Managing Engineering Information: The PLM Landscape
December 31, 1969 |Estimated reading time: 7 minutes
Product lifecycle management is a broad concept that encompasses the management of product-related information from inception through end-of-life. This article makes the case for the use of a specialized engineering information management (EIM) system on the engineer’s desktop during the design process.
By Jack Woida
Product lifecycle management (PLM) is a concept encompassing the management of product-related information from inception through initial marketing definition, design, prototyping, manufacturing, after-sales service, to product end-of-life. There are companies that market PLM systems, but it typically requires a collection of many systems, some commercially available, some internally developed, to fully cover information management needs throughout the product lifecycle. This is especially true for electronic products during the design and development phase, where traditional PLM systems are not designed to manage the work-in-process (WIP) data needed in engineering.
This article highlights the benefits of a specialized engineering information management (EIM) system on the engineer’s desktop during the design process. This system will focus on managing all of the decision support data engineers need to make correct information choices during the design phase of the product lifecycle, and will interface to the broader PLM system to focus on managing all of the information needed to manufacture a product, including the collection, approval, and configuration management of information from multiple disciplines as the product moves through the rest of the lifecycle.
A Distinction Between EIM and PLM
On the surface, both EIM and PLM systems provide similar capabilities for data management, but there is one crucial difference between them. PLM systems are not designed for editing the actual detailed design data. In other words, PLM systems are not designed to work efficiently and directly with design authoring tools. Data must be extracted from the design tools, properly prepared for manufacturing, and then must go through a formal release process with all proper approvals before being allowed to go into the PLM system.
Design authoring tools operate on different internal file formats for performance and functionality purposes. Constantly converting between these proprietary internal file formats and the more-open data exchange formats every time a design is checked in or out of the data-management system is simply not workable during design where frequent changes are an integral part of the process. WIP design data management must be lightweight, easy to use, and deal with working design files in the context of design authoring tools, while offering the basic protection needed to ensure data integrity. EIM systems are designed for this type of data management.
There are three points to consider:
- The distinction between component information and design libraries, and the importance of managing both must be considered. Padstack shapes are controlled precisely to optimize manufacturing yield and reliability. Using the same component in two different designs and two different manufacturing processes probably requires two different shapes for the padstacks - one for each manufacturing process.
- It is increasingly common for organizations to have global operations with multiple sites around the world where they can use the same component as much as possible at all sites. But at the same time, different sites often have different manufacturing operations and need their own design libraries.
- Because design libraries must work with design tools directly, the information system must be deeply integrated with design tools. PLM systems are not suited to this task, but EIM systems are (Figure 1).
Figure 1. Relationship of engineering information to enterprise information.
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Understanding the Relationship Between EIM and PLM Systems
An EIM system’s main functions are EDA library management, component information management, design data management, management of bill of materials (BOMs) during the WIP phase, design collaboration, and integration with enterprise-level information systems, including PLM systems, ERP systems, and others involved in managing the supply chain. Electronic design tools are tightly integrated with a design data management (DDM) system. This is a key point because it allows the design team to access information in the context of their design tools. The DDM becomes the engineer’s desktop.
EDA Library Management
Managing EDA libraries is key in developing high-quality electronic products. Not only are EDA libraries more complex than their MCAD counterparts, the situation is more difficult in many companies that have grown through mergers and acquisitions, and often are faced with managing multiple libraries from different tool flows or different ECAD vendors. Add to this the difficulty of maintaining consistent libraries for different purposes across multiple locations, and it is clear that a method to manage and keep all of these different library caches in synch is needed.
Component Information Management
One of the most important events in the design of a new electronic product, an event that determines to a large extent the cost of a new design, is when a design engineer selects and instantiates a new component into a schematic. Choosing the right component is an information-intensive decision process, requiring the designer to consider cost constraints, availability of the desired component from corporate or vendor stock, adherence to environmental and regulatory requirements (e.g. FDA Title 21, RoHS, and WEEE), and obsolescence - to ensure that the component is not nearing end-of-life.
These and other factors are side effects of the component choices a designer makes to determine if a product will meet its market window, will be subject to costly and time-consuming redesigns, or will encounter regulatory difficulties. The wrong choices at this stage of the product lifecycle can cede the advantage to a competitor, or cause the product to miss the lucrative early-adopter market, forcing it to be sold later as a commodity item at a much lower margin.
Providing a direct and deep integration into the EDA tools, facilities such as auditing designs for obsolete components, assigning updated values to schematics from the component database, and design prototyping with logical symbols and later corporate part number assignment become out-of-the box solutions. These design-oriented facilities are not possible using a typical PLM system that concentrates on simply managing released-component information.
Design Data Management
It is difficult to manage collaboration across complex development projects, particularly when the team is dispersed geographically. Typically, a design will have multiple trial versions. These intermediate versions have their own lifecycle and versioning schemes, typically invisible to a PLM system that is only interested in the final result. Two key aspects of DDM are managing design files that are created using various tools in the design process and tracking intermediate versions to support “what-if” and other design scenarios (Figure 2).
Figure 2. Typical points of integration between a WIP EIM system and a PLM system.
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WIP BOM Management
A BOM represents product structure, and there are different ways of looking at this. Some examples are:
- Variant BOMs, which give a view of components in a specific product variant;
- Master BOMs, which give a view of all components contained in any variant;
- Structural BOMs, which give a logical, hierarchical view of a product structure;
- Design BOMs, which typically deal in corporate part numbers or generic part information without specifying the final part manufacturer;
- Manufacturing BOMs, which give a hierarchical view of a product as needed for manufacturing, and identify the final supplier and specific manufacturing source of each part.
A designer must analyze BOMs continually in terms of cost and hazardous-substance content. By providing continuous feedback on these, and the ability to benchmark against design constraints set by a project manager, a DDM system supports the designer during WIP and does not have to wait until the end to discover that constraints have been violated or obsolete components have been used in the design.
Integrating DDM and PLM Systems
PLM systems manage the information needed to manufacture a product throughout its life. Design WIP data and processes generally are not of interest at this level. PLM systems accept the released design from a DDM system and manage the product lifecycle. Any additional design changes that are needed during a product’s lifetime, for example, phasing it out of volume production or designing out obsolete parts or redesigns to fix manufacturing problems require a formal engineering change order or change request (ECO/ECR) to check the design out of the PLM system and into the DDM system.
Figure 3. Enterprise data management flow.
Although the WIP design process is part of the overall product lifecycle, it is more complex than the simple lifecycle model managed in a PLM system can support. By allowing the DDM system to manage this design process and perform operations such as retrieving part numbers from PLM at a predefined maturity stage, transferring released designs to PLM, and obtaining lifecycle updates from PLM, both systems can focus on key areas of competence and leverage unique domain expertise (Figure 3).
Conclusion
By combining all of these functions into a single, integrated data management system, combined with design authoring tools, users have a powerful capability that allows them to link design information to component information through the BOM. Because design libraries are also managed in the same system, it is possible to easily trace relationships between manufacturing, design information, and the components used in that design. This becomes invaluable when there is a need to trace problems between the manufacturing floor and the design lab.
Jack Woida, system design division, Mentor Graphics, may be contacted at (503) 685-1314; e-mail: jack_woida@mentor.com.