Since the introduction of the document/file management capabilities in ERP/MRP systems in the 1990’s, the debate has raged about where to keep product data. It is hard to argue with the fact that manufacturing needs access to drawings, specifications, and other technical information to be able to produce a company’s product. Conversely though, very few documentation owners are satisfied with how transactional systems like ERP manage document records and collaboration. So the debate continues today, but has been refined down to a simple question: “If I have ERP, why do I need PDM?”
I propose that the justification for separate PDM and ERP is clear: PDM manages the creation of the idea of a product, and ERP manages the creation of the physical products themselves. Put another way, ERP is about execution and PDM is about planning. To satisfy the need of execution (manufacturing) resources to access the product definition, it is clear that PDM and ERP systems need to communicate and share data. To satisfy the requirement for robust lifecycle management and collaboration tools, however, the systems need to remain separate with clear interfaces defined between them.
The simplest interface between PDM and ERP takes place as a handoff during the normal New Product Introduction process. When a new product is conceived, refined and developed, the PDM system is in control. This continues even past when the final design is approved, as PDM manages the development of tooling and supporting documentation needed to define the manufacturing process.
Once the components are ordered, or shop floor workers are asked to perform work, however, the ERP system is in control. This simple handoff is actually a complex coordination of handoffs. For long-lead items, PDM hands off to ERP in the first week of a project but for normal designs the handoff may take place two or three months into the process. The concept is consistent – PDM handles ideation up through production, and ERP takes over to produce the physical results. In some ways, PDM manages the virtual while ERP manages the physical.
So why is there any debate over PDM and ERP? The gray areas make the battle rage on. Examples of the gray areas include:
- Where is a deviation managed, in the planning (PDM) system with other changes or in the execution (ERP) system where the physical items are being affected?
- If PDM and ERP can both manage BOMs and product structures, where should I maintain as-built information?
- Shop floor routings are part of my production planning, but my ERP system knows more about my shop floor resources than my PDM system does. Where should I keep this “planning” information?
To answer these questions, take a closer look at your business, your existing business systems, and your plans for the future. If you have a nice shiny new ERP system that no one in engineering wants to touch, ask yourself what PDM could be doing to better support that ERP investment. If your shop floor people hate the complexity of your PDM system but are forced to use it to get drawings, look at how you can tie the two systems together better. If you’re looking to adopt new technologies and business systems, ask yourself what the biggest challenges are to your business, planning or execution, and pick your new business systems accordingly.
Regardless of where you sit though, it should be easy to see that PDM can’t do what ERP does and vice versa. So the question is less about PDM versus ERP as about how best to use the tools together.