GRAPHALLOY® Solves Conveyor Chain Sprocket Failures in High-Temperature Composite Curing Process
Before GRAPHALLOY installation: Gap between the sprocket and outside chain bar where the original flanged bushing created wear and clearance issues.
Background
A manufacturer of fiberglass conduit faced recurring failures in a conveyor oven system used to cure resin-wrapped pipe. The curing process requires rotating mandrels to move through a gas-fired oven operating near 400°F, where sprocket assemblies support and rotate each mandrel during curing.
The sprockets rely on bushings mounted on pins to allow smooth rotation. However, the original bushings experienced severe wear. Over time, the inner diameter became deeply scarred and gouged, eventually preventing rotation. When rotation stopped, the sprocket seized, causing equipment damage and unplanned production downtime.
With approximately 300 sprockets in service and a growing failure rate, the plant required a durable, long-term solution.
Operating Challenges
- Intermittent exposure to temperatures approaching 400°F
- Resin contamination during curing cycles
- Rotational loading during oven transport
- Chain-driven motion requiring consistent rotation
- Maintenance downtime and repair costs from bushing failure
Temporary measures such as frequent lubrication and bushing replacement proved ineffective and unsustainable.
Engineering the Solution
GRAPHALLOY engineers reviewed the application and worked with the customer to optimize the bushing design for reliability and longevity.
Key considerations included:
- Eliminating the flange to prevent interference and wear
- Optimizing wall thickness for durability
- Selecting a bronze-grade GRAPHALLOY material suited for temperature and contamination conditions
- Maintaining compatibility with existing sprocket assemblies
An initial test installation of 20 GRAPHALLOY bushings was implemented for evaluation.
Performance Results
After several months of operation:
- Bushings demonstrated exceptional wear resistance
- Sprockets maintained smooth rotation
- No seizure or damage occurred
- Maintenance intervention was reduced
Based on this performance, the customer initiated plans to replace the existing bushings system-wide, requesting a quotation for 350 units with increased wall thickness.
The GRAPHALLOY Advantage
GRAPHALLOY bushings provide self-lubricating performance and dimensional stability in demanding environments where conventional materials fail.
Benefits for high-temperature conveyor systems include:
- Extended service life
- Reduced downtime and maintenance
- Reliable operation without continuous lubrication
- Resistance to contamination and wear
When equipment reliability impacts production throughput, material selection becomes a strategic decision. This application demonstrates how engineered carbon-graphite solutions can improve uptime and operational efficiency.
Have a challenging application? Contact GRAPHALLOY to explore a solution.