2.2 Basic functionality

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The functionality of PDM systems is often divided into two categories: user functions and utility functions. User functions provide functionality for the user to access the PDM system. Different types of users may work with different subsets of these functions. A user may be a consumer (viewing information) or a producer (creating information). User functions can be divided into five categories:

  1. Data vault and document management;

  2. Workflow and process management;

  3. Product structure management;

  4. Classification management;

  5. Program management.

Utility functions provide an interface between different operating environments and encapsulate their complexities to the users. Utility functions can be divided into five categories:

  1. Communications and notification;

  2. Data transport and translation;

  3. Image services;

  4. Administration;

  5. Application integration.

Both user functions and utility functions will be further described in the following sections.

2.2.1 Data vault and document management

PDM systems consist of central locations, referred to as data vaults, used in the control of all types of product information. Data vaults are either physical locations in the file system (any kind of folder or directory) or databases. They provide data access control, data security, and integrity. Two types of data are stored in data vaults:

  1. Product data generated by various applications, such as specifications, CAD models, computer-aided engineering (CAE) data, software executables, maintenance records, services, user and operating manuals, or any kind of information that permits users to access the data. This information is stored in the file system or in a database.

  2. Metadata, which describes different properties of the product data (e.g., who created a specific piece of information and when) and index and definition information about products so that changes (new versions), approval authorizations, and other data can be tracked and audited. The PDM system also offers the functionality to query for a document, either by searching for key metadata (e.g., document title or document number) or free text search.

Users have access authorization to one or several data vaults, where they can check in documents to the data vault and control the alteration of documents after they have been checked in to these locations. To modify a data item, a user checks it out to a local work structure. Check-in and check-out functions provide secure storage and access control to data stored in the data vaults.

When a PDM system is deployed in an organization or in a project, the system administrator must define how the data vaults are to be used. One example of the use of data vaults is shown in Figure 2.3. When the user checks out a document, it will be under PDM control in a work location—a personal physical file location. Only one specific user is permitted to read and write in this work location. Any change made in the document here will not be visible to other users. The document may be changed several times before it will be checked in again into another data vault, the work in process (WIP) vault. All of the members of the project team are provided with access to the WIP vault for viewing or altering the information it contains. When the document has passed the approval process, it will be submitted and stored in the release vault, a file location where users have only read access. The approval process automatically stores information in the release vault to which only the PDM system (a very specific user with system authorities) has write access.

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Figure 2.3: Example of data vault usage.

PDM offers many more functions than storage, check in, and check out for managing documents. A more detailed description of document management is given in Section 2.5.2.

2.2.2 Workflow management

All companies must manage their changes effectively, whether using a tool for managing changes and workflows for strict change control or using manual procedures for managing all changes on paper. Thus, workflow management is a critical part in the product definition life cycle to ensure that the right information is available to the correct users at the proper time. It includes defining the steps in the process, the rules and activities associated with the steps, the rules for approval of each step, and the assignment of users to provide approval support. PDM workflow management provides the mechanisms for modeling and managing defined processes automatically. Data can be submitted to the appropriate workflow for processing. The workflow can transfer the data to nominated users, groups, or project roles to carry out a specific business process. Appropriate information is routed automatically. At any location, the data can be assessed as it progresses through its life cycle.

PDM systems record information at each step in a process, and users can review the change history at any time. Audit and historical records are maintained. Workflow management can help define and control changes in any kind of product data.

2.2.2.1 Change approval—An example of workflow and process management

Figure 2.4 [5] shows an example of an approval process. All documents in which work is in progress are stored in the WIP vault. A work order is sent to the designer when review is necessary. The designer sends the document to designated users for reviewing. The change review board will take care of the comments. When the document is approved, it will be stored in the release vault. Upon approval, the new and modified documents and all data are sent from the WIP to a release vault, and the item now revised becomes generally available. After the work is completed, the newly revised items continue to refer to the work instructions and work orders by which they were generated. This provides a valuable history of the evolution of the design, which allows users to learn from design approaches that have been implemented in the past.

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Figure 2.4: Example of a workflow for change approval.

