Why is it difficult to operate production planning in the system?
The first reason why production planning is said to be the most difficult field in the operation of business systems is because it is difficult to see which requirements are linked to the generated manufacturing orders due to the influence of "manufacturing lot size" and "lead time shifting" in developing requirements based on the requirements.
Secondly, when there are two types of requirements, unofficially indicated and confirmed orders, which are the source data for MRP calculation, it is difficult to replace them successfully without duplication when the latest data is sent from the customer.
- The information that was given to me as an unofficial notice last time has been changed to a final order this time.
- This final order includes the previous final order dubbed as a final order.
The system must take into account the overlapping final orders and unofficial orders from the customer to avoid double registration in the system.
In the above table of expected orders, if we receive the latest data for a total of 10 days, i.e. 4 days of confirmed orders (2nd row) and 6 days of unofficial orders (1st row), and if we assume that the manufacturing instructions are for 3 days (3rd row), then the order backlog at the beginning of the month is 4 days - 3 days = 1 day, and the unofficially announced 6 days plus 7 days will be subject to MRP. It becomes (blue box).
In the case where we receive the latest data for 10 days, which includes 4 days of confirmed orders (line 5) and 6 days of unofficial orders (line 4), we have 3 days of manufacturing instructions (line 6), so the order backlog is 4 days - 3 days = 1 day, plus 6 days of unofficial orders, which is 7 days of MRP (green box) .
In addition, if we receive the latest data for a total of 10 days, including 4 days of confirmed orders (line 8) and 6 days of unofficial orders (line 7), after 3 days, we have 3 days of manufacturing instructions (line 9), so the order backlog is 4 days - 3 days = 1 day, plus 6 days of unofficial orders, which is 7 days of MRP (red box).
Fixed orders are additional and unofficial orders are based on a washout.
To replace unofficial orders with fixed orders, only new fixed orders are added and unofficial orders are replaced.
It is necessary to subtract from the order backlog (i.e., orders that have already been registered and are not in stock) the manufacturing balance that has been fixed as a result of issuing manufacturing orders based on the most recent manufacturing orders developed from the requirement.
- The first and most recent data finalized orders (1-4 days) and unofficial orders (5-10 days) are captured.
- Since final orders (1 to 4 days) are registered for orders but manufacturing instructions (1 to 3 days) are already in place, the remaining orders (4 days) plus unofficial orders (5 to 10 days) are subject to MRP.
- Incorporate the second most recent data finalized orders (4-7 days) and unofficial orders (8-13 days).
- Of the firm orders (4-7 days), the firm orders (5-7 days) that do not overlap with the order no. registered in the first round of firm orders (4-7 days) are registered as orders, but since there is already a manufacturing order (4-6 days), the order backlog (7 days) plus unofficial orders (8-13 days) are subject to MRP.
- Incorporate the third and most recent data finalized orders (7-10 days) and unofficial orders (11-16 days).
- Of the confirmed orders (7 to 10 days), the first and second confirmed orders (8 to 10 days) that do not overlap with the order no. already registered (8 to 10 days) are registered as orders, but since there are already manufacturing orders (7 to 9 days), the order backlog (10 days) plus unofficial orders (11 to 16 days) are subject to MRP.
When confirmed orders and unofficial orders are mixed in MRP requirements, only new confirmed orders are added and all unofficial orders are replaced to prevent the requirement duplication.