Jan 292014
 

We received the following question about Bills of Material (BOMs) from a product development manager:

QUESTION: “How does one balance the need of a BOM to be expedient and fast for real world use, while still trying to make an investment in a universal and reusable bomb?”

That’s a great question for product development teams. Our answer is a series of steps:

STEP 1 – Admit it’s a problem

It may sound like the trite stuff of a 12-step program, but the first step to recovery is admitting you have a problem! There’s nothing wrong with having a problem, and in fact, solving problems is what we went to engineering school to do, didn’t we? Some people will tell you that you can have it all (usability and re-usability) in your BOM structure instantly and without conflict. That’s delusional, but we can make incremental progress over time.

STEP 2 – Define the problem

Going back to our school days, the first thing we would do in our statics or dynamics homework would be to list the forces that are active. There are at least two forces in play, and for the most part they are directly opposed to one another:

  1. Functional Universality / Re-usability – we would like to have a universal BOM that can be re-used and easily modified to work for each product.
  2. Expediency / Practicality – We have to ship the product out the door on a certain timeline. The BOM has to be easy enough to use that we can modify it quickly so that we can get our “day-job” done.

STEP 3 – Recognize that the equilibrium point is dynamic over time

Where we start out on our journey of practicality vs. universality in the BOM is not where those forces may end up in the future. The equilibrium point between those forces will change over time.

In Figure 1, we see that initially the force of expediency/practicality is stronger. Therefore, at first our BOM will mostly focus on the needs of today, rather than the needs of tomorrow. However, over time we can reduce some of the immediate pressure to ship product, because we have invested in the bill of material. The equilibrium point is driven to the right on Figure 1 toward a more universal BOM, which is still practical and expedient for our daily use.

Figure 1 Balancing BOM Usability vs. RE-usability

Figure 1 Balancing BOM Usability vs. RE-usability
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STEP 4 – Knowing the equilibrium point at any point in time

How do we know how to balance the two forces at any given point in time? The recognition of a third force may actually help us simplify the problem. That force is the needs and goals of our management team in the company.

The management team is certainly interested in shipping the product for immediate revenue and profit. However, they are also responsible for stable growth of the company over time. Management needs are a downward pressure that we can use to our advantage, just like the Romans did with their brilliant discovery of the arch.

Figure 2 represents such an idealized arch. The forces of the needs for universality vs. practicality are pushing against one another. Without a third force, certainly the structure would tumble. However, with the third force of management needs, it’s much easier to balance the two forces and know where that equilibrium point is at a given point in time.

Figure 2 Balancing BOM Usability vs. RE-usability with Management Pressure CLICK to ENLARGE

Figure 2 Balancing BOM Usability vs. RE-usability with Management Pressure
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Figure 2 – The down force of management decision making

STEP 5 – Make sure you have a solid keystone

What is the keystone in the arch? The keystone bears the pressure of all three forces and balances them. The keystone in our process is a thoughtful and dynamic owner of the bill of material structure. This might be a consultant, a specific person who specializes in product lifecycle management, or the product development manager. Whoever it is, this person or team should be able to view the opposing forces not as forces that will crush them, but as forces that will help them balance each other.

 

As with any problem in the real world, unfortunately we’re not dealing with a precise science here. However, hopefully this expansion of our framework will be a way to think about making progress, as you balance usability vs. re-usability in your bill of material structure.

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This post is 3rd in a series of posts on ENGINEERING.com about Bills of Materials (BOMs). The first outlines the importance of managing the BOM: Dr. Strangepart: How I Learned to Stop Worrying and Love the BOM. Next is a framework of how to build re-usability into the BOM: Form, Fit, and Function – A Framework for your Bill of Material.

Jan 272014
 

Continuing , the series on the Bill of Material we began with the article Dr. Strangepart: How I Learned to Stop Worrying and Love the BOM, here is a full re-print of the next in the series.  You can find the original at ENGINEERING.com here:

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In my post Dr. Strangepart: How I Learned to Stop Worrying and Love the BOM, we began talking about the extremely complex process of managing the bill of material (BOM). That discussion focused on intelligent part numbers, but today I want to move to the question of whether the BOM is primarily keyed off of the functional use of a part or the specific part number itself. This is a tension that has existed since bills of material were created, when man married an axle to a wheel.

Why do people care whether the BOM is driven by part numbers or the part’s function? The answer is that each has certain advantages. Driving the BOM by actual part numbers is very useful for purchasing and manufacturing, and when an engineer is focusing on an individual piece of hardware. However, when the engineer or a product manager moves from one product to another, a function driven BOM allows him to compare components more easily.

The ability to compare BOMs has huge implications for the ability of engineering to successfully re-use parts. Re-use lowers both the cost of the hardware itself (by re-using tooling and increasing production volumes) while also reducing the engineering time needed to design a new part. Re-use has been the great white hope of the engineering community from time immemorial, but it is very challenging.

Although Product Lifecycle Management software vendors talk about re-use, most companies do a very poor job. Trying to manage re-use without intelligent part numbers and a functional way to look at the BOM is like searching for a single item in a hoarder’s basement that’s jammed full of boxes with no labels. Eventually you give up, go to the store, and buy a new one! That’s one of the big reasons why re-use has struggled in the engineering community.

