Description
Scheduling Production and Process Operations and it contains topics like knowledge of scheduling techniques,developing schedules for maximum throughput, bottleneck resource mgmt, input-output control techniques, lead time control techniques, maintenance scheduling
SCHEDULING PRODUCTION AND PROCESS O P E R AT I O N S
OBJECTIVES
– – – – – –
Demonstrate knowledge of scheduling techniques Exhibit the ability to develop a schedule that maximizes throughput Explain bottleneck resource management Demonstrate an ability to use the input/output control technique Explain lead time control techniques Demonstrate the ability to schedule maintenance activities
2-3
WHAT IS A SCHEDULE?
–A schedule defines the sequence and time allocation for each operation. – A detailed schedule includes
• • • • Sequence constraints Sequence of operations Time estimates Resource utilization and capacity
2-4
OBJECTIVES OF SCHEDULING
–Establish due dates –Determine throughput times –Keep the shop floor running smoothly
2-4a
SELECTION OF SCHEDULING APPROACHES
Case I Make-to-Stock End Product
MPS/FAS FAS MPS
Case II Assemble-to-Order End Product
FAS
Case III Make-to-Order Engineer-to-Order End Product
MPS
Raw Materials/ Components
MPS/FAS—Builds finished items to forecast
Raw Materials/ Components
MPS—Builds components and subassemblies FAS—Final assembly of exact configurations
Raw Materials/ Components
FAS—Builds only
to customer orders
Source: Fogarty, Donald W., John H. Blackstone, and Thomas R. Hoffmann, Production & Inventory Management, 2nd ed. (South-Western Publishing Co., 1991). Reprinted with permission of South-Western Publishing Co.
2-5
INPUTS NECESSARY FOR EFFECTIVE SCHEDULING
–What to make –When to make it –Where to make it –How to make it –How much to make –Time needed to make it –Material availability –Due date –Machine maintenance and failure schedules –Expected rework and scrap percentages –Other demands on the facility
2-5a
SCHEDULING GUIDELINES
–Business priorities –Targets –Rules –Procedures
2-6
PRODUCTION SCHEDULING
– Assists in gaining control over production materials and processes by determining and authorizing production rates and levels – Serves as a performance measure – Utilizes capacity and material plans
2-7
CAPACITY PLANS
• The extremes of capacity planning are – If insufficient capacity is provided, schedules will not be able to accommodate production levels, and • Backlogs will increase. • Delivery performance will deteriorate. • Output levels will not increase. – If more than enough capacity exists, costs may be increased.
2-7a
INFINITE VS. FINITE LOADING
CRP profile for work center 100 Infinite load capacity profile
120 Hours 80 40 Capacity
Past Due
1
2
3 4 Weeks
5
6
7
Finite load capacity profile
Hours
80 40 1
Open shop orders Planned orders
Capacity
2
4 3 Weeks
5
6
7
Source: Vollman, Thomas E., William L. Berry, and D. Clay Whybark, Manufacturing Planning and Control Systems, 4th ed. (Irwin McGraw-Hill, 1997). Reprinted with permission of Irwin McGraw-Hill.
2-8
BACKWARD AND FORWARD SCHEDULING
Start by date
Oper. 10 Oper. 20 Oper. 30 Oper. 40 Oper. 50
Desired finish
Oper. 60
Backward Scheduling
Start date
Oper. 10 Oper. 20 Oper. 30 Oper. 40 Oper. 50
Expected finish
Oper. 60
Forward Scheduling
2-9
MATERIAL PLANS
• – – – – The purpose of material planning is to Provide information to production scheduling Set performance objectives Fulfill the master production schedule Satisfy customer service objectives
2-9a
SCHEDULING PRODUCTION AND PROCESS OPERATIONS
• Production scheduling – Mixed-model scheduling – Rate-based scheduling – Synchronous scheduling • Operations scheduling • Project scheduling
2-10
MIXED-MODEL SCHEDULING
– Mixed-model scheduling facilitates making several different components in varying lot sizes. – The goal is to build every component, according to demand. – A mixed-model line is typically described by the following sequence, where W, X, Y, and Z represent different components. • W-X-Y-W-X-Y-W-X-W-Z
2-11
RATE-BASED SCHEDULING
• – – – – In the presence of the following conditions, consider rate-based scheduling: Time coverage instead of reorder points Demand replacement Backlog management Load schedules tied to a uniform production rate
2-12
SYNCHRONOUS SCHEDULING
–Methods that synchronize all operations with the constraint of the system.
