Product Lifecycle Management

Product Lifecycle Management

Activity Modelling – Engineering Design

David Coombes

09MMP300

P r o d u c t L i f e c y c l e M a n a g e m e n t D e s i g n A c t i v i t y

2 | P a g e D a v i d C o o m b e s – A 9 1 1 6 5 2

Contents Section A ................................................................................................................................................. 4

1. Identify the viewpoint from which the model is being composed. ............................................ 4

2. Produce 3 activity diagrams ........................................................................................................ 5

3. Describe the key activities in the model ..................................................................................... 8

A0 – Design and Manufacture of a CNC component ...................................................................... 8

A1 – Design of a CNC component ................................................................................................... 8

A2 – Manufacture of a CNC component ......................................................................................... 8

A11 – Produce Project Brief ............................................................................................................ 9

A12 – Initial Research ...................................................................................................................... 9

A13 – Produce P.D.S ........................................................................................................................ 9

A14 – Initial Designs ........................................................................................................................ 9

A15 – Validate Designs .................................................................................................................. 10

A16 – Final Design ......................................................................................................................... 10

4. Provide one page of example information flow descriptions ................................................... 10

Customer ....................................................................................................................................... 10

Customer Requirements ............................................................................................................... 10

Design Knowledge ......................................................................................................................... 10

Drawing Standards ........................................................................................................................ 10

Final Drawings ............................................................................................................................... 10

Finished Component ..................................................................................................................... 10

Machine ........................................................................................................................................ 10

Operator ........................................................................................................................................ 11

P.D.S .............................................................................................................................................. 11

Part Program ................................................................................................................................. 11

Patents .......................................................................................................................................... 11

Process Limitations ....................................................................................................................... 11

Time Limit...................................................................................................................................... 11

Tooling........................................................................................................................................... 11

Workpiece ..................................................................................................................................... 11

5. Highlight any significant issues with the model ........................................................................ 11

Section B ............................................................................................................................................... 12

Value ................................................................................................................................................. 12

Advantages ........................................................................................................................................ 12



Limitations ........................................................................................................................................ 12

Section C ............................................................................................................................................... 13

IDEF3 ................................................................................................................................................. 13

UML ................................................................................................................................................... 13

EXPRESS ............................................................................................................................................. 14

Bibliography .......................................................................................................................................... 15



Section A – Build and IDEF0 model to include;

1. Identify the viewpoint from which the model is being composed.

Every IDEF0 model needs a purpose and viewpoint statement. Accompanying the A0 node comes

the reasoning and the perspective, which help to guide and constrain the creation of the model. The

purpose part of the statement embodies the reason why the model was created. Each model will

have a purpose; this determines the structure of the model and ascertains the communication goal

for the model. The viewpoint indicates the perspective in which the information can be seen. This

information can take a different meaning if a different perspective taken to view the model, this

indicates a need for a different, single model for every viewpoint required to be assessed.

For the following diagrams;

The purpose of the model is to assess the design and manufacture stages within the development of

a CNC component. This is taken from the viewpoint of the design team involved with the

development of the CNC component in question.



2. Produce 3 activity diagrams

Purpose: To assess the design

and manufacture stages

within the development of a

CNC component

Viewpoint: The design team

tasked with the development

of stated component.



3. Describe the key activities in the model Accompanying each activity is a description that gives details to the processes required to complete

the activity. This is potentially expanded further by the completion of a decomposition of the

activity.

A0 – Design and Manufacture of a CNC component

This activity encompasses all activities concerned with the design and manufacture of any consumer

required CNC component. This includes all design and manufacturing issues, ranging from evolving a

project brief to completing the manufacture of the product. The inputs related to the design aspect

are from external sources. This reduces the control that the organisation has. In contrary, the

outputs are intended for the use of the enterprise or the customer only. There are no other external

sources that can complicate the outputs from this activity. The activity is expanded in A1.

The main input related directly to design is one that comes from the customer. This is the

information given by the customer, specifying details about the final product. Other inputs involve

the manufacturing side of the activity. Workpiece consists of the blank material that is manufactured

into a completed component. The manufacturing process will directly transform this input into the

output of a completed component.

Controls within the design come mainly in the form of standards and restrictions in the way the

design is completed. The part program is the main control within manufacturing and governs the

way in which the part is produced.

The customer themselves, can be seen as mechanism, where are their requirements are an input.

This is the means by which the activity is performed. The machine and the operator undertaken the

manufacturing task and design knowledge is important when performing most design activities.