2.2.3 Product structure management

When designing a complex product, the management of its component parts is as important as the management of the documents that describe the product. A product structure comprises components (elements), the externally visible properties of those components, and the relationships between them.

Product structure management includes the following activities:

  • Identification and control of product configurations;

  • Management of the development and selection of product variants, including platforms, options, alternates, and substitutes;

  • Linking of product definition data to the structure;

  • Allowance of various domain-specific views of a product structure, such as design and manufacturing views;

  • Transfer of product structure and other data in both directions between PDM and manufacturing resource planning (MRP) or enterprise resource planning (ERP) systems.

A product structure most often forms a hierarchical structure. A traditional mechanical design-oriented definition of a product structure is:

A product structure is a division of parts into a hierarchy of assemblies and components. An assembly consists of other assemblies (subassemblies) and/or components. A component is the lowest level of the structure.

This definition also describes a bill of material (BOM), which is used in manufacturing to collect all the objects and information for building the final product. Figure 2.5 depicts an example of a BOM of a bicycle, which consists of pedals, handlebars, a saddle, a frame, and wheels. In the figure, each of the parts is quantified (e.g., there are two wheels and one saddle).

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Figure 2.5: Quantified BOM of a bicycle.

The business items in a PDM system (defined in Section 2.3.1) can be used to represent any kind of object (or data) describing a product (e.g., requirement objects describing the requirements of a product and functional objects describing the functions of a product). Various kinds of relationships can be used to connect the business items (e.g., described by, requirement for, designed as, built as, and planned as).

In an enterprise, product structures are used in different procedures, which can have different requirements for the breakdown and information content of a product structure. A designer and a manufacturing engineer need to see a product from different perspectives, which results in multiple product structures, as shown in Figure 2.6. Examples of other groups that could need their own structures are business planners, or maintenance, purchasing, and sales departments. These variants of a product structure are often referred to as views, even if this is not a correct usage of the term, as they are often separate structures stored in separate information systems.

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Figure 2.6: Example of different product structures.

Figure 2.7 shows a more detailed example of a product structure. Each business item is of a certain type (e.g., part, assembly, or subassembly), has a name (e.g., can, lid, or container), a unique part number (e.g., 1111, 2222, or 3333), a revision (e.g., 1, 2, or 3), and perhaps also variants (e.g., small, medium, or large). For the variant “cylinder large,” all three revisions are shown to illustrate that an object can exist in several revisions. Revisions are described in Section 2.3.3, and variants are described in Section 2.4.1.

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Figure 2.7: Example of a product structure describing a can with variants and revisions.

PDM systems also identify variants of parts. The can in the example is manufactured in three sizes. The cylinder part has three variants: small, medium, and large. The relationships between the parts may contain rules used for the selection of alternative parts. The three different container variants (large, medium, and small) can be selected with rules. A rule can be, for example, ”if volume larger than 2 dm3, then use cylinder large.” This kind of rule defines what to include in a product. There are also other (exclusive) rules defining invalid combinations of parts and assemblies.

Effectivity is used to define when a part is valid in a product configuration and to select the correct revision of the part. Configuration effectivity is defined in Section 2.5.1.

2.2.4 Classification management

Classification management is the classification of standard components in a uniform way. To support reuse of standard components, the components are classified and information about them is stored in the PDM system as common attributes (attributes defined in Section 2.3.1). Examples of information relating to components are supplier, supplier part number, release date, revision, and material. These attributes are used for querying and retrieval of standard components, items, or objects.

To ensure that a new product reaches the market in the shortest possible time, the reuse of parts of products is essential. Reuse is supported by the possibility of classifying components and attaching attributes to them. These attributes can later be used for querying and retrieval of components to be used. Reuse also leads to greater product standardization, reduced redesign, shorter time to market, savings in purchasing and fabrication, and reduced inventories. Reuse can be at any level of a product in the product structure (e.g., engines, wheels, antennas, software modules, screws, and bolts). When a PDM system is installed, libraries with standard components (with searchable attributes) are often included. User-defined attributes created for specific objects can also be added to these standard components. To make good use of the reuse of components, an organization should define the structure of the available reuseable components.

