Reducing manufacturing times is one of the most direct ways to improve industrial efficiency. In this context, production lead time is the indicator that best reflects how work actually flows within a plant.
Unlike other indicators, lead time does not only measure how much is produced, but how long it takes for an order to be completed, including all the inefficiencies of the system.
What is production lead time
Production lead time is the total actual time it takes for a manufacturing order to be completed, from start to finish, including both productive work and waiting times, stoppages, and incidents.
Lead time measures the total time an order remains within the production system; it does not measure production speed, but rather the overall efficiency of the flow. This includes:
- Actual manufacturing time (value-added work).
- Waiting times between operations.
- Machine downtime.
- Lack of materials.
- Rework or incidents.
How to calculate production lead time
The formula for lead time is: lead time = end date − start date.
For the data to be useful, lead time must be broken down into value-added time, waiting time, and non-productive time.
Reducing lead time is not about producing faster, but about eliminating time that does not add value.
Difference between lead time, cycle time, and delivery time
These three concepts are often confused, but they measure different levels of the production process:
- Cycle time: the time required to complete a specific operation.
- Production lead time: the total time an order spends inside the plant.
- Delivery time: the total time until the product reaches the customer.
In summary, cycle time measures operations, lead time measures the full flow within the plant, and delivery time measures the entire supply chain.
Relationship with other KPIs
Lead time is not optimized directly; it is reduced by improving the factors that generate it.
It is not an isolated indicator, but a direct consequence of how the production system operates. It is closely related to other KPIs, especially those that measure flow, capacity, and efficiency.
WIP (work in progress)
WIP, or work in progress level, has a direct relationship with lead time. As WIP increases, queues between operations grow, waiting times increase, and the system flow slows down. The higher the WIP, the higher the lead time.
This behavior is explained by the fact that each additional order in the system introduces more waiting time before it is processed.
Reducing WIP is one of the most effective ways to reduce lead time without needing to increase production capacity.
Bottlenecks
Lead time is constrained by the operation with the lowest capacity in the system, i.e., the bottleneck.
When one stage of the process operates more slowly than the others, work accumulates before that operation, waiting times increase, and the total order completion time becomes longer. In addition, any variability or downtime at this point has a disproportionate impact on total lead time.
Improving the performance of the bottleneck has the greatest direct impact on reducing lead time.
Continuous flow
Continuous flow is one of the key principles for reducing lead time.
A well-flowing system is characterized by low accumulation of intermediate inventory, fast transitions between operations, and synchronization between processes. The greater the flow continuity, the lower the lead time.
On the contrary, when the flow is interrupted, waiting times appear, WIP accumulates, and the total system time increases.
Reducing interruptions and improving flow continuity is essential to shorten lead time.
Variability
Variability in process times, quality, or availability has a direct impact on lead time.
When the system is variable, mismatches between processes are generated, waiting times increase, and uncertainty grows. The higher the variability, the higher the lead time.
Standardizing processes and reducing variability helps stabilize and reduce lead time.
OEE
OEE (Overall Equipment Effectiveness) measures equipment efficiency in terms of availability, performance, and quality.
A low OEE increases lead time by introducing interruptions and performance losses. Improving equipment availability and stability directly contributes to reducing lead time.
Types of lead time in an industrial environment
Lead time can be analyzed at different levels of the production system or supply chain. Each type helps identify inefficiencies in a specific part of the flow, from procurement to final delivery.
Manufacturing lead time
It is the total time that an order spends inside the production plant, from its release to its completion. It includes processing times, waiting times between operations, stoppages, and incidents within the production environment.
Procurement lead time
It is the time required to obtain materials or components from the moment the order is placed until they are available for use in production. It includes transportation, supply, and the supplier’s administrative processing times.
Total lead time
It is the complete end-to-end process time, from purchasing materials to delivering the product to the final customer. It integrates procurement, manufacturing, storage, and logistics.
Operation lead time
It is the time associated with a specific phase of the production process. It includes the execution time of the operation as well as the waiting times before and after each stage.
Factors affecting production lead time
Lead time is the direct result of how the production system operates.
- Poor planning generates waiting times, priority changes, and imbalances.
- Operations with lower capacity limit the entire system.
- Breakdowns interrupt the flow and increase total time.
- Lack of synchronization or coordination between processes creates idle time.
- Lack of real-time visibility means that, without up-to-date data, decisions are delayed.
How to reduce production lead time with MES
The greatest potential for reducing lead time is often found outside the direct production process and depends largely on the ability to manage the system with real-time information.
In this context, a MES system becomes a very useful tool, as it allows the entire production flow to be visualized, analyzed, and acted upon, making continuous optimization of operations possible.
Operational improvement
Continuous improvement methodologies are most effective when they are based on real process data. An MES provides exactly this foundation, allowing inefficiencies to be identified with precision in terms of where they are generated.
Main improvement areas:
- Reduction of waste identified through real production data.
- Optimization of changeovers through analysis of times recorded in the MES and implementation of SMED methodology.
- Process standardization based on the actual behavior of the system.
- Detection of variability using SPC.
The MES turns operational improvement into a measurable process, rather than one based on estimates.
Flow management (Lean approach)
From a Lean perspective, lead time is strongly influenced by the level of work in progress (WIP) and flow stability. The MES allows this flow to be monitored in real time and helps identify where build-ups are occurring.
Thanks to MES, it is possible to:
- Visualize WIP at each stage of the process.
- Identify queues and waiting times between operations.
- Analyze flow bottlenecks in real time.
- Evaluate the impact of planning changes.
Reducing WIP with real-time visibility directly decreases waiting times and therefore the total lead time.
Production digitalization
MES is the foundation of operational digitalization in the plant, as it connects the physical world of production with structured and usable data.
An MES system allows you to:
- Monitor production in real time.
- Automatically capture data from machines, operators, and orders using IoT.
- Detect bottlenecks as they occur.
- Analyze inefficiencies with full traceability.
- Improve operational decision-making.
An MES like Mapex not only records what happens, but also helps understand why it happens.
How MES impacts lead time
MES directly influences all the factors that determine lead time within the plant. Its value is not in measuring more, but in enabling faster reactions and better decision-making.
It is a platform that helps reduce operational uncertainty by providing real-time visibility of the production system and delivers benefits such as:
- Reduction of waiting times between operations.
- Improved coordination between processes.
- Immediate detection of incidents and stoppages.
- Continuous optimization of production planning.
- Reduction of execution variability.
Real example of lead time reduction with MES
An industrial plant has a total lead time of 10 days: 4 days of actual production and 6 days of waiting times, stoppages, and inefficiencies.
Before digitalization, these times were not visible in a structured way, making it difficult to identify the real causes of delays.
After implementing an MES and using it for operational management, real-time visibility of WIP is achieved, hidden bottlenecks are identified, order sequencing is optimized, and waiting times between operations are reduced.
Lead time is reduced from 10 to 6 days without increasing production capacity. This optimization does not depend on producing faster, but on using the MES to improve visibility, flow, and decision-making within the production system.
FAQs about lead time
What does lead time mean?
Lead time is the total time it takes for a production order to be completed from start to finish, including working time, waiting times, stoppages, and process inefficiencies.
How is lead time calculated?
Lead time is calculated by subtracting the start date of an order from its completion date. Formula: lead time = completion date − start date.
What is meant by lead time?
Lead time refers to the total flow time of an order within a production system or supply chain, from its beginning to its completion or delivery.
What is lead time and takt time?
Lead time is the total time an order takes to be completed within the production system. Takt time is the production rate needed to meet customer demand, calculated as available time divided by demand.
