Metadata – How to store data associated with a part.

 
We continue our series of popular articles related to the management of product information. As already pointed out in the previous issues, ease of search and information retrieval are among the key elements of the PLM philosophy. In order to access, modify and reuse a particular part, you must first know that it exists, then be able to retrieve it quickly.

To make such a search effective, it is not sufficient to refer to the information available in the file system (i.e. name of the file and its folder), even if you use “significant part-numbering “. Nor does the use of database specifically dedicated to technical data (ERP, EDM, etc.) allow an effective retrieval of information. These databases often do not contain all the needed information and rarely take into account the revisions and the history of a particular entity or the associations between the entity and the relating documents.

Therefore it is necessary to rely on more advanced and targeted modes to store these data for the subsequent effective search. That’s why metadata are used. Metadata are keywords and descriptive elements that facilitate searches and allow the selection of certain information or parts according to even complex criteria. Here is an example of metadata that can be associated with parts or assemblies: Description, Material, Surface Treatment, Designer name, Length, Width, Thickness. With this metadata, you can apply a search like the following: search all the 8mm-thick support plates made of anodized aluminum designed by Smith or Jones, of sizes between 400×500 and 600×80.

The effectiveness of the search depends on the number of metadata and their consistency and granularity. This is intended to emphasize that it is preferable to handle non-uniform information using different metadata. Coming back to the example above, it is surely better to treat the material and the surface treatment as separate fields, rather than managing them in a single field. This may seem trivial, but it’s a very frequent mistake the insertion of too much information into a single metadata, making the search less effective.

To make easier the task of inserting data, the best practice is to use a hierarchy of functional families to assign specific metadata to each entity type and thus simplifying the compilation.

An example: commercial components: Weight, Maximum size … Parts machined from plates: length, width, thickness, weight, … parts machined from round bars: length, diameter, weight …

PLM systems and the management of metadata

A PLM system is defined as such when it is capable to handle every type of user-defined metadata. Usually this information is organized during the phase of implementation of the system or in the phase immediately following the installation, when the various features of the PLM system are customized on the base of the needs of the specific company.

This is certainly a very important phase, which has a significant effect on the times and costs of implementation, and of course on the effectiveness of the future use. For many PLM systems, these activities need to be carried out by specialized technicians and inevitably require long times and high costs.

The new information technologies, applied to PLM systems, dramatically reduce these times and costs. In particular, they can be easily configured by the user (who knows better than anyone else his/her company) and not necessarily only in the first phase. They provide flexibility and power, ease of management and efficiency. If the reader is evaluating the implementation of a PLM system, s/he must carefully consider the aspects related to customization and the definition and creation of metadata. The preference to new generation PLM systems has significant advantages on many fronts.