 # Microsoft Dynamics NAV – Two features for reducing manufacturing lead-time

Posted By When you set up Microsoft Dynamics NAV production routing, you may have a question regarding Send-Ahead Quantity and Concurrent Capacities, specifically, what is the purpose of these two fields in the production routing line? (Figure 1) The Send-Ahead Quantity specifies a portion of the lot or batch, sent to a subsequent operation before completion of the current operation for all units of the lot. The purpose of the Send-Ahead Quantity is to reduce the manufacturing lead-time. The next operation is started when the Send-Ahead Quantity is produced.

NAV uses the following formula to calculate the time of the Send-Ahead Quantity:

Start of the next operation = setup time + send ahead quantity * run time + wait time + move time + queue time.

Example:

Produce 100 items on a production order.

If it does not set up a Send-Ahead Quantity, the next operation begins when these 100 items have been finished in the actual operation.

Start of the next operation = 30 minutes setup time + (100 items * 15 minutes run time) + 5 minutes wait time.

As a result, the next operation can be started 1535 minutes after the actual operation starts (Figure 2). If 10 items have been determined as a Send-Ahead Quantity, the next operation can begin when these 10 items have been finished in the operation.

Start of the next operation = 30 minutes setup time + (10 items * 15 minutes run time) + 5 minutes wait time.

As a result, the next operation can be started 185 minutes after the actual operation starts (Figure 3). Concurrent Capacity indicates how many machines or persons are working at the same time. If you enter 5, for example, this means that this work centre will take 1/5 of the time compared to a work centre with the capacity of 1.

Dynamics NAV uses the following formula to calculate the time of the Concurrent Capacity:

Start of the next operation = setup time + quantity*run time*1/concurrent capacity + wait time + move time + queue time.

If the Concurrent Capacity is 1

Start of the next operation = 30 minutes setup time + (100 items * 15 minutes run time) + 5 minutes wait time.

As a result, the next operation can be started 1535 minutes after the actual operation starts (Figure 4). If the Concurrent Capacity is 5

Start of the next operation = 30 minutes setup time + (100 items * 15 minutes run time/5) + 5 minutes wait time.

As a result, the next operation can be started 335 minutes after the actual operation starts (Figure 5).  