Seven Forms of Waste

In Component Talk #24 when discussing lean manufacturing, I said, “No one can afford to ignorant of its strategies and goals.” One of those strategies is the elimination of waste and the first step in that process is to identify what waste is. In putting this article together, I am quoting heavily from Lean for Dummies by Natalie Sayer and Bruce Williams, and excellent introduction to Lean.

Waste in lean manufacturing means wasted effort, wasted resources, and activities that add no value to the end user. Waste is both inevitable – it cannot be completely eliminated, and reducible – we can always improve. And so, on to the list:

Transport

The idea here is that any transportation of materials between “transformational operations” is a waste. Every time you move something it presents an opportunity for damage or injury, to say nothing of the time the transportation took. Poor layouts and disorganization are a frequent cause of transport waste. Conveyance mechanisms take up floor space, and can lead to inventory accumulation. If you’ve ever seen television program on how computer chips are made, you know that the reason that today’s chips are so much more efficient than yesterday’s is the fact that the new chips have reduced the space that the information must move through to almost nothing. When you make billions of production cycles per second, that adds up quickly. It’s no different on a component production floor.

Waiting

Any time a production person is waiting, it is a waste of that resource. Waiting most frequently comes from shortages, unbalanced work loads, need for instruction, or by design (such as watching a machine complete its cycle.) If you see a production person waiting around, ask yourself, “Which one of the reasons listed above is causing them to wait?” and address it. In some cases workers wait because they expect (or know) that whatever they are waiting for will come to them – even though they could simply go get it much faster. They ‘wait for it’ out of habit, and with full knowledge that eventually it will come to them.

Overproduction

Producing more than the customer needs is a waste and causes other wastes – inventory costs, manpower and conveyance cost to deal with the excess product, and consumption of raw materials.

Defect

In keeping with the all-too-obvious idea that we want to ‘do it right the first time,’ any process, product or service that fails to meet specifications is waste. I’ve seen the time taken to fix one missing plate on a truss shut down not just one line, but two (if they share a conveyor) equal to the time that it normally take to build three trusses. That’s a lot of waste, and missing plates are only one kind of defect. How many different types of defects do your products have? Which costs the company the most wasted time and resources? What are your mitigation strategies?

Inventory

Inventory anywhere is non-value-added to the consumer. It not only ties up capital, but it runs the risk of damage, obsolescence, spoilage, and reduced quality. Inventory takes up floor space and other resources to manage and track it. Keeping large inventories may be covering up other issues, such as equipment reliability or poor work practices.

Motion

Any movement of a person’s body that does not add value to the process is a waste. Examples are walking, bending, lifting twisting and reaching. Tacking a plate in place on a truss adds value, but turning around and having to reach to get the plate does not. Motion of the product can also be waste, such as building the truss flat, lifting it into the vertical position to stack or band, and lowering it back to flat for shipping.

Extra Processing

Any process that does not add value to the product is waste. In component manufacturing, this is frequently caused by inadequate technology, such as when we have to re-do an operation (like a finish press.) And given that we do so many things to add value to the products we sell, why not take the time to verify that those activities are indeed valuable? By talking to customers we can make sure that what we are doing is really adding value and/or making sure that the customer understands how to get the maximum value from the things we are doing.

Rating System for Jobs

I’ve been thinking about board feet lately. Board feet is used in our industry as the primary “how much” value of something. “How much did we produce today? How big is that job? It is also sometimes used as a measure of work. “What’s our capacity?” is a question that can be answered in board feet. Board foot really doesn’t tell me much, other than how big a pile of wood it is going to take to build the job. I’ve been thinking about a different way to create a ‘scorecard’ for a job. Something that would tell me at a glance some important details about the job so I could compare it to other jobs and develop norms over weeks and months. Here are some of the things I would like these numbers to tell me:

1. How complicated is the job?

2. How heavy was the material used?

We are going to look some numbers that might shed some light on how one job is different from another - quickly.

Are we going to spend a lot of time setting up, or building trusses? Let’s calculate the number of trusses per setup, by taking the total number of trusses and dividing by the number of “marks” (unique trusses.) I suggest leaving jacks and valleys out of this calculation.

Are these simple trusses, or chopped up monsters? Again, taking the jacks and valleys out, figure the average number of pieces per truss (total pieces for all trusses divided by total number of trusses.)

Are these trusses ‘light weights,’ or are the table guys going to have to do some heavy lifting? Take the total BF and divide by the total LF of boards to create a ‘Weight Score.’

We need to collect data (using MBA or another tabulation program) to see how our jobs score in each of these areas: Trusses per Setup, Pieces per Truss, Weight. Once we have 100 or 200 jobs to refer to, we can compare and begin to assign grades. Rather than using letter grades, I suggest using numbers. Once you have 100 or more data points, figure out what the range is for each metric. For example, you may have jobs that whose Trusses per Setup range from 25 to 2. You will likely see some trends. Try to find the natural breaks within the data. You will end up with a Score for Trusses per Setup that looks something like this:

Example: Scoring System for Jobs – Trusses per Setup

Score Range

1 Over 7

2 4.5 to 7

3 3.8 to 4.5

4 3.1 to 3.8

5 less than 3.1

You want a system that will put your ‘average’ for the factor in the ‘3’ category. Do the same with the other factors we have discussed: pieces per truss and weight. Now you have three measures and a simple scoring system to quickly tell you a lot about the job. You still can use board feet to tell you the size of the job. The scoring system can help you price jobs, estimate the labor needed and see which factor affects labor rates the most. Do you make more on ‘high score’ jobs, or ‘low score’ jobs? If your MH/BF varies a great deal from job to job, perhaps a scoring system like this can help you learn why.