Embrace Conflict for Product Cost Reduction, Part 3

In part 1 and part 2 of this series we have been looking at how physical conflict in design drive up product cost and how the separation principles of TRIZ methodology help us to side step those conflicts.

So far we have looked at three of the five separation principles:

  • Separation in Time
  • Separation in Space (Location)
  • Separation in Space (Axis)

Today we’ll look at two more…

Separation in Scale

The fourth question to ask when you find a physical conflict in your design is, “can I assign one side of the conflict to the ‘whole’ and the other side to the ‘parts’.

For example If I’m an architect designing a sky scraper, I’m confronted by the conflict:

  • Building must be rigid (for user comfort)
  • Building must be flexible ( to withstand seismic and wind events)

Using separation in scale you realize that the rooms need to be rigid but the building as a whole can be flexible.  By designing the building so that the floors hang from the outer shell of the building the conflict  can be resolved.

Another clever use of separation in scale is in the design of body armor. High end body armor needs to be rigid to withstand high power rounds but flexible to allow user agility.  Dragon Skin assigns the “rigid” requirement to ceramic scales and the “flexible” requirement to the system as a whole.  Check out the Dragon Skin Video.

Separation on Condition

The final separation principle we will discuss is closely related to separation in time.  I’ve broken it out because I’ve found that treating it as a separate principle often leads us to look outside  the system proper – another TRIZ technique.

The question to ask here is, “Do the two sides of the conflict occur under different conditions”. If they occur under different conditions, it may be possible to borrow resources from the conditions themselves to solve the problem.

The bimetallic strip in an old school thermostat is a great example – it uses the change in temperature (conditions) to actuate the switch contacts.

 

 

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Embrace Conflict for Product Cost Reduction, Part 2

In the last post I proposed that the  lions share of a products ultimate cost is locked in at the design stage and that much of that “cost of poor design” is driven by design conflicts.

Further, we took a look at the TRIZ methodology and identified two types of conflict: technical and physical.  Today we are going to look at physical conflicts in design and how to deal with them.

Physical Conflicts

A physical conflict exist when opposite properties are required of a product’s functions or elements.  For example, a nail has the property”must move through wood” when it’s being installed and “must not move through wood” when it’s holding your house together.

Physical conflicts group into two structures;

Conflicts of magnitude exist when the product or system requires some characteristic to be at two levels of magnitude or strength. For example “coffee must be hot” to taste good and “coffee must be cool”  to be safe and avoid lawsuits.

Conflicts of presence  exist when some element or function has to be there and not be there. In the case of a draw bridge the roadway “must be there” to allow traffic to pass and “must not be there” to allow ships to pass.

So how do we deal with physical conflicts to reduce product cost?

TRIZ methodology posits three ways;

  • Separation principles
  • System transformations
  • Phase Transformations

Let’s take a look at the first – separation principles

Separation in Time

The first question to ask when you’re confronted by a physical conflict is, “Do the opposing requirements have to exist at the same time?”  The drawbridge mentioned earlier is an example of separation in time.  The roadway “must be there” and it “must not be there” but the two states don’t have to exist at the same time.  By forcing the cars to wait, the requirement can be separated in time and the conflict resolved. Perhaps not the most elegant solution but a good example.

Traditionally TRIZ only has one principle of separation in space but I’ve found it useful to break it into two.

Separation in Space (Location)

The second question to ask is, “Do the opposition requirements or conditions have to exist in the same location.  The idea here is to  think of the product in terms of subsystems and assign each of the opposing requirements to a different subsystem.

A good saute pan should “be massive” (like a cast iron pan) for good thermal properties and “be not massive” for easy of use. By asking this second question we realize that the “be massive” property has to exist only at the point of contact with the burner. This is the idea behind the light aluminum pans with a special heat plate attached to the bottom.

Separation in Space (Axis)

With problems involving motion or location I’ve found that it is also helpful to ask the question, “Can these opposing requirements be separated in their axis of operation.  In other words, can the opposing requirement each be assigned to a different axis: X, Y, Z, Pitch, Roll, Yaw.

For the nail we talked about earlier if we assign the requirement of “must move through wood” to  the roll axis and the “must not move through wood” to the Z axis we have a wood screw.

As a side note, this principle relates closely with another important tool in product cost reduction, namely exact constraint design.

Two More

The remaining two principles of separation require a bit more explanation so we’ll cover those in the next post.

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Embrace Conflict for Product Cost Reduction, Part 1

We may argue a bit about the exact numbers, but most experienced product designers will agree that at least 80% of a product’s ultimate cost is determined during the products design phase and 60% of it is defined solely by the concept chosen.

So it goes without saying that any meaningful attempt at product cost reduction  must address design issues.

Conflict in Design

Product design is really a process of information translation. Translating customer wants into functional requirements then into physical characteristics and finally into process parameters. Within each of these phases there are conflicts between elements. In the customer want domain, it may be the customer’s requirement – that the product be light but strong. In the functional domain there are conflicting requirements to “fix location” and “allow movement”.

Optimization

The traditional approach to dealing with these conflicts is to optimize or find the best trade-off. This may be as simple as an engineer’s best guess or as sophisticated as a designed experiment using response surface methods (RSM) to find a robust optimum. The problem with optimization is that it tends to drive up cost.

Optimization is about finding a balance point between two conflicted elements and that balance has to be maintained by some type of control. It might be tightened manufacturing tolerances or feedback mechanisms or maybe complex product architecture. In any case it’s likely to be expensive.

But what if we could side step the need for optimization altogether.

TRIZ Methodology

TRIZ, which is the Russian acronym for “Theory of Inventive Problem Solving” is a body of knowledge that resolves conflicts via innovation rather than optimization. TRIZ founder, Genrich Altshuller, started developing  the TRIZ methodology in 1946 while working in the “Inventions Inspection” department of the Caspian Sea flotilla of the Soviet Navy. In reviewing hundreds of proposed inventions, Altshuller realized that at the heart of every truly inventive solution there is an unresolved conflict.

Conflicts – Physical & Technical

Altshuller identified two types of conflict: physical and technical. Physical conflicts result when opposite properties are required of a product. For example a nail is required to move in wood (when installed) and not move in wood (when in place). Technical conflicts result when one characteristic of a product gets better while another gets worse. A motor vehicle may get lighter but it also get less crashworthy.

Product Cost Reduction

So wrapping up…

Product cost is largely determined by the design of the product and design is an exercise in dealing with conflicts. The traditional approach to these conflicts is to find an acceptable optimum or trade-off, but trade-offs tend to introduce the need for costly controls. There may be a better way, check back with us as we dig a little deeper into how TRIZ can help us reduce product cost.

 Regards – Matthew Scot Schultz

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