Just in Time Batch and Que - Why does it take so long to get to work?

Batch and Queue, or why does it take so long to get to work?

Delaying anything is adding waste, the waste of waiting, it is better that things flow steadily rather than keep stopping while people wait for something to happen then off again at high speed. Lean manufacturing and Just in Time (JIT) is about creating flow and removing delays, how does this compare to everyday life?

Consider my journey to work this morning, my company moved offices to the other side of the city that I work in so my journey has increased significantly from the original 5 minutes that it used to take to around 40 minutes. But the increase in distance is not that huge, only around 12KM, so why does it take so long?

On my drive this morning I timed how long I was physically travelling for and for how long I sat at traffic lights and was delayed in bottlenecks where several roads converged into one route. The results do not make good reading, I was travelling for only 9 minutes of my 38 minute journey, the other 29 minutes my car was stationary belching out fumes while I waited for lights to change, or I was trying to fight my way through a crush of cars desperately trying to go from several lanes into just 2 or 3.

This is quite similar to many factories that I have worked in over the years, the operators will sit or stand there for several minutes while a machine is cycling doing nothing else, or they will wait for the previous operation to pass them a batch of product to work on, much like sitting at the traffic lights waiting. Then you have the bottle neck situation with many production operations all filtering into one process that is not capable of keeping up with the demand required of it, normally one huge expensive “super” machine that serves the whole factory.

Consider the Dutch town Drachten, they have conducted an experiment here now for several years and switched off all of the traffic lights, the drivers all report that there are no longer any tail backs or delays and that the traffic flows freely and safely! Flow without delays, isn’t this what we want in our factories?

Consider also the City of Milton Keynes in the UK, famous for it’s concrete cows and the roundabouts, I used to live there until just a couple of years ago, traveling around the cities grid system was great, you could get anywhere in the city easily and quickly on it’s network of roads, if one was slow or blocked, you just went across one block and off you went again, few if any delays, a real delight to drive. But it still had its bottle necks, where several roads approached the motorway you had delays and queuing traffic at peak times, so what did they do? They introduced a series of delays on the approaching roads to reduce the amount of traffic reaching the bottle neck, so that no traffic built at the bottle neck itself. These traffic lights on the approaching roundabouts may have reduced the problems at the bottle neck but all they did was move the problem to the approaches of all of these roundabouts, where the problem became even worse as it delayed traffic on other routes as well as that to the motorway and was there all day and night long rather than just at peak periods!

They “solved” the problem at the bottle neck, but all they did was delay the speed at which traffic approached and moved the problem elsewhere, the problem was the capacity of the bottleneck, not the volume of traffic, it was this bottleneck that needed to be dealt with not the volume approaching it!

The traffic is batched at each set of lights, the flow from the process (the road leading to the light) is collected together in one batch before being released into the next process (the next road) only to again be batched together at the next set of lights. I traveled from next to where I work a few nights ago at 4am (don’t ask why) and ignored the traffic lights on my journey home, it took 7 minutes (without breaking the speed limits), not 40 minutes!

Another example of the superiority of flow is the roundabouts here, despite the fact that the drivers here ignore most of the road rules the flow around the roundabouts is fairly constant but there are still queues at peak times. However you can always tell when the traffic police have decided to “improve” the situation by stopping the incoming traffic from each road in turn to speed up the flow of traffic around the roundabout, when they do this the queue on the approach to the roundabout is normally 3 to 4 times longer than normal, but they still do it! Flow is superior and faster than batch and queue every time.

We see delays everywhere we look in our everyday life and we complain bitterly, when was the last time you sat happily waiting to see a doctor or a dentist in the “waiting” room! You arrive for your “appointment” and you then wait!

Why do we complain about it in our everyday life but we accept it in our workplaces? We need to work on implementing the principles of lean manufacturing to remove these delays so that we can achieve flow through Just In Time principles.

Seven Wastes|Waste of over processing

In a previous post on how to implement lean manufacturing I discussed the seven wastes, within this post I will discuss the waste of over processing. Wasting time and other resources doing something that adds no value to the customer.

What does this mean? Sorry to Rolls Royce for using the following example but it is probably one of the most frequently used examples, why polish the rotor blades of the engine where it does nothing for the function and cannot be seen! How often have you seen processes where they paint or finish areas of a product that never get seen and where it will have functional benefit.

Sometimes it is necessary to paint unseen areas due to the risk of corrosion, but is there a better cheaper alternative? Could you coat the material with a cheaper alternative, or use materials that were not prone to corrosion in the first place.

In addition to these obvious wastes, think about the functionality of your product, is it really adding any value to the customer or are you doing far more than he really wants? What is the point of having a refined top of the range suspension for use on perfect UK and US motorways and highways if the car will be driven on rough concrete roads with poor joins and multiple pot holes? Do you think that the ford car produced for the European and US market has the same suspension as that produced in India for the Indian domestic market?

