Predictive Maintenance for OHT Wheel Alignment in Semiconductor Manufacturing
A leading semiconductor manufacturer was facing critical challenges in maintaining precise alignment of its Overhead Hoist Transport (OHT) systems—an essential component for high-speed wafer handling. Even minor misalignment of OHT wheels could result in machine crashes, leading to costly equipment damage, unplanned production downtime, and potential yield loss.
Over time, wheel wear and tear further increased the risk of misalignment, making early detection and proactive maintenance essential. However, existing manual inspection methods were time-consuming, reactive, and unable to keep pace with the high throughput demands of semiconductor production.
The customer required a high-speed, high-accuracy wheel thickness measurement system capable of:
- Detecting gradual wheel wear as part of a predictive maintenance strategy
- Preventing misalignment-related crashes and avoiding scrap
- Reducing unplanned downtime and maintenance costs
- Ensuring consistent quality, reliability, and operational efficiency.
To meet these requirements, an automated, real-time monitoring solution was critical.
The Technology
Omron delivered a fully integrated sensing and control solution designed to enable predictive maintenance without compromising production speed.
Key system components included:
ZP-LS300 Sensor Head, ZP-L3000 Amplifier and ZP-EIP Communication Unit
The ZP-LS300 Sensor Head paired with the ZP-L3000 Amplifier delivers high-precision, non-contact measurement of OHT wheel thickness, enabling early wear detection before misalignment occurs. Designed for high-speed, vibration-prone environments, the system provides stable detection, a wide dynamic range, and highly accurate signal processing. A key Strength of the ZP-L series is its ability to measure reliably on any surface material, ensuring consistent performance across diverse applications. Enables seamless EtherNet/IP connectivity enables real-time data transmission and seamless integration with the factory network.
S8VK-C12024 Power Supply
S8VK-C12024 provides a stable and robust 24 VDC power source, even under fluctuating load and harsh factory conditions. Designed for industrial environments with vibration, electrical noise, and temperature variation, the S8VK-C maintains consistent output voltage, protecting measurement accuracy and preventing signal instability during high-speed OHT movement.
The solution was further enhanced with PC-based software for automated data collection, visualization, and analysis. This enabled continuous monitoring of wheel thickness trends, early identification of abnormal wear patterns, and timely maintenance planning—without disrupting high-speed production.
At a glace
With Omron’s solution in place, the semiconductor manufacturer achieved significant operational improvements:
- Predictive Maintenance Enabled
Continuous wheel thickness monitoring allowed proactive replacement before failures occurred.
- High-Speed, High-Accuracy Measurement
Precise measurements were achieved without impacting OHT throughput or cycle time.
- Reduced Scrap and Downtime
Misalignment-related crashes were eliminated, significantly reducing costly repairs and production interruptions.
- Improved Operational Efficiency
Overall equipment effectiveness (OEE) improved through reduced maintenance intervention and higher system reliability.
- Data-Driven Decision Making
Automated data logging provided valuable insights for quality analysis and long-term maintenance planning.
Predictive Maintenance
Omron’s precision sensing and control technologies empower semiconductor manufacturers to transition from reactive maintenance to a predictive, data-driven approach. By continuously monitoring OHT wheel conditions and analyzing real-time data, manufacturers can anticipate failures before they occur, reduce unplanned downtime, and protect critical equipment.
