Mistake Proofing (Poka-yoke)-How it save upto one million dollar in industry

Good Morning Friends,

Today's our topic is Mistake proofing/Poka-Yoke.

Generally the most effective way to achieve quality is to avoid having defects in the first place. It is much less costly to prevent a problem from ever happening than it is to find and correct the problem after it has occurred. In this article we can learn What is Poka Yoke, How it helps save the million of money, When to use it, how to use it, benefits of Poka yoke etc.

What is Mistake proofing/Poka yoke?

Poka-Yoke is a Japanese term that means “mistake-proofing”. It is the use of any automatic device or method that either makes it impossible for an error to occur or makes the error immediately obvious once it has occurred.  In other words, the goal is to make an object that prevents the user from messing up. Small design features and visual clues can influence the safety and efficiency of everyday objects.

The main aim of mistake proofing is:

Prevent a defect from occurring and when this is not possible, Detect the defect every time  occurs.

When to use mistake proofing?

Poka-yoke can be used wherever something can go wrong or an error can be made. It is a technique, a tool that can be applied to any type of process be it in manufacturing or the service industry. Errors are many types -

Processing error: Process operation missed or not performed per the standard operating procedure. 

Setup error: Using the wrong tooling or setting machine adjustments incorrectly.                     Missing part: Not all parts included in the assembly, welding, or other processes.
Improper part/item: Wrong part used in the process.  

Operations error: Carrying out an operation incorrectly; having the incorrect version of the specification.

Measurement error: Errors in machine adjustment, test measurement or dimensions of a part coming in from a supplier.

How to use mistake proofing?

Step by step process in applying Poka-yoke:

1. Obtain or create a process flow chart also Pareto chart of the error. Review each step, thinking about where and when human errors are likely to occur.
2. For each potential error, work back through the process to find its source.
3. For each error, think of potential ways to make it impossible for the error to occur. Consider:  Elimination—eliminating the step that causes the error,Replacement—replacing the step with an error-proof one,Facilitation—making the correct action far easier than the error.
4. If you cannot make it impossible for the error to occur, think of ways to detect the error and minimize its effects. Consider Inspection method , setting function and regulatory function.
5. Choose the best mistake-proofing method or device for each error. Test it, then implement it. Three kinds of inspection methods provide rapid feedback:

• Self-inspection means workers check their own work immediately after doing it.
• Successive inspection is done at the next step of the process by the next worker.
• Source inspection checks, before the process step takes place, that conditions are correct. Often it’s automatic and keeps the process from proceeding until conditions are right.

Practical Example of Poka yoke:

1. Sensors

Proximity sensors emit a high-frequency magnetic field and detect an upset in the field when an object enters it. They can be used to detect the presence or absence of an object.

Applications

• Sensing of tank or bin level
• Confirmation of part or object passes by
• Detection presence or absence of object
• Positioning of work piece

2. Error Detection & Alarms

In general, an error detection device can provide a visual alarm such as a flashing light or an audible alarm such as a horn or siren.These devices signal that a problem is either about to occur or has just happened. With a warning effect, the response is not automatic; someone has to take action.

Applications

• The signal must be triggered by something in the process, usually a sensor.

3 Some bad and good Poka Yoke

Here we can consider example of credit card

bad Poka yoke- credit card slot requires card to be slid in only one (of four possible) directions
better Poka yoke -credit card slot accepts card either direction, but only on correct side
even better Poka yoke - credit card slot accepts card slid no matter how you do it
poke-yoke = chip in credit card, just get it anywhere near card reader


Ideally, poka-yoke ensures that proper conditions exist before actually executing a process step, preventing defects from occurring in the first place. Where this is not possible, poka-yoke performs a detective function, eliminating defects in the process as early as possible. Don't allow defects to occur in your processes by neglecting to prevent mistakes in your work. Use poka-yoke to make the work easier and mistake proof your process


Thanks friend for reading, I welcome for any comments or feedback about post.
also please reply for any details information.
Thank You.

How to Line balncing or leveling the Production -Heijunka

Dear Friends,

Todays our Topic of  Heijunka-Line balancing or Leveling the production.

In the todays session we can learn about what is Heijunka, what is need of it, how to implement it, Implementation with Practical example (Case study),also benefits to your factory after implement this Heijunka concept.

What is Heijunka?