•Drum-buffer-rope •Kanban
2-13
OPERATIONS SCHEDULING
– Operations scheduling is the assignment of start or completion dates to activities. – It is the process of setting goals, targets, and measures. – Operations scheduling considers • Setup and run times at each operational step • Move times between work centers • Wait and queue times
2-14
THE OPERATIONS SCHEDULING DATA Order for part #2222
Quantity = 10 pieces, due 04/15
Routing Information
Total Setup . Seq. W/C Description Queue & Run Wait Move Time 10 140 Cutoff 8.0 2.8 2.0 1.0 13.8 20 30 102 270 Drill Grind 12.0 12.0 5.3 4.6 3.0 2.0 1.0 1.0 21.3 19.6
54.7
54.7 hours = 6.84 days = 6 days, 7 hours, 12 minutes
2-15
THE OPERATIONS SCHEDULE
Operation schedule with one eight hour shift
04/05 M 04/06 T 04/07 W 04/08 Th 04/09 F 04/12 M 04/13 T 04/14 W 04/15 Th 04/16 F
Operation 10: Cutoff Start 04/05 - Finish 04/06 13.8 hours
Operation 20: Drill Start 04/06 - Finish 04/09 21.3 hours
Legend
Queue time Wait time Setup and run time Move time
Operation 30: Grinding Start 04/09 - Finish 04/13 19.6 hours
2-16
OPERATION SCHEDULING STEPS
1. 2. 3. Obtain data for product or components to be produced. Choose scheduling method. Load facility.
4.
5. 6.
Schedule.
Release work to shop; execute schedule. Provide feedback to initial load and schedule.
2-16a
PROJECT SCHEDULING ACTIVITIES
– – – – Estimating the duration of each activity. Determining the sequence of activities. Calculating the start and finish times for each activity. Identifying the critical path.
2-17
EXAMPLE OF A SIMPLE PROJECT
Activity ID
Optimistic
Most Likely
Pessimistic Predecessors
A B C D E F G
2 4 4 2 1 4 5
3 9 6 5 1 4 6
4 14 8 8 1 10 13
None None None A, B C A D, E
2-18
ACTIVITY-ON-ARROW DIAGRAM
Arrows represent activities and nodes represent events.
1 A F
Start
B
2 C 3
D
4
G
Finish
E
2-19
ACTIVITY-ON-NODE DIAGRAM
Arrows represent relationships and nodes represent activities.
A
F
Start
B
D
Finish
G C
E
2-20
SCHEDULING FORWARD PASS
Day 3
1 A
Day 1
F
Day 14 Day 20
Start
B
2 C
Day 9
D
4
G
Finish
E
3
Day 6
2-21
SCHEDULING BACKWARD PASS
Day 9
1 A
Day 1
F
Day 14 Day 20
Start
B
2 C
Day 9
D
4
G
Finish
E
3
Day 13
2-21a
INPUT/OUTPUT CONTROL TECHNIQUE
Input
Input
Input
Queue
Capacity Output
2-22
INPUT/OUTPUT CONTROL REPORT
Work center #102: 6 - inch radial drills
Cumulative deviation tolerance: 30 hours
Week Ending
Input Planned Actual Cum. deviation
Output Planned Actual Cum. deviation As of: 04/01
03/02 03/09 03/16 03/23 03/30 04/06 04/13 04/20
182 197 15 207 213 6 203 180 -8 207 202 1 172 168 -12 207 206 0 178 191 1 207 210 3 207 205 193 189 -3 207 212 8 193 182 205 208 210
207
207
207
Queue (Beginning queue: 300 hours) Planned 275 271 236 Actual 284 262 224
191
192
195
2-23
ACTUAL INPUT/OUTPUT LESS THAN PLANNED
Actual output less Actual input less than planned output than planned input Not enough input? Feeding work centers behind schedule
Input
Queues and lead times increase Insufficient capacity?
