Just-In-Time (JIT) Scheduling

Key Concepts

Just-In-Time (JIT) Scheduling is used to accommodate last-minute changes to orders and prevent damage or spoilage of inventory by preventing jobs from starting too early. JIT means that your operations start with just enough time to be completed by the needed date. An operation must begin by the JIT Start Date, or else the job will be late.

Just-In-Time Scheduling is centered on minimizing waste by controlling the delivery of raw materials as needed, which minimizes the indirect costs of work in progress (WIP) and materials storage. In addition, JIT relies heavily on having stable and reliable suppliers as delays in material availability can disrupt the entire production flow. 

JIT Scheduling Options

The operation's JIT start date can be found under the Operation tab of the Jobs dialog, which can be accessed by double-clicking on an operation in the Gantt.

For example, if an operation has a working content of one hour, the JIT start date will be set to one hour before the operation's need date.


JIT Release Rules

Release rules can be applied to allow an activity to schedule before its JIT start date. Under the Optimize drop-down menu, select whether you wish to use JIT with Global Headstart or JIT with Resource Headstart, and specify the number of JIT Slack days to apply. JIT Slack represents the maximum number of days before the JIT start date that the activity can be scheduled. Slack days provide some additional time between the end date of the operation and its needed date to accommodate last-minute variations.

For example, if the release rule is set to JIT with Global Headstart and 2 JIT Slack is specified, the operation will start 2 days before its JIT Start Date.


If you wish to set different slack days for different resources, you can select the JIT with the Resource Headstart release rule from the Optimize button. Then, double-click on each resource to open the Resource dialog and select the Headstart Span to use under the Optimization tab. Higher Headstart values will allow the activity to schedule earlier in time, while lower Headstart values will allow for more Just-In-Time scheduling.