Heijunka is the “Leveling the type and quantity of production over a fixed period of time. This enables production to efficiently meet customer demands while avoiding batching and results in minimum inventories, capital costs, manpower, and production lead time through the whole value stream.”

Heijunka (pronounced hi-JUNE-kuh) is a Japanese word that means “leveling.” When implemented correctly, Heijunka  helps organizations meet demand while reducing while reducing wastes in production and interpersonal processes.

Relationship Among Predictability, Flexibility and Stability Is Heijunka – When implemented correctly, Heijunka provides predictability by leveling demand, flexibility by decreasing

changeover time and stability by averaging production volume and type over the long term.

Heijunka concept:

Your customer orders will most likely fluctuate from day-to-day. One day they will want 10 black and 5 red parts, the next day could be 12 red and 7 black. The obvious problem in this scenario is that one day the customer will order 15 parts and the next day they require 19. On the third day they may only require 13 parts. Whatever the numbers, they will vary.

Levelized production is used to smooth out that variance. Using the above example, if the level volume is set at 15 parts per day, production would replenish the 15 parts that were ordered. On the second day, as the order is 19 parts (4 parts higher than our levelized production volume) they would still build 15 parts and the shipping area would take 4 parts from an inventory called "Fluctuation stock". On the third day, the order was 13 parts, which is two less than our Heijunka volume, two parts can be rebuilt and put back into fluctuation stock. Heijunka concept applied in two ways as follows.

1) Leveling by Volume or Type

In order to set the level volume for production, you will need a good forecast and a good record of shipping history. The forecasts will be the driving force for setting the volume but the history of customer orders will let you understand the level of fluctuation you can expect from any one of your customers.

This fluctuation is key to setting your fluctuation stock levels. If a customer can vary 30% a day for 3 days, then you will need to be prepared to carry 90% of a day in fluctuation stock. If it can not be replenished throughout the week, it should be rebuilt over the weekend if time allows. This may seem contradictory to the waste of inventory  principle, but this is controlled stock (through the use of kanbans). There is also a huge benefit in other areas that will off-set this inventory.

2) Leveling by Line balancing production (Internal factory)

Here the concept of line balancing come in to picture. Every worker should have to do the  same work to increase the line efficiency. No one should be over burden or no one should be Waiting.

Core Concepts to Guide Heijunka Implementation

Keeping in mind the core concepts about heijunka will help keep a company heading in the right direction.

• Takt time: The time it takes to finish a product in order to meet customer demand; can be thought of as the customer buying rate. It is the guidance for the entire heijunka implementation.
• Volume leveling: Manufacture at levels of long-term average demand and keep a buffer inventory proportional to variability in demand, stability of production process and shipping speed.
• Type leveling: Essentially, make every product every day and reserve capacity for changeover flexibility; use a heijunka box to visualize the production flow and schedule.
• Work slowly and consistently: Taiichi Ohno, founder of the Toyota Production System, says it best: “The slower but consistent tortoise causes less waste and is much more desirable than the speedy hare that races ahead and then stops occasionally to doze. The Toyota Production System can be realized only when all the workers become tortoises.”
• Changeover time: Efficiency of changeover is the fulcrum of heijunka; narrowing changeover times helps tighten the value stream between supply and demand.

Case Study/Practical Example:

All operator are doing consecutives operation process as Process

 Operator 1 - have 5 Min work to complete Plugging Process

Operator 2 - have 25 Min work to complete Assembly process

Operator 3 - have 15 Min work to complete Taping process

Operator 4 - have 13Min work to complete Testing & Packing

In this condition Operator 1 has very less work to do so he may can produce overproduction or he may ideal.

In case of operator 2 has more work so he required more time he has overburden and pressure

In case of operator 3 has 15 min  work so he waiting for piece to get from Operator 2

In this way all next process are waiting that is wastages.

Here Line balancing Ratio is very Low.

                                         Total work content (Add all times)

Line balancing ratio=       No of station * Longest station

                                      5+25+15+10

Line balancing ratio=     4*25                   = 55%

For improvement purpose we plan to conduct line balancing.

Action-

Time study conducted for each Process.

Sub divided each process as per content wise tact Time

then Redistributed work to each operator as per Tact time

Each operator got almost equivalent work so summary as follows.

