Question

One unit of A is made of two units of B and one unit of C. B is made of three units of D and one unit of F. C is composed of three units of B, one unit of D, and four units of E. D is made of one unit of E. Item C has a lead time of one week; Items A, B, E, and F have two-week lead times; and Item D has a lead time of three weeks. Lot- for-lot (L4L) lot sizing is used for Items C, E, and F; lots of size 20, 40, and 160 are used for Items A, B, and D, respectively. Items A, B, D, and E have on-hand 'beginning) inventories of 5, 10, 100, and 100, respectively, all other items have zero beginning inventories. We are scheduled to receive 10 units of A in Week 3, 20 units of B in Week 7, 40 units of F in Week 5, and 60 units of E in Week 2; there are no other scheduled receipts. If 20 units of A are required in Week 10, use the low-level-coded bill-of-materials (product structure tree) to find the necessary planned order releases for all components. (Leave no cells blank - be certain to enter "0" wherever required.) 2 0 0 Period Gross requirements Scheduled receipts Projected available balance Net requirements Planned order receipts Planned order releases Item A OH = 5 LT = 2 SS = 0 Q = 20 0 0 10 0 0 10 0 0 0 0 0 0 Gross requirements Scheduled receipts Projected available balance Net requirements Planned order receipts Item C OH = 0 LT = 1 SS = 0 Q = L4L 0 10 0 10 0 0 O C

Answer 1

Steps to create the MRP 1) Enter the gross requirement as per Master Planning Schedule (MPS). Gross requirement of components is calculated as per usage in parent item. 2) Enter Schedule Order Receipts (SR), if there are any. 3) Project On hand is calculated by this formula = Previous period project on hand + Scheduled receipts + Planned order receipts - gross requirement 4) Net requirement = Gross requirement - Projected on hand 5) Planned Order Release (POR) is manually entered such that time phased planned order receipt is equal to net For example, if lead time is 1 period, and there is net requirement of 80 units in period 3, then there is a planned order release for 80 units in period 2, i.e. 1 period prior to the period in which requirement occurs. Planned Order Release quantity is as per the Lot size specified, i.e. LFL, or Fixed Order Quantity, or POQ or EOQ or in Multiples of a specified quantity. 6) If there is safety stock specified for an item, then safety stock quantity is added in Planned Order Release so that Project On Hand remains greater than or equal to safety stock as specified.

MRP Item 0 1 2 3 4 5 6 7 8 9 10 0 0 0 0 0 0 0 0 20 0 0 0 0 0 0 0 0 0 10 15 5 5 5 5 15 15 15 15 A Gross Requirement SR = 10(3) Scheduled Receipt SS = Projected on Hand Net Requirement L= 2 Planned Order Receipt Q= 20 Planned Order Release 15 0 15 0 15 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 20 0 0 0 0 0 20 0 0 Item 0 1 2 3 4 5 6 7 8 9 10 |С 0 0 0 0 0 0 0 20 0 0 SR = 0 0 0 0 0 o 0 0 0 0 0 0 SS= 0 0 0 0 0 0 0 0 0 Gross Requirement Scheduled Receipt Projected on Hand Net Requirement 1 Planned Order Receipt LFL Planned Order Release 0 0 0 0 0 0 0 20 0 0 0 L= 0 0 0 0 0 0 0 20 0 Q = 0 0 0 0 0 0 20 0 0 0 Item 0 1 2 3 4 5 6 7 8 9 10 0 0 0 0 0 0 60 40 0 | В SR = 0 0 0 0 0 0 0 SS = 10 10 10 10 10 Gross Requirement 20(7) Scheduled Receipt Projected on Hand Net Requirement 2 Planned Order Receipt 40 Planned Order Release 10 0 10 0 0 0 0 10 0 0 20 10 30 40 10 0 0 10 0 0 0 0 0 0 0 0 0 0 30 40 L = 0 0 Q= o 0 0 40 40 0 0

Item 0 1 2 3 4 5 6 7 00 9 10 D 0 0 0 0 120 120 0 0 0 20 0 SR = 0 0 0 0 0 0 0 0 0 0 SS = 100 100 100 0 0 Gross Requirement Scheduled Receipt Projected on Hand Net Requirement 3 Planned Order Receipt 160 Planned Order Release 100 0 0 100 0 140 20 20 0 0 0 0 0 0 0 0 0 0 0 160 0 0 0 L = Q= 0 0 0 0 0 160 0 0 0 0 0 0 Item 0 1 2 3 3 4 5 1 6 7 00 9 10 E 160 0 0 0 0 80 0 0 0 0 0 0 SR = 60 0 0 0 0 0 0 0 0 SS = 100 0 0 0 0 0 Gross Requirement 60(2) Scheduled Receipt Projected on Hand Net Requirement 2 Planned Order Receipt LFL Planned Order Release 100 0 0 0 0 0 0 0 0 0 0 0 80 0 0 0 0 L = 0 0 0 80 0 0 0 0 Q = 0 0 0 80 0 0 0 0 Item 0 1 2 3 4 5 6 7 00 9 10 F 0 0 0 40 40 0 0 0 0 SR = 0 0 0 0 0 0 0 0 0 0 0 0 SS = 0 0 0 0 0 0 Gross Requirement 40(5) Scheduled Receipt Projected on Hand Net Requirement 2 Planned Order Receipt LFL Planned Order Release 0 0 0 0 0 40 0 0 0 0 0 0 0 0 0 40 40 L = 0 0 0 0 0 0 0 Q= 0 0 0 40 0 0 0 0 0 0