material requirements planning (mrp)
DESCRIPTION
Material Requirements Planning (MRP). Summary of Scheduling Process. FORECAST ROUGH-CUT CAPACITY PLANNING PRODUCTION PLAN MASTER PRODUCTION SCHEDULE (MPS) MATERIAL REQUIREMENTS PLANNING (MRP) CAPACITY REQUIREMENTS PLANNING - PowerPoint PPT PresentationTRANSCRIPT
Material Requirements Planning (MRP)
Summary of Scheduling Process
FORECAST
ROUGH-CUT CAPACITY PLANNING
PRODUCTION PLAN
MASTER PRODUCTION SCHEDULE (MPS)
MATERIAL REQUIREMENTS PLANNING (MRP)
CAPACITY REQUIREMENTS PLANNING
SHOP FLOOR CONTROLS VENDOR CONTROLS
MRP
Material Requirements Planning (MRP) – Translates MPS into Schedule of Component Requirements, Order Quantities, and Times
Manufacturing Resource Planning (MRP II) – Computes Resource Requirements, i. e. Labor
Enterprise Resource Planning (ERP) – Has Financial, Marketing, Etc. Components
Nature of Demand
Independent Demand – Demand Outside of Firm, on MPS (Vanilla Ice Cream)
Dependent Demand – Derived Demand within Firm (Cream, Vanilla Flavoring, Etc.)
MRP Inputs
Master Production Schedule (MPS)
Bill of Materials (Parts List)
Inventory Status – On Hand
Lead Times
MRP Outputs (Objectives)
Determine Requirements– What to Order
– How Much to Order
– When to Order
– When to Schedule Delivery
Keep Priorities Current
MRP Example 1
The Protecto Corporation sells special survival kits to the visitors of Congress and the state legislatures. In April there are requirements for 1000 kits. Each kit contains:
two ear plugs
one bottle of extra strength aspirin
five paper gas masks
one box
one label
The firm only manufactures the ear plugs and the gas masks. The other parts are purchased. Each ear plug uses two ounces of wax and .08 hours of labor time. Each gas mask uses a sheet of cardboard, one-half ounce of wax, and .10 hours of labor.
Bill of Materials: Example 1
Product Structure Tree
W a x (2 )
E a r P lug s (2 ) A sp irin (1 )
C a rd b oa rd (1 ) W a x (0 .5 )
G a s M a sks (5 ) B o x (1 ) L a b e l (1 )
K it (1 )
Component Parts & Labor Requirements
Ear Plugs (2 x 1000) = 2000
Aspirin (1 x 1000) = 1000
Gas Masks (5 x 1000) = 5000
Boxes (1 x 1000) = 1000
Labels (1 x 1000) = 1000
Cardboard (1 x 5000) = 5000
Wax (2 x 2000) + (.5 x 5000) = 6500
Labor Hours (.08 x 2000) + (.1 x 5000) = 660
Cardboard Sheets if 3% Scrapped
Adjustment for Scrap:
Scheduled Units = MRP / (1 – Scrap %)
Scheduled Units = 5000 / .97 = 5155
Standard Time = MRP / (1 - % Delay)
ST = 0.66 / 0.8= 0.825 Hours
Actual Time = ST / Labor Efficiency
AT = 0.825 /.9 = 0.920 Hours
Standard and Actual Labor Time – 20 Worker Idle Time
MRP Example 2 In order to make one starship, you need 3 warp engines and 4
impulse engines. Each warp engine requires 10 dilithium crystals, 7 units of platinum, and 3 antimatter pods. Each impulse engine requires 2 antimatter pods and 4 units of platinum. The lead times are:
Item Lead Time
Starship (SS) 2 years
Warp Engine (WE) 3 years
Impulse Engine (IE) 1 year
Dilithium Crystal (DC) 2 years
Antimatter Pods (AM) 1 year
Platinum (PL) 2 years
The Federation has ordered 3 starships to be delivered in AD 2379.
