Constrained Capacity Production Leveling

Overview

Constrained Capacity Production Leveling (CCPL) combines capacity planning, inventory planning, and level-scheduling techniques to enable manufacturing organizations to smooth out the fluctuations in customer demand and produce finished goods at stable production volumes that are feasible based on their capacity constraints.

The following capabilities are being provided as part of the Constrained Capacity Production Leveling application:

  • Tools to automatically smooth the Master Production Schedule at key finished goods work centers to ensure a consistent level of production that is constrained to fit within the available capacity in the work centers
  • Ability to review and revise a constrained Master Production Schedule in a safe sand-box environment

Selection and Configuration of the Level Loaded Work Center

The first step in using the Constrained Capacity Production Leveling Application is to select the work centers that will be level-loaded using the Constrained Capacity Production Leveling application.

These work centers will be the bottleneck work centers that constrain the output of finished products.  Once identified, each level-loaded work center will need to be configured using the Work Center Data Maintenance application.

Guidelines for selecting a level-loaded work center:

  • The level-loaded work center is defined on the routing of the finished product
  • The level-loaded work center can be any work center on the finished product
  • The level-loaded work center should be on the bottleneck operation of the routing of the finished product
  • There should be only one level-loaded work center on the routing of the finished product

Note: you can only have one level-loaded work center on the process routing of a product. Having more that one level-loaded work center on the routing will result in a schedule with gapped or overlapped production operations.

After you have selected the work centers to be level-loaded, open the Work Center Data Maintenance application to configure these work centers.  The settings for configuring the level-loaded work centers are shown below.

Enable Level Loading:  All work centers that are to be planned using constrained capacity need have the Enable Level Loading checkbox checked.

Frozen Time Fence: The frozen time fence is used to hold (freeze) the schedule in the closest periods to prevent any changes (demand or inventory) from automatically affecting the schedule.  The frozen time fence is specified as the number of rolling days from the current date.  

Define Tags Priority (optional): Item Tags can be used to define criteria for grouping and sorting the sequence of production orders that are scheduled on the work center.  Any criteria that is going to be used for scheduling must first be defined as a Tag and associated to the product through the Item Management Tag functionality.  Once the Item Tags have been defined, you need to click on the Define Tags Priority link to select the Tags that should be utilized for scheduling at this work center. In the Work Center Manage Tags dialog, use the check-boxes in the Included column to select the Tags that should be used to schedule products in this work center.  After selecting the Tags, use the toggle control at the top of the dialog window to switch to the Tag Prioritization View.

In the Tag Prioritization View, use the drag and drop control in the view to vertically order the Tags in the priority that the Tags should be used in sorting production orders in the work center.  The Tags that are higher up in the list have a higher priority when applied in the sequencing rules defined for the work center.

The Items without tag sequencing toggle control is used to specify the sort priority for production orders of items that do not have any of the selected Tags.

Define Sequencing Criteria: This link is used to open up the dialog for selecting the criteria will be used to sequence the production orders at this work center.

Group By: determines the size of the buckets for selecting the production and suggested orders to be grouped. The options are:

  • Due Date which will group the orders with the same due date together before sorting them
  • Due Week which will group the orders with the same due week together before sorting them

The default rule if no rule is selected is to sort all orders by their due date in ascending order.

The All Rules list displays all the criteria that is available for sorting production orders (within the selected weekly or daily bucket).

The Selected Rules List displays all the criteria that have been selected for use in sorting production orders at the work center.  The following rules are available for sequencing jobs in a work center:

  • Item Classification Desc: sorts the production orders by their Item Classification values in descending order
  • Item Tags Desc: sorts the production orders by their Tag Priority, which has been defined in the Tag Priority dialog (see above).

The priority for the application of the selected rules is determined by their order in the Selected Rules list, with the rules higher up in the list being selected first.

In the example shown in the Define Sequencing Criteria dialog below, the orders will first be sorted by their due week in ascending order, and for any production orders due on the same week, the Item Tags Desc rules will be used to sequence those orders, after which the Item Classification will be used to sequence the orders sharing the same tags.

