In the world of manufacturing, every second counts. Managers are always looking for ways to optimize production processes, reduce waste, and improve overall efficiency. One critical metric that helps in achieving these goals is cycle time. However, cycle time is often confused with other related concepts like processing time and takt time. In this article, we'll dive deep into what cycle time really means, how it's calculated, and how manufacturers can leverage it to streamline their operations.
Understanding Cycle Time
Cycle time is defined as the time required to complete one unit of a product from start to finish at a specific workstation or production stage. It includes both the actual processing time and any auxiliary activities like loading, unloading, or machine setup. Essentially, it's the time a product spends at each step of the manufacturing process.
There are two main approaches to measuring cycle time:
1. Effective Cycle Time: This includes all the supporting steps like loading and unloading. It measures the time from the start of one process to the start of the next process at a given workstation.
2. Machine Cycle Time: This only accounts for the time a unit is actively being worked on or processed by a machine. It excludes any auxiliary activities.
Regardless of the approach, cycle time is a crucial KPI that provides managers with valuable insights into production efficiency and helps identify areas for improvement.
Calculating Cycle Time
For products processed individually, cycle time is calculated by dividing the total process duration by the number of units produced.
CT (per unit) = Process duration / Total units produced
For example, if a CNC machine takes an hour to process 60 units, its productivity is 60 units/hour, and its cycle time is 60 minutes / 60 units = 1 minute per unit.
When products are processed in batches, cycle time corresponds to the processing time for the entire batch.
CT (per batch) = Process duration for a batch
Let's say a bakery oven bakes 100 loaves of bread in 45 minutes. The cycle time for the baking process would be 45 minutes, regardless of whether you're baking 1 loaf or the full batch of 100.
Cycle Time Loss and Optimization
Cycle time loss occurs when equipment runs slower than its ideal speed or when there are minor stoppages that don't qualify as full downtime. The ideal cycle time, usually specified by the equipment manufacturer, serves as the benchmark for measuring cycle time loss.
To calculate cycle time loss, measure the total running time and subtract the ideal cycle time for all units processed.
Cycle time loss = Running time – (Total units × Ideal cycle time)
Reducing cycle time loss is key to optimizing overall cycle time. This can be achieved by:
- Providing thorough employee training
- Implementing effective maintenance practices
- Ensuring high raw material quality
- Eliminating bottlenecks and process inefficiencies
By minimizing cycle time, manufacturers can also reduce overall production lead times.
Cycle Time vs. Processing Time
While often used interchangeably, cycle time and processing time are distinct concepts. Processing time is the total time a product spends in the entire manufacturing process, from raw material to finished good. It includes perform time, inspection time, move time, and queue time.
Cycle time, on the other hand, refers to the time spent at each individual production step or workstation. Processing time and cycle time are only equivalent if the entire manufacturing process consists of a single operation, which is rare in most industries.
Cycle Time vs. Takt Time
Takt time is the pace of production needed to meet customer demand. It's calculated based on the available production time and the number of units required.
For example, if a factory operates 8 hours per day and needs to produce 400 units to meet daily demand, the takt time would be 8 hours × 60 minutes / 400 units = 1.2 minutes per unit.
Takt time provides a drumbeat for production, ensuring that output matches demand. If demand is high, takt time may equal cycle time. However, if demand is low, takt time will be greater than cycle time to avoid overproduction.
Leveraging MRP for Cycle Time Management
A manufacturing resource planning (MRP) system is a powerful tool for managing and optimizing cycle times. By setting realistic cycle times for each operation, an MRP system can accurately schedule production, provide a clear overview of the production timeline, and help identify potential delays or capacity constraints.
When shop floor workers report their activities, the MRP system can generate reports comparing actual cycle times to the planned standards. This data helps managers spot trends, identify inefficiencies, and make informed decisions to optimize production.
The robust data collection and analysis capabilities of MRP software make it a much more effective solution for cycle time management compared to manual methods or spreadsheets.
Conclusion
Cycle time is a critical metric that offers valuable insights into manufacturing efficiency and productivity. By understanding what cycle time is, how it's calculated, and how it differs from related concepts like processing time and takt time, managers can make data-driven decisions to optimize their production processes.
Implementing best practices like employee training, preventive maintenance, and quality control can help minimize cycle time loss and improve overall cycle times. Moreover, leveraging the power of an MES system like HESH can provide manufacturers with the tools and insights they need to effectively manage cycle times, identify improvement opportunities, and ultimately boost their bottom line.
In today's competitive manufacturing landscape, every second counts. By mastering the concept of cycle time and using the right tools to optimize it, manufacturers can increase efficiency, reduce costs, and deliver high-quality products to their customers faster than ever before.