Bill of Materials: Example 2
Product S tructure Tree
D ilith iu m C rys ta l (1 0 ) P la tin um (7 ) A n tim a tte r P od (3 )
W a rp E n g in e (3 )
A n itm a tte r P od (2 ) P la tin um (4 )
Im p u lse E n g ine (4 )
S ta rsh ip (1 )
MRP CalculationsStarship: Lead Time 2 Years
Warp Engine: Lead Time 3 YearsGross Requirements
Scheduled Receipts
Available
Net Requirements
Planned Order Receipts
Planned Order Releases
Year 2372 2373 2374 2375 2376 2377 2378 2379
Gross Requirements
Scheduled Receipts
Available
Net Requirements
Planned Order Receipts
Planned Order Releases
3
33
3
00
9
99
9
00
MRP CalculationsStarship: Lead Time 2 Years
Impulse Engine: Lead Time 1 YearGross Requirements
Scheduled Receipts
Available
Net Requirements
Planned Order Receipts
Planned Order Releases
Year 2372 2373 2374 2375 2376 2377 2378 2379
Gross Requirements
Scheduled Receipts
Available
Net Requirements
Planned Order Receipts
Planned Order Releases
3
33
3
00
12
1212
12
00
MRP CalculationsWarp Engine: Lead Time 3 Years
Dilithium Crystal: Lead Time 2 YearsGross Requirements
Scheduled Receipts
Available
Net Requirements
Planned Order Receipts
Planned Order Releases
Year 2372 2373 2374 2375 2376 2377 2378 2379
Gross Requirements
Scheduled Receipts
Available
Net Requirements
Planned Order Receipts
Planned Order Releases
9
99
9
00
90
9090
90
00
MRP Calculations:
Work from Top to Bottom of Product Structure Tree (Low-Level Code Order)
Subtract Out Any Items On Hand
Combine Common Components – Put on the Same Table. If on the Same Square, Add.
MRP Extensions:
Multiple Bills of Material
On Hand Quantities
On Order Quantities
Spare Parts
MRP Example 3
A firm makes two products, A and R. A computer file reveals the following information about A and R, and their component parts:
Item On Hand Lead Time MPS Lot Size On Order
A 10 3 Weeks 160 (week 8) 1
B 0 2 Weeks 400
C 0 1 Week 400 (week 5) 1
D 200 3 Weeks 500
E 0 1 Week 1 200 (week 2)
R 20 3 Weeks 145 (week 7) 1
Bill of Materials: Example 3
Product Structure Tree for Item A
D (3 )
C (2 ) E (3 )
B (2 ) E (4 )
A (1 )
Bill of Materials: Example 3
Product Structure Tree for Item R
C (2 ) E (3 )
B (4 )
R (1 )
MRP CalculationsA: Lead Time 3 Weeks, Low-Level Code 0
D: Lead Time 3 Weeks, Low-Level Code 1Gross Requirements
Scheduled Receipts
Available
Net Requirements
Planned Order Receipts
Planned Order Releases
Week 1 2 3 4 5 6 7 8
Gross Requirements
Scheduled Receipts
Available
Net Requirements
Planned Order Receipts
Planned Order Releases
160
150150
100
450
250500
500
0200
150
250 250 250
MRP CalculationsR: Lead Time 3 Weeks, Low-Level Code 0
B: Lead Time 2 Weeks, Low-Level Code 1Gross Requirements
Scheduled Receipts
Available
Net Requirements
Planned Order Receipts
Planned Order Releases
Week 1 2 3 4 5 6 7 8
Gross Requirements
Scheduled Receipts
Available
Net Requirements
Planned Order Receipts
Planned Order Releases
145
125125
200
500
0500
800
0300
125
800
0
300
Low Level Codes
Item E is What Low-Level Code?
Item C is What Low-Level Code?
Can You Do the MRP Tables for Items C and E?
Material Planners
People Who Manage MRP System Release Manufacturing Orders (MO) or
Purchasing Orders (PO) Reschedule Due Dates of Open Orders
as Needed Reconcile Orders and Find Cause Solve Shortages by Expediting Coordinate with Others
Material PlannerWorks with:
Planned Orders Released Orders Firm Planned Orders Exception Messages Transaction Messages
Material Planner UsesFeedback for Priorities
Suppliers Actions Through Purchasing
Early or Late Completions or Differing Quantities
Management Actions (Changing MPS)