Sample Answers to Exercises and Thought Questions: Chapter 10
EX 10.1
Draw a schematic for a wristwatch, using only functional elements (without assuming any particular physical working principles or components).
(Based on a solution by Roddy Tranum)
Draw a schematic for a wristwatch, using only functional elements (without assuming any particular physical working principles or components).
(Based on a solution by Roddy Tranum)
EX 10.2
Describe the architecture of a Swiss Army knife. What advantages and disadvantages does this architecture provide?
(Based on a solution by Mark Parrish)
A Swiss Army knife can be thought of as consisting of numerous independent physical elements, or chunks, capable of performing a myriad of independent functional elements that include slicing, screwing, sawing, poking, and picking, just to name a few. These chunks include blades, screwdrivers, scissors, awls, toothpicks, and, depending on the model and price, as many as forty other handy instruments, each with its own specific purpose.
Each of its chunks implements one functional element, and the functional interactions between these chunks are minimized. However, two important interactions remain between chunks: 1) the blades must each interface to the knife body chunk, and 2) each blade requires clearance from the side to access the fingernail dents. In spite of these interactions which require some detail design attention, the Swiss Army knife provides a nearly perfect example of a modular architecture.
Modular product architecture has the following advantages:
Modular product architecture has the following disadvantage:
Product Performance—Modularity inhibits the performance gains possible through the practice of function sharing between physical elements.
It is interesting to consider what the more integral architecture alternative might be like. Perhaps a single-bladed tool that can do everything?
EX 10.3
Take apart a small electromechanical product (which you are willing to sacrifice if necessary). Draw a schematic including the essential functional elements. Identify two or three possible clusterings of these elements into chunks. Is there any evidence to suggest which architecture was chosen by the development team?
(Based on a solution by Chris Rice)
For this exercise, a General Electric model 2-9167A telephone base was disassembled. A schematic of the physical elements is shown below.
Describe the architecture of a Swiss Army knife. What advantages and disadvantages does this architecture provide?
(Based on a solution by Mark Parrish)
A Swiss Army knife can be thought of as consisting of numerous independent physical elements, or chunks, capable of performing a myriad of independent functional elements that include slicing, screwing, sawing, poking, and picking, just to name a few. These chunks include blades, screwdrivers, scissors, awls, toothpicks, and, depending on the model and price, as many as forty other handy instruments, each with its own specific purpose.
Each of its chunks implements one functional element, and the functional interactions between these chunks are minimized. However, two important interactions remain between chunks: 1) the blades must each interface to the knife body chunk, and 2) each blade requires clearance from the side to access the fingernail dents. In spite of these interactions which require some detail design attention, the Swiss Army knife provides a nearly perfect example of a modular architecture.
Modular product architecture has the following advantages:
- Product Change—Modularity allows product changes to be made to a few isolated functional elements without affecting the design of other chunks. This enables the firm to minimize the physical changes required to achieve a functional product change.
- Product Variety—Products built around modular product architectures can be easily varied.
- Component Standardization—The manufacturing firm can decrease unit manufacturing costs by using the same component or chunk in multiple products.
- Product Development Management—Modularity minimizes the coordination efforts between teams tasked with designing independent chunks.
Modular product architecture has the following disadvantage:
Product Performance—Modularity inhibits the performance gains possible through the practice of function sharing between physical elements.
It is interesting to consider what the more integral architecture alternative might be like. Perhaps a single-bladed tool that can do everything?
EX 10.3
Take apart a small electromechanical product (which you are willing to sacrifice if necessary). Draw a schematic including the essential functional elements. Identify two or three possible clusterings of these elements into chunks. Is there any evidence to suggest which architecture was chosen by the development team?
(Based on a solution by Chris Rice)
For this exercise, a General Electric model 2-9167A telephone base was disassembled. A schematic of the physical elements is shown below.
There are a number of important notes to make about the architecture of this telephone. First, we can describe its modularity; it has a relatively integral architecture. We notice that there are many functions which all interrelate in the telephone. For instance, the buttons, while integrated with the plastic housing, are also intimately connected to the circuitry which itself is all very interconnected. Most likely, the development team was attempting to better the performance of the telephone by integrating many parts together. However, we do notice some modularity. Modularity is evident in components such as the memory buttons, the receiver switch, and the slide switches, all of which can be found on other GE phones. By standardizing these parts, GE can make other products with these parts and achieve economies of scale. It would seem that the development team was less interested with issues such as upgrades, add-ons, and wear, since when a phone becomes worn or obsolete the entire unit is generally replaced rather than a portion. Thus, modularity is less important for the exterior.
Although the phone is rather integrated, several chunks can be identified. Keypad circuitry is contained on a single board separate from the main circuitry on the back of the phone, thus identifying two possible chunks. However, since the circuit elements are probably arranged somewhat differently from phone to phone, they can be considered a chunk because their basic composition most likely remains essentially the same throughout GE's low-end telephone products and therefore GE engineers probably designed these circuits as a standard chunk or module. The exterior can be considered a chunk because there are several components which must blend and fit together to achieve the desired styling and ergonomics. The jack interfaces are also a chunk because they are standardized to fit existing phone cables. Finally, the ringer is isolated as its own chunk, perhaps to reduce the likelihood of incidental interactions such as vibration with other chunks.