Input
Work released late
May run out of work
Output
Output
Late orders
2-24
ACTUAL INPUT/OUTPUT GREATER THAN PLANNED
Actual output greater than planned output Actual input greater than planned input Feeding work centers ahead of schedule Work released early Queues and lead times increase
Input
May run out of work Excess capacity
Input
Output
Output
2-25
ACTUAL OUTPUT COMPARED TO INPUT
Actual output less than actual input Preceding work centers ahead Released early Queues and lead times increase Not enough capacity
Actual output greater than actual input Feeding work centers behind schedule Released late May run out of work Idle capacity, late orders
Input
Input
Output
Output
2-26
PRIORITIZING
– Competition for manufacturing resources exists. – Priorities must be established and revised to reflect • Current shop conditions • Material availability • Customer needs
2-27
PRIORITY RULES
• – – – – – – Commonly used priority rules include First come, first serve Earliest due date Shortest processing time Shortest total processing time Fewest operations Slack time
– Critical ratio
Source: Fogarty, Donald W., John H. Blackstone, and Thomas R. Hoffmann, Production & Inventory Management (South-Western Publishing Co., 1991). Reprinted with permission of South-Western Publishing Co.
2-27a
ESTABLISHING PRIORITY EXAMPLE
Order W X Y Z
Due Date 105 107 111 113
Current Operation Time 1.5 1.0 2.0 3.5
Total Operation Time Remaining 3.0 4.5 4.0 7.0
Mfg. Lead Time Remaining 5.5 9.0 7.0 8.5
Number of Operations Remaining 4 6 5 3
Slack Time (ST) 2.0 2.5 7.0 6.0
Critical Ratio (CR) .91 .78 1.57 1.53
Present Date = Day 100 Lead Time Units = Days
2-28
CALCULATING SLACK TIME AND CRITICAL RATIO
– Slack time
•
Slack time ? (due date)? (presentdate)? (totaloperation time remaining)
– Critical ratio
Critical ratio ?
due date ? present date mfg. lead time remaining
2-28a
DISRUPTIVE PRIORITIES
– – – –
Squeaky wheels Gravy jobs Informal hot lists Red tags, green tags, and rush stickers
2-28b
BOTTLENECK MANAGEMENT
• Steps to bottleneck management 1. Identify the bottleneck. 2. Keep the bottleneck working. 3. Only feed into the process what can be handled at the bottleneck. 4. Accelerate and improve the bottleneck. 5. Once the bottleneck has been improved, start at step 1 again to find the new bottleneck.
2-29
ELEMENTS OF LEAD TIME
–Queue time –Setups or changeovers –Run time –Wait time –Move time
2-29a
ELEMENTS OF LEAD TIME
Review open order Prepare shop packet Pick and issue Move to 1st operation
Order Release
Setup time Queue time Run time Wait time Move time
Operation Sequence 10
Queue S/U, etc.
Operation Sequence 20 Operation Sequence 10-Setup Details
Adjust Run 1st Piece Tear down Mount tools, fixture Clean up
2-30
TYPES OF LEAD TIME
• There are three types of lead time that must be consistent for effective planning and control. – Planned - used by the detailed planning processes – Scheduled - determined by the detailed scheduling processes – Actual - time from release of lot until the items are available for use
2-30a
FUNCTIONS OF LEAD TIME
– Determines when orders must be released – Determines work-in-process inventory investment – Affects customer service • Customers benefit from short lead times. • Irregular delivery due to inconsistent lead times causes problems. • Shorter lead times allow more flexibility.
2-30b
OVERLAPPING AND LOT SPLITTING
1 10 20 30 40 Original Schedule
Operation sequence 20 With overlapping
50
Working days
Operation sequence 10
Legend
With lot splitting at Op 20
Queue time Setup time Run time
Wait time
With flow production Move time
2-31
LOT SIZE • Small lot sizes have several benefits.
–Improved costs
• Return on inventory assets • Return on the total asset base • Exposure to scrap and rework
–Improved quality
• Feedback on quality problems • Transition of engineering change
–Improved delivery responsiveness
• Manufacturing lead times • Frequency of access to equipment • Product-mix flexibility
2-32
LEAD-TIME CONTROL IN FLOW PRODUCTION
• Flow production affects lead time in the following ways. – Queue, setup, wait, and move times are minimized. – Run time is compressed as lot sizes are reduced. – Quality processes reduce the risk of increasing actual lead times.
2-32a
MAINTENANCE
There are two types of planned maintenance:
–Preventive
• Adjustments • Replacements • Basic cleanliness
–Predictive
• Nondestructive testing • Statistical analysis
The benefits of maintenance are
? ? ?
