Language:


Order Dates in Purchase Order Plans

When you create a Purchase Order Plan, each Item will be given a Needed Date. In the case of a Purchase Order Plan that you create from a Sales Forecast (i.e. using the 'Create Purchase Order Plan' Maintenance function), the Needed Date for each Item will be the first day of the Sales Forecast period (i.e. the first day of a week or month), so that the Items will be in stock ready to sell during the week or month. Each Item will also be given an Order Date. The Order Date is the date when a Purchase Order should be issued in order for the Item to arrive on the Needed Date. This section describes how Order Dates will be calculated.

The calculation of the Order Date in a Purchase Order Plan row usually requires there to be a Default Purchase Item for the Item in question (but if you have specified a Supplier in the header of a Purchase Order Plan or in an individual row, the Purchase Item does not have to be marked as Default). If you have specified a Delivery Days (i.e. the number of days needed for the Supplier to deliver the Item) in the Purchase Item, this figure will be copied to the Del. Days field in the Purchase Order Plan row and will be used to calculate the Order Date (Order Date = Needed Date - Del. Days).

A Purchase Order Plan created by the 'Create Purchase Order Plan' Maintenance function may contain many Items that need to be ordered within a few days of each other (usually these will be components required by Production Plans). The result can be many Purchase Orders, some of which only contain a few Items.

If you would like these Items to be amalgamated in a single Purchase Order (providing they will be ordered from the same Supplier), you can specify a number of Buffer Days in the Forecast Settings setting. Items to be ordered within that number of days will be given the same Order Date in the Purchase Order Plan.

If you specify a number of Buffer Days, the 'Create Purchase Order Plan' Maintenance function will sort the Items to be ordered by Order Date. It will then add the number of Buffer Days to the earliest Order Date and find the other Items that need to be ordered within that number of Buffer Days. These Items will all be given the same Order Date. It will then add the number of Buffer Days to the earliest Order Date in the remaining Items and repeat the process.

For example, a Purchase Order Plan will contain Items with the following Order Dates if the number of Buffer Days is 0:

13 October
16 October
17 October
19 October
20 October
This Purchase Order Plan will result in five Purchase Orders.

If you have set the number of Buffer Days to 5, the Order Dates in the Purchase Order Plan will be set as follows:

13 October
13 October (original date 16 October is within five days of 13 October)
13 October (original date 16 October is within five days of 13 October)
19 October (19 October is not within five days of 13 October, so this date isn't changed)
19 October (original date 20 October is within five days of 19 October)
As a result, the Purchase Order Plan will result in two Purchase Orders (providing the Items can be ordered from the same Supplier).

If you have set the number of Buffer Days to 6, the Order Dates in the Purchase Order Plan will be set as follows:

13 October
13 October
13 October
13 October
20 October
Again, the Purchase Order Plan will result in two Purchase Orders.

---

The Calculation Formula in the MRP module:

Go back to: