ASQ CQA – 5. Quality Tools and Techniques Part 6

12. 5B2 Lean – Introduction and Benefits

So this is the key difference between six sigma and Lean. Before we talk about anything further, let’s talk about the benefits of Lean. As I earlier told, the focus of Lean is to reduce waste. And that is the first benefit of implementing Lean. That in lean you reduce waste. Waste is anything which is nonvalue added activity. Anything which doesn’t add value is a waste.

And that’s what we focus here on Lean to reduce the waste. Another benefit of Lean is to improve quality and customer satisfaction. Because whatever we do, we keep focused on customer requirements. Anything which doesn’t add value to the customer is a waste and we reduce those waste. That way we improve the quality and we improve the customer satisfaction. Reducing inventory is another important aspect or the benefit of lean. Inventory is a big problem in the organization. It’s not only the money which gets tied up in the inventory, but the inventory gets obsolete.

You need to maintain the inventory and inventory is the cause of number of other problems. Defect gets hidden in the inventory. So we will talk about that a little bit later. But reducing inventory in itself is a good benefit of Lean. Lean reduces cycle time because we try to remove all those activities which do not add value to the client.

That way we reduce the cycle time. Lean looks at flexible manufacturing where we can change the model from one model to another model, switch quickly, use one item or handle one item at a time. That leads to flexible manufacturing. Safety is another important thing when we use tools such as five S which helps us in maintaining our workplace and make the workplace safer. And as we implement Lean, we do engage employees in this process and which leads to employee morale increasing. Because employees are involved in the process, they are engaged in improving processes and that improves the employee more.

13. 5B2 Lean Philosophy

And these parts are identify value, map the value stream, create flow, pull pull and seek perfection. So these are five key components of lean. And this particular slide has lot of information in just one single slide. So let’s give it some time. Let’s start with item number one, which is identifying value, which is the first philosophy of Lean whatever you do, you do based on what customer needs. So when we say identify value, what we mean is specify what creates value from customers perspective, don’t think from organizations perspective don’t think what you think a customer wants you actually need to go and check with customer what customer needs so once you identify customer needs then everything should be focused on those customer needs only.

So that is the first principle of Lean, or the first philosophy of Lean is that identify value, what customer wants, what is valuable to customer, and what is non value. Added activity for customer the next thing what you do is map the value stream you might be aware of things such as flowchart in flowchart you say that you do operation number one process one then you go to process number two. Then you go to process number three or so on. That’s a flow chart. But in that flowchart we have some activities which are value added activities. Some activities are non value added activities. Non value added. Activities let’s quickly talk about some examples some examples of that is repairing so if there are defects you repair customer is not paying for you to make things wrong and repair customer is paying that you create a thing right first time and sell it to them.

So if you repair, if you rework, if you reject something, all those things are non value added activities. And even inspection is a non value added activity because you are supposed to make things right in first go so when we talk of value stream map this is similar to flow chart but here we are looking at all those activities which add value to the customer we will talk about value stream map later on. But here what we need to understand is that we need to identify all the steps in the process chain which are value added and which are non value added activities. And once we have identified non value added activities. We need to reduce or eliminate them all together so that whatever is left adds value to the customer. The third philosophy is create flow. So here what we want is that value should flow.

Through the process chain. So process one, process two. So the value, whatever is important to the customer flows from one step to another step continuously unstopped. You don’t want to have inventory, you just want to have a regular. Flow of value in the value chain. That’s the third philosophy. The fourth philosophy, which is very important philosophy, is pull. Pull versus push. What happens in many organization is that they make something. So let’s say if a company is making these mouses, they make, let’s say 100,000 mouses and then sell it in Lean. What we look at is that everything should be from customers perspective, it should be pulled.

So rather than making something and then selling here in Lean, we look at first getting order and then based on that, making everything. So everything is made as per the customer demand. So customer is at one end and then there is a process one, process two, process three. And let’s say last one is the customer. So customer demand basically actuates process number three. Process number three will actuate process number two. Process three will ask process two to give it a piece or an item so that it can process that and send it to the customer. Process two will pull from process one. So when things are needed, then only things are produced that’s we can say in very simple language, you produce only when something is needed. Don’t produce something and then try to create demand for that. Coming to the fifth of philosophy of Lean, which is seek perfection. And earlier also we talked that we don’t want to create defective items and then repair those. What we want to do is create perfection, make things right in the first go. Strive for perfection by continually improving to produce exactly what customer wants rather than making something, and then trying to adjust that and trying to repair that to make sure that customer accepts that. So this is the fifth principle, which is seek perfection. So these are five key philosophies of Lean.