Increased flexibility Reduced material handling Improvements in the flow
2-32b
MAINTENANCE
• Maintenance begins with simple housekeeping.
–Simplification –Organization –Discipline –Cleanliness –Participation
2-32c
SUMMARY
– – – – – –
Demonstrate knowledge of scheduling techniques Exhibit the ability to develop a schedule that maximizes throughput Explain bottleneck resource management Demonstrate an ability to use the input/output control technique Explain lead time control techniques Demonstrate the ability to schedule maintenance activities
2-33
doc_247970604.ppt
Scheduling Production and Process Operations and it contains topics like knowledge of scheduling techniques,developing schedules for maximum throughput, bottleneck resource mgmt, input-output control techniques, lead time control techniques, maintenance scheduling
SCHEDULING PRODUCTION AND PROCESS O P E R AT I O N S
OBJECTIVES
– – – – – –
Demonstrate knowledge of scheduling techniques Exhibit the ability to develop a schedule that maximizes throughput Explain bottleneck resource management Demonstrate an ability to use the input/output control technique Explain lead time control techniques Demonstrate the ability to schedule maintenance activities
2-3
WHAT IS A SCHEDULE?
–A schedule defines the sequence and time allocation for each operation. – A detailed schedule includes
• • • • Sequence constraints Sequence of operations Time estimates Resource utilization and capacity
2-4
OBJECTIVES OF SCHEDULING
–Establish due dates –Determine throughput times –Keep the shop floor running smoothly
2-4a
SELECTION OF SCHEDULING APPROACHES
Case I Make-to-Stock End Product
MPS/FAS FAS MPS
Case II Assemble-to-Order End Product
FAS
Case III Make-to-Order Engineer-to-Order End Product
MPS
Raw Materials/ Components
MPS/FAS—Builds finished items to forecast
Raw Materials/ Components
MPS—Builds components and subassemblies FAS—Final assembly of exact configurations
Raw Materials/ Components
FAS—Builds only
to customer orders
Source: Fogarty, Donald W., John H. Blackstone, and Thomas R. Hoffmann, Production & Inventory Management, 2nd ed. (South-Western Publishing Co., 1991). Reprinted with permission of South-Western Publishing Co.
2-5
INPUTS NECESSARY FOR EFFECTIVE SCHEDULING
–What to make –When to make it –Where to make it –How to make it –How much to make –Time needed to make it –Material availability –Due date –Machine maintenance and failure schedules –Expected rework and scrap percentages –Other demands on the facility
2-5a
SCHEDULING GUIDELINES
–Business priorities –Targets –Rules –Procedures
2-6
PRODUCTION SCHEDULING
– Assists in gaining control over production materials and processes by determining and authorizing production rates and levels – Serves as a performance measure – Utilizes capacity and material plans
2-7
CAPACITY PLANS
• The extremes of capacity planning are – If insufficient capacity is provided, schedules will not be able to accommodate production levels, and • Backlogs will increase. • Delivery performance will deteriorate. • Output levels will not increase. – If more than enough capacity exists, costs may be increased.
2-7a
INFINITE VS. FINITE LOADING
CRP profile for work center 100 Infinite load capacity profile
120 Hours 80 40 Capacity
Past Due
1
2
3 4 Weeks
5
6
7
Finite load capacity profile
Hours
80 40 1
Open shop orders Planned orders
Capacity
2
4 3 Weeks
5
6
7
Source: Vollman, Thomas E., William L. Berry, and D. Clay Whybark, Manufacturing Planning and Control Systems, 4th ed. (Irwin McGraw-Hill, 1997). Reprinted with permission of Irwin McGraw-Hill.
2-8
BACKWARD AND FORWARD SCHEDULING
Start by date
Oper. 10 Oper. 20 Oper. 30 Oper. 40 Oper. 50
Desired finish
Oper. 60
Backward Scheduling
Start date
Oper. 10 Oper. 20 Oper. 30 Oper. 40 Oper. 50
Expected finish
Oper. 60
Forward Scheduling
2-9
MATERIAL PLANS
• – – – – The purpose of material planning is to Provide information to production scheduling Set performance objectives Fulfill the master production schedule Satisfy customer service objectives
2-9a
SCHEDULING PRODUCTION AND PROCESS OPERATIONS
• Production scheduling – Mixed-model scheduling – Rate-based scheduling – Synchronous scheduling • Operations scheduling • Project scheduling
2-10
MIXED-MODEL SCHEDULING
– Mixed-model scheduling facilitates making several different components in varying lot sizes. – The goal is to build every component, according to demand. – A mixed-model line is typically described by the following sequence, where W, X, Y, and Z represent different components. • W-X-Y-W-X-Y-W-X-W-Z
2-11
RATE-BASED SCHEDULING
• – – – – In the presence of the following conditions, consider rate-based scheduling: Time coverage instead of reorder points Demand replacement Backlog management Load schedules tied to a uniform production rate
2-12
SYNCHRONOUS SCHEDULING
–Methods that synchronize all operations with the constraint of the system.