Alongside the output of the completed component are results from the design of the component. A

completed PDS can be seen as an output along with finalised drawings. These documents can be

used to aid a similar project.

A1 – Design of a CNC component

This design activity embraces all aspects related to designing a new component. This includes the

identification of needs and combines them into a marketable product. This potentially marketable

product is further developed and eventually put into manufacture. This activity is expanded in A11

The only input comes from an external source, customer requirements, and initiates the whole

process. The controls are manly rules and regulations associated with design of any product. Design

knowledge is the most important mechanism and influences design significantly. The output from

the design process; drawing and a completed PDS, are both a final output but also information

needed to complete the manufacturing stage.

A2 – Manufacture of a CNC component

The second design activity within the first decomposition relates to all aspects considered when

manufacturing a component. This defines the process of making the product, turning the stock

material into a usable product. This includes; all equipment essential, skills required, resources

needed and the quality assurances necessary for a successfully manufactured product.



Both of the outputs from the design stage are included within the manufacture of the product. The

completed PDS is used as controlling action throughout the manufacturing stage. Whereas the

drawings produced from the design stage can be used as a direct input from the design stage. The

part programme which controls the activity is shown. The machine and operator are the resources

used when producing the part, therefore are shown as mechanisms and the output of a finished

component is indicated.

A11 – Produce Project Brief

The first stage within any design process is to complete a project brief; this will be comprised using

information received from the customer requirements. This product brief will give brief details to

the needs of the product and what should be achieved once the product is finally produced. It

should be possible to determine all areas of research from the product brief.

A12 – Initial Research

This is where all information is gathered relating to any aspect of the final product. This will consist

of researching into existing products, the usage of the product in service and information regarding

to the materials and processes used. This will provide all the information required to complete the

design process successfully.

The completed project brief will control the activity, giving a lead to all areas that need researching.

Design knowledge will assist the research progress. The inherent knowledge of materials and

processes will reduce the time taken throughout the research phase.

A13 – Produce P.D.S

Product design specification is vital to any design process, is constrains the designs that follow. It

ensures that all designs meet the product need, without being un-marketable and un-producible.

The PDS can continue to be edited throughout the design stages, some designs may throw up

ambiguities within the specification.

The completed research will act as the input of the production of the product design specification.

This research will aid the characterization of numerous items including; price, size, weight,

functionality, production methods, quality assurance and many others. Process limitations will

control the production of the specification; it will constrain the design at subsequent stages also.

Again design knowledge will be the means by which the PDS is created.

A14 – Initial Designs

By using the PDS an input initial designs will be developed. This process will consist of a

brainstorming of all ideas. This almost exhausted list will be developed and the final design chosen

from the catalogue of initial ideas.

Design knowledge, including creativity will again be the mechanism within this activity. There will be

numerous controls, helping the limit and channel the designs. Initially any patents, hopefully

uncovered within the research phase, will need to be considered. These patents cannot be

encroached on. Following this, design and drawing standards will need to be adhered to. These

standards ensure the uniformity of products information throughout the design stage. This will

enable people from outside of the design process to understand the drawing.



A15 – Validate Designs

From the hopefully large list of initial designs, a process is needed to reduce these down, in order to

produce a final design. This final design will be developed within the validation and again afterwards.

This selection process can be completed by numerous methods, one of which is a design matrix. This

assesses each individual design related to part of the specification, the design scored on each of

these items and the best score indicates which the best design is.

The design knowledge and opinions on the quality of the designs are the main other information

needed to complete this activity.

A16 – Final Design

Once the final design has been the selected, the activity is to develop it and to produce technical

drawings and all the information required to manufacture the component.

The input will be the information gained whilst validating the designs in the previous stage. As with

the generation of initial ideas the controls and mechanisms will be identical. Restrictions such as

standards for drawings and existing patents will need to be adhered to. The design knowledge of the

restrictions stated will aid the development of this activity and the production of the require output.

4. Provide one page of example information flow descriptions

Customer

Mechanism – This is the source of the information which initiates the whole design process. This is

also the source, if any more information is required and aids the project brief activity mainly.

Customer Requirements

Input – The information gained from the customer which initiates the whole process and is the

reason for completing the task. Indicates the needs of the user.

Design Knowledge

Mechanism – This is the knowledge from the designer that may aid the process. This includes;

knowledge of the manufacturing process, the drawing standards and initial knowledge of the

component.

Drawing Standards

Control – Conforming to BS 8888 will ensure the drawings can be understood by other people

outside the organisation.

Final Drawings

Output –The final drawings will be a physical output of the design process, these will be used

throughout the manufacturing stage but will still be a physical output once the process is complete.

