Abstract:
This invention relates to a method for production planning in which changing demands and current demands are combined and separated into fixed demands, time-flexible demands, and quantity-flexible demands before being prioritized according to a set of rules that optimize efficient handling of changing demands while minimizing changes in and maximizing flexibility of a production schedule.

Description:
BACKGROUND ART 
     Modern production planning uses various methods and techniques to determine when and how much of certain products are to be produced in order to satisfy customer demand while optimally using available resources, available inventories, and available time. Typically, a production plant, through a regularly scheduled process, would determine a plant production schedule for a certain time frame based on plant capacity, current customer orders, and forecast demands. Knowing expected delivery dates is often important for customers, so production plans typically detail rigid production schedules and shipment dates. 
     It is common, in many industries that rely on production plants, for customers to wish to change their orders. Customers may wish to change the product type ordered, quantity ordered, or delivery date requested in order to fulfill their own obligations. Such changes are typically considered the next time the plant production schedule is evaluated. In some cases, the plant may be able to accommodate such a change with little to no problems. However, in many cases, when a change requested is too large or too close to the final production date, a plant is simply unable to accommodate the customer&#39;s wishes and either the customer or the plant will be financially damaged as a result. 
     In some solutions, such as that described in U.S. Pat. No. 6,393,332, a planning system will attempt to schedule new customer orders in a fashion that uses the plant capacity closest to the required completion date so as to use less of the near-term plant capacity. In these solutions, the plant is able to accommodate more last-minute changes because the last-minute resources are assigned last. However, such planning systems are prone to plant underutilization because established orders become locked into the fulfillment plan without a chance to be reevaluated and repositioned along the production timeframe. 
     In solutions where the existing orders are reevaluated in determining whether or not a plant can accommodate a demand change, order competition may arise between the existing and updated orders. As customer orders compete for production resources, new or updated orders for one customer can lead to rescheduling of other customers&#39; orders, even ones with previously confirmed production or shipping dates. As a result, production plants managers are placed in a position where they must weigh the costs and benefits of either accepting the requested changes to their production schedule or maintaining the commitments of the current customer demands already established in the production schedule. 
     Customer demand changes can therefore result in high organizational and administrative costs. Also, such demand changes may force the production plant to miss established deadlines, thus leading to a decline in customer satisfaction. Either situation leads to missed revenue growth opportunities or possible revenue loss. Any unreliable lead times deprive customers of a reliable planning base for their own operations and increase variability in the supply chain, which can lead to a need for large, inefficient safety stocks. 
     Some current solutions that overcome these drawbacks use a “frozen zone” time period in their production plans. During the “frozen zone” time period, which usually extends for a period of several days or weeks prior to the delivery date depending on the production complexity, no changes in a customer&#39;s order are allowed. This approach, while alleviating the difficult change-or-stay decision dilemma of the manager in charge of production planning, takes out any short-term flexibility once available in the ordering and production process. A customer is then locked into an order after a certain date even if the customer&#39;s needs drastically change. This problem is exacerbated in industries with short life-cycle products. This restriction on ordering freedom can cause customers to shop around for a production plant with a shorter “frozen zone” time period which may only be offered by a small number of production plants with large enough safety assets. 
     Another solution to the change-or-stay decision dilemma is used in some production plants where customers or distribution channels are assigned different importance levels. In some of these plants, the production schedules allocate a limited product supply or limited resources to minor accounts in order to ensure order fulfillment for key accounts. While this solution fixes allocation of supply, it reduces the flexibility available for producers or consumers to follow market demand. This reduced flexibility again jeopardizes revenue opportunities. 
     Additionally, many current solutions, including U.S. Pat. No. 6,393,332, use complicated algorithms and systems that take longer to run and analyze and require specialized systems and implementations that can greatly increase start-up costs. As a result, there is a current need for a fulfillment planning system which can operate with more efficiency and economy. This need is felt more in smaller and younger operations in need of a fulfillment planning system. 
     Many current solutions, such as U.S. Pat. No. 7,295,990, attempt to solve fulfillment planning solutions by forecasting ahead in an attempt to guess future demand. While this technique has its benefits, there are also numerous risks inherently involved in forecasting which make such systems unusable in certain fields. As a result, there is a current need for a fulfillment planning system which is capable of creating an accurate and efficient fulfillment plan without relying on estimated and forecast data. This need is especially prevalent in risk-adverse fulfillment operations that are unable to accommodate excessive safety stocks or unfulfilled orders. 
     There is a current need for a fulfillment planning system which, among other benefits, provides: Reliability of production plans for customers; Steadiness of production plans; Supply and production flexibility in terms of both quantity and time, and; Alignment of marketing and sales strategy with supply. There is also a current need for a fulfillment planning system which can accomplish these goals efficiently and economically. 
     SUMMARY OF THE INVENTION 
     While some preferred embodiments of the invention are implemented through software means such as a spreadsheet program, it is readily apparent to one skilled in the art that this invention can be implemented in a number of other ways. 
