MCT and Lead Times

MCT as defined further in this section is a time-based metric that allows you to measure production lead time. It is an important metric as a lot of indirect production costs are related to lead time and lead time reduction also helps in improving cost, quality and on-time delivery.

MCT stands for Manufacturing Critical -path Time, and its formal definition is the typical amount of calendar time from when a customer submits an order, through the critical path, until the first end-item of that order is delivered to the customer.

Typically, the MCT is assessed for a part of the enterprise and in the context of 24Flow for the shopfloor.

The MCT is visualized via an MCT map, and 24Flow allows you to build such MCT maps based on the data captured throughout the production process.

The MCT map serves as a tool to better understand the lead time and identify areas for improvement.

In an MCT map, gray space identifies the time someone is actually working on an order. On the contrary, white space is the time nothing happens to an order. In a manufacturing context, gray space is typically less than 5% of MCT.

Traditional efficiency programs focus on reducing the time spent for processing jobs, however these will typically only have a limited impact on lead time.

MCT is measured in ‘real time’, not ‘working time’. In case data is already in calendar time, there is nothing specific to be done. In case the data is based on actual working time, there is a ‘normalization’ based on the following formula:

MCT portion = (Raw data hours) x 7 / (Weekly working hours)

More information on the MCT concept can be found in the book MCT Quick Reference Guide by Rajan Suri.