Result-

All operator are doing consecutives operation process as Process

 Operator 1 - have 15 Min work to complete Plugging Process

Operator 2 - have 15 Min work to complete Assembly process

Operator 3 - have 1 Min work to complete Taping Process

Operator 4 - have 10Min work to complete Testing & Packing

In this condition Operator 1 has got more additional work of operator 2 so he is not ideal

In case of operator 2 has got balance work so no overburden and pressure

In case of operator 3 has 15 min  work so he not need to wait, he got job on time

In this way all next process are Finished on time without delay, productivity increased.

Here Line balancing Ratio is very Low.

                                         Total work content (Add all times)

Line balancing ratio=       No of station * Longest station

                                      5+25+15+10

Line balancing ratio=     4*15                   = 92%

Benefits of Heijunka Line Balancing-

• Promote one piece flow by line balancing

• Avoid overburden so reduction of stress levels in the production area.

• reduce the wastages like overproduction, rework, motion, over processing

• reduce Variation in the production load and demand

• reduction in inventory levels

• stability of your manpower and reduction of unnecessary overtime.

In this way we can implement the line balancing concept in our factory, we earn more profit also to increase the productivity of the plant. please comments if you have any difficulty in implementing the Heijunka in factory also for any feedback.

Thanks!!!!!

How to do process mapping -Value stream mapping

Good  Morning Friends,

Today's Our topic is Value stream mapping.

Here some people are confuse about value stream mapping (VSM) and plant layout. in layout we are mentioning only plant or machinery layout, flow from inside the plant but in VSM we are taking care of parts and information flow. its not only related to equipment flow  but also information & parts from customer to supplier end. we can see in details how it works & helpful to industry.

Below we will go through

What is VSM

VSM Symbols

Defining the process boundaries

The Process Steps

Information Flows

Process Data

Calculating the Time Line

Multiple Suppliers and Customers

Interpreting the Data

Next Steps (Ideal and future state maps)

What is value stream mapping?

Value stream mapping is a lean-management method for analyzing the current state and designing a future state for the series of events that take a product or service from its beginning through to the customer. At Toyota, it is known as "material and information flow mapping".

This enables you to see at a glance where the delays are in your process, any restraints and excessive inventory. Your current state map is the first step in working towards your ideal state for your organization.

Value Stream Analysis-

Planning tool to optimize the result of eliminating waste.

Select the product/family

identify the current state VSM which describe the process as it today

Apply lean technique to reduce the waste.

Create future state of VSM which describe the ideal state based on lean principles

Purpose of VSM & Why its required in Lean?

1) Provide optimum value to the customer through a complete value creation process with minimum waste in:

– Design (Concept to customer)

– Build (order to delivery)

– Sustain (in-use through life cycle to service)

2) Many organizations pursuing “lean” conversions have realized that improvement events alone are not enough

3) Improvement events create localized improvements, value stream mapping & analysis

strengthens the gains by providing vision and plans that connect all improvement activities

4) Value stream mapping & analysis is a tool that allows you to see waste, and plan to eliminate it

VSM Symbol-

The picture to the below shows some of the commonly used value stream mapping symbols and their meanings. It is not necessary to use these specific symbols, if you have symbols that are more relevant / descriptive for your processes then use those.

Guideline to create VSM-

1) Select the product or product family

Firstly we need to decide what it is exactly that we wish to map, in a company with many products there may have to be some initial work done to identify which product or family group of products that should be mapped, we may decide to go with highest volume or value, or take a longer term strategic look at those product ranges that we expect to do more business with in the future or we may be guided by our customers as to what to map.

2)Bound the Process

We need to decide the limits of our map, most value stream maps are conducted from supplier through to customer within an organization and these should be the first boxes placed on your VSM to bound the process. It is possible to map the entire supply chain, in this case the start and end points for your process map would be the raw materials and the final consumer.

3)Process Steps

process flow start from customer to supplier or supplier end. The process steps are the various operations that are performed on the product, these are generally located in a single place with one point that inventory enters and then leaves. We are not breaking down each operation into specific tasks, there are other process mapping techniques such as flow charting that would be a better tool for analyzing to that level of detail.

4)Add Information flow-

One of the things that differentiates a VSM from most other mapping tools is the inclusion of the information flows into the map. We need to include how the customers order product, frequency and method, and how we translate that back to our supplier. We also include how we then communicate requirements to our processes to ensure that we produce what the customer wants.

