Metal-Core MC Nylon Gear Casting 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.

A leading national paper packaging machinery and electrical drive group in Shanghai deployed Haifeng’s in-situ metal-core MC nylon gear casting line. The project was commissioned to manufacture high-torque, silent transmission gears (Ø 800 mm pitch diameter, 120 mm face width) for dryer cylinder drive sections on high-speed paper machines.

Previously, the paper machinery used all-metal forged alloy steel helical gears. With over 30 dryer cylinders meshing synchronously, metal-to-metal impact created deafening acoustic noise reaching 98 dB(A), violating industrial occupational noise regulations. Earlier attempts to bolt external cast nylon gear rims onto cold steel hubs failed because thermal expansion differentials caused the nylon to crack around bolt holes under 120°C steam heat, resulting in catastrophic gear stripping and downtime.

Haifeng deployed an integrated in-situ casting cell centered on the HF-MCG120-INS system. By preheating knurled steel splined hubs to 160°C under nitrogen induction and infiltrating toughened caprolactam into tool cavities under 1 kPa vacuum, the line produced hybrid gears with zero interfacial shrink stress. The finished gears transmit continuous torques up to 4,500 N·m, cut drive noise by 15 dB(A), and operate reliably at 120°C.

Review point: Sound-pressure reduction in dB(A) and sound-power results under GB/T 3768 require consistent definitions and test geometry. 4,550 N·m torque and 8,000-hour life are different qualification claims. The stated March 2026 8,000-hour follow-up needs reconciled implementation/test dates. A metal core is an insert, not a third liquid chemical stream.

Concept illustration: Generated concept illustration for process discussion; not a photograph of the specified machine, a customer facility or a delivered project.

Configuration reported in the supplied brief.

Haifeng engineered an automated in-situ casting cell designed for hybrid metal-plastic component synthesis. Forged 40Cr steel hubs machined with axial dovetail knurling are grit-blasted and loaded into a medium-frequency induction heating chamber, heated to 160°C ± 2°C under nitrogen in 60 seconds.

A robotic transfer arm transfers the 160°C hub into an Invar gear tooth mold preheated to 165°C. The tool clamps shut under hydraulic pressure while vacuum pumps draw the cavity down to 1 kPa.

The HF-MCG120-INS machine meters toughened caprolactam monomer and activator at 135°C, injecting 18 kg of active formulation through a dynamic mixing head into the vacuum tool in 45 seconds. Negative pressure draws monomer into narrow tooth roots without air pockets.

As the nylon polymerizes isothermally at 165°C, it crosslinks directly around the hot steel hub. Because both materials cool together during post-cure oil annealing, thermal contraction stresses are neutralized, eliminating shrink cracking and yielding an interface withstanding 4,500 N·m shear torques.

Sound-pressure reduction in dB(A) and sound-power results under GB/T 3768 require consistent definitions and test geometry. 4,550 N·m torque and 8,000-hour life are different qualification claims. The stated March 2026 8,000-hour follow-up needs reconciled implementation/test dates. A metal core is an insert, not a third liquid chemical stream.