Example 3

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.