Is it worth using an expensive computer chip capable of many millions of calculations per second if it will be utilized in a very simple application where a much simpler and cheaper version could be utilized. Are you defining tolerances of fractions of a mm where actually much wider tolerances could be allowed?

When implementing lean manufacturing we want to aim for perfection, but that perfection is what the customer values not more. Ensure that instructions and standards are clear to ensure that we do not incur the waste of over processing.

If you want to learn how to implement lean manufacturing, you need to not only think if each step in the process is adding value, but is that value required? Is that value in excess of what the customer needs?

In the next post about how to implement lean manufacturing I will talk about the waste of over production, one of the most serious of the Seven Wastes. Use this link to return to a full list of wastes for waste reduction.

Seven Wastes|Waste of Transportation

In a previous post on how to implement lean manufacturing I discussed the seven wastes, within this post I will discuss the waste of transportation. The waste of transporting the product from one location to another.

The waste of transportation is distinct from the related member of the seven wastes, that of motion, in that transportation is the movement of product from one location to another rather than the motion of the person or the machine.

This is commonly a major waste in many companies, moving of product from one area of the factory to another for the next operation rather than the next operation being adjacent minimizing the movement. To demonstrate the distances travelled within the processes, I once worked on a project to improve the efficiency of a company producing ground to air missiles! The missiles actually travelled further in the production process than they could travel when they were fired!

One of the things that you try to achieve when learning how to implement lean manufacturing is flow of product through the factory. The ideal situation within any process would be the product moving from one process to the next without any gaps or delays. You need to minimize the waste of transportation. Of the seven wastes this is normally a symptom of other wastes, the wastes of inventory and overproduction.

Most factories try to organize themselves into functional areas, one area for cutting, one for machining and another for assembly. This is a common set up within factories. Batches of material are cut in the first section, then palletized, stored then eventually transported on a fork truck to the next section. The palletizing, the storage and transportation are all waste, none of it adds any value to the product that the customer wants to pay for.

A better organization for the shop floor would be to organize the area into product lines using similar processes, that way the individual processes could be brought closer together to enable flow and reduce the transportation. If processes are adjacent would you need to produce large batches? If you don’t have large batches can you just hand or slide the product on purpose build racks to the next process eliminating the need for transportation?

So what we are looking for is the lean approach, which is that of a close coupled layout which enables one piece flow and eliminates the need for transportation.

So if you are learning how to implement lean manufacturing and you walk into a factory and see fork trucks and pallet pump trucks everywhere you look, you can be pretty sure that they have the waste of transportation as one of their seven wastes. For a full list of wastes use this link for waste elimination.

Seven Wastes|Waste of Motion

In a previous post on how to implement lean manufacturing I discussed the seven wastes, within this post I will discuss the waste of motion. This is the waste of time and effort due to any motion of the man or machine that does not add any value to the product.

This waste of motion has a long history of being documented, Frank Gilbreth a guru of time and motion from the time of Taylor specialized in this area. He highlighted the many motions that a bricklayer made when building a wall, the bricklayer bending down to ground level to pick up a heavy brick then having to bring it up to working height. This wasted time as well as having the potential to cause stress to the back of the individual involved. (He also was also the inspiration behind the “cheaper by the dozen” films but that is getting away from how to implement lean manufacturing, I am sure that you can find much information about him if you want to learn about his life and works.)

As already discussed earlier while we were writing about how to implement lean manufacturing, anything that does not directly add value to the product is waste, lifting the brick from floor to working height is not adding any value therefore it is waste. It is also a health and safety issue in many places, and with today’s society being heavily focused on finding blame for any problem and applying a financial penalty to the responsible it would be sensible to minimize any unnecessary motion of this type! You will see in many companies now self adjusting tables that keep the product to be processed at just the right height for the operator to eliminate bending as the stack reduces in height as it is used.

The motion within a machine can also be wasteful contributing to the waste of processing time. You often see after a machine is loaded with product the tool will move towards the holding fixture to begin it’s work. The tool obviously has to be clear of the fixture to enable the operator to load it, but often it is far to far away which means that time is wasted as it travels to the jig. This may be only a few seconds but if the process is repeated as often it is, many times over a shift, the loss can add up quite significantly.

In addition to this, the movement speed is often left at the same rate as the “working” speed, so instead of the machine moving rapidly from one position to the next when not actually applying any work it moves at the slower work speed.

Again, stand and watch and study what actually happens, it is surprising what you will observe if you take the time to actually watch what is happening. Watch and question what you see. Why is the material where it is, can it be brought closer? Why do we have to keep turning the product and switching hands, is there a better more efficient method?

So watch and question everything, this is how to implement lean manufacturing, in my next post I will continue to discuss the seven wastes, moving onto the waste of transportation. To go to the full list of waste use this link for waste elimination.

