Sunday, February 7, 2010

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.

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