Setup time, when an operation has to restart

I have just realised that Navision only schedules Setup Time once, even if the operation is interrupted and has to restart later. I think this is a problem for everyone, I’m posting this to make people aware. As always, any solutions are welcome. Here is a detailed example. Suppose, for simplicity, that Item A has a routing with just one operation, Setup Time = 80 minutes, Run Time = 10 minutes. Item B also has a routing with just one operation, Setup Time = 80 minutes, Run Time = 10 minutes. Items A and B use the same Machine Center, but it needs to be retooled when switching over from A to B or B to A (this is the Setup Time of 80 minutes). The Machine Center is available for 8-hours (480 minutes) a day. Now I create Sales Orders as follows: 40 Item A, Receipt Date 23 / 03 88 Item B, Receipt Date 24 / 03 Item A needs 80 + (40x10) = 480 minutes, so it will be scheduled to run on 22/03. Item B needs 80 + (88x10) = 960 minutes, so it could be finished in two days. In fact, Navision schedules it to start on 21/03 and 23/03. But this means there is no Setup Time on 23/03, even though the Machine Center has to switch from producing Item A to Item B.

Hi Alastair You talk about operations being interrupted, so you get half way through making A, then have a rush job in B and it therefore does not take into account the set-up time of A when it restarts. The routing is a plan, the actuals are recorded, so you would capture a variance here. However your example does not discuss this - are you saying the setup of the second job at a work centre does not take into consideration the set-up time? What version are you running? Running this through with differnet dates and settings I can see that the set-up time of Item B is included in the start-end time calculation in V4.0.

Hi Steven, I tried this in version 4.0. I don’t understand when you say:

quote:

The routing is a plan, the actuals are recorded, so you would capture a variance here.

What I meant was that the second job includes 180 minutes of Setup Time, but only on 22/03. Since the Machine Center was working on a different item on 23/03, it should include another 180 minutes of Setup Time on 24/03. Would you agree? Alastair

Hi Alastair My reference is to the scenario I thought you had - you start A, stop A start B and restart A. Navision will not be able to plan for 2 set-up times of the same operation - this variance is captured when you report output and the actual set-up time. Still I am getting confuised!! You have 2 items, each with different routings, but through the same work centre. Navision will plan to run as follows: item A - setup time, item A run time, then item B setup time and item b run time. Are you saying it puts all 160 minutes of setup time first, then the run time for A then the run time for B?

Hi Steven, the scenario is as you described below (though the actual name for B is alphabetically before the actual name of A, which is why Navision first looks for a timeslot for B, and then looks for timeslot(s) for A):

quote:

you start A, stop A start B and restart A.

Navision did not do what you described here:

quote:

Navision will plan to run as follows: item A - setup time, item A run time, then item B setup time and item b run time. Are you saying it puts all 160 minutes of setup time first, then the run time for A then the run time for B?

What it did was setup A, 300 mins runtime A, setup B, runtime B, 480 mins runtime A. It should have included another setup time for A before the 480 mins run time, as the machine center will need to switch over from B. But, as you said, it didn’t:

quote:

Navision will not be able to plan for 2 set-up times of the same operation

I see this as a bug, as it will play havoc with actual schedules. If the plan involves hundreds of different items, there will probably be several orders that are interrupted by other orders, and the planner will have to add the setup time for each one. There are other complications too - e.g. if an order is split into blocks of time, any block that is shorter than the setup time has to be discarded. In a busy planning environment, all of this could make quite a difference.

Hi Alastair I suggest you log it if you feel it is a bug, but do not hold your breath - Microsoft will “probably” tell you that the system is not designed to handle this scenario. It is designed for an operation to be completed from the perspective of the schedule. If you break this, you need to enter these details into the order, for example manually create a new routing line for that order to reflect the set-up time. Remeber also that Navision is the lighter option in manufacturing solutions - maybe ask in the Axapta forum, which has greater manufacturing options (I believe), if Axapta handles this scenario. Microsoft may infact tell you your solution is Axapta, not Navision.

Hi, Navision can handle your senario (I belive)! … but you don’t have multiple setup and run time on the same line. … but you will need to restructure your routings and may need to configure phantom routings. regards, Henrik

Henrik, that sounds interesting. Could you give more details about how you would set up the routings? Thanks, Alastair