Seven Wastes|Waste of Waiting

In a previous post on how to implement lean manufacturing I discussed the seven wastes, within this post I will discuss the waste of waiting. A fairly obvious waste you would think, waiting for the previous operation, or the machine to finish what it is doing.

Why do people end up waiting? Generally they are waiting because the processes are not balanced, that is they don’t all take the same amount of time. Even in the best flow lines it is very difficult to have all operations perfectly balanced. But in a lot of manufacturing companies this is a major waste.

You see one machine starved of product as the previous process has not finished producing the large batch of components and the batch cannot be moved until all complete. You see people standing idle waiting for the fork truck to transport that large pallet of material. The operator on the machining centre watching the machine patiently while it completes its eight minute cycle.

Just go and stand in the center of your company and watch what is going on, how many times do you see people just waiting, or working slowly so as not to bring attention to the fact that they do not have enough work?

When learning how to implement lean manufacturing, you learn how to make the value flow at the pull of the customer. As I have already mentioned before when discussing Just In Time (JIT), the ideal would be to have a single piece flow, the product moving through each process when required by the customer. The idea at this point is to try to balance each operation so that they take as close as possible the same amount of time. If you go into a car assembly plant and watch the operators on the line, they all have the same amount of time to complete the work before the car has moved into the next section. If the work took too long then it would not be complete before the next section began their work!

Many of the other wastes contribute to the waste of waiting, one process will often be waiting for the previous as rework is completed due to the waste of defects and so on.

As to the operator waiting for his CNC machine to cycle for eight minutes or the injection molding operator watching his ninety second cycle, many companies now will have them operating multiple machines organized in a cell to utilize their time fully. But so many still have the operators stood there waiting “in case something goes wrong!” The operator could be loading the next products into an additional fixture, working on the next operations or running additional machines, but not just waiting – do you really want to pay someone to stand and watch a machine for the bulk of their day?

So if we are going to learn how to implement lean manufacturing we need to learn how to eliminate this waste of waiting. The easiest thing here is to look at our flow and try to balance it. Tools such as Heijunka can be used here to help with balancing the flow, more about the tools in future posts. Look at our scheduling within the factory, we often plan delays into the process! Look at the physical locations of machines and processes and try to bring them closer together. Reduce batch sizes to as small as possible, aim for single piece flow.

So if you are learning how to implement lean manufacturing and you walk into a factory and see people waiting everywhere you look, you can be pretty sure that they have the waste of waiting as one of their seven wastes. To return to the list of wastes use this link for waste elimination.

Seven Wastes|Waste of Waiting

The waste of waiting; processing time

In a previous post on how to implement lean manufacturing I discussed the seven wastes, within this post I will discuss the waste of waiting, specifically processing time. Excessive time spent processing product will cause your product costs to be higher, or alternatively your profit margin to be lower.

Processing time if excessive will cost you time and therefore money. It will give you low productivity therefore high labour costs. Your machine costs will be higher and utilization lower. All of this leading to as I said above higher costs or lower profit.

This also reduces your capacity, you are using your time and resources doing something that ties up your machinery and people and not allowing them to work on new business opportunities. I have been into many businesses that have had to turn away work because they do not have the capacity to fulfill the contracts.

The causes of excessive processing times are many, often they are down to the people aspect, they are not properly trained or do not have the required skills. The methods that they are using are not right or are not clearly documented causing variation.

The machine or jigs that they are using may be worn or incorrectly set. There is poor knowledge of how to operate the machinery and how to set it up. This may cause additional problems such as defects also. I have been into many factories to investigate the cause of defects and delivery delays and found many problems in this area. Like defects people tend to live with the problems without dealing with them.

I have seen many instances where an operator will spend time forcing either defective product into a fixture or correct product into an incorrectly set fixture, this taking excessive time to do but the operator just continues to do it month after month.

When you learn how to implement lean manufacturing you will spend much of your time watching processing on the shop floor. You will see many times wasteful acts due to incorrectly set machines or defective supplied products that have gone on for years. The operators live with the problems, thinking that they are doing you a favour by working around the problem but actually slowing down the process. It often becomes part of the training handed down from one operator to the next!

We often have excessive processing times due to our supplied product either being wrong or wrongly specified. How long do some machining operations spend doing “roughing cuts” to bring material closer to size for machining rather than buying in material at the right size.

Design often plays a vital role in processing time, for example fixing being placed in difficult to access locations for assembly. They can often be moved or eliminated altogether by altering the design so that components “snap” together without the use of separate fixings.

Watch every step of a process and question every aspect of it, why does the machine run at that speed? Why are there so many fixings? Are there always burrs to remove? Does the fixture always have to move so far before the operation begins? You will be surprised what you will see, just take a few hours and just watch one of your processes and use some simple good old fashioned common sense.

As I continue my ramblings about how to implement lean manufacturing I am sure you will find many techniques that are relevant to eliminating wastes such as Kaizen. My next posting will continue with the waste of waiting. To return to the list of wastes for waste elimination use this link.