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Lead time scheduling problem

Former Member
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Dear colleagues:

Problem statement: Although we choose to perform leadtime scheduling in MRP, the system still reads inhouse production time, to determine direction of scheduling.

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The specific symptoms & MRP behavior are as follows

1) If the duration of inhouse production time is not long enough, such that the start date of the production order falls in to future from Today's date, then the system performs BACKWARD scheduling using the routing

2) If the duration of inhouse production time is long enough, such that the start date of the production order falls in past from Today's date, then the sytem performs FOWARD scheduling using the routing.

The business impact of this is causing several of our planned orders to be unncessarily 'Rescheduled in' or moved much earlier than requirement dates.

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At the outset, the above symptoms may appear that this is standard functionality but upon close examination, there seems to be quirks to the way lead time scheduling in MRP works. Let me explain further.

The master data and configuration that we are using is as follows.

1. Start date in Past - Disallowed in Configuration

2. Inhouse production time ~ 80 days

3. Routing ~ 2 days

4. Reduction strategies used - YES

We recognize that 2 & 3 above are not in sync and it is not a common best practice. The client uses long lead times in material master to accommodate the total replenishment time of the product ahead of the routing creation.

Here are the questions -

1. Does MRP always perform basic scheduling as a first step, even if we choose lead time scheduling?

Is this a standard logic?

2. How do we force MRP to look at ONLY routings and not to look at INHOUSE PRODUCTION TIME

for determining the direction of scheduling when we perform Lead time scheduling?

Thanks and regards,

PKV

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Answers (2)

Answers (2)

rupesh_brahmankar3
Active Contributor
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Dear,

If we do the lead time scheduling system always take time from routing the consider your schedule margin key to define basic date.

By scheduling routings, you can better control the lead times.

1. scheduling in routing (CA02 ) as :

Call up the operation overview for the routing.

2. Choose Extras-- Scheduling -- Schedule.

You reach the Scheduling dialog box.

3. Maintain the data on the dialog box. The system proposes Backward scheduling for the scheduling type.

4. Choose Continue.

You reach the Enter overview variant dialog box.

5. Enter the overview variant you want to use to display the scheduling results. Choose Continue.

The routing is scheduled. You reach the Schedule Overview screen containing the scheduling data.

6. After the scheduling run has been carried out, click on scheduling Result-- update material master

You use this function to update material master. Go to the CA96 and update material master.

After that run MRP (MD02) with planning mode-3 deleted and recreated and checks your result.

Also OPU5 for your plant, order type & scheduler. Adjust dates - select Adjust basic dates, dep req to opn dates.

To find out basic dates this is the formula given below:

For Backward scheduling:

Opening period+ Inhouse prod time + GR processing time

For Forward scheduling:

Inhouse prod time + GR processing time

Hope it will sove your problem

Regards,

R. Brahmankar

Former Member
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Hi,

1. Does MRP always perform basic scheduling as a first step, even if we choose lead time scheduling? Is this a standard logic?

A: No, if you select basic date scheduling, system will do that only. It won't do lead time scheduling. Eventhough it is doing lead time scheduling means in OPU5- define scheduling parameters for planned orders, if mark in scheduling field system will do lead time scheduling only.

2. How do we force MRP to look at ONLY routings and not to look at INHOUSE PRODUCTION TIME

for determining the direction of scheduling when we perform Lead time scheduling?

A: Try this setting explained below. In OPU5 select your plant, order type & scheduler. Adjust dates - select Adjust basic dates, dep req to opn dates.

It means that system will consider inhouse prod time and basic dates will schedule according to that. But with this settings, these basic dates will change to scheduled dates. So planned order will not fall in past dates, system will not reschedule by forward scheduling.

Note: Do above settings in planned order ie OPU5, because these basic dates will go to production order.

Regards,

Dharma