We discussed in a recent blog post how lean can be applied in any industry. But when we talk about lean manufacturing, we refer specifically to the application of lean for manufacturing.
By applying lean tools, manufacturers can identify wasteful activities, problems and opportunities to improve productivity.
So if you're looking for ways to transform your manufacturing performance, here are 14 lean manufacturing productivity tools you need to know about.
Often, simply observing processes in action can reveal an abundance of improvement opportunities. This is the notion behind Gemba walks. Gemba is a Japanese term meaning “the real place” - i.e. where the work takes place. Going to the ‘Gemba’ is one of the most important elements of gaining process understanding. It’s often the first step in building a lean environment as it provides a springboard to process improvement opportunities.
Going to the ‘Gemba’ involves observing the processes first hand, taking pictures and videos, sampling parts, copying documents and speaking to the workers. It’s the only way you can really understand how effective and efficient your processes are. It’s easy to get bogged down in reports and focus on KPIs, but it’s simply not enough to rely on this. It’s about looking at the process in action from start to finish and seeing first hand what happens.
2. Error proofing
Errors can lead to defects. But errors are not inevitable. They can be eliminated with tools like Error proofing. Sometimes referred to by its Japanese term 'Poka-Yoke', Error proofing is a simple method that can be applied to detect and prevent defects.
It has three functions:
Shutdown - stop when defect is predicted or detected;
Warning - signals that defect is predicted or detected;
Control - prevent defects from occurring or from passing to next process.
Error proofing techniques usually include:
Limiting: Setting a limit or requirement that can’t be exceeded
Interlocking: Ensuring a combination of actions are undertaken where necessary to prevent an error occurring
Alarming: Giving some form of warning before or after a mistake has occurred
Housekeeping: Ensuring there is a place for everything and everything is in its place.
5s emphasises the importance of a clean, tidy and well-organised workspace to maintain optimum productivity levels and safety. It includes the monitoring and measurement needed to ensure that the workplace contains only what is needed, when it is needed, and where it is needed.
The implementation of 5s involves five ordered steps:
Sort - eliminate what is not needed
Set In Order - arrange items so they can be located quickly
Shine - keep tools and equipment ready to use
Standardise - implement standard ways of working
Sustain - keep to the rules and continue to improve every day.
Creating a Lean 5s workplace is necessary to ensure:
Time is not wasted locating equipment, searching systems, searching computers for files or documentation
Processing time is reduced as equipment, documents and information is within easy reach of the workplace
Time is not wasted as a result of equipment not working properly, such as machines, robots, printers, computers, vehicles, pc applications and systems
Safety is improved through having a tidy, uncluttered, clean and accessible workplace
To ensure visual controls can be easily seen and remain up to date within the workplace.
4. SMED ‘Single Minute Exchange of Dies’ / Rapid changeover
SMED - ‘single minute exchange of die’ - is a system designed to ensure quick changeover times of equipment. Changeover steps can be internal (the machine has to stop operating) or external (the machine can continue operating). The concept of SMED is that moving as many changeover steps as possible to external will reduce the changeover time to 'single' digits - i.e. less than ten minutes.
The benefits of SMED include:
Shorter equipment downtime at changeovers providing higher productivity
Increased machine/equipment/systems utilization
Reduced process lead time and customer wait time
Improved quality due to less storage related defects
Simpler, safer, better understood and standardised changeovers.
5. Total Productive Maintenance (TPM)
Equipment problems can have a dramatic impact on manufacturing operations. And this is where TPM comes in; it focuses on maximising the operational efficiency of equipment. All workers are empowered to play an active role in preventative and predictive maintenance, to ensure no breakdowns, no delays due to slow running equipment, no defects and no accidents.
TPM combines a 5s methodology with eight supporting activities, often referred to as ‘pillars’:
Focused improvement - small groups of employees working together to make regular improvements to equipment operation so problems can be identified early on
Autonomous maintenance - operators are given responsibility for routine maintenance tasks of the equipment they use, such as cleaning, oiling, inspection and diagnosis of potential problems
Planned maintenance - maintenance tasks are scheduled based on the historic failure rate of equipment and for times when equipment is not in use to reduce downtime
Quality management - ensures equipment is able to detect and prevent errors during production
Early equipment management - total life cycle costs are optimised as knowledge gained through previous TPM activities is used to improve the design of new equipment. Design for use by operators, design for maintenance and design for reliability minimises the risk of expensive and disruptive retrofits during and after commissioning.
6. Plan - Do - Check - Act (PDCA)
PDCA is a cyclical approach to continuous improvement which aims to improve the quality and effectiveness of a process. First championed by quality management pioneer W. Edwards Deming, it is also known as the Deming cycle, the Shewhart cycle, or Plan - Do - Study - Act (PDSA).
The PDCA approach emphasises that once improvements have been made we should seek out further improvements, and that this should be a continuous process.
Plan - Establish the objectives and processes necessary to make a change/improvement to solve a defined problem.
Do - Implement the plan in a small-scale test environment under controlled conditions.
Check - Monitor and evaluate the results against objectives and report the outcome.
Act - Apply any improvements needed and roll out the changes to a wider area. Update standard operating procedures and continue to monitor the process so the gains are sustained. Then move onto the next cycle of PDCA.
PDCA reinforces the importance of process improvement as an ongoing, iterative process.
7. Cause & Effect (Fishbone or Ishikawa) Diagram
When faced with a problem, it's crucial to identify the root cause before you come up with a solution. But with so many processes and so many possible reasons for a problem occurring, how do you even begin to know where to look?
The Cause and Effect or C&E diagram was first created by Kaoru Ishikawa in 1968 and is a team approach used to identify root cause relating to an effect. In a brainstorming session, all information is organised to show all the possible causes of a problem and the relationship among them.
