Transcript Chapter 11
Chapter 13
Material Requirements Planning
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
MRP
Computerized
inventory control &
production planning system
Schedules
component items when they
are needed - no earlier and no later
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 2
2
When to Use MRP
Dependent
and discrete items
Complex products
Job shop production
Assemble-to-order environments
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 3
3
MRP Inputs & Outputs
Master Production Schedule
Product
Structure
File
Material
Requirements
Planning
Inventory
Master
File
Planned Order Releases
Work Orders
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
Purchase Orders
2000 by Prentice-Hall, Inc
Rescheduling Notices
Ch 13 - 4
4
MRP Inputs
Master
production schedule
Product
structure file
Inventory
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
master file
2000 by Prentice-Hall, Inc
Ch 13 - 5
5
Master Production Schedule
Drives
MRP process with a schedule of
finished products
Quantities represent production not
demand
Quantities may consist of a combination
of customer orders & demand forecasts
Quantities represent what needs to be
produced, not what can be produced
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 6
6
Master Production Schedule
MPS
Period
Item
1
2
3
4
5
6
7
8
Clipboard
86 93 119 100 100 100 100 100
Lapboard
0 50
0 50
0 50
0 50
Lapdesk
75 120 47 20 17 10
0
0
Pencil Case 125 125 125 125 125 125 125 125
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 7
7
Product Structure Tree
Clipboard
Clip Assembly
(10)
Board
(1)
Rivet
(2)
Top Clip
(1)
Bottom Clip
(1)
Pivot
(1)
Spring
(1)
Sheet
Metal
(8 in2)
Sheet
Metal
(8 in2)
Spring
Steel
(10 in.)
Iron
Rod
(3 in.)
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
Level 0
Pressboard
(1)
2000 by Prentice-Hall, Inc
Level 1
Finish
(2oz.)
Level 2
Level 3
Ch 13 - 8
8
Indented Bill of Material
LEVEL
0----1----2----3--2----3--2----3--2----3-1---1----2---2-© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
ITEM
Unit of Measure
Clipboard
Ea
Clip Assembly
Ea
Top Clip
Ea
Sheet Metal
In2
Bottom Clip
Ea
Sheet Metal
In2
Pivot
Ea
Iron Rod
In
Spring
Ea
Spring Steel
In
Rivet
Ea
Board
Ea
Press Board
Ea
Finish
Oz
2000 by Prentice-Hall, Inc
Quantity
1
1
1
8
1
8
1
3
1
10
2
1
1
2
Ch 13 - 9
9
Inventory Master File
Description
Item
Item no.
Item type
Product/sales class
Value class
Buyer/planner
Vendor/drawing
Phantom code
Unit price/cost
Pegging
LLC
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
Board
7341
Manuf.
Ass’y
B
RSR
07142
N
1.25
Y
3
Inventory Policy
Lead time
Annual demand
Holding cost
Ordering/setup cost
Safety stock
Reorder point
EOQ
Minimum order qty
Maximum order qty
Multiple order qty
Policy code
2000 by Prentice-Hall, Inc
2
5,000
1
50
25
39
316
100
500
100
3
Ch 13 - 13
10
Inventory Master File, Con’t.
Physical Inventory
On hand
Location
On order
Allocated
Cycle
Difference
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
100
W142
50
75
3
-2
Usage/Sales
YTD usage/sales
MTD usage/sales
YTD receipts
MTD receipts
Last receipt
Last issue
Codes
Cost acct.
Routing
Engr
2000 by Prentice-Hall, Inc
1,100
75
1,200
0
8/25
10/5
00754
00326
07142
Ch 13 - 14
11
Inventory Accuracy
1. Maintain orderly stockrooms
2. Control access to stockrooms
3. Establish & enforce procedures for
inventory withdrawal
4. Ensure prompt and accurate entry of inventory
transactions
5. Take physical inventory count on a regular
basis
6. Reconcile inventory discrepancies in a timely
manner (use cycle counting)
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 15
12
The MRP Matrix
Lot size:
LT:
Gross requirements
Scheduled receipts
Projected on hand
Net requirements
Planned order receipts
Planned order releases
PD
1
2
3
4
5
6
7
8
9
Item
name or number identifying scheduled item
LLC
low-level-code; lowest level at which item
appears in a product structure
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 16
13
10
Parts Of MRP Matrix
Lot size
order multiples of this qty; can be min/max qty
LT (lead time)
time from order placement to receipt
PD (past-due)
orders behind schedule
Gross requirements
demand for item by time period
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 17
14
Scheduled receipts
quantity already on order & receipt date
released orders become scheduled receipts
Projected on hand
expected on-hand inventory at end of period
Net requirements
net amount needed after on-hand
adjustments
Planned order receipts
net requirements adjusted for lot-sizing
Planned order releases
planned order receipts offset by lead time
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 18
15
Capacity Requirements
Planning (CRP)
Computerized
system that projects load
from material plan
Creates
load profile
Identifies
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
underloads and overloads
2000 by Prentice-Hall, Inc
Ch 13 - 25
16
Capacity Terms
Load
profile
Capacity
Utilization
Efficiency
Load
Load percent
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 26
17
Capacity Requirements
Planning
MRP planned
order
releases
Routing
file
Capacity
requirements
planning
Open
orders
file
Load profile for
each machine center
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 28
18
Initial Load Profile
Hours of
capacity
Normal
capacity
1
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2
3
4
5
6
Time (weeks)
2000 by Prentice-Hall, Inc
Ch 13 - 31
19
Adjusted Load Profile
Hours of
capacity
Work an
extra shift
Overtime
Push back
Pull ahead
Push back
1
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2
3
4
Time (weeks)
2000 by Prentice-Hall, Inc
5
6
Ch 13 - 32
20
Remedies for Underloads
1. Acquire more work
2. Pull work ahead that is scheduled for
later time periods
3. Reduce normal capacity
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 33
21
Remedies for Overloads
1. Eliminate unnecessary requirements
2. Reroute jobs to alternative machines or work
centers
3. Split lots between two or more machines
4. Increase normal capacity
5. Subcontract
6. Increase the efficiency of the operation
7. Push work back to later time periods
8. Revise master schedule
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 34
22
Problems with MRP
Material
requirements plan is first;
capacity is an afterthought
MRP
assumes fixed lead times
Excessive
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
reporting requirements
2000 by Prentice-Hall, Inc
Ch 13 - 43
23
Manufacturing Resource
Planning (MRP II)
Extension
of MRP
Plans all resources needed for running
a business
Variations include
Service
Requirements Planning (SRP)
Business Requirements Planning (BRP)
Distribution Requirements Planning
(DRP)
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 38
24
MRP II Modules
Forecasting
Customer order entry
Production planning /
master production
scheduling
Product structure / billof-material processor
Inventory control
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
Material
requirements
planning
Capacity planning
Shop floor control
Purchasing
Accounting
Financial analysis
2000 by Prentice-Hall, Inc
Ch 13 - 39
25
Prospects for MRP/MRP II
Coordinates company strategy among
different functional areas
Responds quickly to what-if? questions at
various levels of detail
BOM processors, purchase modules, &
customer order entry are standard
requirements for Manufacturing Information
Systems
Monitors design & vendor quality, & customer
service
Builds trust, teamwork, & better decisions
Cash-flow planning & profit/cost projections
© 2000 by Prentice-Hall Inc
Russell/Taylor Oper Mgt 3/e
2000 by Prentice-Hall, Inc
Ch 13 - 44
26