Constrained Capacity Production Leveling Application

After the work centers have configured, the Level Loading menu will need to be selected to access the schedule on each of the level-loaded work centers.

You will be prompted by the Recalculate button (shown below) to recalculate the capacity on level-loaded work centers if there have been any changes in the work center, routing data or the requirement plan.

After the capacity has been recalculated, you can use the work center selection drop-down to select for viewing each of the capacity constrained work centers.

When a capacity constrained work center is selected, each of the days that are being scheduled is shown in a row, with each of the production orders scheduled in the work center shown in its selected row. The first row shows the days in the Frozen Period, and the jobs scheduled to be produced on the work center during the frozen period.  All past due production orders are also shown in the frozen period.  The name of each daily period is shown on left-most column of the application, called the Daily Capacity Parameters, with the following fields:

  • Capacity: the number of hours of capacity available on the work center for the day
  • Utilization Percentage: the percentage of the capacity that is scheduled for the day
  • Load: the number of hours of capacity that is scheduled for the day
  • Units: the number of units of production scheduled for the day
  • Available:  the percentage of capacity that is not scheduled

The following columns are displayed on the application:

  • Info: Contains the Clean-To-Build information for the item
  • Item: Contains the Item Code
  • Start Time: Contains the start time of the operation that is scheduled on the work center
  • End Time: Contains the end time of the operation that is scheduled on the work center
  • Duration: Contains duration of the operation that is scheduled on the work center
  • Qty Scheduled: Contains the number of units scheduled to be produced on the work center
  • Target Due Date: Contains the due date of the production order
  • Delay: Contains the amount of time the production order will be delayed when compared to its original due date (from the requirement plan).  The Delay field is color-coded to  highlight the state of inventory coverage for the finished good on the scheduled date. The following color codes are used:
    • Green: There is more than 24 hours of inventory coverage given the scheduled date
    • Yellow: There is inventory on hand but there is less than 24 hour of inventory coverage given the scheduled date
    • Red: There is no inventory on hand to cover the schedule date.
  • Order #:  Contains the order number for the production order or suggested order
  • Scheduled End Time: Contains the date and end time that the production/suggested order is scheduled to be completed as a result of the capacity constrained schedule
  • Item Class: Contains the Item Class associated to the item
  • Attributes: The Tags (that are associated to the item) that are used in sequencing production/suggested orders at the work center
  • Days on Hand: The number of days of on-hand inventory, calculated using the projected inventory, one day before the due date of the production/suggested order

Generating a Constrained Schedule

You need to generate/regenerate a constrained schedule after any changes are made to the product's routing or the work center data. Click the Recalculate button to generate or regenerate a constrained schedule.

The Recalculate button will schedule all the production order operations that have start dates after the frozen time fence using the sequencing rules that have been defined for the work center.  After the constrained schedule is generated the start time for each scheduled production order operation will be scheduled to start immediately after the end time of the previous operation in the schedule.

Prior to generating the constrained schedule for a level-loaded work center, each period on the schedule of the work center will suffer from capacity under-utilization (under 100%) or capacity over-utilization (over 100%), as shown below.

After generating the constrained schedule for a level-loaded work center, each period of the work center's schedule will have full capacity utilization (100%), as shown below.

Editing the Constrained Production Plan

A user can modify the generated constrained production plan by editing the due dates and quantities of the production orders and suggested orders. To edit a production or suggested order, the user needs to click on the Quantity Scheduled or Target Due Date fields on the Constrained Capacity Production Leveling application, which will open the Order Edit dialog where the user can update the production or suggested order.  

Feedback to Requirement Plan

After the production plan has been generated and edited in the Constrained Capacity Production Leveling application, the production plan needs to be sent to the Requirement Planning application where the dependent demand for its components can be generated. Please see the following documentation for more information on sending the constrained production plan to Requirement Planing.

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