Forum Discussion
Link Procurement Tasks to deliver Just-In-Time without using up slack?
Brett --
I will be a bit of a "contrarion" on this situation. In your example, the Predecessor (aka Driving task) is the Material Delivered task. What I mean by this is that the Start date of the Material Delivered task determines the Finish date of the Order Materials task. In a situation like this, in spite of the fact that some people recommend against this, I would recommend you use a Start to Finish dependency (that weird "backwards" dependency) with the Material Delivered task as the Predecessor and the Order Materials task as the Successor.
Yes, I know this this seems to be backwards scheduling, and yes, I know that some companies FORBID their PMs from using Start to Finish dependencies, but in your situation, I think this dependency accomplishes exactly what you want. Using this dependency, you can determine the Start date of the Order Materials task, based on its Duration, and on the Start date of the Material Delivered task. In the end, I am a pragmatist, breaking all the "rules" to give you a solution that actually works in your situation. Hope this "contrarion" solution helps. 😁
Dale,
Thank you for the response. The Start to Finish seems to be the cleanest, quickest way to show "order by" dates in the schedule. The drawback seems to be that, if a material delivery is delayed, this won't show the impact to subsequent tasks, correct? For example, if you are halfway thru a 6-week material lead time, you should be receiving material in 3 weeks. But you find out you won't get the material for 4 weeks (one week later than scheduled) how do you show this delay in your schedule? With Start to Finish relationship type, the schedule will say the subsequent task can Start before Material Delivery is finished.
Thank you
Brett --
Good question. In a situation like this, I would first increase the Duration of the Order Material task by one week, and then I would apply a SNET constraint on the Material Delivery task that shows the new delivery date.
When you set the initial Start to Finish task dependency, you could manage the risk for the possibility of the order taking longer by adding Lead time (Negative lag) to the dependency, such as by adding 1 week of Lead time. I realize this is not a perfect solution, then I hope this helps.