     The dynamic fulfillment planning process described herein allows for automated adaptation of an existing production schedule to dynamically updated customer demands. There is no need to forecast future demand and the generated fulfillment plan allocates any updated production across the fulfillment timeframe with minimal impact. 
     In some preferred embodiments, a demand refers to customer orders, source or destination channels, source or destination regions, available parts or components, or combinations thereof. Additional or alternate demands may be easily incorporated into this process as necessary in order to determine the production schedule based on any number of desired signals not mentioned herein. The demands are interpreted as demand signals. Each demand signal is represented as a time series of requested quantities. In some preferred embodiments, updated demand information is received and automatically processed in three phases: a demand evaluation phase, a demand prioritization phase, and a fulfillment plan generation phase. 
     In a preferred embodiment, during the demand evaluation phase, an updated demand signal is analyzed and matched against a baseline demand signal. The baseline demand signal represents the current customer demands as currently planned for fulfillment. The updated demand signal represents a new set of customer demands not currently incorporated into the fulfillment plan. Analysis and matching calculations isolate the updated demand signal into a set of constrained demand signals. In some preferred embodiments, the constrained demand signals are a fixed-committed demand signal, a time-flexible demand signal, and a quantity-flexible demand signal. Fixed-committed demand signals represent that demand which is established and will be completed as previously planned. Time-flexible demand signals represent that demand which is to be completed during later time periods within the fulfillment timeframe. Quantity-flexible demand signals represent that demand which can change in quantity without impacting the fulfillment plan. 
     In some preferred embodiments, during the demand prioritization phase, each constrained demand time series created during the demand evaluation phase is processed according to a set of one or more priority rules that assign priorities to each series. The priority rules of the prioritization phase can be customized to each user, industry, product, production plant, or other variable. In some preferred embodiments, the priority rules are created by the plant&#39;s central governance body or a marketing body to ensure the plant&#39;s high-level goals are achieved. Some preferred embodiments of this invention ensure that the type of demand signal (fixed-committed, time-flexible, or quantity-flexible) is included as a priority rule. Some preferred embodiments of priority rules include rules that prioritize customers, channels, regions, markets, or other factors. 
     In some preferred embodiments, during the fulfillment plan generation phase, the prioritized demand time series generated in the demand prioritization phase are processed in light of the available supply and resources in the production network. The result of this phase is a new production schedule that incorporates the updated demand with minimized changes to the production schedule while adhering to the priority demands of the particular production plant where it is employed. 
     The process of this invention ensures generation of a feasible production schedule that respects previous commitments as far as required, while, at the same time, giving the fulfillment plant and its customers quantity flexibility and time flexibility to meet their own changing demands. This process maximizes production efficiency without relying on risky forecasts and adheres to necessary production plant goals to align supply chain planning with marketing and corporate strategy automatically and dynamically whenever customer demands are updated. The end results include a more efficient production planning process, greater flexibility for customers, a reduced “Frozen Zone” time period, decreased safety stocks, decreased reliance on risk, and easy implementation of marketing goals and corporate strategy. 
     It is readily apparent to one skilled in the art that the Dynamic Fulfillment Planning method may be used in any field where a changing demand load must be incorporated into a fulfillment plan with limited time or resources. While the examples in this description show the Dynamic Fulfillment Planning process&#39;s use in a production plant, the method may also be used in other fields. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
       In the supplied figures, time series are generally shown as boxes containing 1×5 spreadsheets. Steps and values are generally shown as boxes containing only text. This diagrammatic convention is not intended to limit the disclosure in any way, but rather to clarify a description of a preferred embodiment. 
         FIG. 1  is a flow chart showing a preferred embodiment of a timeframe containing five time periods. 
         FIG. 2  is a high-level flow chart showing a preferred embodiment of the invention detailing the phases necessary for processing of the initial baseline demand and updated demand signals. 
         FIG. 3  is a flow chart showing a preferred embodiment of the invention detailing the steps of the demand evaluation process. 
         FIG. 4  is a flow chart showing a preferred embodiment of the invention detailing the steps of the demand prioritization process. 
         FIG. 5  is a flow chart showing a preferred embodiment of the invention detailing the steps of the fulfillment plan generation process. 
         FIG. 6  is an example spreadsheet of a preferred embodiment of the invention showing example calculation results based on an example baseline demand and example updated demand. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
     The equations used in this description may contain traditional mathematical expressions or functions available in typical spreadsheet programs, such as certain versions of Microsoft Excel. It is understood by those skilled in the art that the equations disclosed may be easily modified or translated for implementation in other programs, apparatuses, or programming languages. 
     The following disclosure includes calculation steps separated into separate phases. It is understood by those skilled in the art that the calculation steps may be completed in any other order and with or without being separated into different phases, except where logic requires otherwise. 
     Referring to  FIG. 1 , in a fulfillment process, demand signals comprise a time series of requested quantities per product, per customer, or per channel, for each time period (TP)  12  over a timeframe (TF)  14 . The length of the timeframe (TF)  14  is the sum of the lengths of all time periods (TP)  12 . Equation 1 shows an example of a generalized TF  14  calculation, where “n” is the number of time periods in the particular time frame and “TP x ” represents the current time period. 
     