Finished Component

Output – The needs of the customer should be satisfied within the final component. All acts within

the process are targeted at producing the final component.

Machine

Mechanism – The means by which the final product will be produced.



Operator

Mechanism – The operator will run the machine and ensure the machine is working, and can

complete the manufacturing process.

P.D.S

Output – The product design specification is the result of all the research within the design stage.

This will be a physical output, in the form of a document. It will also act as a guide for a lot of the

designs.

Part Program

Control – This will control the machine, and ensure the part produced is what is required.

Patents

Control – If there are any existing products in the market, there are potential patents in force,

prohibiting certain designs from being sent to market.

Process Limitations

Control – Every manufacturing process will have certain limitations, these can be avoided by

considering the process within the design stage.

Time Limit

Control – The customer will require the component within a certain time limit. This will control the

amount of time spent at each stage throughout the process.

Tooling

Input – The tooling within the machine will do the actual production. These are expendable items

which will get used up within the manufacturing process.

Workpiece

Input – This blank of material will eventually become the finished component.

5. Highlight any significant issues with the model

There are many issues within IDEF0 modelling. Some of which can be overcome, others have been

overcome using different methods of activity modelling.

Within the diagram above, the research and PDS activity will be continuous processes. The model

indicates that once these have been completed they are forgotten and never considered again. This

is not the case. The research will continue throughout the design process, especially when

innovative designs are put forward. The PDS can be altered, flaws within the PDS can be highlighted

at the design stage, and the PDS will need altering then.

Design knowledge is also a very broad area, and to be combined under one mechanism results in it

influencing numerous activities within the design process. This mechanism could easily be

decomposed into a number of different aspects. The consequence of this would be that more

mechanisms would be included but they would individually influence fewer activities, thus resulting

in less confusing within the model.



Section B – From the results, comment briefly on the value of the model produced. Explaining

both the advantages and the limitations of the IDEF0 approach

Value

There are numerous values associated with any IDEF0 model. One of the main uses of the model is

to help organise the analysis of a system. Within the example model above the design and

manufacture of a CNC component individual activities can be seen significantly easier and the

organised nature means the analysis of the process is more straightforward to complete. Along with

this, good communication between all aspects of the process is encouraged. This heightened level of

communication produces a process which ultimately runs smoother and more effectively.

Advantages

One of the first main advantages is that it is a well documented technique. This leads way to a highly

standardised way of working, and way of producing the model. This in turn can reduce confusion

and mean it is easier for people from outside the process to understand the activities and the flow.

The formal method of categorizing the inputs, outputs, mechanisms and controls supports this ease

of understanding. To compliment the broad use of the IDEF0 modelling technique, there are a

number of tools that can be used to aid the production of a diagram.

The process is a simple one, and a user can be taught how to create a model in a very short space of

time. This ease of learning makes this type of modelling very popular and increases the areas of use.

IDEF0 modelling also provides a controlled manner in how the information is broken down, this

means that any one of the design process, the activities can be scrutinised and any anomalies can be

rectified easily. These more detailed views, can give a better insight into the design process and also

into the product of itself.

Changes within an organisation are regularly needed; these changes occasionally need to link with

changes in the process flow. By viewing the activities and the organisation separately it is easier to

visualise the changes that potentially could take place.

Limitations

One problem with the IDEF0 model is its inclination to represent the activities in a sequence even if

the processes activities are not necessarily completed in a sequence. With the activity boxes flowing

from top left to bottom right, it is simple to see the diagram as a sequence. If an output from one

activity is seen as an input to the next, this sequence assumption can be easily made.

Problems can arise within the modelling when it comes to considering multiple activities at any one

time. It is difficult to describe more than one activity at any one time; this again leads to the

sequential view.

Another issue can come in decision making within the model, this is to decide what aspects are a

considered an activity within the diagram or as part of the decomposed model afterwards. This is an

opinion and is decided by the creator of the model. Certain aspects of the model can be grouped

under a single heading; this would mean that a further decomposed model would be required. If this

decomposition only consists of two activities there could be possibility to combine these activities



into the model above. This is an opinion of the models creator, and could be interpreted a different

way by someone else looking at the model.

Difficulties can arise within the IDEF0 models due to the concise nature of the flows and activity

boxes. This means ambiguities within the meaning of some of these statements can cause confusion

within the meanings. This is overcome by the list of information flow descriptions. This provides

excessive work but reduces the confusion within the understanding of the model.

Section C – Identify and discuss the value of other competitive or complementary methods which

might be used when configuring a PLM system to support an engineering design department or any

other business activity concerned with product lifecycle.

