Forum Discussion
Link Procurement Tasks to deliver Just-In-Time without using up slack?
In MS Project, what is the recommended way to link procurement tasks such that the duration is the lead time of the material, the task "finishes" (material delivers) when needed by the subsequent task, and we know when to "start" the task (order material)?
If we link the procurement task to the subsequent task with Finish-Start and As Late As Possible, and the subsequent task has total slack (float), this will push the subsequent task back in the schedule and use up its float. If we use Start-Finish, the dates line up but the procurement task doesn't drive the subsequent task as it should (if procurement gets behind schedule, it won't push the subsequent task). If we use the "deadline" feature, we are still tying ourselves to a date rather than letting the schedule dynamically determine when we need to order materials.
What is the correct way in MS Project to schedule the ordering of materials so that delivery occurs just-in-time as determined by the scheduled start of the subsequent task?
1 Reply
Every task in a critical path network has an earliest start, earliest finish, latest start, latest finish.
The early dates are the ones normally displayed in the entry table and in the Gantt chart views. That's because those are of most immediate interests because we want to know first of all how soon can tasks start, and that's also why we need the predecessors as a priority, especially the FS0 one that every task should have.
However, that's just what it does out of the box. You can easily make a custom view to display bars for the latest dates (format, bar styles), and of course they are all there in the schedule table, along with the free float and the total float.
Stick to good ol' reliable CPM. The most important feature of the method is that we schedule forwards, not backwards. If you are toying with ALAP constraints and weird links, like SF and positive and negative lag, to model just- in-time or some other management fad, you can end up doing a lot of gymnastics which are unnecessary and somewhat futile anyway.
Keep it simple. Plan to place an order for parts or materials or something asap. There is a lead time, say 60 days. It has a FS0 successor which is 100 days out. There is 40 days of free float, so you can choose any day between day 1 and day 40 to place the order.
Any help?
