Examples of Production Scheduling

The following examples illustrate how PeopleSoft Manufacturing creates and maintains operation schedules. These examples illustrate how the system calculates actual start and due dates and times for different operations using forward and backward scheduling.

Note: These examples assume that you are not using the PeopleSoft Supply Planning solvers to schedule production.

The examples use these types of shop floor operations:

  • Example 1: Operations with no overlap; queue and setup are done sequentially.

  • Example 2: Operations with no overlap; queue and setup are done concurrently; queue time is less than setup time.

  • Example 3: Operations with no overlap, queue and setup are done concurrently; setup time is less than queue time.

  • Example 4: Operations with no overlap; setup is not included.

  • Example 5: Operation overlap; queue and setup are done sequentially.

These production times are used for all examples:

Op

Queue

Setup

Run

Intransit

Overlap

10

None

1 hour

5 hours (.5 hr/unit)

2 hours

None

20

1 hour

3 hours

10 hours (1 hr/unit)

1 hour

None

Note: Even though PeopleSoft Manufacturing calculates start and due dates and times to the minute, hours are used to make it easier to manually calculate these shop floor operation examples.

All examples assume a 24-hour day with an operation start quantity of 10 units. The start of the operation is when setup starts.

This diagram shows an example of operations with no overlap and the queue and setup are done sequentially:

 Example 1: Queue time is one hour, and setup time is three hours

Operation

Operation Start

Run Start

Operation Due

10

Day 1, 8:00 a.m.

Day 1, 9:00 a.m.

Day 1, 2:00 p.m.

20

Day 1, 5:00 p.m.

Day 1, 8:00 p.m.

Day 2, 6:00 a.m.

Forward Scheduling Calculations

Production ID Start Date and Time = Day 1, 8:00 a.m.

This table lists the steps that you take to calculate the start and due date and times for the first operation (Operation 10):

Step

To Calculate

Use

Notes

1

Operation 10 start date and time.

Production ID's start date and time.

This calculation assumes that queue cannot occur at the first operation.

2

Operation 10 run start date and time.

Operation start date and time + setup time.

None.

3a or

Operation 10 run time (time and unit).

Operation start quantity × run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of time per unit.

3b

Operation 10 run time (units/time).

Operation start quantity and run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of units per time unit.

4

Operation 10 due date and time.

Run start date and time + run time.

None.

This table lists the steps that you take to calculate start and due dates and times for the second operation (Operation 20):

Step

To Calculate

Use

Notes

1

Operation 20 start date and time.

Previous operation's (Operation 10) due date and time + previous operation's in transit time + current operation's queue time.

None.

2

Operation 20 run start date and time.

Current operation start date and time + setup time.

None.

3a, or

Operation 20 run time (time and unit).

Operation start quantity × run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of time per unit.

3b

Operation 20 run time (units/time).

Operation start quantity and run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of units per time unit.

4

Operation 20 due date and time.

Current operation run start date and time + run time.

If you have a schedule with more than two operations, repeat steps 1 through 4 in this table until all subsequent operation due dates and times are calculated.

Backward Scheduling Calculations

Production ID Due Date and Time = Day 2, 6:00 a.m.

This table lists the steps that you take to calculate the start and due date and times for the last operation (Operation 20):

Step

To Calculate

Use

Notes

1

Operation 20 due date and time.

Production ID's due date and time − current operation's in transit time.

None.

2a, or

Operation 20 run time (time and unit).

Operation start quantity × run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of time per unit.

2b

Operation 20 run time (units/time).

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of units per time unit.

3

Operation 20 run start date and time.

Current operation's due date and time − run time.

None.

4

Operation 20 start date and time.

Current operation's run start date and time − setup time.

None.

This table lists the steps that you take to calculate start and due dates and times for the prior operation (Operation 10):

Step

To calculate

Use

Notes

1

Operation 10 due date and time.

Subsequent operation's (Operation 20) start date and time − subsequent operation's queue time − current operation's in transit time.

None.

2a, or

Operation 10 run time (time/unit).

Operation start quantity × run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of time per unit.

2b

Operation 10 run time (units and time).

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of units per time unit.

3

Operation 10 run start date and time.

Current operation's due date and time − run time.

None.

4

Operation 10 start date and time.

Current operation's run start date and time − setup time.

If you have a schedule with more than two operations, repeat steps 1 through 4 in this table until all previous operation due dates and times are calculated.

This diagram shows an example of operations with no overlap and the queue and setup are done concurrently. The queue time is less than the setup time:

 Example 2: Queue time is one hour, and setup time is three hours

Operation

Operation Start

Run Start

Operation Due

10

Day 1, 8:00 a.m.

Day 1, 9:00 a.m.

Day 1, 2:00 p.m.

20

Day 1, 4:00 p.m.

Day 1, 7:00 p.m.