There are numerous ways of activity modelling available that can complement the IDEF0 technique,

but equally as numerous are the quantity of methods that are seen as competition to the IDEF0

approach. These include;

IDEF3

IDEF3 is a progression from IDEF0 and deals with some of the problems encountered when using

IDEF0. Rather than IDEF0 having activities modelled, with; inputs, outputs, controls and mechanisms,

IDEF3 concentrates around the processes. The sequences of activities are comprised by three main

aspects; process-centred diagrams, object-centred diagrams and elaboration forms. The IDEF3

model can be utilised to model numerous processes. This includes modelling a current business

system or process, modelling a proposed system or process and developing a model of the process

or system from different viewpoints. There are two different views developed within IDEF3

modelling. The first is Process Flow Description (PFD); this describes the how the process works.

Secondly there is The Object State Transition Description (OSTD), which portrays the alterations an

object makes during the process. To fully describe a system, these two descriptions are used

together. These individually describe a different part of the whole process. Many of the advantages

seen within IDEF0 are also continued through into IDEF3. These include; the high level of

documentation, simplistic model and controlled manner in how the information is broken down.

Alongside these advantages, others can be seen that are not common with IDEF0. Firstly it allows an

easy mechanism for capturing process information. This is slightly different to that of IDEF0, where

IDEF0 provides a good tool for process design, IDEF3 concentrates on the process information.

Depending on the requirements of the model, as selection process between to two will need to take

place. IDEF3 provides an excellent chronological view upon the whole process. This allows easy

definition of all relationships and indicates easily if a proposed process is realistic. IDEF3 finds it

difficult to handle unexpected circumstances. Especially when models are created for existing

processes, the model cannot adjust when unforeseen events are introduced into the workflow.

Further to this, IDEF3 finds it difficult to identify problems which are hidden within multiple tasks,

due to the behaviour of each object creating the workflow.

UML

Unified Modelling Language (UML) is a general purpose modelling language created by the object

management group. The Unified Modelling Language (UML) is used to define, envisage, adjust,

construct and document the substance of an object-oriented software intensive system under

development. UML can be applied to all processes and throughout the development lifecycle. The



modelling language can also be applied to numerous technologies. There have been methods to

improve the language, this has happened in the form of revisions to the language, with UML 2 being

the most updated revision. By using this object orientated approach, it is easier to model the way

real world entities behave. It also uses a modular approach, producing objects that can be

constructed independently to other objects. There is a need to define between the UML model and

the set of diagrams of a system. UML diagrams represent two different views of a system model.

These are static and dynamic. The static diagrams highlight the physical objects and the attributes

within a system, whereas dynamic diagrams show behaviours and calibrations amongst objects

within the system. One of the advantages of UML is the ability is for it to model just about any type

of application, running on any type and combination of hardware, operating system, programming

language, and network, in UML. This gives an incredibly large number of areas in which this

modelling technique can be applied. Another advantage is that the model is produced in a natural

way and Transactional, Real-time, and Fault-Tolerant systems can be modelled in a specific way.

Finally the effectiveness to model large, complex, activities makes it a very suitable for a number of

applications. One of the issues that face creators of a UML documents is that there is no specific

standardised file format. This results in individual vendors providing a program which produces

models that are not interchangeable between different software. Even though it is effective at

producing large and complex models, these models are not easy to complete. There is a very high

level of understanding needed to create a large complex model.

EXPRESS

EXPRESS modelling language is a data modelling language for product data. EXPRESS is formalized in

the ISO Standard for the Exchange of Product model STEP (ISO 10303), and standardized as ISO

10303-11. It is used to model entity types. This model can be defined in 2 ways, textually and

graphically. Textually can be seen as the most important; with inputs coming in the form of an ASCII

file. Graphical representation is more user-friendly and easier to understand. One of the advantages

that EXPRESS modelling has is the standards attached to it. This standardised form means that a

single method of producing models is adhered to by all, reducing the confusion when interpreting

other models. Also by using EXPRESS-G the model can be represented in a more understanding way,

making the model ultimately easier to use. The problem with EXPRESS-G notation is that it struggles

to formally specify complex constraints.



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Rumbaugh, J., Jacobson, I., & Booch, G. (2004). Unified Modeling Language Reference Manual, The

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Schenck, D. A., & Wilson, P. R. (1994). Information modeling: the EXPRESS way. New York: Oxford

University Press.

Whitman, L., Huff, B., & Presley, A. (1997). Structured models and dynamic systems analysis: the

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