Production orders are scheduled automatically depending on the following:
- A production order position in the queue.
Production orders with a higher position are scheduled first. - A production order start date.
- The sequence of operations in the bill of materials (BOM).
- Planning intervals of production departments.
- Availability of the work centers or work center types.
For each production order, scheduling steps are the following:
- Determine the sequence of operations as follows:
- If all operations consume components from stock, take the sequence from the BOM’s Operations tab.
- If an operation consumes a component that must be produced, include a sequence of operations from the component BOM. In the resulting sequence, these operations precede the operation that consumes the component.
- Schedule operations from the sequence.
Scheduling operations from sequence
Operations are scheduled according to the following rules:
- Find the work center types assigned to the operations.
- Find the work centers included in the work center types.
- Find Planning intervals of production departments that include work center types.
- Check the work centers availability. If a work center type is not assigned to an operation, check the work schedule of a company specified in the production order.
- Determine an operation start date as follows:
- If an operation is the first in the sequence, its start date is the production order start date.
- If an operation is NOT the first in the sequence, its start date is the date closest to the end date of the previous operation.
- For each operation, determine how many times it is performed to produce the ordered product quantity. Do one of the following:
- If in the BOM, the Fixed check box is cleared for an operation, calculate the quantity of operations by the following formula:
Quantity of operations = product Quantity in a production order / product Quantity in BOM
If the resulting number is not integer, round it up. - If in the BOM, the Fixed check box is selected for an operation, assume that operation is performed once.
- If in the BOM, the Fixed check box is cleared for an operation, calculate the quantity of operations by the following formula:
- For each operation, schedule the determined quantity of the operations on the planning intervals closest to the operation start date according to the work center availability or a company’s work schedule.
- For each operation, determine the end time as follows:
- Find the last planning interval that the operation is scheduled on.
- Take the end time of this interval.
Production scheduling example
The production orders queue contains two production orders:
Number |
Description |
Priority |
Start date |
Due date |
01 |
Production order for 2 stools |
High |
03.07.2020 |
06.07.2020 |
02 |
Production order for 8 stools |
Medium |
03.07.2020 |
06.07.2020 |
BOM for 1 stool includes the following:
Operations
Operation number |
Next operation |
Operation |
Standard time |
Fixed |
1 |
0 |
Stool assembling |
1 min |
No |
Components
Component |
Quantity |
Unit |
Operation |
Produce |
Bill of materials |
Stool leg |
4 |
pcs |
Stool assembling |
Yes |
Stool leg BOM for 5 legs |
Stool seat |
1 |
pcs |
Stool assembling |
No |
A work center type is not assigned to the Stool assembling operation. This means that a company can perform this operation any number of times on any date within the company’s work schedule. The schedule is 5 work days a week starting from Monday. A work day is from 8 AM to 5 PM.
Stool leg BOM for 5 legs includes the following:
Operations
Operation number |
Next operation |
Operation |
Standard time |
Fixed |
1 |
0 |
Wood sharpening |
10 min |
No |
Components
Component |
Quantity |
Unit |
Operation |
Produce |
Bill of materials |
Beam |
2 |
m |
Wood sharpening |
No |
Details of the work center type assigned to the Wood sharpening operation:
Operation |
Standard time |
Work center type |
Work center |
Department |
Planning interval |
Stool assembling |
10 min |
Wood sharpening equipment |
Wood sharpening machine |
Production |
5 min |
These details show that the Wood sharpening machine is assigned to the Wood sharpening operation. This operation is performed in the Production department with the planning interval of 5 minutes. The Wood sharpening machine is available according to its availability schedule.
Scheduling flow
The scheduling flow includes the following:
- Production order 01
- Production order 02
Production order 01
The Production order 01 for 2 stools is on the top of the queue. So, it is scheduled first.
The scheduling steps are the following:
- According to BOM, the following is required to produce 1 stool:
- Complete 1 Stool assembling operation.
- Produce 4 stool legs before performing the Stool assembling operation.
- To produce 4 stool legs, complete the Wood sharpening operation.
So, the sequence of operations for production order 01 starts with Wood sharpening. The next and the last operation is Stool assembling.
- Schedule the operations for production order 01.
Scheduling operations for production order 01
Operations for production order 01 are scheduled as follows:
- Determine the following:
- The Wood sharpening equipment is assigned to the Wood sharpening operation.
- No work center type is assigned to the Stool assembling operation.
- Determine that the Wood sharpening equipment includes the Wood sharpening machine.
- Determine the following:
- Planning interval for the Wood sharpening operation is 5 min.
- Planning interval for the Stool assembling operation is not defined.
- Determine the following:
- The Wood sharpening machine is available 9 hours a day from 8 AM to 5 PM.
Any work day is available for scheduling operations. - The company’s work schedule is 9 hours a day from 8 AM to 5 PM.
Any work day is available for scheduling operations.
- The Wood sharpening machine is available 9 hours a day from 8 AM to 5 PM.
- Determine that the production order start date is 03.07.2020.