Day 2, 5:00 a.m.

Forward Scheduling Calculations

Production ID Start Date and Time = Day 1, 8:00 a.m.

This table lists the steps that you take to calculate the start and due date and times for the first operation (Operation 10):

Step

To Calculate

Use

Notes

1

Operation 10 start date and time.

Production ID's start date and time.

This calculation assumes that queue doesn't occur at the first operation.

2

Operation 10 run start date and time.

Operation start date and time + setup time.

None.

3a, or

Operation 10 run time (time/unit).

Operation start quantity × run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of time per unit.

3b

Operation 10 run time (units and time).

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of units per time unit.

4

Operation 10 due date and time.

Run start date and time + run time.

None.

This table lists the steps that you take to calculate start and due dates and times for the second operation (Operation 20):

Step

To Calculate

Use

Notes

1

Operation 20 start date and time.

Previous operation's (Operation 10) due date and time + prior operation's in transit time.

This calculation assumes that queue time is less than setup time.

2

Operation 20 run start date and time.

Current operation start date and time + setup time.

None.

3a, or

Operation 20 run time (time/unit).

Operation start quantity × run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of time per unit.

3b

Operation 20 run time (units and time).

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of units per time unit.

4

Operation 20 due date and time.

Current operation run start date and time + run time.

If you have a schedule with more than two operations, repeat steps 1 through 4 in this table until all subsequent operation due dates and times are calculated.

Backward Scheduling Calculations

Production ID Due Date and Time = Day 2, 5:00 a.m.

This table lists the steps that you take to calculate the start and due date and times for the last operation (Operation 20):

Step

To Calculate

Use

Notes

1

Operation 20 due date and time.

Production ID's due date and time − current operation's in transit time.

None.

2a, or

Operation 20 run time (time/unit).

Operation start quantity × run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of time per unit.

2b

Operation 20 run time (units and time).

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of units per time unit.

3

Operation 20 run start date and time.

Current operation's due date and time − run time.

None.

4

Operation 20 start date and time.

Current operation's run start date and time − setup time.

None.

This table lists the steps that you take to calculate start and due dates and times for the prior operation (Operation 10):

Step

To Calculate

Use

Notes

1

Operation 10 due date and time.

Subsequent operation's (Operation 20) start date and time − current operation's in transit time.

This calculation assumes that queue time is less than setup time.

2a, or

Operation 10 run time (time/unit).

Operation start quantity × run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of time per unit.

2b

Operation 10 run time (units and time).

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of units per time unit.

3

Operation 10 run start date and time.

Current operation's due date and time − run time.

None.

4

Operation 10 start date and time.

Current operation's run start date and time − setup time.

If you have a schedule with more than two operations, repeat steps 1 through 4 in this table until all previous operation due dates and times are calculated.

This diagram shows an example of operations with no overlap, the queue and setup are done concurrently, and the setup time is less than the queue time:

 Example 3: Queue time takes three hours and setup takes one hour

Operation

Operation Start

Run Start

Operation Due

10

Day 1, 8:00 a.m.

Day 1, 9:00 a.m.

Day 1, 2:00 p.m.

20

Day 1, 6:00 p.m.

Day 1, 7:00 p.m.

Day 2, 5:00 a.m.

Forward Scheduling Calculations

Production ID Start Date and Time = Day 1, 8:00 a.m.

This table lists the steps that you take to calculate the start and due date and times for the first operation (Operation 10):

Step

To Calculate

Use

Notes

1

Operation 10 start date and time.

Production ID's start date and time.

This calculation assumes that queue doesn't occur at the first operation.

2

Operation 10 run start date and time.

Operation start date and time + setup time.

None.

3a, or

Operation 10 run time (time/unit).

Operation start quantity × run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of time per unit.

3b

Operation 10 run time (units and time).

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of units per time unit.

4

Operation 10 due date and time.

Run start date and time + run time.

None.

This table lists the steps that you take to calculate start and due dates and times for the second operation (Operation 20):

Step

To Calculate

Use

Notes

1

Operation 20 start date and time.

Prior operation's (Operation 10) due date and time + prior operation's in transit time + (queue − setup time of current operation).

This calculation assumes that setup time is less than queue time.

2

Operation 20 run start date and time.

Current operation start date and time + setup time.

None.

3a or

Operation 20 run time (time/unit).

Operation start quantity × run rate (converted to hours) + fixed run (converted to hours).

Use this calculation if the run rate is in terms of time per unit.

3b

Operation 20 run time (units and time).

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of units per time unit.

4

Operation 20 due date and time.

Current operation run start date and time + run time.

If you have a schedule with more than two operations, repeat steps 1 through 4in this table until all subsequent operation due dates and times are calculated.

Backward Scheduling Calculations

Production ID Due Date and Time = Day 2, 5:00 a.m.

