This chapter tells you everything you need to know about manufacturing scheduling.
This chapter covers the following topics:
Oracle Manufacturing schedules production orders and operation dates using three scheduling methods:
detailed scheduling
repetitive line scheduling
dynamic lead time offsetting
The following table lists the Oracle Manufacturing products that schedule orders and operations, and indicates their scheduling method:
| Product | Scheduling Function | Scheduling Method |
|---|---|---|
| Oracle Work in Process | Schedule Discrete Jobs | Detailed Scheduling |
| Oracle Work in Process | Schedule Repetitive Schedules | Repetitive Line Scheduling |
| Oracle Bills of Material | Compute Manufacturing Lead Times | Detailed Scheduling |
| Oracle Master Scheduling/MRP | Compute Planned Order Start Date | Dynamic Lead Time Offsetting |
| Oracle Master Scheduling/MRP | Compute Planned Order Component Requirement Dates | Dynamic Lead Time Offsetting |
| Oracle Capacity | Load Planned Order Resource Requirements | Dynamic Lead Time Offsetting |
| Oracle Inventory | Compute Requirement Dates for Assemble to Order Item Components for ATP Checks | Dynamic Lead Time Offsetting |
Detailed scheduling is based on detailed resource availability and usages and is the most precise scheduling method in Oracle Manufacturing. It takes into account minute to minute resource availability information as well as exact resource requirements from routings to schedule precise start and end dates and times for jobs and operations. Detailed scheduling is an infinite scheduling algorithm-so it does not take into account load from other discrete jobs. However, you can simulate the scheduling impact of the load by adding queue, move, and wait resources.
Oracle Work in Process schedules discrete jobs using detailed scheduling. Each resource required on a job is scheduled consecutively. Work in Process can either forward schedule, backward schedule, or both from an operation.
Work in Process schedules repetitive production using repetitive line scheduling, schedules each resource in sequence based upon the shift workday calendar, the amount of the resource required, and the number of assigned resources that can be simultaneously scheduled.
Related Topics
Overview of Discrete Manufacturing, Oracle Work in Process User's Guide
Overview of WIP Scheduling, Oracle Work in Process User's Guide
Repetitive line scheduling is based on production line attributes including start and stop times, line speed, line capacity, and lead time. Repetitive line scheduling uses your workday calendar and the line start and stop times rather than detailed resource shift availability.
For lines with a lead time basis of Fixed, you must enter a fixed lead time. Oracle Manufacturing uses this fixed lead time for all repetitive assemblies assigned to the line. For lines with a lead time basis of Routing-based, you can automatically compute manufacturing lead time based upon a repetitive assembly's routing.
Work in Process lets you specify the production line where you build each assembly and the line speed determines the production run rate to schedule that assembly on that line. If you have a fixed speed line, all assemblies should use the same line speed. For variable speed lines, you need to specify different speeds for each assembly. The line speed for any particular assembly cannot exceed the line's maximum rate.
Work in Process lets you define production lines and specify a start and stop time for each line. You must also specify the minimum and maximum hourly rate on each line, and specify whether a line's lead time is fixed or routing based.
Overview of Lead Time Management
Defining Production Lines, Oracle Work in Process User's Guide
Dynamic lead time offsetting is based on order quantity, lead times, and the workday calendar. It is a faster scheduling method that quickly estimates the start date of an order, an operation, or a resource.
Dynamic lead time offsetting always computes a date that is a particular number of days from a specified date in the workday calendar. It accounts for changes in lead time based on order quantity, using the fixed and variable components of manufacturing lead time, as well as operation and resource offsets.
Oracle Manufacturing functions whose processing performance is most critical use dynamic lead time offsetting while other functions that schedule exact operation and resource start and end times use detailed scheduling.
For example, Master Scheduling/MRP generates MRP plans as quickly as possible, so it schedules planned order start dates using dynamic lead time offsetting. Work in Process, however, uses detailed scheduling to schedule jobs since it schedules resource usages in departments with exact start date, end dates and times, not scheduling a resource when one is not available.
Results from detailed scheduling and dynamic lead time offsetting may differ. The more resource availability exceptions and capacity modifications from the workday calendar you have, the more detailed scheduling results differ from dynamic lead time offsetting results. Assigning preprocessing lead time to manufactured items can also produce different results; detailed scheduling does not use lead times in its calculations while dynamic lead time offsetting does.