An alternative architecture might arrange the keypad circuitry and the buttons into a single chunk. Possibly all of the switches, jacks, and buttons could be considered as a single chunk. My guess is that the GE team wished to design a product that appeared integral from the outside but used modularity inside.
TQ 10.1
Do service products such as bank accounts or insurance policies have architectures?
Yes. A bank account and an insurance policy are each a collection of modular features. For example, the bank account may include checking account, ATM card, overdraft protection, savings options, interest options, direct deposit, electronic payments, etc. These features are combined in different ways for different customers, exhibiting a modular architecture.
TQ 10.2
Can a firm achieve high product variety without a modular product architecture? How (or why not)?
Product variety can certainly be achieved in a number of ways. On the one hand, it is possible to create a large variety of products using no modularity at all—but this is difficult and does not work in many cases. For example, most injection molding shops generally do not exploit the concept of modularity at all, yet they produce a high variety line of one-piece moldings. They use unique tooling for each product and the results are highly integrated. Another way to achieve product variety is through flexible manufacturing systems, where the variety is accomplished by programming the machines to create different products. While these strategies are successful, they are less appropriate for a complex line of electromechanical assembled products.
Modularity allows a manufacturer to obtain high product variety using relatively few standard modules. For example, Sony produces a small number of different tape transport mechanisms for their Walkman line. They add variety to the line by using different casings, electronics, and feature options along with one of the standard tape transports. This modular strategy allows Sony to produce the most complex component (the tape mechanism) in high volumes. Another example is provided by the Swatch example described in the chapter.
For the molding shop described above to utilize the principle of modularity, they might design mold tooling for a line of products such that they can interchange components of the mold to create slightly different moldings, comprising the product line.
TQ 10.3
The argument for the motorcycle architecture shown in Exhibit 5 is that it allows for a lighter motorcycle than the more modular alternative. What are the other advantages and disadvantages? Which approach is likely to cost less to manufacture?
(Based on a solution by Steve Goldt)
Advantages:
Disadvantages:
Manufacturing:
The more modular approach would most likely cost less to manufacture because it uses standardized components which can be manufactured in volume. In addition, the performance requirements for the relatively integral transmission might demand more expensive materials or manufacturing processes that would offset any savings due to reduced material usage.
TQ 10.4
There are thousands of architectural decisions to be made in the development of an automobile. Consider all of the likely fundamental and incidental interactions that any one functional element (say safety restraints) would have with the others. How would you use the documentation of such interactions to guide the decision about what chunk to place this functional element in?
The safety restraint example is useful to illustrate the use of interaction information to plan chunks. Consider two alternative scenarios with respect to a portion of this system, seat belts: On the one hand, if the seat-belt restraint system hardware were to interact only with the seat system, then the restraint system designers need to interact quite closely with the seat system developers in order to assure that these systems function properly together. In this case, the seat belt system would perhaps belong in the seat system chunk. On the other hand, if the seat belt system concept required attachment points as the body pillars, doors, and center console, this arrangement would require different and much more complex interactions between several design teams. In this case, the seat belt system might become part of multiple chunks, now including seats, body, and interior systems.
TQ 10.5
The schematic shown in Exhibit 9-6 includes 15 elements. Consider the possibility of assigning each element to its own chunk. What are the strengths and weaknesses of such an architecture?
Assigning each element to its own chunk allows the fourteen elements to be independently designed as individual components or subsystems. This would be desirable in the situation where each component is also to be used separately in other DTM products. The designers of each element would want to make the detailed design decisions with standardization of these components in mind, and this freedom can perhaps be best achieved through modularity.
There are many drawbacks to this approach of extreme modularity. First of all, product performance may suffer when the fourteen components are designed rather independently because the designers may emphasize component functionality at the expense of system performance. In order to achieve the desired performance of the overall product, the team will need to consider all of the interactions between the elements. In this case, the interactions all occur between chunks, rather than within. It may therefore be difficult to achieve the necessary level of coordination between designers required to reach the target performance level.
Although the phone is rather integrated, several chunks can be identified. Keypad circuitry is contained on a single board separate from the main circuitry on the back of the phone, thus identifying two possible chunks. However, since the circuit elements are probably arranged somewhat differently from phone to phone, they can be considered a chunk because their basic composition most likely remains essentially the same throughout GE's low-end telephone products and therefore GE engineers probably designed these circuits as a standard chunk or module. The exterior can be considered a chunk because there are several components which must blend and fit together to achieve the desired styling and ergonomics. The jack interfaces are also a chunk because they are standardized to fit existing phone cables. Finally, the ringer is isolated as its own chunk, perhaps to reduce the likelihood of incidental interactions such as vibration with other chunks.
