July 5, 2022
Overall Equipment Efficiency (OEE)
Overall Equipment Efficiency (OEE)
Extrusion engineers and Teams are often tasked with supplying yield metrics when reporting to management. The challenge is how to report this metric. Extrusion yield based on resin consumption is almost impossible to calculate due to start up variations and varying process yields (process stability). Add to that spooled product yields cannot be calculated at extrusion easily and is usually determined at the customer (end use) site. The only true yield count attainable is with cut to length systems with sort select enabled, and only once product is being collected, meaning startup scrap may not be included.
The most effective and valuable way to monitor extrusion processes and yields is through setting up a program to monitor extrusion efficiencies (Overall Equipment Efficiency). Bottom line, the goal of an extrusion capability is being able to efficiently meet the customer demands and maintain high quality. Extrusion efficiency is key and helps identify and guide Extrusion Teams to where best to focus Continuous Improvement Programs (CIPs). OEE is a powerful tool improve a manufacturing capability.
Yields at extrusion are a combination of not only the robustness of the validation, but also the capability of the extrusion system. Very often yields of an extrusion process are not considered as part of the validation. Additionally, existing extrusion systems may not have been specifically designed for the newer products being introduced (thinner walls and sub-0.001-inch tolerances), especially with the newer polymers coming available.
The real value of OEE is with identifying those extrusion processes that are troublesome to run. This is often long setup times, but also can be poor process stability. These processes can also be inconsistent with good (processing) days and bad days. Once benchmarks are set up for the various extrusions the biggest opportunities will become obvious. Typically, a process is broken down into setup, string-up to collect (dial in time) and collection time. Once opportunities are identified, lean or 6-sigma projects should be chartered to implement solutions.
One area of lost time that is easy to identify (low hanging fruit) is downtime related to line break down and setup, which happens almost daily on medical lines. Disassembly of extrusion components at the line, which can include melt pumps and filters as well as the extrusion head and other adapters, can take considerable time (up to 2-3 hours). Complete line downtime from run end to run start can take up a whole 8-hour shift, especially with multi-layer systems. With the development of quick-change carts and a dedicated tool room Team (tooling controls) this process can be done in less than 30 minutes for a single layer line!
Not enough can be said about the contribution of tooling controls to OEE improvements. Maintaining quality extrusion components will prevent additional downtime when setups are found to not achieve the required quality specifications (and yield at collection). Tooling changes after line startup, filter changes, and incorrect setups all effect OEE. Please refer to my articles related to tooling control for further details about tooling control programs.
OEE programs are quite prevalent out in industry, but one should be cautioned about setting a goal based on other industries. One should approach an OEE program by benchmarking all the processes to determine what the current capability is. As data is collected analysis over time will start to highlight those products/products that are inconsistent and yielding poorly and thus targets for CIPs. As projects are identified and improvements are implemented the OEE metric will improve.
One additional comment that needs to be considered is the involvement of the extrusion operators as part of the process. Often implementation of such a program can be seen as rating an operator’s capability. Though this is true, the approach needs to be taken that the goal is to find weaknesses within the system that hinders the operator’s (the team as a whole) ability to make good product efficiently, error free and easy (as possible). What part of the challenge for the operators are the instructions and tools supplied to achieve success? Operators need to be part of the process as they are key to collecting data (timing) as well as supplying additional information related to process challenges. CIP projects will often identify training as one of the contributors to improved OEE.
In conclusion, OEE programs are a more effective way of monitoring process efficiency and as such yields. OEE programs allow for easily identifying and prioritizing CIP projects. It is important to note that both Lean Sigma and 6-sigma (DMAIC) projects will come out of OEE programs, as these will identify a lot of low hanging fruit.
The most effective and valuable way to monitor extrusion processes and yields is through setting up a program to monitor extrusion efficiencies (Overall Equipment Efficiency). Bottom line, the goal of an extrusion capability is being able to efficiently meet the customer demands and maintain high quality. Extrusion efficiency is key and helps identify and guide Extrusion Teams to where best to focus Continuous Improvement Programs (CIPs). OEE is a powerful tool improve a manufacturing capability.
Yields at extrusion are a combination of not only the robustness of the validation, but also the capability of the extrusion system. Very often yields of an extrusion process are not considered as part of the validation. Additionally, existing extrusion systems may not have been specifically designed for the newer products being introduced (thinner walls and sub-0.001-inch tolerances), especially with the newer polymers coming available.
The real value of OEE is with identifying those extrusion processes that are troublesome to run. This is often long setup times, but also can be poor process stability. These processes can also be inconsistent with good (processing) days and bad days. Once benchmarks are set up for the various extrusions the biggest opportunities will become obvious. Typically, a process is broken down into setup, string-up to collect (dial in time) and collection time. Once opportunities are identified, lean or 6-sigma projects should be chartered to implement solutions.
One area of lost time that is easy to identify (low hanging fruit) is downtime related to line break down and setup, which happens almost daily on medical lines. Disassembly of extrusion components at the line, which can include melt pumps and filters as well as the extrusion head and other adapters, can take considerable time (up to 2-3 hours). Complete line downtime from run end to run start can take up a whole 8-hour shift, especially with multi-layer systems. With the development of quick-change carts and a dedicated tool room Team (tooling controls) this process can be done in less than 30 minutes for a single layer line!
Not enough can be said about the contribution of tooling controls to OEE improvements. Maintaining quality extrusion components will prevent additional downtime when setups are found to not achieve the required quality specifications (and yield at collection). Tooling changes after line startup, filter changes, and incorrect setups all effect OEE. Please refer to my articles related to tooling control for further details about tooling control programs.
OEE programs are quite prevalent out in industry, but one should be cautioned about setting a goal based on other industries. One should approach an OEE program by benchmarking all the processes to determine what the current capability is. As data is collected analysis over time will start to highlight those products/products that are inconsistent and yielding poorly and thus targets for CIPs. As projects are identified and improvements are implemented the OEE metric will improve.
One additional comment that needs to be considered is the involvement of the extrusion operators as part of the process. Often implementation of such a program can be seen as rating an operator’s capability. Though this is true, the approach needs to be taken that the goal is to find weaknesses within the system that hinders the operator’s (the team as a whole) ability to make good product efficiently, error free and easy (as possible). What part of the challenge for the operators are the instructions and tools supplied to achieve success? Operators need to be part of the process as they are key to collecting data (timing) as well as supplying additional information related to process challenges. CIP projects will often identify training as one of the contributors to improved OEE.
In conclusion, OEE programs are a more effective way of monitoring process efficiency and as such yields. OEE programs allow for easily identifying and prioritizing CIP projects. It is important to note that both Lean Sigma and 6-sigma (DMAIC) projects will come out of OEE programs, as these will identify a lot of low hanging fruit.
© Copyright Extrusion Consulting, Inc., 2022. All rights reserved.
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© Copyright Extrusion Consulting Inc. 2023 All rights reserved.