- Calculate how many times the operations must be performed:
- For the Wood sharpening operation, consider that 2 stools are ordered. For 2 stools, 8 legs are required. The stool leg BOM says that 1 Wood sharpening operation produces 5 legs. Then this operation must be performed 2 times.
- For the Stool assembling operation, consider that 2 stools are ordered. The stool BOM says that 1 Stool assembling operation produces 1 stool. Then this operation must be performed 2 times.
- Put the Wood sharpening operation on the production schedule. Apply the following:
- The Wood sharpening machine is available on any work day.Then the operation start date is the production order start date 03.07.2020. The operation start time is the machine start time 8 AM.
- The operation Standard time is 10 min. In this example, it takes 2 Planning intervals of 5 min.
- The operation must be performed 2 times. Then it takes 4 Planning intervals.
Date
03.07.2020
Planning intervals
8:00:00
8:04:59
8:05:00
8:09:59
8:10:00
8:14:59
8:15:00
8:19:59
8:20:00
8:24:59
12
planning intervals9:25:00
9:29:59
9:30:00
9:34:59
Wood sharpening machine
PO1WS
PO1WS
PO1WS
PO1WS
where:
PO1WS - Production order 01, Wood sharpening operation
- Put the Stool assembling operation on the production schedule. Apply the following:
- Any work day is available on the company’s work schedule. Then the operation start date is the production order start date 03.07.2020.
- The previous operation ends at 8:19:59 AM. Then this operation start time is 8:20.
- A work center type is not assigned to the Stool assembling operation. Then assume that the company has unlimited capacity for performing this operation within Standard time. Then it takes 1 min to perform 2 operations.
Date
03.07.2020
Planning intervals
8:00:00
8:04:59
8:05:00
8:09:59
8:10:00
8:14:59
8:15:00
8:19:59
8:20:00
8:24:59
12
planning intervals9:25:00
9:29:59
9:30:00
9:34:59
Wood sharpening machine
PO1WS
PO1WS
PO1WS
PO1WS
Company
PO1SA
where:
PO1WS - Production order 01, Wood sharpening operation
PO1SA - Production order 01, Stool assembly operation
Production order 02
The Production order 01 for 2 stools is scheduled. Then schedule the Production order 02 for 8 stools.
The scheduling steps are the following:
- Determine the sequence of operations in the same way as for Production order 01 .
- Schedule operations for Production order 02.
Scheduling operations for production order 02
Operations for production order 02 are scheduled as follows:
- Determine the following:
- The Wood sharpening machine is occupied with production order 01 on 03.07.2020 up to 8:19:59. Then the machine is available from 8:20 AM to 5 PM.
- On the company’s work schedule, 03.07.2020 is available for scheduling operations from 8 AM to 5 PM.
- Determine that the production order start date is 03.07.2020.
- Calculate how many times an operation must be performed:
- For the Wood sharpening operation , consider that 8 stools are ordered. For 8 stools, 32 legs are required. The stool leg BOM says that 1 Wood sharpening operation produces 5 legs. Then this operation must be performed 7 times.
- For the Stool assembling operation, consider that 8 stools are ordered. The stool BOM says that 1 Stool assembling operation produces 1 stool. Then this operation must be performed 8 times.
- Put the Wood sharpening operation on the production schedule. Apply the following:
- The operation start time is 8:20 AM.
- The operation Standard time is 10 min. In this example, it takes 2 Planning intervals of 5 min.
- The operation must be performed 7 times. Then it takes 14 Planning intervals.
Date
03.07.2020
Planning intervals
8:00:00
8:04:59
8:05:00
8:09:59
8:10:00
8:14:59
8:15:00
8:19:59
8:20:00
8:24:59
12
planning intervals9:25:00
9:29:59
9:30:00
9:34:59
Wood sharpening machine
PO1WS
PO1WS
PO1WS
PO1WS
PO2WS
PO2WS
PO2WS
Company
PO1SA
where:
PO1WS - Production order 01, Wood sharpening operation
PO1SA - Production order 01, Stool assembly operation
PO2WS - Production order 02, Wood sharpening operation
- Put the Stool assembling operation on the production schedule. Apply the following:
- The operation start date is 03.07.2020.
- The operation start time is 9:30. For production order 02, it is the end time of the Wood sharpening operations.
- A work center type is not assigned to the Stool assembling operation. Then assume that the company has unlimited capacity for performing this operation within Standard time. Then it takes 1 min to perform 7 operations.
Date
03.07.2020
Planning intervals
8:00:00
8:04:59
8:05:00
8:09:59
8:10:00
8:14:59
8:15:00
8:19:59
8:20:00
8:24:59
12 planning intervals
9:25:00
9:29:59
9:30:00
9:34:59
Wood sharpening machine
PO1WS
PO1WS
PO1WS
PO1WS
PO2WS
PO2WS
PO2WS
Company
PO1SA
PO2SA
where:
PO1WS - Production order 01, Wood sharpening operation
PO1SA - Production order 01, Stool assembly operation
PO2WS - Production order 02, Wood sharpening operation
PO2SA - Production order 02, Stool assembly operation
Both production orders in the queue are scheduled.