An alternative architecture might arrange the keypad circuitry and the buttons into a single chunk. Possibly all of the switches, jacks, and buttons could be considered as a single chunk. My guess is that the GE team wished to design a product that appeared integral from the outside but used modularity inside.
TQ 10.1
Do service products such as bank accounts or insurance policies have architectures?
Yes. A bank account and an insurance policy are each a collection of modular features. For example, the bank account may include checking account, ATM card, overdraft protection, savings options, interest options, direct deposit, electronic payments, etc. These features are combined in different ways for different customers, exhibiting a modular architecture.
TQ 10.2
Can a firm achieve high product variety without a modular product architecture? How (or why not)?
Product variety can certainly be achieved in a number of ways. On the one hand, it is possible to create a large variety of products using no modularity at all—but this is difficult and does not work in many cases. For example, most injection molding shops generally do not exploit the concept of modularity at all, yet they produce a high variety line of one-piece moldings. They use unique tooling for each product and the results are highly integrated. Another way to achieve product variety is through flexible manufacturing systems, where the variety is accomplished by programming the machines to create different products. While these strategies are successful, they are less appropriate for a complex line of electromechanical assembled products.
Modularity allows a manufacturer to obtain high product variety using relatively few standard modules. For example, Sony produces a small number of different tape transport mechanisms for their Walkman line. They add variety to the line by using different casings, electronics, and feature options along with one of the standard tape transports. This modular strategy allows Sony to produce the most complex component (the tape mechanism) in high volumes. Another example is provided by the Swatch example described in the chapter.
For the molding shop described above to utilize the principle of modularity, they might design mold tooling for a line of products such that they can interchange components of the mold to create slightly different moldings, comprising the product line.
TQ 10.3
The argument for the motorcycle architecture shown in Exhibit 5 is that it allows for a lighter motorcycle than the more modular alternative. What are the other advantages and disadvantages? Which approach is likely to cost less to manufacture?
(Based on a solution by Steve Goldt)
Advantages:
- The relatively integral architecture might enable greater acceleration due to the lighter weight.
- The relatively integral architecture might create an aesthetic quality to distinguish it versus other motorcycles.
- The relatively integral architecture allows for function sharing and nesting that minimizes material use, reducing one aspect of the manufacturing cost.
Disadvantages:
- The relatively integral architecture would require a greater number of physical changes in order to achieve functional changes for upgrades, add-ons, adaptation, wear, consumption, flexibility in use, or re-use.
- The relatively integral architecture would increase the effort and cost required to provide product variety in response to customer orders.
- The relatively integral architecture is probably non-standard compared to BMW's other motorcycles. Therefore, the chunk must be produced in relatively small volumes and cost/quality might be adversely affected.
- The relatively integral architecture will require greater integration, conflict resolution, and coordination during the detail design phase of the development.
- The relatively integral architecture would make it difficult to allocate the detailed design of the structural support function and the power conversion function to different teams or suppliers.
- The relatively integral architecture would make it difficult to implement a design change in one functional element without also making a change in the other functional element.
Manufacturing:
The more modular approach would most likely cost less to manufacture because it uses standardized components which can be manufactured in volume. In addition, the performance requirements for the relatively integral transmission might demand more expensive materials or manufacturing processes that would offset any savings due to reduced material usage.
TQ 10.4
There are thousands of architectural decisions to be made in the development of an automobile. Consider all of the likely fundamental and incidental interactions that any one functional element (say safety restraints) would have with the others. How would you use the documentation of such interactions to guide the decision about what chunk to place this functional element in?
The safety restraint example is useful to illustrate the use of interaction information to plan chunks. Consider two alternative scenarios with respect to a portion of this system, seat belts: On the one hand, if the seat-belt restraint system hardware were to interact only with the seat system, then the restraint system designers need to interact quite closely with the seat system developers in order to assure that these systems function properly together. In this case, the seat belt system would perhaps belong in the seat system chunk. On the other hand, if the seat belt system concept required attachment points as the body pillars, doors, and center console, this arrangement would require different and much more complex interactions between several design teams. In this case, the seat belt system might become part of multiple chunks, now including seats, body, and interior systems.
TQ 10.5
The schematic shown in Exhibit 9-6 includes 15 elements. Consider the possibility of assigning each element to its own chunk. What are the strengths and weaknesses of such an architecture?
Assigning each element to its own chunk allows the fourteen elements to be independently designed as individual components or subsystems. This would be desirable in the situation where each component is also to be used separately in other DTM products. The designers of each element would want to make the detailed design decisions with standardization of these components in mind, and this freedom can perhaps be best achieved through modularity.
There are many drawbacks to this approach of extreme modularity. First of all, product performance may suffer when the fourteen components are designed rather independently because the designers may emphasize component functionality at the expense of system performance. In order to achieve the desired performance of the overall product, the team will need to consider all of the interactions between the elements. In this case, the interactions all occur between chunks, rather than within. It may therefore be difficult to achieve the necessary level of coordination between designers required to reach the target performance level.