This table lists the steps that you take to calculate the start and due date and times for the last operation (Operation 20):

Step

To Calculate

Use

Notes

1

Operation 20 due date and time

Production ID's due date and time − current operation's intransit time

None.

2a, or

Operation 20 run time (time/unit)

Operation start quantity × run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of time per unit.

2b

Operation 20 run time (units and time)

Operation start quantity / run rate (converted to hours) × fixed run (converted to hours)

Use this calculation if the run rate is in terms of units per time unit.

3

Operation 20 run start date and time

Current operation's due date and time − run time

None.

4

Operation 20 start date and time

Current operation's run start date and time − setup time

None.

This table lists the steps that you take to calculate start and due dates and times for the prior operation (Operation 10):

Step

To Calculate

Use

Notes

1

Operation 10 due date and time

Subsequent operation's (Operation 20) start date and time − (queue time - setup time of subsequent operation) - current operation's intransit time

This calculation assumes that setup time is less than queue time.

2a, or

Operation 10 run time (time/unit)

Operation start quantity x run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of time per unit.

2b

Operation 10 run time (units and time)

Operation start quantity/ run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of units per time unit.

3

Operation 10 run start date and time

Current operation's due date and time − run time

None.

4

Operation 10 start date and time

Current operation's run start date and time − setup time

If you have a schedule with more than two operations, repeat steps 1 through 4in this table until all prior operation due dates and times are calculated.

This diagram shows an example of operations with no overlap and the setup is not included:

 Example 4: Queue time is three hours

Operation

Operation Start

Run Start

Operation Due

10

Day 1, 8:00 a.m.

Day 1, 9:00 a.m.

Day 1, 2:00 p.m.

20

Day 1, 2:00 p.m.

Day 1, 5:00 p.m.

Day 2, 3:00 a.m.

Forward Scheduling Calculations

Production ID Start Date and Time = Day 1, 8:00 a.m.

This table lists the steps that you take to calculate the start and due date and times for the first operation (Operation 10):

Step

To Calculate

Use

Notes

1

Operation 10 start date and time

Production ID's start date and time

This calculation assumes that queue doesn't occur in the first operation.

2

Operation 10 run start date and time

Operation start date and time + setup time

Setup is always included at the first operation.

3a, or

Operation 10 run time (time/unit)

Operation start quantity x run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of time per unit.

3b

Operation 10 run time (units and time)

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of units per time unit.

4

Operation 10 due date and time

Run start date and time + run time

None.

This table lists the steps that you take to calculate start and due dates and times for the second operation (Operation 20):

Step

To Calculate

Use

Notes

1

Operation 20 start date and time

Prior operation's (Operation 10) due date and time + prior operation's intransit time + current operation's queue time - current operation's setup time

This calculation assumes that setup can be completed any time after the first operation run has started. The start date and time represent the latest possible time that you should begin setup.

2

Operation 20 run start date and time

Current operation start date and time + setup time

None.

3a, or

Operation 20 run time (time and unit)

Operation start quantity x run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of time per unit.

3b

Operation 20 run time (units/time)

Operation start quantity and run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of units per time unit.

4

Operation 20 due date and time

Current operation run start date and time + run time

If you have a schedule with more than two operations, repeat steps 1 through 4 in this table until all subsequent operation due dates and times are calculated.

Backward Scheduling Calculations

Production ID Due Date and Time = Day 2, 3:00 a.m.

This table lists the steps that you take to calculate the start and due date and times for the last operation (Operation 20):

Step

To Calculate

Use

Notes

1

Operation 20 due date and time

Production ID's due date and time - current operation's intransit time

None.

2a, or

Operation 20 run time (time and unit)

Operation start quantity x run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of time per unit.

2b

Operation 20 run time (units/time)

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of units per time unit.

3

Operation 20 run start date and time

Current operation's due date and time - run time

None.

4

Operation 20 start date and time

Current operation's run start date and time - setup time

This calculation assumes that setup can be completed any time after the first operation run has started. The start date and time represent the latest possible time that you should begin setup.

This table lists the steps that you take to calculate start and due dates and times for the prior operation (Operation 10):

Step

To Calculate

Use

Notes

1

Operation 10 due date and time

Subsequent operation's (Operation 20) start date and time - subsequent operation's queue time - current operation's intransit time

The run start date and time is used and setup is not included. The setup at Operation 20 can be completed at the same time the prior operation is being run.

2a, or

Operation 10 run time (time/unit)

Operation start quantity x run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of time per unit.

2b

Operation 10 run time (units and time)

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of units per time unit.

3

Operation 10 run start date and time

Current operation's due date and time - run time

None.

4

Operation 10 start date and time

Current operation's run start date and time - setup time

If you have a schedule with more than two operations, repeat steps 1 through 4 in this table until all prior operation due dates and times are calculated.