So, how do we balance the tension between these two things? Here is a simple framework for thinking about the BOM that I call Form, Fit, and Function.

CLICK to ENLARGE

Figure 1 CLICK to ENLARGE

By function, I mean what the part is actually doing, what its purpose in life is. By form I mean the specific piece of hardware or part that we’re dealing with. In Figure 1 there is a simple example of how function and form relate to each other. Typically, the superset will be function. The function in this case is to provide rear vision to a driver of a vehicle. The function is the result of the part operating correctly. The part itself is the form that “delivers” that function. In this case, we might provide rear vision by designing a mirror, a camera, or some sort of sensor.

The third part of the framework is the fit of the part. However, by fit I don’t mean the actual geometric tolerances or real estate that the part occupies. What I mean is, “What are the unique attributes of the part that make it “fit” the function, i.e. accomplish the function?”

Figure 2 shows another example of a functionally controlled BOM. In this case, we’re using an example of the propulsion of a vehicle, perhaps a jet aircraft. In this case we show propulsion as a top level Function, along with sub-levels of the powerplant, how the power is transferred, and the cooling system.

Hiller Associates Form & Fit Functional BOM

Figure 2 Hiller Associates Form & Fit Functional BOM Example
CLICK to ENLARGE!

 

The coolant is the Form that satisfies the Function of the cooling system. We assign an intelligent part number for the specific coolant. One might ask, when do I move from a Function to a part number (Form)? The answer to that is, whenever it is convenient. It will take a little bit of time for your team to develop a functional BOM that has a manageable level of hierarchy in it.

TIP: Any more than three or four levels of hierarchy can be very difficult to manage.

There is a many-to-many relationship between the Function and the Form (part). Depending on how far down the Function tree we go, we may need to attach more than one Form (part) to satisfy a function. On the other hand, if our functional tree is deeper, on certain products there may be one assembly (Form) that satisfies more than one Function on the functional tree.

Moving to Fit, we see that each Form may have multiple attributes (ways of fitting the function). The coolant “fits” our functional need by the attributes that it has. In general there will be a one-to-many relationship between Form (part) and Fit (attributes) respectively.

Form, Fit, and Function is a simple way to look at how we structure our products. It lends itself well to re-use of parts, but also for the re-use of work break down structures that are used in aerospace and defense.

Some companies are now working on constructing skeleton “Starter” or “Universal” BOMs that they re-use for each new product. The idea is to start with a generic BOM, and then add and delete to match the needs of a new product. The goal is for the company to have one universal BOM, or one for each unique product group.

This is a great idea in theory, but it’s not trivial to execute. To do this in your own company will likely take your engineering team, product management, and a consultant a year or more to find a structure that suits your needs. However, once this is done, the speed and re-use advantages should be significant. Hopefully, the Form, Fit, and Function BOM Framework will give you a simple way to think about it!

Jan 232014
 
BOM Away from Hiller Associates

Yesterday, we began a series of articles at one of our media partners, www.ENGINEERING.com.  Instead, of focusing on Product Cost Management, we are focusing on another maddeningly difficult problem with critical implications to the Firm:  structuring the Bill of Material to promote ease of use… and re-use.  We will reprint the article below, and you can view the original here:

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A few months ago, unleaded client and asked me an interesting question.   That question was how does one reconcil the tension between specific parts or hardware vs. the functional use in the product of those parts.    This client was from a major fortune 500 company with a bill of material (BOM) containing thousands of parts on each product.  I was a bit taken aback, at first, by this question.  Although it is a very difficult question and subject, I assumed that most major companies were old hands at dealing with this tension.  I was wrong.

This reminded me that something that might seem old hat or common sense to one person, might be very interesting to another.  For example, when I graduated from the university and went to work for Ford Motor Company, I was taught that the Ford part numbering system.  Ford uses a system for parts that is an intelligent part numbering system, in which the part number makes it obvious which product programs , functional type of hardware, and what version of the part is being described

Hiller Associates - Intelligent Part Numbers

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This system of numbering parts has been around for goodness knows how long.  It is no great secret in the auto industry.  I’m sure every person at Chrysler, GM, the foreign auto companies know the Ford system of numbering parts.  In fact, apparently , eBay even teaches us about the Ford part numbering system.  It’s very straightforward and makes complete sense.  As a young engineer, fresh out of school, who didn’t know any better, I assumed that every company had a similar intelligent part numbering system.  However, when I gained a little bit more experience and maturity, I realized that Ford’s ingenious but simple system was not so common sense at all throughout industry.  In fact, most companies I have met in manufacturing have nothing more than a sequential part numbering system that tells nothing about the part for which you were looking.

The point here is not for me to glorify the Ford part numbering system.  I’m sure there are companies with even better and more intelligent part numbering systems out there.  In fact, we don’t even have to go back into the horrors of the group technology fad in the late eighties or early nineties to know that!  No, my point is that relatively simple and logical ways of classifying (but not over classifying things!) on the BOM can really help us in our management of engineering parts and the product.

Therefore, in the next few weeks, I plan to post a series of articles that talk about these ways that we can view the bill of material and help ourselves and our company.  I look forward to hearing what other experts in the product life cycle management will have to say in comments.

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