MRP starting Shop Orders on Non Shop Calendars Days with Variable Lead

[pticarl]

Macola v7.6.100a - SQL

We are using Variable Lead Time to calculate shop order start dates in MRP. Until recently we have not had our standard lot sizes sufficiently large enough to meet the integer datatype of the field. I have changed 3 parts to a larger standard lot size which fixes the problem. MRP does now take into account the variable production time required by one of our processes.

Unfortunately, the orders in MRP are now scheduled to start on a Sunday (which is not a work day on our Shop Calendar). When the shop order is computer generated and passed to SFC, the start date is moved back 2 days and now starts on a Friday.

I should note that all of our other parts still schedule correctly on work days.

Any idea why this is so?

Thank you,
Carl

Even with variable scheduling MRP should not be scheduling on non-production days should it?

 

[TLeaders]

I would suggest two things to check.
First: The Shop calendar that MRP uses is the Default shop calendar that is set up on global manufacturing control file (Manufacturing Setup). This may not be the same calendar that SFC is using to schedule the shop orders. Check that calendar for “Include In MRP – Yes” flag. In answer to your question Yes MRP will schedule on “closed” days.
Second: Is more of a question. Are the Sunday dates on new orders (CP) created by MRP or orders that have been copied in from SFC. If the orders are from SFC, MRP will honor the dates even if the start date on an order is on a closed MRP date. If the problem is on new orders it is most likely to be the default calendar.

Remember that the shop calendars have two functions. 1-labor scheduling using the open/closed flags (SFC,CRP) and 2-Material scheduling using the Include in MRP flag(MRP).

Good Luck

 

[pticarl]

Tleaders,

The problem is on New CP orders created by MRP. When we generate the orders and move them into SFC for some modifcations the dates are set correctly by the SFC calendar. I will look into the differing calendars issues since it looks like that is the main issue.

Thanks for responding

 

[pticarl]

Update,

I have checked the calendars and both modules are using the same one, with Sunday flagged as "Include in MRP - NO". I am not sure what the problem is, since a re-reading of the help files seems to indicate that Macola shouldn't be scheduling this way.
I will keep looking into it and if I come to a resolution I will share it with everyone. For our purposes it really isn't a deal breaker by having MRP schedule start days that are not production days, as long as SFC continues to move the days correctly. A fair percentage of our parts have variable lead times and it will be nice to get MRP and SFC to schedule more closely. We can live with a little error there if we have too.

Thanks