This diagram shows an example of operations overlap. The queue and setup are done sequentially. Assume that operations have overlap expressed as a percent (100% = total overlap, 0% = no overlap) or send ahead quantity. If overlap is expressed as a percentage, assume that all units are available for processing at the start of the run or soon after:

 Example 5: 80 percent overlap or a send ahead quantity of 2 units

Operation

Operation Start

Run Start

Operation Due

10

Day 1, 8:00 a.m.

Day 1, 9:00 a.m.

Day 1, 2:00 p.m.

20

Day 1, 1:00 p.m.

Day 1, 4:00 p.m.

Day 2, 2:00 a.m.

Forward Scheduling Calculations

Production ID Start Date and Time = Day 1, 8:00 a.m.

This table lists the steps that you take to calculate the start and due date and times for the first operation (Operation 10):

Step

To Calculate

Use

Notes

1

Operation 10 start date and time

Production ID's start date and time

This calculation assumes that queue doesn't occur in the first operation.

2

Operation 10 run start date and time

Operation start date and time + setup time

None.

3a, or

Operation 10 run time (time/unit)

Operation start quantity x run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of time per unit.

3b

Operation 10 run time (units and time)

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of units per time unit.

4

Operation 10 due date and time

Run start date and time + run time

None.

This table lists the steps that you take to calculate start and due dates and times for the second operation (Operation 20):

Step

To Calculate

Use

Notes

1a, or

Operation 20 start date and time; overlap expressed as a percentage

Prior operation's (Operation 10) start of run + [prior operation's total run time x (1 - overlap percent / 100)] + prior operation's intransit time + current operation's queue time

None.

1b

Operation 20 start date and time; overlap expressed as a send ahead quantity

Prior operation's (Operation 10) start of run + (prior operation's run rate x send ahead quantity, converted to hours) + prior operation's fixed run time + prior operation's intransit time + current operation's queue time

None.

2

Operation 20 run start date and time

Current operation start date and time + setup time

None.

3a, or

Operation 20 run time (time/unit)

Operation start quantity x run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of time per unit.

3b

Operation 20 run time (units/time)

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of units per time unit.

4

Operation 20 due date and time

Current operation run start date and time + run time

If you have a schedule with more than two operations, repeat steps 1 through 4 in this table until all subsequent operation due dates and times are calculated.

Backward Scheduling Calculations

Production ID Due Date and Time = Day 2, 2:00 a.m.

This table lists the steps that you take to calculate the start and due date and times for the last operation (Operation 20):

Step

To Calculate

Use

Notes

1

Operation 20's due date and time

Production ID's due date and time - current operation's intransit time

None.

2a, or

Operation 20 run time (time/unit)

Operation start quantity x run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of time per unit.

2b

Operation 20 run time (units/time)

Operation start quantity/ run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of units per time unit.

3

Operation 20 run start date and time

Current operation's due date and time - run time

None.

4

Operation 20 start date and time

Current operation's run start date and time - setup time

None.

This table lists the steps that you take to calculate start and due dates and times for the prior operation (Operation 10), with an operation overlap expressed as a percentage:

Step

To Calculate

Use

Notes

1

Operation 10 due date and time, when operation overlap is expressed as a percentage

Subsequent operation's (Operation 20) start date and time - subsequent operation's queue time - current operation's intransit time + [current operation's total run time x (overlap percent / 100)]

None.

2a, or

Operation 10 run time (time/unit)

Operation start quantity x run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of time per unit.

2b

Operation 10 run time (units/time)

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of units per time unit.

3

Operation 10 run start date and time

Current operation's due date and time - run time

None.

4

Operation 10 start date and time

Current operation's run start date and time - setup time

If you have a schedule with more than two operations, repeat steps 1 through 4 in this table until all prior operation due dates and times are calculated.

This table lists the steps that you take to calculate start and due dates and times for the prior operation (Operation 10), with an operation overlap expressed as a send ahead quantity:

Step

To Calculate

Use

Notes

1

Operation 10 due date and time, when operation overlap is expressed as a send ahead quantity

Subsequent operation's (Operation 20) start date and time - current operation's intransit time - subsequent operation's queue time + [current operation's run time x (Operation start quantity - send ahead quantity)]

None.

2a, or

Operation 10 run time (time and unit)

Operation start quantity x run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of time per unit.

2b

Operation 10 run time (units/time)

Operation start quantity / run rate (converted to hours) + fixed run (converted to hours)

Use this calculation if the run rate is in terms of units per time unit.

3

Operation 10 run start date and time

Current operation's due date and time - run time

None.

4

Operation 10 start date and time

Current operation's run start date and time - setup time

If you have a schedule with more than two operations, repeat steps 1 through 4 in this table until all prior operation due dates and times are calculated.