Product structure modeling: Difference between revisions

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A '''product structure''' is a hierarchical decomposition of a product, typically known as the [[bill of materials]] (BOM).

The structure of a product is a breakdown of the product in several items and parts, together with a relationship between them. Product structure modeling goes beyond this concept and provides an integrated model to support all of the product life cycle aims based on a common logical framework, which integrates all the data generated throughout the product life cycle. Thus product structure modeling is mainly involved in the hierarchical decomposition of a product.

As business becomes more responsive to unique consumer tastes and derivative products grow to meet the unique configurations, BOM management can become unmanageable. For manufacturers, a bill of materials (BOM) is a critical product information record that lists the raw materials, assemblies, components, parts and the quantities of each needed to manufacture a product.

The traditional fixed parts list ([[Bill of Materials]]) becomes unmanageable when the number of items and therefore structures increases. Therefore more advanced modeling techniques are necessary to cope with these circumstances. Also changes or an alternative to a [[Product (business)|product]] is an aspect why product structure modeling is needed. Especially with configurable products modeling of the structure is efficient, because variants, for example, grow exponential. Therefore, changing a small part of a [[Product (business)|product]] can have multiple impacts on other product structure models.

Concepts within this entry are all caps locked in order to indicate these concepts.

Advanced modeling techniques are necessary to cope with configurable products where changing a small part of a product can have multiple impacts on other product structure models. Concepts within this entry are in capital letters in order to indicate these concepts.

==Product structure concepts==

Several concepts are related to the subject of product structure modeling. All these concepts are discussed in this section. These concepts are divided into two main aspects. First the product breakdown is discussed which involves all the physical aspects of a [[Product (business)|product]]. Second, different views at the product structure are indicated.

===Product breakdown===

[[Image:Product_structure_modeling_metaProduct structure modeling meta-data_model1data model1.gif|right|thumb|300px|Figure 1: product structure concepts]]Figure 1 illustrates the concepts that are important to the structure of a [[Product (business)|product]]. This is a [[Meta-modeling_techniquemodeling technique|meta-data model]], which can be used for modeling the instances in a specific case of product structuring.

===Product breakdown===

The core of the product structure is illustrated by the product components (ITEMS''[[wikt:item|item]]s'') and their RELATIONSHIPS''relationships''. Thus, this involves the linking between ITEMSitems related to the [[Product (business)|product]].

[[Image:Product_structure_modeling_meta-data_model1.gif|right|thumb|300px|Figure 1: product structure concepts]]Figure 1 illustrates the concepts that are important to the structure of a [[Product (business)|product]]. This is a [[Meta-modeling_technique|meta-data model]], which can be used for modeling the instances in a specific case of product structuring.

The ASSEMBLY''[[manufacturing|assembly]]'' can existconsist of SUBASSEMBLIES''subassemblies'' and PARTS''parts'', whereas SUBASSEMBLIES''subassemblies'' can also consist of other SUBASSEMBLIESsubassemblies or PARTSpart. Thus, this is typically hierarchically ordered. These concepts are generalized into the concept of ITEMitem. This classification is overlapping, due to the fact thatbecause a SUBASSEMBLYsubassembly could be a PARTpart in another ASSEMBLYassembly configuration.

The core of the product structure is illustrated by the product components (ITEMS) and their RELATIONSHIPS. Thus, this involves the linking between ITEMS related to the [[Product (business)|product]].

Due to differentiation and variation of items several concepts must be indicated into the product breakdown structure. Three concepts are involved in this differentiation, namely ALTERNATIVES''alternatives'', VARIANTSvariants and REVISIONS''revisions''. An ALTERNATIVEalternative of an ITEMitem is considered as a substitute for that particular item, whereas a VARIANTvariant is another option of an item which the consumer can choose. When an error occurredoccurs at a part or subassembly, it needneeds to be revised. This revisionsrevision indicatedindicates the change history of athe productitem.

The ASSEMBLY can exist of SUBASSEMBLIES and PARTS, whereas SUBASSEMBLIES can also consist of other SUBASSEMBLIES or PARTS. Thus this is typically hierarchically ordered. These concepts are generalized into the concept of ITEM. This classification is overlapping, due to the fact that a SUBASSEMBLY could be a PART in another ASSEMBLY configuration.

Due to differentiation and variation of items several concepts must be indicated into the product breakdown structure. Three concepts are involved in this differentiation, namely ALTERNATIVES, VARIANTS and REVISIONS. An ALTERNATIVE of an ITEM is considered as a substitute for that particular item, whereas a VARIANT is another option of an item which the consumer can choose. When an error occurred at a part or subassembly, it need to be revised. This revisions indicated the change history of a product.

==Product structure conceptsviews==

===Product structure views===

Product structure views are made upon several activity domains within the company. Due to the fact not everyone in the company has to have a detailed overview of the product several components with their attributes can be extracted.