       
         
           
             
               
                 
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     In some preferred embodiments, a typical time period (TP)  12  would encompass one day and a typical time frame (TF)  14  would encompass one work week, so the typical number of time periods in the particular time frame would equal five. It is readily apparent to one skilled in the art that other amounts of TP  12  and TF  14  are possible, depending on the specific production plant. 
     Referring to  FIG. 2 , for each planning cycle, the dynamic fulfillment planning process goes through three phases in order to generate a new production plan  66 . The phases are demand evaluation  60 , demand prioritization,  62 , and fulfillment plan generation  64 . 
     Referring to  FIG. 3 , in the demand evaluation  60  phase, updated demand signals (UD)  22  are received for a certain product, customer, or channel, as a quantity per time period (TP)  12 . Baseline demand (BD)  18  signals normally already exist for a certain product, customer, or channel as a quantity per time period (TP)  12 . During an initial planning cycle, where no existing orders are incorporated, the baseline demand (BD)  18  is the set of zeroes for all time periods (TP)  12 . The sum of all baseline demand (BD)  18  signals over all time periods (TP)  12  is the total baseline demand (TBD)  24 . Equation 2 shows an example of a generalized TBD  24  calculation. 
     
       
         
           
             
               
                 
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     The sum of all updated demand signals starting from the first TP  12  to a specified TP m  is the cumulative updated demand (CUD)  27  for that TP m . Equation 3a shows an example of a generalized calculation for the CUD  27 . The sum of all updated demand signals over all periods is the total updated demand (TUD)  26 . Equation 3b shows an example of a generalized calculation for the TUD  26 . 
     
       
         
           
             
               
                 
                   
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     A cumulative exceeding demand (CED) 28 is calculated based on equation 4.
 
 CED =MAX(0,( CUD−TBD ))  Equation 4
 
     The CED  28  calculated for each time period  12  will show in which time period  12  the cumulative updated demand (CUD)  27  will begin to exceed the total baseline demand (TBD)  24 . As long as the CUD  27  can be met by the current plan, the CED  28  will be zero. When the CUD  27  begins to exceed the current plan&#39;s capacity, the CED  28  will no longer be zero. The CED  28  of the final time period  12  of the timeframe  14  will equal the total exceeding demand (TED)  30 . Equation 5 shows how the calculation of the CED of the final time period  12  of the timeframe  14  will look as it calculates the TED  30 .
 
 CED   (n)   =TED =MAX(0,( TUD−TBD ))  Equation 5
 
     The normalized delta NΔ  32  is then calculated for each time period from 0 to n according to the series of equations listed under equation 6. It is readily apparent to one skilled in the art that the number of periods may be less than four in order to achieve the intended results of this equation series.
 
 NΔ   (0) =MIN( UD   (0) ,( TED−NΔ   (1)    . . . NΔ   (n−2)   −NΔ   (n−1)   −NΔ   (n) ))
 
 NΔ   (n−2) =MIN( UD   (n−2) ,( TED−NΔ   (n−1)   −NΔ   (n) ))
 
 NΔ   (n−1) =MIN( UD   (n−1) ,( TED−NΔ   (n) ))
 
 NΔ   (n) =MIN( UD   (n)   ,TED )  Equation 6
 
     The resultant series of NΔ  32  values shows a redistribution of the total exceeding demand (TED)  30  backwards across the timeframe  14 . This step minimizes changes in the production schedule. 
     The normalized updated demand (NUD)  34  is then calculated for each time period  12  according to equation 7 where the NUD  34  is the difference between the UD  22  and NΔ  32 .
 
