PDS vs. PPM and Implications for BOM and PLM Management

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Is the PDS the Future?

There has been a lot of focus on SCM’s emphasis on the PDS vs. the PPM. The concept is that PDS should be used when possible because PDS has much more flexibility when it comes to engineering change management. However, there are a few disadvantages with this approach.

  • PDS is more complex and difficult to setup than the PPM at least at first
  • It is not at all clear that SAP is a good place to manage engineering changes, this is a presumption by SAP, but its foundations are not strong
  • However engineering change management is only one reason to move to the PDS.
  • We have not analyzed, and have not seen analysis for how well PDS incorporates changes from third party BOM management software.

As we have noted in this post…

http://www.scmfocus.com/servicepartsplanning/2009/04/21/is-sap-plm-for-real/

…change management in SAP ERP is weak. This is primarily because the material management functionality in SAP was never designed with change management or document management in mind. A solution that is extremely effected at BOM and change management is Arena Solutions, which can be sampled at this link.

http://www.scmfocus.com/servicepartsplanning/2008/12/12/arena-solutions-and-where-used-view/

Our perfect solution would have Arena performing the BOM management, and then sending it over to SAP ERP’s material management. In this case would the PDS be able to reflect the changes easier than the PPMs? More specifically, would the extra work involved with setting up PDS be worth the effort.

Undiscussed Constraint Management Maintenance

One issue we have with the PDS is it focuses the attention on engineering change management. What we have not hear much addressed and what we have seen as the main limiting factor to implementing PPDS is that clients do not update their PPMs or PDSs. This means that after the implementation, the accuracy of the production plan increasingly deviates from the realities of the manufacturing floor. This could be managed from two different directions

  • From the process side…..which SAP and the large consulting companies are really not doing – that is explaining the significant maintenance involved with constantly updating the system with changing production constraints.
  • By making the PPM and PDS more easy to update, because right now its still a big ball of effort, which means many companies will not do it and will hope that the old constraints are “good enough.”

The best rundown of the differences between PPMs and PDSs is at the link below.

http://wiki.sdn.sap.com/wiki/display/SCM/Difference+between+PDS+and+PPM

Conclusion

This post is designed to stimulating thinking more than answer a specific question. Essentially, we are proposing that the BOM management and lifecycle management for companies using SAP be rethought. Also, we think more attention needs to be placed on getting clients to actually maintain their PPMs and that that should take first priority over emphasizing PDS as “new objects” for planning. That is the PDS can be wrong even if engineering changes are updated.