Planning worksheet creates over capacity and runtime errors

andySOLTEC

I'm using the Planning Worksheet to plan production orders. Despite having capacity constrained resources, the resulting production orders are exceeding the available capacity and providing erroneous durations of routing operations. Is there a known issue with this, or can anyone help me figure out what is causing these results? I originally encountered this in a clients setup, though I have since confirmed this also occurs in an un-modified Cronus db.

I am using a serial routing which uses two machine centres belonging to the same work centre as follows: -
W/C - BAY01
M/C - BAY01-M01
M/C - BAY01-M02

The client operates 24 hours a day Mon 6am to Sat 6am on a 3 shift (8 hour) pattern, with the working day starting at 14:00. As a result the second shift is split into two as it crosses the midnight barrier, 2 hours then 6.

The routing is as follows: -
100 - START
200 - BAY01-M01 - 60mins (Capacity constrained to 100% capacity 1)
210 - BAY01-M02 - 30mins (Capacity constrained to 100% capacity 1)
300 - LABOUR
400 - OUTPUT (Routing Link, all components in stock)

Based a sales order for 4 different items (qty 10)all using this same routing, I end up with 4 production orders. When I investigate the start and end dates on the routing operations I find that after the first two orders, the duration of the operations begins to extend beyond a simple multiplication of quantity x runtime.

Hopefully the above will help any reader to understand the issue, I know these things can be setup dependant, however I've tried to provide everything I did for the Cronus test.

Thanks
Andy

NAV 2009 R2 RTC- Build 32012 & 34869 (Tested on both)

andySOLTEC

This still occurs if the second operation 210 is a machine centre belonging to a different work centre

andySOLTEC

After further testing I can add more information to this. NAV is correctly calculating the amount of capacity needed, however as you can see in the second image, it is leaving gaps between the capacity entries and this is pushing back the end time. In this example there is an hour gap between the third and fourth entries.

The first image shows the machine load, where you can see that a single operation has been split into multiple capacity entries which have allowed the partial entries to intermingle. You can see the aprox 1 hour entry that has pushed back the completion of production order 101022 show in the second image.

Can anyone suggest why NAV is splitting this capacity requirement?