Category Archives: PLM
PDS vs. PPM and Implications for BOM and PLM Management
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.
PLM and LifeCycle Planning in SCM DP
As with biology, all products have a lifecycle.
Where Can PLM Be Found in SCM?
There is a solution provided by SAP called PLM. It resides in SAP ERP. This post covers why this solution is a marketing fiction that has gradually lost all credibility in the marketplace.
http://www.scmfocus.com/servicepartsplanning/2009/04/21/is-sap-plm-for-real/
However, there are also PLM capabilities in the SAP SCM side although they are often not conjectured or presented in the context of PLM. Life-cycle management here needs to be differentiated from bill of material (BOM) management as the terms are often confusingly commingled. Best of breed solutions like Arena for BOM management have little to do with the life-cycle functionalities that will be discussed in this post.
http://www.scmfocus.com/servicepartsplanning/2008/12/12/arena-solutions-and-where-used-view/
PLM in Demand Planning
For some reason PLM has become highly associated with SAP ERP as a solution, even though there is not a lot there. There is however more significant PLM functionality in SAP SCM, even though it is not actually called PLM. More confusingly, what SAP calls PLM in SAP ERP both does not exist as a product, and is consequently not used by companies. PLM is best thought of a a series of independent functionalities rather than a specific product.
This post will describe a few areas where PLM exists in SCM.
- Like Profiles: This is used when attempting to use the demand history of an old item and superimpose it as the demand history for a new item which has no history. This is performed in the following
- Phase In – Phase Out: This functionality exists both within DP and within SPP. This essentially groups products by historical demand into profiles. Phase in profiles are increasing in quantity over time, while phase out profiles are decreasing in quantities over time. However, the angle of incline (thinking graphically) depends upon the profile selected. That is some profiles increase or decrease more rapidly. This is a profile that is assigned per material.
Path = SAP APO – Demand Planning – Environment – Life Cycle Planning
A Phase Out Planning Service – exists in SCM, but it is in SPP, not in DP and is executed from the Planning Service Manager or PSM
http://www.scmfocus.com/sapplanning/2008/12/18/spp-planning-profiles/
Another area which deals with PLM in SCM is the supersession functionality in SPP – the specialized planning module for service parts. This is beyond the scope of this article, but is fully explained here.
http://www.scmfocus.com/sapplanning/2009/04/18/spp-supersession/
http://www.scmfocus.com/sapplanning/2007/12/13/part-supersession-in-sap/
Furthermore phase in phase output planning, which is also related to life cycle planning is covered in this post.
Product interchangeability, which is a far less sophisticated version of SPP supersession, is said by SAP to exist in the following modules:
- DP
- SNP
- CTM
- PPDS
- GATP
In one of our next posts we will address product interchangeability in SCM across all the modules.
References
http://www.amazon.com/Sales-Inventory-Planning-SAP-APO/dp/1592291236
http://help.sap.com/saphelp_scm70/helpdata/EN/8e/d4ef37e9a4ba6ee10000009b38f842/frameset.htm
Part Supersession in SAP
What is Part Supersession?
Supersession is one of the most important functions in any service parts planning system. Supersession is used to both:
- Substitute one part for another part
- Obsolesce parts due to engineering changes driven by PLM (Product Lifecycle Management) that need to be replaced by newer versions
The supersession configuration in service parts planning systems allows this to be performed automatically during the planning. In MCA SPO this supersession is handled by configuring whether the part is subject to supersession and the type of supersession (One Way or Two Way that applies). We will use the description of supersession in the MCA Service Parts Optimizer Glossary of Terms:
Supersession in MCA
Used to specify that a Part should be replaced with a different Part (referred to as a Planned Part). Supersession processes are part of the forecasting batch process. They transform demand, population and inventory data to reflect it on the currently planned versions of the Part. Three types of supersession processes are performed on data within SPO: Demand Supersession, Contract Population Supersession and Inventory Supersession – MCA Glossary
Supersession Type
Indicates the type of Supersession applicable to a Part. This value (ONE-WAY or TWO-WAY) is used to determine if inventory of the superseded Part can be used for satisfying demands for the superseding Part. Inventory of TWO-WAY superseded Parts is added to the inventory of their superseding Parts, whereas inventory of ONE-WAY superseded. – MCA Glossary
Supersession in SAP
When an external system that is specialized for service parts planning tells SAP what to do, SAP can simply execute the recommendations made by the external system. However, the question arises what SAP ECC’s capabilities are with supersession.
