Page 1

Product Lifecycle Management Activity Modelling – Engineering Design David Coombes 09MMP300


Product Lifecycle Management

Design Activity

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 2|Page

David Coombes – A911652


Product Lifecycle Management

Design Activity

Limitations ........................................................................................................................................ 12 Section C ............................................................................................................................................... 13 IDEF3 ................................................................................................................................................. 13 UML ................................................................................................................................................... 13 EXPRESS............................................................................................................................................. 14 Bibliography .......................................................................................................................................... 15

3|Page

David Coombes – A911652


Product Lifecycle Management

Design Activity

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.

4|Page

David Coombes – A911652


Product Lifecycle Management

Design Activity

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.

5|Page

David Coombes – A911652


Product Lifecycle Management

6|Page

Design Activity

David Coombes – A911652


Product Lifecycle Management

7|Page

Design Activity

David Coombes – A911652


Product Lifecycle Management

Design Activity

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. 8|Page

David Coombes – A911652


Product Lifecycle Management

Design Activity

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.

9|Page

David Coombes – A911652


Product Lifecycle Management

Design Activity

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.

10 | P a g e

David Coombes – A911652


Product Lifecycle Management

Design Activity

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.

11 | P a g e

David Coombes – A911652


Product Lifecycle Management

Design Activity

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

12 | P a g e

David Coombes – A911652


Product Lifecycle Management

Design Activity

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 13 | P a g e

David Coombes – A911652


Product Lifecycle Management

Design Activity

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.

14 | P a g e

David Coombes – A911652


Product Lifecycle Management

Design Activity

Bibliography Dorador, J. M., & Young, R. I. (2000). Application of IDEF0, IDEF3 and UML methodologies in the creation of information models. International Journal of Computer Integrated Manufacturing , 430445. Feldmann, C. G. (1998). The practical guide to business process reengineering using IDEF0. New York, NY, USA : Dorset House Publishing Co., Inc. . Kappes, S. (1997). Putting your IDEF0 model to work. Business Process Management Journal , 151161. Rumbaugh, J., Jacobson, I., & Booch, G. (2004). Unified Modeling Language Reference Manual, The (2nd Edition). Pearson Higher Education . Rumbaugh, J., Jacobson, I., & Booch, G. (2005). Unified Modeling Language User Guide, The (2nd Edition). Addison-Wesley Professional . 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 integration of the IDEF0/IDEF3 modeling methods and discrete event simulation. Winter Simulation Conference (pp. 518 - 524 ). Atlanta, Georgia, United States : IEEE Computer Society .

15 | P a g e

David Coombes – A911652


Product Lifecycle Management  

PLM - Coursework

Advertisement
Read more
Read more
Similar to
Popular now
Just for you