2.2.5 Program management

The support for project management provided by a PDM system involves standard functions such as definition of work breakdown structures (WBS), resource allocation, and project tracking. The purpose of this kind of functionality in a PDM system is that it enables the relation of the project data to the product data. This makes it possible to see with which parts of a product a specific project is working and the extent to which resources have been expended on this particular part of the product. The usage of PDM systems for project management is further explained in Section 2.5.5.

Today, most PDM systems are integrated with specialized project management tools. Effective support for project management is then provided with the possibility of relating product and project data with each other.

2.2.6 Communication and notification

As part of the implementation of workflow support, notifications can be automatically sent to the users. A notification can be sent to make a user aware of a specific operation (e.g., check in) or when a specific state has been reached (e.g., when a change has been approved). Each user, or role, can decide to which types of notification he or she wishes to subscribe. Typically, a user is interested in everything happening within a specific project or part of the product, or a user may be interested in all parts that reach a specific state. A sufficient level of awareness may be achieved by subscribing to the appropriate notifications. Electronic mail is often used as the medium for notifications.

2.2.7 Data transport and translation

PDM stores and manages data produced by many different applications. This information is often retrieved for reading or changing in the same application, but there may be a need to (at least) read the data in another application.

In a PDM system, predefined translators can be used for converting data from one application for use in another and for displaying information. The system administrator sets up the translators and the users therefore do not need to know which data translators to apply. Events can trigger automatic data translation from one application format to another.

2.2.8 Image services

Visualization tools support collaborative work by making it possible for all users to view images. Images can be stored and accessed as any other data in the PDM systems or in, for example, CAD systems. Scanned documents, two-dimensional drawings, and three-dimensional CAD models can then be viewed and marked up using standard visualization capabilities. The PDM system has add-on functionality for interoperability between CAD systems and the PDM system. For example, information represented by raster and vector images, together with portable definition file (PDF) viewing, allows users to view drawings and other design data in the PDM system, even though the data is stored in a CAD system. PDM solutions may also provide visualization capabilities within the products. View, markup, and annotation functions are commonly used during change reviews. This function can significantly improve communication between reviewers and others.

2.2.9 System administration

PDM systems, like any other computer system, need system administration. For PDM systems, this administration is more complicated and contains more tasks. The system administration functions include installation and maintenance, role management, workflow definition, operational parameters, system performance monitoring, database and network configuration, access and change permissions, user authorizations, setting up new projects and authorization of project team members, approval procedures, data backup and security, database migrations to later versions, customization, and data archival. These systems can be customized in many ways: matching business needs, tailoring the user interface to satisfy particular needs, integrating third-party applications (tools), adding new functionality, changing terminology, tailoring system information messages, and extending the standard data model to include company-specific data types. The customization, and the consequent requirements for education and maintenance, will need resources and efforts to be successful.

2.2.9.1 Role management

Role management is a part of system administration. Many roles, mechanical designers, software designers, project managers, and service support people are involved in the life cycle of a product, performing only particular tasks and therefore needing different access rights to product data. Role management includes such functions as setting up user accounts, groups, access rights, and security levels and the maintenance of all users and corresponding roles and groups.

2.2.10 Application integration

Integration with authoring, visualization, and other collaborative tools is important to establish a single source of product data. Information is created once for use throughout the product development process, and one source electronically colocates geographically dispersed authors and users.

Integrations range from the less complex, such as that with text editors, to tight integrations as with CAD/computer-aided manufacturing (CAM) and ERP systems. Integration with text editors (e.g., Microsoft Word and Adobe FrameMaker) includes the addition of such functions as check in and check out of documents to and from the text editor. This supports the user with automatic transferring of documents without manual work and detailed knowledge of the PDM system. Integration with CAD/CAM systems is more difficult because CAD/CAM systems manage various relationships between the parts, both parts structures and system-specific relationships, resulting in a network of interrelated files. Integration with ERP systems includes the transfer of parts structures with attributes. This kind of interdomain integration is often the most difficult to achieve.



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Implementing and Integraing Product Data Management and Software Configuration[... ]ement
Implementing and Integrating Product Data Management and Software Configuration Management (Artech House Computing Library)
ISBN: 1580534988
EAN: 2147483647
Year: 2006
Pages: 122

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