What is Data Management?

Manufacturing companies are usually good at systematically recording component and assembly drawings, but often do not keep comprehensive records of attributes such as 'size', 'weight', 'where used' etc. As a result, engineers often have problems accessing the information they need. This leaves an unfortunate gap in their ability to manage their product data effectively. Data management systems should be able to manage both attribute and documentary product data, as well as relationships between them, through a relational database system.

With so much data being generated, a technique to classify this information easily and quickly needs to be established.

Classification should be a fundamental capability of a PDM system. Information of similar types should be capable of being grouped together in named classes. More detailed classification would be possible by using 'attributes' to describe the essential characteristics of each component in a given class.


Classification of Components

Components will be entered in the database under a variety of classes which suit your business needs. Classes themselves can be grouped together under convenient broad headings. This allows all your company's working stock of components to be organized in an easily traceable hierarchical network structure. Each part can be given its own set of attributes. Additionally, some systems allow you to register that certain components are available with specific 'optional' attributes. This can be invaluable in controlling Bills Of Materials (BOMs) for reasons that we will deal with in the chapter headed 'Evaluating Systems for Process and Management'.

Classification of Documents

Documents relating to components and assemblies can be similarly classified; for example, classes might be 'drawings', '3D models', 'Technical publications', 'Spread Sheet Files', etc. Each document can have its set of attributes - part, number, author, date entered. And, at the same time relationships between documents and the components themselves can be maintained. So, for example, a dossier for a specific 'bearing assembly' could be extracted, containing 2D drawings, solid models, and FEA files.

PDM systems vary greatly in their classification capability. Some have none. Others support the ability to define a classification only at the time when the database is implemented. More recent PDM systems have provided a capability that can be defined and modified at will as the demands of the organization change.

Product Structure

The third way product data can be accessed is by product structure. For any selected product, the relationship between its component assemblies and between the parts that make up these assemblies should be maintained. This would mean that you could open a complete Bill of Materials, including documents and parts, either for the entire product or selected assemblies. One distinct advantage is the ability to hold not just the physical relationships between parts in an assembly but also other kinds of structures; for instance, manufacturing, financial, maintenance or document relationships. So, it is possible for specialist team members to see the product structured from their point of view.

Querying the Data

As you can imagine, you need to be able to 'get at' the components and assembly data by a variety of routes. You could move up and down a classification tree; pick your way through a product structure; simply call-up the data you want by searching for it by name or part number, or search for groups of data by specifying an attribute or combination of attributes. For example, you could ask to see all stainless steel rivets with anodized shanks less than 10mm long.

Understanding Product Data Management(PDM)

The Challenge is to maximize the time-to-market benefits of concurrent engineering while maintaining control of your data and distributing it automatically to the people who need it - when they need it. The way PDM systems cope with this challenge is that master data is held only once in a secure 'vault' where its integrity can be assured and all changes to it monitored, controlled and recorded.
Duplicate reference copies of the master data, on the other hand, can be distributed freely, to users in various departments for design, analysis and approval. The new data is then released back into the vault. When a 'change' is made to data, what actually happens is that a modified copy of the data, signed and dated, is stored in the vault alongside the old data which remains in its original form as permanent record.
This is the simple principle behind more advanced PDM systems. To understand it more fully, let us look separately at how these systems control raw product data (Data Management and Process Management).