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Materials
Requirement Planning |
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-Information
Required |
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To complete the MRP analysis, problem specific
data is required. This is entered on the MRP worksheet. The table
below, called the master production schedule (MPS), shows the
production requirements for the three products for the next 12
periods, weeks, in this case. The demands for the finished goods
may be determined from actual orders or through forecasts. |
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The table below shows data required for
each part. The first column is the part number or name. The second
column is the current on hand inventory. The third column describes
the inventory replenishment policy, called the lot sizing policy.
The column labeled Policy Parameter shows the parameter for the
lot sizing policy. Its meaning is different for the various policies.
No parameter is required for LFL or WW. The Lead Time is the time
required between when an order for the part is released to the
shop and when it will be received. The Cost Added is the the direct
cost expended to purchase or manufacture one unit of the part.
Only the raw materials have costs for the example. The last column
designates the setup cost for a production run for the part. |
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For each part, we must also specify the
scheduled receipts for each period in the time horizon. These
indicate the amounts that will arrive due to orders placed at
an earlier time. For the example we assume that there are no
scheduled receipts.
The following lot sizing policies are allowed. |
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Abbreviation |
Policy |
Definition |
| LFL |
Lot for lot |
Deliver in each period the amount
required |
| FOP |
Fixed order period |
When a delivery is required deliver
the amount required for the next m periods, where m is
a parameter of the policy. |
| FOQ |
Fixed order quantity |
When a delivery is required deliver
the amount Q, where Q is a parameter of the policy. If
the current requirement exceeds Q deliver the amount of
the current requirement. |
| WW |
Wagner-Whiten |
Determine the optimum production
schedule that minimizes the sum of the setup plus inventory
costs for the time horizon. |
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