Truck Frame and Chassis Processing

Truck frame and chassis processing are core processes in truck manufacturing, involving material selection, structural design, production processes, and quality control. Truck frame and chassis processing involve multiple processes, requiring comprehensive consideration of equipment selection, process efficiency, and quality control. The following are the main process flows:

Side Rail Production Process

• Raw Material Preparation: Using high-strength steel plates or coils, often purchased as fixed-length materials.
• Forming Process:
  • Stamping: Using hydraulic presses and forming dies (with insert blocks for easy product switching) to stamp steel plates into U-shaped side rails, suitable for straight beams and variable cross-section beams. Requires multiple equipment adjustments to reduce flange springback.
  • Roll Forming: Coiled material is gradually deformed through roll forming dies, offering high precision and suitable for straight beam production. Requires subsequent edge cutting (such as plasma or laser cutting).
• Hole Processing:
  • Side rails have approximately 300-500 holes, distributed on the web and upper and lower flanges, with more than 10 hole diameters (<φ20 mm for assembly, ≥φ36 mm for wiring or electrophoresis hanging).
  • Processing methods include:
    • Plasma Cutting: Used for large-size, low-precision holes or blanking.
    • CNC Punching: Suitable for multi-variety, small-batch production, with high efficiency (new equipment can punch multiple surfaces simultaneously).
    • Die Punching: Suitable for large-volume, stable-quality hole processing, but die modification is difficult.
    • Drill Press Marking and Drilling: Used for temporary hole position adjustments.
• Surface Treatment:
  • Mechanical Treatment: Shot blasting, shot peening, or sandblasting, forming uniform pits through high-speed abrasive impact to enhance paint adhesion. Dust removal and noise reduction must be considered.
  • Chemical Treatment: Steam cleaning or pickling to remove drawing oil, rust preventive oil, and rust.
• Stress Relief: Processing and welding introduce stress, which needs to be released through heat treatment or hole processing to prevent beam deformation.

Crossmember Production Process

• Structural Types: Crossmembers are mostly stamped crossmembers (simple bending, π-shaped, or multi-piece riveted/welded) or tubular crossmembers (commonly used in lightweight frames, simple structure, low cost).
• Processing Methods: Blanking, punching, and forming through dies, welding or riveting on fixtures during mass production.

Frame Assembly

• Assembly Process (taking Shaanxi Heavy Duty Automobile as an example, a total of 9 processes):
  1. Side rail online preparation
  2. Side rail and crossmember assembly
  3. Support plate and standard part assembly
  4. Tail beam assembly, etc.
• Connection Methods:
  • Riveting: The most common, simple process, reliable connection, vibration and impact resistance, and uniform force transmission. Fixture positioning ensures dimensional accuracy.
  • Welding: Used for frames with smaller loads, fixtures are required to ensure dimensions. Due to welding hardening, it is limited to specific scenarios.
  • Bolted Connection: Used for small brackets that rivet guns cannot reach, requiring high-strength bolts and anti-loosening measures.
• Special Processing: Dump trucks require the assembly of cast intermediate supports, and tractors require the processing of fifth wheel mounting holes.

Subsequent Processing and Forming

• Finishing: Milling, drilling, grinding, or polishing to remove excess material, trim edges, and ensure dimensions and surface finish meet specifications.
• Quality Inspection: Using the quality table inspection method to check the accuracy of bending, punching, riveting, and other processes, suitable for new frame development.

Lightweight Development Trend

• Policy Driven: As the country increases its supervision of overloading, standard load transportation has become the mainstream, and lightweight design is key to improving transportation efficiency.
• Technical Means:
  • Dovetail Beam Design: Different heights at the front and rear widths. High-strength steel is used in areas with high stress, and lightweight materials are used in areas with low stress to reduce weight.
  • Aluminum Alloy Frame: Such as Auman S1, the first commercialized aluminum frame in China, significantly reducing weight.
  • High-Strength Steel Plate: Tensile strength of 510-610MPa, balancing strength and lightweight, requiring hot pressing, roll forming, and other processes to avoid fracture or warpage.