Operation longer than any available working hours in workstation Assembly

[amitsaxena01]

As per the discussion based on https://discuss.erpnext.com/t/v5-logic-around-production-order-operations-workstation/5818, it seems that if the time taken for the operation is longer than 1 day then it has to be broken down into smaller operations. This seems to be counter intuitive to the real world cases. Generally in manufacturing, if an operation on the workstation is in process and the operation is not completed within a day, then it can be spilled over next day. If the process is atomic and cannot be spilled over for next day, then over time is applied so that the work is completed. I believe thats how erp process should work. The problem with current system is :

1. If the planning will be done in one clear chunk, then there will a lot of chunks where the workstations will be free leading to loss.
2. The time to produce the item specially if the quantity is more will increase exponentially. It will take less effective cost to make a single piece than in bulk. Generally bulk orders cost less.

[umairsy]

If the planning will be done in one clear chunk, then there will a lot of chunks where the workstations will be free leading to loss.

Have you defined working hours in the Workstations? If yes, then it will ask you to split the operation, so that timeslot can be created for the same day itself.

The time to produce the item specially if the quantity is more will increase exponentially. It will take less effective cost to make a single piece than in bulk. Generally bulk orders cost less.

The value of FG item is calculated based on value of raw-material + operations. If purchased items values are less, then value of the FG item will reduce automatically. For now, it doesn't take into account the operations cost.

[amitsaxena01]

@umairsy Thanks for your reply.

Have you defined working hours in the Workstations? If yes, then it will ask you to split the operation, so that timeslot can be created for the same day itself.

There are operations that cannot be broken down into smaller operations. Let me take an example. Say there is an aluminium casting workstation that can produce 1 piece per 10 second. The setup time for the die in the workstation is 3 hours and take down time for the die from the workstation 2 hours. There is an order for 10000 pieces which is a normal lot. The time required on the workstation in :

3 + 10000*10/3600+2 = 32.77 hrs.

if the workstation works for 8 hrs that it will take slightly more than 4 days to complete the work. Even if I set the working hours as 24 hrs I will not be able to fit it in. I feel breaking it down into smaller operations is neither possible nor practical. Moreover even if we do it will still not be helpful. Another way to do it is to break it down into smaller lots to fit it in 8 hrs. The problem with that approach is how does that system know that we need the setup and takedown or not. If my workstation is working continuously on one product then there should not be setup and takedown operation. However if out of 10000 I have to make only 100 in the first lot and rest after a few days after the lot gets approved then there will be two setup and takedown operations. Hence ideally when ever we start a lot there is a setup and takedown operations. You can also imagine how difficult it will be for the supervisor to plan if he has to allot a resource daily. And the kind of problem that it make lead to if somebody else allots that resource before he could on the second day. It will be a race condition. Taking another example if you have to book the conference hall for the ERPNext conference for two days, do you book it for two days or for each talk?

The value of FG item is calculated based on value of raw-material + operations. If purchased items values are less, then value of the FG item will reduce automatically. For now, it doesn't take into account the operations cost.

I am sorry but I think you miss understood what I am saying. What I was referring to was if we have to have a clean chunk of time then I may not be able to start the work even if have a time available on the workstation. This will result in wastage leading to increase of cost