When the MASTER''Master STRUCTUREStructure'' is made out of the several items of the product assembly, multiple views can be made upon this MASTER''Master STRUCTUREStructure''. Thus this MASTER''Master STRUCTUREStructure'' contains every item in detail, which is important to the ASSEMBLY''Assembly'' of the product.[[Image:Product_structure_modeling_metaProduct structure modeling meta-data_model2data model2.gif|centre|thumb|500px|Figure 2: Different product structure views]]

==The modeling process==

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! Activity !! Sub-Activity !! Description

|-

| rowspan=3 | Define product components || Identify parts || Identifying parts is concerned with the so-called [[bill of materialmaterials]]. Thus the materials are described for each product. Output of this activity is a list of parts for each product.

|-

| Specify sub-assemblies || Several parts mulled together are described as a subassembly. But can also be an atomic component, which is part of the whole assembly.

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| rowspan=2 | Define product structure views|| Specify needed views || The necessary views, which are important for the product, are specified.

|-

| Create AD specific views || De viewsViews on the MASTER''master STRUCTUREstructure'' are created for each Activity Domain (AD).

|}

==Process-data model==

When combining the activities with the concepts of the product structure model it will result in a [[Meta-modeling_techniquemodeling technique|process-data diagram]]. This diagram displays the steps which need to be taken within the process of product structure modeling together with the deliverables, at the right side, which are outcomes of these activities.

[[Image:Product structure modeling Process-Data diagram.gif|centre|thumb|500px|Figure 3: Process-Data diagram product structure modeling]]

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===Define product components===

First, all components are identified and indicated. In the area of car manufacturing, the product components are as follows. A car (ASSEMBLY) consists of several SUBASSEMBLIES such as the body and the engine of the car. The engine for example is assembled in several parts such as screws and small pipes.

===Define product assortment===

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===Create master structure===

After structuring the product with all the listed items and relationship between them this must be combined into one MASTER STRUCTURE which contains all of the details of the product. In case of the car, all items from engine to screw must be documented in one MASTER STRUCTURE.

[[Image:Product structure modeling example master structure.gif|centre|Figure 6: product master structure]]

===Documenting===

When the MASTER STRUCTURE of the car is created one must link this structure with documents which contains the product definition of this specific car. Primarily, this consists of an extensive description of the car which is linked to the MASTER STRUCTURE of this product.

===Define product structure views===

In case of the car manufacturer multiple views can be madederived out offrom the car assembly. For example a structure from a sales point of view will need more detail about the functions and characteristics fromof the car rather than detailed information about the body. Thus a sales manager needs information about the color of the car or the type of gear (automatic of manual).

From a purchasing view more information is needed about the mixing of the paint instead of the general color, which is only needed for the customer. Purchasing department also needs more information about the suppliers of the used components within the manufacturing of the car, so they can easily overview where which component is used and from which supplier isit comes from.

[[Image:Product structure modeling example product structure views.gif|centre|Figure 7: product structure views]]

== See also ==

* [[ISO 10303]]

* [[Assembly modelling|Assembly modeling]]

* [[Bill of Materialsmaterials]] (BOM)

* [[Product breakdown structure]]

==See alsoBibliography ==

* Hvam, L. (1999). A procedure for building product models. <i>''Robotics and Computer-Integrated Manufacturing, 15</i>'', pp. 77-87

*[[ISO 10303]]

* Peltonen, H. (2000), Concepts and an Implementation for Product Data Management. <i>''Acta Polytechnica Scandinavica, Mathematics and Computing Series No. 105</i>'', pp. 188

*[[Assembly modelling]]

* Rampersad, H.K. (1995). Concentric Design of Robotic Assembly Systems. <i>''Journal of Manufacturing Systems, 14</i>''(4), pp. 230-243

*[[Bill of Materials]]

* Svensson, D., & Malmqvist, J. (2002). Strategies for Product Structure Management at Manufacturing Firms. <i>''Journal of Computing and Information Science in Engineering, 2</i>''(1), 50-58.

*[[Product breakdown structure]]

==Bibliography==

Hvam, L. (1999). A procedure for building product models. <i>Robotics and Computer-Integrated Manufacturing, 15</i>, pp. 77-87

Peltonen, H. (2000), Concepts and an Implementation for Product Data Management. <i>Acta Polytechnica Scandinavica, Mathematics and Computing Series No. 105</i>, pp. 188

==References==

Rampersad, H.K. (1995). Concentric Design of Robotic Assembly Systems. <i>Journal of Manufacturing Systems, 14</i>(4), pp. 230-243

{{Reflist}}

[[Category:Computer-aided design]]

Svensson, D., & Malmqvist, J. (2002). Strategies for Product Structure Management at Manufacturing Firms. <i>Journal of Computing and Information Science in Engineering, 2</i>(1), 50-58.

[[Category:Product lifecycle management]]