and inspected. The floor carries the payload, so its structure is set by the rated load and the chassis it mounts on.

Step 2: Side and rear panels

Side boards and rear panels are roll-formed, then riveted or welded according to the body design. Roll forming gives consistent profiles along the full length of the panel.

Step 3: Front panel assembly

Front protection frames and panel assemblies are welded and checked before the body is joined.

Step 4: Body welding

Body modules are assembled in fixtures, welded, repaired and cleaned before inspection. Fixtures hold every body in the same position, which keeps dimensions repeatable from one unit to the next.

Step 5: E-coating

The whole body is electrophoretically coated. E-coating reaches corners, seams and the inside of profiles that spray paint cannot, which is why it improves corrosion resistance. The group's e-coating capacity is about 100,000 cabs a year.

Step 6: Paint and inspection

High-temperature baking paint is applied over the e-coat, and the finish is inspected before assembly.

Step 7: Final assembly

The body is lifted, mounted and given its final checks before delivery.

Step 8: Final inspection

Finished cargo bodies are inspected and moved to the qualified vehicle area or the warehouse.

What this means for buyers

• Consistency: fixtures and roll-formed profiles keep bodies the same across a batch.
• Durability: full e-coating plus baking paint protects the body where corrosion usually starts.
• One supplier: fabrication, welding, surface treatment and assembly are managed in one flow, with capacity of about 30,000 cargo body sets a year.
• Spare parts: floor, front, side and rear boards and body accessories are available.

About Hailong Group

Hailong Group was founded in 1955 and is certified to IATF 16949, ISO 9001, ISO 14001 and ISO 45001. Not sure which body type you need? Read how to choose a truck cargo body.