Key takeaways
- Centerlining contributes to consistent product quality as it reduces and controls product and process variability
- It offers numerous benefits, such as simplifying operations, reducing waste and improving safety
- Digital tools enhance the centerlining process with instant access to key data and trends
Manufacturers need to ensure their products consistently meet or beat the often-changing demands of their customers. A quality product that satisfies the customer is achievable when the manufacturing process runs optimally, assisted by a process known as centerlining. This blog discusses the centerlining process and its benefits in a manufacturing environment.
The centerlining process in manufacturing
Centerlining is a methodology used in manufacturing to reduce and control product variability, contributing to consistent product quality. In addition, centerlining increases machine efficiency and assists in stabilizing a production process around a central product specification.
The repetitive four-step PDCA (Plan-Do-Check-Act) cycle enables continuous improvement of processes, products and services, and it covers the two objectives of centerlining:
- Plan and Do – determine the best settings for a process
- Check and Act – ensure the best settings are always used
These two points are discussed in more detail below – see 4 steps to prepare for centerlining.
The underlying approach in centerlining is to Eliminate, Simplify, Standardize and Automate (ESSA) machine settings in order to streamline processes and remove inefficiencies, thereby improving Overall Equipment Effectiveness (OEE).
Standard operating procedures (SOPs) are step-by-step instructions for carrying out routine operations. They can help to reduce variability by outlining how machines are set up and operated. We suggest you visually display the SOP near the machine and then review it regularly so that it remains up to date.
Learn how to develop a customer-focused quality improvement plan.
Centerlining can be applied to various activities in operations
- Machine positioning
- Timing
- Speed and rate settings
- Temperature settings
- Conveyor guides
- Infeed and outfeed of process
- Inspection points and sensors
4 steps to prepare for centerlining
The four steps involved in preparing for centerlining are as follows:
Identify the important process factors or variables
The key variables in your manufacturing process can be determined by operators and agreed upon by the relevant stakeholders. It’s important to select the correct variables if you truly expect to have a positive effect on the process and product quality. That’s why it’s advisable to get a subject matter expert, such as a process, technical or quality specialist, to evaluate your process and identify the variables you’ll centerline.
Determine the best settings and ranges for all the important variables – by grade or product if multiple products are being produced
Your next step will be to create limits for these key variables. Here, you’re basically determining the acceptable range for each variable – with upper and lower control limits – to allow for flexibility to deal with outside influences. Anything falling outside of the acceptable range will result in unacceptable product quality. The implementation of these settings will be the responsibility of asset care personnel. See graph below.
Control limits and center line
Determine how these variables affect the process and the product
Once your key variables and variable limits have been established, you’ll need to monitor them to evaluate your newly centerlined process. This is where access to accurate, clearly presented data is enormously important. (Although it’s possible to evaluate a centerlined process using manual methods of data recording, it’s time-consuming to record and recall that data, and the possibility of data error is quite high.)
Ensure that the centerlined settings are always used during production
Now that you’ve figured out your optimal process, here’s where you refine your formula. Inform operators and engineers about your new processes and make resources available that allow them to easily understand any changes you’ve implemented. At this stage, you’ll want to make sure you have solid reporting on an hourly, daily or weekly basis to evaluate product quality against centerlines.
Discover the 12 steps to reduce variation with centerlining.
Important roles and responsibilities in the centerlining process
The operator:
- Checks center lines at every shift
- Ensures machines are running at centerline
- Collects centerline data and communicates nonconformances to work team and multidisciplinary team meetings
A subject matter expert (process specialist, technical specialist, quality expert) will identify adjustable points and verify technical correctness of settings.
A centerline process owner (department managers, process engineer, best practice leader, quality manager) will be the coach or trainer of the centerline process and ensure that centerlining is implemented effectively.
Maintenance personnel will make necessary enhancements to machines and assist in compiling documentation.
How digital tools enhance the centerlining process
Data records about machine setups and adjustments are often stored on printed paper, which can be time-consuming to access or update. Nowadays, some forward-thinking manufacturers are using digital tools such as mobile devices or digital dashboards to retrieve and store operational data. This includes quality measurements and information about adjustments to specific machines. These digital tools can use machine learning and historical data to automatically derive adjustments.
The tools help to automate the centerlining process, provide easily accessible information about a process, and help operators complete their task faster and more efficiently.
The benefits of centerlining
Centerlining offers many benefits – it:
Improves quality:
- Builds quality into the process
- Generates fewer rejects and less scrap
Provides operational stability:
- Reduces adjustments and randomness
- Eliminates variation caused by unnecessary adjusting and tinkering
- Provides a baseline for operational performance
Simplifies operation:
- One right way to set up machines — processes are run at settings that provide the optimum performance
- Tinkering at the beginning of shifts is eliminated which facilitates shift changeovers
- Visual controls on machines facilitate setups and adjustments
- Supports problem-solving as the “What has changed?” question becomes easier to answer
Improves safety:
- Reduces the amount of manual adjusting and therefore the risk of injury
Improves reliability performance:
- Establishes a repeatable process
- Highlights material issues with confidence as machines have been set up in the best way
- Reduces downtime as setup information is readily available
Improves machine operating efficiency (and OEE) :
- Eliminates unnecessary adjustments
- Simplifies and enables more accurate changeovers
- Reduces setup time (a best practice of ensuring that changeovers and setups are done in the shortest and most cost-effective way)
- Reduces machine downtime
- Reduces machine variation
- Enables quicker ramp-ups
- Enables production run to target
- Reduces minor stops
Improves yield and reduces waste
Facilitates short-interval control and problem-solving
Identifies potential problems
A continuous process
Centerlining is a never-ending process, and continuous work on all of the steps is needed in order to reap the most benefits.
Centerlining alone, however, cannot achieve all of the potential benefits. The best results can only be achieved if the equipment is properly maintained and upstream processes are also centerlined. Additionally, easy access to process data and trends from past runs can enhance centerlining efforts by making it easy to determine where the process is, where it’s supposed to be, and where it has been historically.
Learn how to make key information easily accessible on the factory floor.
Frequently asked questions
What is centerlining in manufacturing?
Centerlining is a methodology used in manufacturing to reduce and control product variability, contributing to consistent product quality. It stabilizes a production process around a central product specification and increases machine efficiency. The approach identifies the optimal settings for key process variables, then ensures those settings are always used during production.
What are the four steps to prepare for centerlining?
The four steps are: identify the important process factors or variables; determine the best settings and ranges for each variable, with upper and lower control limits; determine how those variables affect the process and product through monitoring; and ensure the centerlined settings are always used during production, supported by regular reporting on product quality.
What are the benefits of centerlining?
Centerlining improves quality by building it into the process and generating fewer rejects. It provides operational stability, simplifies machine setup, improves safety by reducing manual adjustment, and boosts reliability and Overall Equipment Effectiveness. It also reduces waste, shortens setup time, and makes problem-solving easier because the question “What has changed?” becomes simpler to answer.
Who is responsible for the centerlining process?
Centerlining involves several roles. The operator checks center lines each shift, keeps machines running at centerline, and collects data. A subject matter expert identifies adjustable points and verifies settings. A centerline process owner coaches the process and ensures effective implementation. Maintenance personnel enhance machines and help compile documentation.
How do digital tools improve the centerlining process?
Digital tools improve centerlining by replacing printed records with mobile devices and digital dashboards that store and retrieve operational data instantly. They can use machine learning and historical data to automatically derive machine adjustments. This automates parts of the process, makes information easily accessible, and helps operators complete their tasks faster and more accurately.