The logic of MPS and MRP within BPCS are quite similar. And, one can certainly set all Items to be MPS. I have two (2) client who do this in order that only MPS Generation (MRP500) needs to be run. However, adding to what Daniel and Roy have observed in their posts, there is one other critical difference between what MPS and MRP do in BPCS. In the MPS Generation (MRP500), the Item's MPS Horizon Days is taken into consideration when Planned Orders are created. That is, the concept of MPS Horizon is that our goal is to try and establish a fixed or controlled Master Production Schedule. Therefore, when MPS generates, it is not permitted to create a Planned Order within the Item's Horizon Days because that time period is controlled by the Planner. Thus, it creates the Planned Order on the first day after the Horizon Date, but with an Expedite Message. This message alerts the Planner to the fact that there is an earlier requirement. The job of the Planner is to determine if this new Planned Order can indeed be slotted within the Horizon and if so, it can be maintained in MRP Maintenance (MRP510) to place its Due Date earlier. However, the Planner must also change it from a Planned Order to a Firm Planned Order so that it will remain on this earlier Date. The MRP Explosion (MRP600) does not consider the Horizon Days and will create a Planned Order on whatever Date is required. This distinction is critical in deciding how best to manage your overall planning for Production and for Procurement. Specifically, if the Horizon is used and Planned Orders are created after the Horizon Date with Expedite Messages, then the corresponding Component Requirements will also be scheduled further out. Then, when the Planned Order is moved earlier, those corresponding Component Requirements will also advance. To properly coordinate the manufacturing and procurement functions, these departments must be coordinated in terms of the timing of when they perform their reviews. For example, the procedure could be as follows: 1. MPS will be run overnight. 2. First thing in the morning, the MPS Planners will review the MRP Exception Messages. Actions will be taken to respond to those messages and to revise the Planned/Firm Planned Orders and Shop Orders by 10:00 AM (for example). 3. Then, MPS is regenerated based on the revised plan, followed by the MRP Explosion. 4. Once complete, the Procurement people will review the MRP Exception Messages for their Items and take appropriate actions to schedule them as needed. I hope that these comments help to put this discussion into the proper perspective. Les Mittman Office&Fax: 847-459-5763 Cell: 847-858-5235 ----- Original Message ----- From: "Roy Luce" <lwl@xxxxxxxxxxxxx> To: "'SSA's BPCS ERP System'" <bpcs-l@xxxxxxxxxxxx> Sent: Friday, October 20, 2006 11:30 AM Subject: Re: [BPCS-L] Resell Purchased / Master Schedule ?
My background in MPS goes back to the mid and late 1970's when Arista Manufacturing Systems out of Winston-Salem, NC developed and marketed the first MPS module. The primary usage of MPS is not to "... create smaller subsets of capacity or order critical items." Rather MPS's focus is to manage the production plan. The production plan consists of a fixed quantity to be produced within a given timeframe - typically weekly - over a company's planning horizon. Rather than drive sales demand directly into MRP it is this fixed weekly production quantity that drives MRP and its planning of purchased and manufactured sub-components. Driving MRP off a planned production quantity, rather than directly from sales orders stabilizes the production floor. Rarely is it necessary to interrupt production to rush a priority order. MPS logic is simple, allowing the production plan to be managed with very little data analysis. The first step is to set a weekly production quantity. This is done by evaluating sales forecasts and using rough cut capacity planning to determine the feasibility of the production plan. In day to day operations booked sales orders consume the uncommitted portion of the production plan (known as the Available to Promise quantity or ATP) reducing the ATP quantity. When the ATP goes negative the sales orders' promise dates are moved to the nearest period with available ATP (nearest ATP may be in an earlier or later period). Only when the ATP goes negative and there are no other alternatives, is the production plan number increased. The primary benefit realized from using MPS is a very high on time shipment performance. In the 1980's and early 90's on time shipment performance climbed into the high 90 percentile range. Use of MPS diminished as customers began to demand shorter lead times and specific date shipments. Specific date shipment requirements in particular render the MPS ineffective. The effort to set and manage a daily production plan takes away from the effort required to meet