When do you release production orders and why?

We use PCS projects with estimated cost and release production orders quite a long time (around 7 days) before production actually starts, this causes issues if the estimated BOMs change.

How do you do it?

Ideally the production order should be released on the day on which the actual production is to be carried out. Further the estimated materials can be changed even after release of the production order through Maintain estimated materials session.

Thanks, I realise that I can change the estimated materials after the production order is released.

Buy why should I leave it as late as possible?

I would say you would release as close to manufacture as possible as then you know it is based on the latest routing & BOM. Also if the order gets amended for quantity or date you don't have to reprint all the paperwork.

There is also a practical reason to release orders as close to their planned start time as possible. Many times, if a work center is given multiple jobs, the operator(s) will 'cherry pick' the easiest. This is especially true if workers are on an incentive plan.

Additionally, if you follow TOC methodology, and have the ability to use alternate work centers in an attempt to break constraints, you don't want to allocate or move materials until you are sure that the correct work center is performing the work.

I had a professer who said something like..."if you let all the cows out into the field...they're going to eat the grass". He was talking about this very issue.

Following on from hexagenia's point, it would also avoid the issue of inventory being created when it may not be required yet. If the production dept. can't see the order, they can't make it.

And last but not least, depending on the costing parameter, the estimated cost are frozen. Thus when changing BOM or Routing after release but before real production the cost will change, then valuation cost will be calculated at the actual site instead of the estimated site. In most situations this is not wanted.
Resulting in releasing the order at latest posible moment.

Even if you release a production order a week before the start date it can still be cancelled and a new planned order generated and released, which overcomes any issues with the latest Bom / Routing. It's more about how you comunicate the change in issue between engineers / production.

From technical point of view, you are correct as long as no costs are booked to finance for example for warehouse transfers against estimated materials to the shopfloor on the first operation.
From functional point of view you want to release as late as possible as operators have the habbit to pick the easiest orders first or plan their own workcenter as suffisient as possible, not looking at the other department that can run into trouble of this local action.
This will result in delivering components produced to feed other workcenters to late in time!!! and will disrupt the planning for the other workcenters unwanted.
The company goal to have smoot operation true the whole company is not met due to the fact of releasing too much orders at one time!!

From technical point of view, you are correct as long as no costs are booked to finance for example for warehouse transfers against estimated materials to the shopfloor on the first operation.
From functional point of view you want to release as late as possible as operators have the habbit to pick the easiest orders first or plan their own workcenter as suffisient as possible, not looking at the other department that can run into trouble of this local action.
This will result in delivering components produced to feed other workcenters to late in time!!! and will disrupt the planning for the other workcenters unwanted.
The company goal to have smoot operation true the whole company is not met due to the fact of releasing too much orders at one time!!

From technical point of view, you are correct as long as no costs are booked to finance for example for warehouse transfers against estimated materials to the shopfloor on the first operation.
From functional point of view you want to release as late as possible as operators have the habbit to pick the easiest orders first or plan their own workcenter as suffisient as possible, not looking at the other department that can run into trouble of this local action.
This will result in delivering components produced to feed other workcenters to late in time!!! and will disrupt the planning for the other workcenters unwanted.
The company goal to have smoot operation true the whole company is not met due to the fact of releasing too much orders at one time!!

I would agree that it is not ideal but it can be done. We developed a work to list which determines the work order from the planned requirement dates and is sorted by work centre. therefore people are told by the sytem what they should be working on, so they don't have the option to cherry pick.