 NUD=UD−NΔ   Equation 7
 
     Through the use of NΔ  32  values and equations 6 and 7, the total exceeding demand (TED)  30  is subtracted from the total updated demand (TUD)  26  in incremental steps across the least number of time periods  12  starting with a given period and given skimming direction—either backwards or forwards in time. To accomplish different skimming methods, NΔ  32  values can be calculated with an offset “n” value. For example, the NΔ  32  demand signal can be shifted so that the first time period  12  of the NΔ  32  demand signal corresponds with any time period  12  of the current timeframe  14 . Furthermore, the NΔ  32  demand signal can be adjusted so that increasing time periods  12  in the NΔ  32  demand signal correspond to decreasing time periods  12  in the current timeframe  14 . The total normalized updated demand (TNUD)  36  now equals the total baseline demand (TBD)  24 . 
     In some preferred embodiments, it is optimal to start skimming with the last time period  12  of the timeframe  14  and, moving backwards in time by increments of one time period  12 , subtracting NΔ  32  from UD  22  until NΔ  32  is zero. Using this approach, short term demand requests are affected as little as possible, making requests for quantity adjustments available as late as possible. 
     A satisfied normalized updated demand (SNUD)  38  can be calculated for each time period  12  as the minimum of the baseline demand (BD)  18  and the normalized updated demand (NUD)  34  for that time period  12 , as seen in equation 8.
 
 SNUD =MIN( BD,NUD )  Equation 8
 
     The satisfied normalized updated demand  38  time series is less or equal to baseline demand  18  and normalized updated demand  34  in each time period, thus creating a time series representing satisfied demand in the new production plan. 
     The exceeding normalized updated demand (ENUD)  40  is the demand by which normalized updated demand  34  exceeds baseline demand  18  in any time period  12 , but which can still be satisfied within the timeframe  14 , since the total ENUD  40  plus SNUD  38  equals total baseline demand (TBD)  24 . The ENUD  40  is calculated as the non-negative values of BD subtracted from NUD as shown in equation 9.
 
 ENUD =MAX(0,( NUD−BD ))  Equation 9
 
     Demand undershoot (DU)  42  is the demand by which normalized updated demand (NUD)  34  undershoots baseline demand (BD)  18  in any time period, and thus shows new, free capacity as compared to BD  18 . The DU  42  can be calculated as the non-negative values of NUD  34  subtracted from BD  18  as shown in equation 10.
 
 DU =MAX(0, BD−NUD )  Equation 10
 
     Therefore, through the previous calculations, the updated demand (UD)  22  can be separated into a total exceeding demand (TED)  30  as shown in equation 5, a satisfied normalized updated demand (SNUD)  38  as shown in equation 8, an exceeding normalized updated demand (ENUD)  40  as shown in equation 9, and a demand undershoot (DU)  42  as shown in equation 10. 
     Referring to  FIG. 4 , during the demand prioritization  62  phase, each of the DU  42 , SNUD  38 , and ENUD  40  time series can be converted into updated demand signals based on type. DU  42  demand signals are quantity-flexible demand signals  44  because they show available room to change quantity within certain time periods  12  of the current timeframe  14 . SNUD  38  demand signals are fixed-committed demand signals  46  because they represent the demand that is already committed and will be completed as scheduled. ENUD  40  demand signals are time-flexible demand signals  48  because they represent the demand that will not be completed as scheduled, but will nevertheless be completed within the current timeframe  14 . 
     The demand signals can then be ranked based on a predetermined ranking process  50  using user-configurable sorting criteria  52 . In a preferred embodiment, one of these criteria is the demand signal type. The demand signals are then prioritized into a high priority demand signal  54 , a middle priority demand signal  56 , and a low priority demand signal  58 . It is readily apparent to one skilled in the art that more or less than three ranks of priority may be used to prioritize any number of demand signals. In a preferred embodiment, the fixed-committed demand signal  46  is the high priority demand signal  54  and its production and delivery date remains in the original time period  12 . In this embodiment, the time-flexible demand signal  48  is a middle priority demand signal  56  and its production and delivery date may shift to a later time period  12 , but will remain within the timeframe  14 . In this embodiment, the quantity-flexible demand signal  44  is the low priority demand signal  58  and its production and delivery date may shift to a later time period  12  and possibly a later timeframe  14 . 
     During the fulfillment plan generation  64  phase, as shown in  FIG. 5 , the prioritized demand signals  54 ,  56 , and  58  are matched to other constraints  56 . These other constraints  72  include such constraints as resource capacities and plant capabilities. In a matching step  74 , the constraints  72  are applied to the ranked signals and a new production plan  66  is issued with the updated demand  22  being covered as priorities and resources permit. Any demand which cannot be covered is clearly identified and can be incorporated into the next planning cycle or next timeframe. 
     The advantages of the above described embodiments and improvements are readily apparent to one skilled in the art as enabling the effective and efficient dynamic generation of a fulfillment plan. Additional design considerations may be incorporated without departing from the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited by the particular embodiments or forms described above, but by the appended claims.