•Drum-buffer-rope •Kanban
2-13
OPERATIONS SCHEDULING
– Operations scheduling is the assignment of start or completion dates to activities. – It is the process of setting goals, targets, and measures. – Operations scheduling considers • Setup and run times at each operational step • Move times between work centers • Wait and queue times
2-14
THE OPERATIONS SCHEDULING DATA Order for part #2222
Quantity = 10 pieces, due 04/15
Routing Information
Total Setup . Seq. W/C Description Queue & Run Wait Move Time 10 140 Cutoff 8.0 2.8 2.0 1.0 13.8 20 30 102 270 Drill Grind 12.0 12.0 5.3 4.6 3.0 2.0 1.0 1.0 21.3 19.6
54.7
54.7 hours = 6.84 days = 6 days, 7 hours, 12 minutes
2-15
THE OPERATIONS SCHEDULE
Operation schedule with one eight hour shift
04/05 M 04/06 T 04/07 W 04/08 Th 04/09 F 04/12 M 04/13 T 04/14 W 04/15 Th 04/16 F
Operation 10: Cutoff Start 04/05 - Finish 04/06 13.8 hours
Operation 20: Drill Start 04/06 - Finish 04/09 21.3 hours
Legend
Queue time Wait time Setup and run time Move time
Operation 30: Grinding Start 04/09 - Finish 04/13 19.6 hours
2-16
OPERATION SCHEDULING STEPS
1. 2. 3. Obtain data for product or components to be produced. Choose scheduling method. Load facility.
4.
5. 6.
Schedule.
Release work to shop; execute schedule. Provide feedback to initial load and schedule.
2-16a
PROJECT SCHEDULING ACTIVITIES
– – – – Estimating the duration of each activity. Determining the sequence of activities. Calculating the start and finish times for each activity. Identifying the critical path.
2-17
EXAMPLE OF A SIMPLE PROJECT
Activity ID
Optimistic
Most Likely
Pessimistic Predecessors
A B C D E F G
2 4 4 2 1 4 5
3 9 6 5 1 4 6
4 14 8 8 1 10 13
None None None A, B C A D, E
2-18
ACTIVITY-ON-ARROW DIAGRAM
Arrows represent activities and nodes represent events.
1 A F
Start
B
2 C 3
D
4
G
Finish
E
2-19
ACTIVITY-ON-NODE DIAGRAM
Arrows represent relationships and nodes represent activities.
A
F
Start
B
D
Finish
G C
E
2-20
SCHEDULING FORWARD PASS
Day 3
1 A
Day 1
F
Day 14 Day 20
Start
B
2 C
Day 9
D
4
G
Finish
E
3
Day 6
2-21
SCHEDULING BACKWARD PASS
Day 9
1 A
Day 1
F
Day 14 Day 20
Start
B
2 C
Day 9
D
4
G
Finish
E
3
Day 13
2-21a
INPUT/OUTPUT CONTROL TECHNIQUE
Input
Input
Input
Queue
Capacity Output
2-22
INPUT/OUTPUT CONTROL REPORT
Work center #102: 6 - inch radial drills
Cumulative deviation tolerance: 30 hours
Week Ending
Input Planned Actual Cum. deviation
Output Planned Actual Cum. deviation As of: 04/01
03/02 03/09 03/16 03/23 03/30 04/06 04/13 04/20
182 197 15 207 213 6 203 180 -8 207 202 1 172 168 -12 207 206 0 178 191 1 207 210 3 207 205 193 189 -3 207 212 8 193 182 205 208 210
207
207
207
Queue (Beginning queue: 300 hours) Planned 275 271 236 Actual 284 262 224
191
192
195
2-23
ACTUAL INPUT/OUTPUT LESS THAN PLANNED
Actual output less Actual input less than planned output than planned input Not enough input? Feeding work centers behind schedule
Input
Queues and lead times increase Insufficient capacity?