customer demands. The cure has been to remove MPS from the picture and drive MRP directly from sales orders. However there has been a price to pay. As customer demands change (add this line item, change this ship date, cancel this order, etc.) so must the daily production plan and since the daily production plan is driven directly from sales orders it changes daily. Managing daily priorities is now the focus and as a result on time shipment performance has suffered. Today firms count themselves doing well if they ship above 90% on time. I know of several firms whose objective is to ship 90% on time and expend tremendous efforts to make that happen. Roy Luce Systems Plus - Midwest Direct: 847-540-9635 800-913-7587 Cell: 847-910-0884 Fax: 847-620-2799 Email: rluce@xxxxxxxxxxxxxxxxxxx -----Original Message----- From: bpcs-l-bounces+lwl=ix.netcom.com@xxxxxxxxxxxx [mailto:bpcs-l-bounces+lwl=ix.netcom.com@xxxxxxxxxxxx] On Behalf Of Daniel Warthold Sent: Friday, October 20, 2006 8:29 AM To: SSA's BPCS ERP System Subject: Re: [BPCS-L] Resell Purchased / Master Schedule ? If you regenerate MRP as often as you regenerate MPS, there should not be any problems. The requirements of the MRP items will be cought, and al the necessary orders will be planned to cover these requirements. As a matter of fact., I dont see as much of a need today to spit items between MPS and MRP, given the speed computers can regenerate MRP. My understanding is, 20-30-40 years ago, because MRP took hours to run, there was a need to cut the MRP generation process into a smaller subset of capacity critical or order critical items, the MPS items , and the other non-critical items: the MRP items. Any toughts on this? Daniel Warthold ----- Original Message ----- From: "Al Mac" <macwheel99@xxxxxxxxxxx> To: "BPCS_L discussion" <bpcs-l@xxxxxxxxxxxx> Sent: Friday, October 20, 2006 1:24 AM Subject: [BPCS-L] Resell Purchased / Master Schedule ?* One rule of thumb says MRP140 needs to "M" Master Schedule End Items that we manufacture and sell for customers, so that MRP will calculate what's needed of all components to be manufactured or purchased. * Another rule of thumb says raw material that we purchase to be used as components of the manufactured parts, nor any sub-components, should not be "M" coded, just the end items that we sell the customers. * A dispute has come up with respect to what is the correct Master Schedule coding for items that are coded purchased, but can also be sent customers as THEIR service or repair parts? It has been several years since we had MRP education, so different people memories stray into disagreements needing clarification. I had thought that when the raw materials show up as components of master scheduled items, currently on customer orders, that MRP will correctly calculate how many we need thanks to both dependent and independent requirements, but if a customer orders a supply of our raw materials, that are not currently needed due to being in the BOM of master scheduled active items, then by not having these raw materials master scheduled, we have effectively told MRP to ignore these requirements, and that having extra items coded as master scheduled did no harm to MRP. We are on BPCS 405 CD mixed mode. We run MRP500 then MRP600 by facility, with a few extra runs of MRP500 thanks to a prior thread on BPCS-L regarding parts complexity. Our BOM has several levels. We used to be heavy into DRP resupply orders, but that part of our business is now about dad. - Al Macintyre http://en.wikipedia.org/wiki/User:AlMac http://www.ryze.com/go/Al9Mac BPCS/400 Computer Janitor ... see http://radio.weblogs.com/0107846/stories/2002/11/08/bpcsDocSources.html -- This is the SSA's BPCS ERP System (BPCS-L) mailing list To post a message email: BPCS-L@xxxxxxxxxxxx To subscribe, unsubscribe, or change list options, visit: http://lists.midrange.com/mailman/listinfo/bpcs-l or email: BPCS-L-request@xxxxxxxxxxxx Before posting, please take a moment to review the archives at http://archive.midrange.com/bpcs-l. Delivered-To: daniel.warthold@xxxxxxxxxxxx-- This is the SSA's BPCS ERP System (BPCS-L) mailing list To post a message email: BPCS-L@xxxxxxxxxxxx To subscribe, unsubscribe, or change list options, visit: http://lists.midrange.com/mailman/listinfo/bpcs-l or email: BPCS-L-request@xxxxxxxxxxxx Before posting, please take a moment to review the archives at http://archive.midrange.com/bpcs-l. Delivered-To: lwl@xxxxxxxxxxxxx -- This is the SSA's BPCS ERP System (BPCS-L) mailing list To post a message email: BPCS-L@xxxxxxxxxxxx To subscribe, unsubscribe, or change list options, visit: http://lists.midrange.com/mailman/listinfo/bpcs-l or email: BPCS-L-request@xxxxxxxxxxxx Before posting, please take a moment to review the archives at http://archive.midrange.com/bpcs-l. Delivered-To: lmittman@xxxxxxxxxxxxx
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