Master Scheduling/MRP computes component requirement dates for planned orders using the offset percentage for the operation where each component is used. Master Scheduling/MRP multiplies the operation offset percentage times the planned order lead time to get offset days, and then finds the workday that is the number of days past the planned order start date.
Oracle Capacity offsets resource requirement dates the same way that Master Scheduling/MRP offsets component requirement dates, except it uses resource offset percentages. Oracle Capacity computes resource offset days as the planned order lead time multiplied by the resource offset percentage. Oracle Capacity then finds the workday that is the number of days past the work order start date to find the resource start date and time.
Oracle Inventory lets you check component available to promise (ATP) for assemble to order (ATO) and Pick to Order (PTO) items. Oracle Bills of Material allows you to specify the components of an ATO or PTO product that must be promised using ATP. When you check ATP for a product having such components, Inventory determines the requirement date for components by first computing the manufacturing lead time for that product using the dynamic lead time calculation and then finding the date that is the number of workdays before the requested ship date. Inventory assumes that all ATO product components are required at the beginning of the ATO job.
Related Topics
Overview of Lead Time Management
Overview of Material Requirements Planning, Oracle MRP User's Guide
Overview of On-hand and Availability, Oracle Inventory User's Guide
Bills of Material lets you automatically compute item, bill of material and routing information required for dynamic lead time offsetting. You can also maintain lead time information manually.
Dynamic lead time offsetting uses the following lead time attributes for discretely manufactured items:
fixed lead time
variable lead time
preprocessing lead time
Dynamic lead time offsetting uses the following lead time attributes for repetitively manufactured items:
processing lead time
fixed lead time
Dynamic lead time offsetting uses the following lead time attributes:
preprocessing time
processing lead time
post-processing lead time
When computing manufacturing lead times, operation and resource offsets are automatically assigned to a routing. For material and resource requirement planning, you can optionally include offsets when computing requirement dates.
Related Topics
Overview of Lead Time Management
Dynamic lead time offsetting offsets dates in two steps, computing total lead time and offsetting the date by total lead time. Total lead time contains both fixed lead time and the quantity-dependent portion of lead time. Preprocessing lead time is also included for discrete items.
Note: Total lead time equals processing lead time.
To compute the total lead time for discrete items use the following equation:
preprocessing lead time + fixed lead time + (order quantity x variable lead time)
Compute the total lead time for repetitive items using the following equation:
fixed lead time + (daily rate x processing lead time)
Offset the date by total lead time using the following equation:
start date = requirement date - total lead time
Important: Oracle Manufacturing offsets the requirement date by the total lead time using the workday calendar, accounting for any non-workdays. Before subtracting total lead time, Oracle Manufacturing determines the workday for the requirement date. After offsetting by total lead time, the calendar date is derived from the starting workday.
Example
Master Scheduling/MRP uses dynamic lead time offsetting to compute a planned order release date. Master Scheduling/MRP computes total lead time and then uses the workday calendar to calculate the planned order release date.
Suppose your MRP plan produced a requirement for 100 discretely manufactured assemblies on March 12 and the following information exists for that assembly:
Requirement date = 12-MAR
Fixed lead time = 2 days
Variable lead time = .05 days (1 day per 20 units)
Preprocessing lead time = 0 days
Order quantity = 100
Master Scheduling/MRP first computes the total lead time as follows:
Total lead time = 0 + 2 + (100 x .05) Total lead time = 7 days
Suppose your organization's workday calendar has a workday pattern with five days on and two days off. Workdays 1 - 5 are March 1 - 5. Saturday and Sunday, March 6 and 7, are off. Workdays 6 - 10 are March 8 - 12.
Master Scheduling/MRP then calculates the planned order release date as follows:
Start date = requirement date - total lead time Start date = (12-MAR) - 7 days
Convert planned order requirement date to a workday (using your organization's workday calendar).
Start date = Date ((Workday 10) - 7)) Start date = Date (3)
Finally, determine the start date.
Start date = 03 - MAR (planned order release date)
Related Topics
Overview of On-hand and Availability, Oracle Inventory User's Guide
Overview of Material Requirements Planning, Oracle MRP User's Guide