Heavy-Duty Composite Leaf Spring HP-RTM Line in China

Illustration notice. Process illustrations are not verified photographs of this installation.

Project reference basis. Figures and configuration details are reported in the supplied project brief. They are reference values for the stated application, rather than verified acceptance results or a guarantee for another installation. Confirm the source records, material, tooling, operating schedule and test method when assessing a comparable project.

Haifeng successfully engineered and commissioned an automated High-Pressure Resin Transfer Molding (HP-RTM) production line for a major Chinese commercial vehicle suspension manufacturer, reducing suspension leaf spring tare weight by 65% while delivering over 1 million cycles of fatigue endurance. The project encompassed the turnkey delivery of specialized high-pressure resin dosing machines, multi-stage vacuum extraction units, dynamic mold thermal conditioning skids, and digital interface coordination for the customer's heavy hydraulic press.

Prior to commissioning, the manufacturer assembled suspension assemblies using conventional heavy multi-leaf steel springs. Heavy steel assemblies imposed severe unsprung weight penalties on commercial fleets, degraded ride comfort, and suffered from corrosion-induced fatigue failures. The client required an industrial-scale manufacturing system capable of injecting low-viscosity thermoset resins into ultra-thick (up to 40mm), densely packed unidirectional glass fiber preforms under extreme pressure, eliminating dry-spot delamination and compressing demold cycles down to 5 minutes.

Operational since June 2026 on a continuous two-shift production schedule across a 280 m² footprint, the workcell delivers consistent component repeatability. By implementing Haifeng's closed-loop Ratio Lock flow algorithms and high-velocity impingement injection heads, the client consistently manufactures rugged, corrosion-free composite leaf springs complying with rigorous commercial vehicle chassis durability standards.

Planning a related production line

Use this record as an application-specific reference. Reinforcement introduction, resin chemistry, tooling, consolidation and qualification differ between RIM, LFI, SMC and HP-RTM. A result from one process does not establish performance of another.

Production brief for technical discussion

Provide a finished-product drawing or sample, material data, target output, automation needs and factory conditions. Haifeng will review the process, equipment interfaces and acceptance plan for your own production goals.

Concept illustration — not a photograph of delivered equipment or a customer installation.

The 65% weight reduction and over one million fatigue cycles are results for this project’s spring configuration and conventional multi-leaf steel comparison. Fatigue observations refer to the recorded dynamic bench tests; load-deflection, environment and acceptance conditions are specific to the component program. These results do not guarantee the same outcome for a different spring or constitute injection-machine ratings.

Haifeng deployed an extreme-pressure HP-RTM dosing platform engineered for thick-section composite preforms, coordinating impregnation and cure within the project’s reported 5-minute complete molding cycle:
1. Extreme-Pressure Stoichiometric Ratio Lock: Heavy-duty axial displacement pumps meter resin components under extreme pressure with ±0.5% stoichiometric accuracy, driving resin deep into 40mm-thick fiber stacks.
2. Deep Vacuum Evacuation Skid: High-flow vacuum pumps pull tool cavity air down to <10 mbar before injection begins, supporting air-entrapment control; actual internal defects require component inspection.
3. Multi-Zone Thermal Stability: Dynamic TCU loops maintain upper and lower mold platen temperatures within ±0.8°C, preventing thermal exotherm runaway while accelerating core cure.
4. Self-Cleaning High-Pressure Injection Head: An industrial impingement mixing head executes instantaneous 0.3-second mechanical clean cut-offs without chemical solvent flushes, maximizing continuous uptime.