According to SAP web sources, supersession resides in:
- Advanced Planning and Scheduling (in SCM)
- Supply Chain Management
- Service Parts Management (within SCM)
- In ECC
Supersession in SAP SCM/APO
SAP documentation states that its SCM module has supersession capability. However, the SAP Service Parts Planning solution is so lightly installed (as of mid 2007) that it does not well represent the supersession capability on a typical SAP install, specificially SAP ECC. However, outside of SPP, APO has supersession (called substitution or interchangability outside of service parts). The way to arrive at it as of SCM 5.0 is to goto
APO – Master Data – Application-Specific master data – Product and Location Interchangeability – Maintain Interchangeability group
You can apply the substitution here or if you are using CTM, in the CTM profile. (see our sister blog for an explanation of CTM)
http://www.scmfocus.com/sapplanning/2009/05/09/ctm/
This is fairly simple, you can see from the screenshot that we have populated the following information:
- The Group Type (supersession chain)
- The Group name – SNAPP_GROUP
- The Group description
- What the supersession is relevant for (for both planning and ATP)
- Next set the preceding part and the succeeding part
Finally we save this and we will have just created an Interchangeable Group.
Next I need to assign a location. What this means is we can create supersession relationships that just apply for particular locations but not for others.
We have not been able to verify this, (as we presently lack access to a SCM 2007 aka SCM 5.1 system), however the functionality of supersession – interchangability has been enhanced and is now located at:
Advanced Planning and Optimization (SAP APO) – Service Parts Planning (SPP) – Master Data and General Functions for SPP – Product Interchangeability in SPP
The enhancement relates to the ability to use form fit function classes in addition to product supersession. “That is you can define a product as the leading product for each subgroup of a form fit function class. DRP then consolidates the demands and stock of the location products by adding the demand and stock of the non-leading location products with substitute orders to the demand and stock of the leading location product. – SAP SCM 2007 Release Notes
Supersession in SAP ERP
Within SAP ECC, supersession is approximated by the Material Determination functionality. However, within SCM, SAP states that the rule based Available to Promise check does provide this functionality. In ECC product substitution functionality is called Material Determination (MD). The SAP definition of Material Determination is:
“Material determination enables the automatic substitution of materials in sales documents during sales order processing. For example, during the course of a sales promotion, the system can, during sales order entry, automatically substitute a material that has promotional packaging. A consumer product may have a special wrapper for, for example, the Christmas season. Using material determination, the system substitutes the material only during the specified period. Material determination is used for:
- Customer-specific product numbers with your own material numbers
- International Article Numbers (EANs) with your own material numbers
- Substituting discontinued materials with newer materials” – SAP Help
Interesting features of material determination
- MD happens during the sales order process
- Sales document types (A&D Contract, Repair Quotation, etc.) can be set for MD
This screen shows the connection settings between the Sales Doc Type and Material Determination
Where Should Supersession be Performed?
Supersession logic can be maintained in both the planning system and the execution system. That is both in MCA and SAP. They can be for different purposes however. A few options are:
- Planning supersession can be performed in MCA, while execution supersession can be performed in SAP ECC (for sustainment, production supersession is a different matter).
- Planning supersession can be performed in MCA with no sustainment supersession data maintained in SAP ECC. However inventory planners can still use MCA’s user interface to determine the superseeded part, and then execute the supersession in SAP.
In either case SAP will respect the supersession that is performed in SAP as it would be inherent in the New Buy List that came from MCA. The basic questions are:
- Is having the execution supersession available in SAP (allowing automated supersession within SAP ECC) worth the additional effort in configuring MD and in the continual maintenance of this supersession list in SAP?
- Is the MD functionality capable of providing similar functionality as comes with MCA? That is, is the substution functionality, which is fairly basic, and which would provide automated supersession worth maintaining instead of looking at the MCA user interface and reading supersession relationships from MCA?
Supersession in SAP Documentation
The document below from SAP is light on details.
sap%e2%80%a6service_parts_management.pdf
The best write up on supersession in SAP that we have seen is at:
http://help.sap.com/saphelp_dimp50/helpdata/EN/f7/a62238b497a552e10000009b38f842/content.htm
