Using Lot Sizes with MRP and APS

You can set up items to be produced in minimum and maximum "lot" quantities in a production run. The system considers the maximum lot size parameter (Order Maximum) before the minimum (Order Minimum) and multiple (Order Multiple) lot size parameters. All parameters described in this topic are located on the Planning tab on the Items or Multi-Site Items form.

The fields described in this topic apply only to MRP and APS planning. You define the lot size used for item costing in the Lot Size field.

Using Order Maximum

Note:  This section applies to APS; MRP does not support Order Maximum.

Applying an Order Maximum value to an item allows you to load a demand across many resources to improve efficiency and speed. This parameter applies only to manufactured end items (that is, parent items but not their components). When planning a demand for an end item, the system breaks the order quantity into multiple loads of the size specified in the Order Maximum parameter. For example, if Order Maximum is 50, and the order quantity is 100, the system plans two loads, each with a quantity of 50. The system treats each load as a separate demand. For each load, at each level of the bill of material, the system considers planned supplies, inventory, scrap/shrinkage, and Order Minimum/Order Multiple.

The last load will contain the remainder of the original quantity. For example, if the Order Maximum value is 1000, and the order is for a quantity of 100,002, the system plans the order as if it were for 99 separate loads of 1000 items each and one load of 1002 items.

If you are not using planned order consolidation, the system creates a single planned order for each load created by the Order Maximum function. Also, if you view the demand detail on the Demand Detail Chart APS form, you will see the multiple loads. You may also view the individual loads on the Resource/Resource Group Gantt Chart APS form.

Note: 

In some situations, if the parent item uses the Order Maximum parameter and its component items use the Order Minimum parameter, the system may generate unnecessary, excess planned supplies. If you encounter this situation, consider enabling the Manufactured Supply Switching parameter on the Planning Parameters form and on the Items record for the parent item.

Using Order Minimum/Multiple

The Order Minimum and Order Multiple parameters allow you to produce items in a minimum lot size and in a specific multiple. Minimum and multiple are lot sizes for manufactured items and are the supply order sizes recommended for purchased items. If the demand quantity is less than the Order Minimum, the system creates the planned order for the order minimum value. If the Order Minimum value is less than the demand quantity, the system adds Order Multiples to the Order Minimum value until the planned order quantity is greater than or equal to the demand quantity. A value of 0 indicates that the system does not enforce minimum or multiple. The table below shows some examples.

Note: If you are using MRP, the PLN quantity is at least the Order Minimum quantity, and is rounded up so that the PLN quantity will be a multiple of the Order Multiple quantity.
Order Min. Order Mult. Demand Qty APS PLN Qty MRP PLN Qty
1 50 1 1 50
3 50 1 3 50
3 50 10 53 50
1 50 50 51 50
50 50 50 50 50
50 50 51 100 100
0 50 51 100 100
0 50 10 50 50
10 0 8 10 10
Note:  Other demands can use any leftover quantities created by Order Minimum/Order Multiple calculations.

Realize that the primary purpose of APS is to develop a plan for every order, building or acquiring only what is needed when it is needed (providing flexibility to react to customer changes). Using Order Minimum and Order Multiple when planning in APS mode may increase lead times, inventory levels, and commit the shop floor to build quantities that may not be needed.

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