5) Collect and add data

This where we need to do a little thinking and some work, get the team to collect data regarding the performance of each step of the process; typical types of date to collect are;

• Inventory
• Cycle time (time taken to make one product)
• Change over time (from last good piece to next)
• Up-time (on-demand machine utilization)
• Shifts worked
• Net available working time
• Scrap rate
• Pack size/pallet sizes
• Batch Size

6)Time line & Inventory

We create the time line to give us information about total process times and lead times for inventory through our processes; we use the inventory at each stage and the daily demand to calculate the amount of stock in days and add this to the top of the time line, this will allow us to calculate a total lead time. The cycle time for one product is then placed in the lower portion and this will be added to give a total processing time.
It is usual to at this point to have lead times that are several days to several weeks and processing times that are only a few minutes which highlights just how much waste there is in our system.

7) Multiple Suppliers and Customers in VSM

The map produced above is a fairly simple map with just one customer and one supplier, more often than not we have multiple suppliers and customers and it may be necessary to draw on more than one. In this case the process is still the same but when you calculate your timeline use the worst case for inventory. If you have many suppliers it may be worth concentrating on your most important suppliers or grouping them into similar types such as fasteners.
More often than not you can still show multiple customers as one, or if required as groups with similar requirements such as weekly or monthly demands.

Step by step procedure with case study (Practical example) :

I would like to give live example of my Ex company Tata yazaki. It producing wiring harness, here at production we face some problems as follows.

-Shortage in the supply of harness to the Tata customer

-High level of inventory and safety stock of almost 10 days

-Quality complains are increasing day by day so big problem to Maintain the PPM.

Problem are going to increased day by day so start a Gambia meeting in factory. Action done as follows, guideline help to Improve the VSM.

1) Select your Team

We select the team   that each area or stakeholder of the process is represented e.g. Sales, Purchasing, Warehouse etc.


2) Select process to be mapped

Value Stream Mapping is suitable for most businesses and can be used in Manufacturing, Logistics, Supply Chain and some Service orientated Organizations so we select map based on that.

3)Collect data and produce current map

We collected data of process times, inventory or materials information, customer (or demand)requirement the future state maps will be developed using information captured here so it’s imperative

4) Critic current stage

we have big problem in our process flow also Layout so change that accordingly also done brainstorming process to get the idea.

-Challenge the current thinking, encourage your team to make suggestions, look for areas of waste.

5)Map future state

-Compile the future state map on the base of current state of map and the critiques

6) Create action plan and deploy it

Taking a future state map consider an action plan that could be implemented to change the current process to the future state

7)Measure the benefits

as per problem check, we got benefits in inventory, also less material handling, no shortage in demand of supply to the customer also customer satisfaction level increased and our factory rating change from B+ to A .

Key Tips  for VSM:

• Experience directly. You (or your team) should follow the whole value stream yourself. Don’t rely on impressions, assumptions, or conversations about how things “usually” happen. If it’s a physical thing, walk it, use a stopwatch to time various steps, and experience it all as directly as possible. At least one team member needs to walk the whole stream. If you rely on subteams to walk different portions, and nobody walks the whole thing, you will miss an essential perspective to VSM.
• Sketch an initial VSM by hand. Start by sketching in pencil as you document the steps. Later you can use chart-drawing software to communicate and collaborate better and map out a future/ideal state.
• Do initial walk-through. You might start with a quick walk to experience it at an overview level, and then do it again in more detail.
• Try doing it in reverse, from end product or service to its origins. Various items could become more clear and meaningful with that perspective. Many veteran VSM practitioners do it this way.
• Keep asking why. In Lean Six Sigma, it’s sometimes called the Five Whys. The idea is to simply ask why something is done as it is. To the response, another why is asked. This continues until you drill down to the ultimate basis for the action.

 If you have any doubt or query about value stream mapping creating or overview please reply me.

Thanks

Lean manufacturing principle-step by step principle

Good Morning Friends,

 Lean manufacturing principles-Implementation

There are several key lean manufacturing principles that need to be understood in order to implement lean. Failure to understand and apply these principles will most likely result in failure or a lack of commitment from everyone in your organization. Without commitment the process becomes ineffective. This page reviews some of the more critical lean manufacturing principles and should help you get started. Consider these to be the "guiding principles" of lean manufacturing as there are others that have not been included.

The five-step thought process for guiding the implementation of lean techniques is easy to remember, but not always easy to achieve:

1. Specify value from the standpoint of the end customer by product family.
2. Identify all the steps in the value stream for each product family, eliminating whenever possible those steps that do not create value.
3. Make the value-creating steps occur in tight sequence so the product will flow smoothly toward the customer.
4. As flow is introduced, let customers pull value from the next upstream activity.
5. As value is specified, value streams are identified, wasted steps are removed, and flow and pull are introduced, begin the process again and continue it until a state of perfection is reached in which perfect value is created with no waste.

 Lean Manufacturing Principles-

Elimination of Waste

One of the most critical principles of lean manufacturing is the elimination of waste (known as muda in the Toyota Production System).

The Seven Wastes of Lean Manufacturing are;

• Transport
• Inventory
• Motion
• Waiting
• Over-Processing
• Overproduction
• Defects

Although the above mentioned types of waste were originally geared toward manufacturing, they can be applied to many different types of business. The idea of waste elimination is to review all areas in your organization, determine where the non-value added work is and reduce or eliminate it.

Kaizen (Continuous Improvement)

Kaizen is the strategy where employees work together proactively to achieve regular, incremental improvements in the manufacturing process.

It should truly form the basis of your lean implementation. Without continuous improvement your progress will cease. As the name implies, Continuous Improvement promotes constant, necessary change toward achievement of a desired state. The changes can be big or small but must lend itself toward improvement (often many small changes are required to achieve the target). The process truly is continual as there is always room for improvement.

Continuous Improvement should be a mind-set throughout your whole organization. Do not get caught up in only trying to find the big ideas. Small ideas will often times lead to big improvements.

Respect For Humanity

The next lean manufacturing principle has to do with people. The most valuable resource to any company are the people who work for it. Without these people the business does not succeed. When people do not feel respected, they tend to lose respect for the company. This can become a major problem when you are trying to implement lean.
Most people want to perform well in their jobs. Not only do they go to work to earn a living, but they also want to develop a sense of worth in their work. They want to feel like they have contributed to the company goals, like their work and effort has meant something.
Some of the methods to ensure your people know you respect them is through constant communication, praise of a job well done, listening to their ideas and helping out when necessary.

Heijunka (Levelized Production)

Heijunka is a form of production scheduling that purposely manufactures in much smaller batches by sequencing (mixing) product variants within the same process
As mentioned on the home page, the foundation of lean manufacturing is levelized production. The basis of this principle is that the work load is the same (or level) every day. Most manufacturing companies are at the mercy of their customers for orders. Before producing product, they wait to get orders. This leads to increased delivery lead time which may not satisfy customer requirements.

On the other end of the spectrum, some companies will produce based strictly on a forecast. This may result in excess product that is not required by the customer. it takes into consideration both forecast and history. The key ingredient for this lean manufacturing principle is utilization of a pull system.

 

Just in time

Pull parts through production based on customer demand instead of pushing parts through production based on projected demand. Relies on many lean tools, such as continuous flow, Heijunka, Kanban, Standardize work and Takt time   Working in conjuction with levelized production, this principle works well with kanbans (a pull system). It allows for movement and production of parts only when required. This means components are not used in product that is not required and no time is wasted building unsaleable product.

Just in time helps to maintain inventory level, also due to just in time concept material & money will not stuck, money flow will be fast. also product  quality will increased so customer satisfaction level will increased.

Quality Built In

The last key lean manufacturing principle that I would like to touch on is Quality in built. The idea behind this principle is that quality is built into the manufacturing process. Quality is built into the design of the part. Quality is built into the packaging. Throughout all areas of the product, from design to shipping, quality is a major consideration.
Automation with a human touch falls within this principle. Machines that can detect defects and stop production are an excellent example of this principle. Part profile mistake-proofing, which prevents an operator from mis-orienting parts, is another excellent example. In Lean Manufacturing (or any other system), the focus must be on doing it right the first time.

 

There are some more principle also involve, you get from basic lean manufacturing concept blog. I am happy after looking the there is someone interested to learn the lean manufacturing. this will not direct helpful to implement the lean manufacturing but helpful to understand the fundamental of the lean.

Thanks friends for reading, in the next blog we can see how to implement the lean manufacturing concept in factory.

Thanks and have a nice day!