14. 5B2 Lean – Value Stream Mapping (VSM)

It shows the flow of material, it shows the flow of information and it show how raw material gets converted to finished goods. So the value stream map covers from the receipt of order to the final delivery. So that’s the scope of a value stream map and it helps you in identifying what are the processes which add value and what are the processes which do not add value and which can help help you in improving your overall process. Now, with this, let’s quickly look at an overview of a value stream map. So here on this slide, you see a very simple value stream map. The center of this value stream map is the production control. So this is something which controls everything. Then here you have the supplier and here you have the customer. So value has to flow from one end to another end. Customer needs to get value. Now, from supplier you receive material and this is shown by this truck here, which shows that weekly you receive material or inputs from the supplier. And then this input flows through these three processes. Process one, process two and process three. And once the process three is complete, then this is shipped to the customers. Now, when we talk about process one, process two and process three, here in these boxes you will see the details related to these processes. And I will show you this box in little bit more detail later on.

So here at the bottom, if you see, it tells you how much time it takes. So if you look at this, the material which we get from supplier and reaching to the process one takes one day and then this process is just taking ten minutes. Then after ten minutes, this waits for two days. The item which was produced in process one waits for two days here, and then process two takes five minutes. Then again a waiting time of two days and then again a process time of seven minutes and then a wait time of ten days before this item is shipped to the customer. So here if you look at the total lead time, the total time it takes from one end to another end is 15 days. So the time material starts from the supplier to the time it reaches the customer, it takes 15 days. But whereas the total time you are doing any work on that is just 22 minutes. So these are sort of things which value stream map identifies. So this was a very high level overview of a simple value stream map.

Now let’s look at some of the components which we have in value stream map. So here are some of the symbols. And the symbols which I am showing here are just the commonly used symbols. Only this symbol and the value stream map which I showed you earlier was taken from a software called SigmaXL. SigmaXL will cost you around $250 for the license. And that was the software which was used for this demonstration. So here I have six symbols on this slide. The first one is supplier and customer. So this is the symbol which you saw earlier on the value stream. Map. If this symbol is on the left side then this is the supplier and if this symbol is on the right side then this is the customer. The same symbol is used both for supplier and customer and then we also had this production control symbol there. So this is basically a central production scheduling and controlling station.

And then we were showing trucks which were for external shipment. We shown this for getting material from supplier and shipping. Material to the customer. And here in this truck, you put the frequency. Also, in the example which we took, this frequency was weekly. So we received material weekly from the supplier and we ship the finished product weekly to our customer. Another important symbol is the symbol for the operator, which you see here and here you see the number of operators also. So whether we have one operator or two operator, that will be shown here in this box. And then if you have multiple processes done in a work cell, this is shown by this symbol. This is the work shell symbol. We did not use this symbol in the example which we saw on the previous slide. Another symbol here is inventory store, where we store our inventory. So these are the six important symbols which you have on a value stream map. Let’s look at another four symbols which are related to flow. Here we. Have push arrow. And this we saw when we had process one and process two. So process one and process two. In between that, we saw this push arrow.

So push arrow means that the material is pushed by the production process, regardless of the need of the next operation. Another symbol which we did not see in the example is first in, first out. Lane so this is basically shows that whatever material comes first goes out fast. These. Two symbols the arrow and this arrow. Zigzag arrow. These are for manual information flow and electronic information flow. The electronic information symbol was related to sharing information with the supplier and the customer. So the information which we were sharing in that example with customer and supplier were using electronic information flow whereas within the factory we were using manual information flow. So from the production control the information related to production was manually transferred to operator number one. Two and three. So these are some of the commonly used symbol in value stream mapping coming to this box which we saw earlier in value stream map and we said that we will talk about this later. So here. In this box you have information related to process.

This is a typical information here. And this information in the box could change from case to case. So here what we have in these boxes is the cycle time, how much time it takes to produce the item. That was ten minutes, seven minutes, etc. This is something which goes in this box that this particular process takes seven minutes. And then we have a change over time. How much time it takes to change over from one model to another model that’s also mentioned here. Then we have a batch size. How much is the batch size? Are we doing one item flowing at a time or we are doing batches of production? And then we have percent uptime. This is the history of the machine. How much time the machine is up and running. And then we have first pass yield. First pass yield is related to the quality of product from that particular process. How much is the percent of items which are good first time without doing any rework. Without retouching.

So this is also put as a part of process information. So this process information box you will have against each of the processes which gives you a good overview of the process. Now, the question is how do we use value stream map? So the first thing what you want to do is look at the current state, go through step by step through all these processes and you draw the current state of the process. And this is what I have shown here. In the current state I have three processes. I have supplier, customer and then I have the transportation of material weekly. So this is shown on the left. Then you apply lean principles on this current state and see which of these activities are valuable value added, which of these activities are non value added activities, which of these activities could be combined together.

So you do all that analysis applying lean principles and then you come out with the future state. Now, what I’m showing here in this picture is using the lean principles I could reduce three operations to two operations. So this is how you use value stream.