Potential causes are grouped into categories, such as materials, equipment, people, environment, methods or measures. This gives structure to the diagram. It is also why it is often referred to as a ‘fishbone’ diagram - as this is what it looks like with the problem making up the fish head and the categories making up the body.
Once the diagram has been built, the 5 Whys method (see below) is used to identify the root cause of the effect.
8. The 5 Whys
The 5 Whys is a simple problem-solving technique that helps get to the root of a problem quickly. It’s a relatively simple method to use as it doesn’t require any data or statistical analysis. Anyone can use it so it encourages workers to be proactive in solving problems. The idea is that each time you ask ‘why’ a problem may have occurred you move closer to identifying a solution. But you don't need to stop at five... keep going until you get to the root cause. By peeling back the layer of symptoms you eventually get to the root of the problem. And save the hassle of the same problem occurring again and again.
The typical steps to conducting a 5 Whys analysis are:
Appoint a 5 Why facilitator
Create the 5 Why team using people with personal knowledge of the systems and processes under review
Create the problem statement
The facilitator asks why the problem happened and records the team response
To ensure that the response is the root cause the facilitator asks – ‘If the most recent response were corrected, is it likely the problem would recur?’ If the answer is yes, it is likely this is a contributing factor, not a root cause, so the facilitator asks Why again and continues to do so until the root cause is identified.
9. Cellular manufacturing
Cellular manufacturing is an approach whereby equipment and workstations are arranged to facilitate continuous production flow.
In a traditional manufacturing environment, similar machines are placed together. In cellular manufacturing systems machines are grouped together according to the families of parts products, therefore improving flow and eliminating waste (e.g. transport of materials, inventory) to improve lead times.
In a manufacturing ‘cell’, all operations necessary to produce a component or sub-assembly are performed in close proximity, therefore enabling production to move as quickly as possible to make a wide variety of products, while making as little waste and possible.
10. Takt Time
Takt Time refers to the average rate needed to produce a finished product based on customer requirements and available working time. Often referred to as the heartbeat of production in lean manufacturing, it provides a simple and consistent method of pacing production. It is calculated by dividing available time by the number of products that need to be produced to meet customer demand.
If there are a total of 8 hours (or 480 minutes) in a shift (gross time) less 30 minutes lunch, 30 minutes for breaks, 10 minutes for a team briefing and 10 minutes for basic maintenance checks, then net Available Time to Work = 480 - 30 - 30 - 10 - 10 = 400 minutes.
If customer demand were 400 units a day and one shift was being run, then the line would be required to output at a minimum rate of one part per minute in order to be able to keep up with customer demand.
Once a takt system is in place bottlenecks can be easily identified when the product does not move on time. And the takt time leaves only a certain amount of time to perform value-adding work, resulting in greater motivation to eliminate all non-value adding tasks.
11. Standardised Work
This is a powerful tool that is too often underestimated in lean manufacturing. It refers to documenting or using other forms of media e.g. graphics, images, video, the tasks that make up the value stream to create best practice standards - ‘standardised work’.
Having clear documentation and guidance on the methods, materials, tools and processing times required to meet takt time for a given job is essential for reducing variability, injury and maintaining high productivity levels. It is also profoundly useful for training of new operators. And it adds discipline to the work culture which is essential in a lean environment where building effective teams is a key goal.
Standardised work is also paramount to continuous improvement. As a standard is improved, it is documented and becomes the baseline for further improvements, and so on. Improving the standardised work is an ongoing process.
12. One-piece flow / Continuous flow
The concept of 'One piece flow' or 'Continuous flow' refers to a part or item being passed along a process without stopping. Ideally, they move along a process where they are subjected to value-adding activities that create the finished product or service for the customer.
In manufacturing, equipment is often required to process more than one type of product with varied daily order volumes and task times. This may lead to processes not being be perfectly balanced. Process steps are not producing at the same rate, therefore there are delays, queues and inventory build up as a result, i.e. no flow. But when the same product is being produced every second, every day, every week, continuous flow can be implemented leading to mass production, standard processing and high productivity.
13. Pull System / Kanban
A Pull or Kanban system is a scheduling system for regulating the flow of goods. The idea is for production to take place on the 'pull' of the customer to prevent the accumulation of excess inventory or overproduction.
The primary goal of a pull system is to synchronise activities across the value stream with customer demand.
Once the pull system is in place, secondary goals can be achieved:
Reducing inventory (working capital)
Reducing lead time
Reducing labour, overhead and productivity costs
Pull Systems help provide process stability, making it easier to control the process and manage it as changes in demand occur. And less WIP clears the way to see and focus on problem areas, allowing analysis and improvements to be made.
14. Heijunka / Leveling the Workload
Manufacturing success comes down to being able to meet customer demand. However, buying patterns are often unpredictable. The Heijunka (Japanese for ‘levelling’) technique helps manufacturers to meet unpredictable customer demand patterns and eliminate waste by levelling the type and quantity of production output over a fixed period of time.
The first step in levelling production is to set the pace of manufacturing to the takt time. This helps to create a level manufacturing process that is free of bottlenecks. Manufacturers that implement a Heijunka levelling system in their processes will have greater flexibility to produce what the customer wants, when they want it, and will benefit from a reduced inventory of unsold goods. While Gemba is best used at the start of the lean journey, Heijunka is better suited to later stage lean implementation, once the lean philosophy has been embedded into processes.
Applying these productivity improvement tools can transform your manufacturing performance. The more opportunities you have to see waste and remove it, to get to the root of problems, and to eliminate variations and defects, the better equipped you will be to grow your manufacturing organisation in today's increasingly global, competitive and demanding environment.