Input
Work released late
May run out of work
Output
Output
Late orders
2-24
ACTUAL INPUT/OUTPUT GREATER THAN PLANNED
Actual output greater than planned output Actual input greater than planned input Feeding work centers ahead of schedule Work released early Queues and lead times increase
Input
May run out of work Excess capacity
Input
Output
Output
2-25
ACTUAL OUTPUT COMPARED TO INPUT
Actual output less than actual input Preceding work centers ahead Released early Queues and lead times increase Not enough capacity
Actual output greater than actual input Feeding work centers behind schedule Released late May run out of work Idle capacity, late orders
Input
Input
Output
Output
2-26
PRIORITIZING
– Competition for manufacturing resources exists. – Priorities must be established and revised to reflect • Current shop conditions • Material availability • Customer needs
2-27
PRIORITY RULES
• – – – – – – Commonly used priority rules include First come, first serve Earliest due date Shortest processing time Shortest total processing time Fewest operations Slack time
– Critical ratio
Source: Fogarty, Donald W., John H. Blackstone, and Thomas R. Hoffmann, Production & Inventory Management (South-Western Publishing Co., 1991). Reprinted with permission of South-Western Publishing Co.
2-27a
ESTABLISHING PRIORITY EXAMPLE
Order W X Y Z
Due Date 105 107 111 113
Current Operation Time 1.5 1.0 2.0 3.5
Total Operation Time Remaining 3.0 4.5 4.0 7.0
Mfg. Lead Time Remaining 5.5 9.0 7.0 8.5
Number of Operations Remaining 4 6 5 3
Slack Time (ST) 2.0 2.5 7.0 6.0
Critical Ratio (CR) .91 .78 1.57 1.53
Present Date = Day 100 Lead Time Units = Days
2-28
CALCULATING SLACK TIME AND CRITICAL RATIO
– Slack time
•
Slack time ? (due date)? (presentdate)? (totaloperation time remaining)
– Critical ratio
Critical ratio ?
due date ? present date mfg. lead time remaining
2-28a
DISRUPTIVE PRIORITIES
– – – –
Squeaky wheels Gravy jobs Informal hot lists Red tags, green tags, and rush stickers
2-28b
BOTTLENECK MANAGEMENT
• Steps to bottleneck management 1. Identify the bottleneck. 2. Keep the bottleneck working. 3. Only feed into the process what can be handled at the bottleneck. 4. Accelerate and improve the bottleneck. 5. Once the bottleneck has been improved, start at step 1 again to find the new bottleneck.
2-29
ELEMENTS OF LEAD TIME
–Queue time –Setups or changeovers –Run time –Wait time –Move time
2-29a
ELEMENTS OF LEAD TIME
Review open order Prepare shop packet Pick and issue Move to 1st operation
Order Release
Setup time Queue time Run time Wait time Move time
Operation Sequence 10
Queue S/U, etc.
Operation Sequence 20 Operation Sequence 10-Setup Details
Adjust Run 1st Piece Tear down Mount tools, fixture Clean up
2-30
TYPES OF LEAD TIME
• There are three types of lead time that must be consistent for effective planning and control. – Planned - used by the detailed planning processes – Scheduled - determined by the detailed scheduling processes – Actual - time from release of lot until the items are available for use
2-30a
FUNCTIONS OF LEAD TIME
– Determines when orders must be released – Determines work-in-process inventory investment – Affects customer service • Customers benefit from short lead times. • Irregular delivery due to inconsistent lead times causes problems. • Shorter lead times allow more flexibility.
2-30b
OVERLAPPING AND LOT SPLITTING
1 10 20 30 40 Original Schedule
Operation sequence 20 With overlapping
50
Working days
Operation sequence 10
Legend
With lot splitting at Op 20
Queue time Setup time Run time
Wait time
With flow production Move time
2-31
LOT SIZE • Small lot sizes have several benefits.
–Improved costs
• Return on inventory assets • Return on the total asset base • Exposure to scrap and rework
–Improved quality
• Feedback on quality problems • Transition of engineering change
–Improved delivery responsiveness
• Manufacturing lead times • Frequency of access to equipment • Product-mix flexibility
2-32
LEAD-TIME CONTROL IN FLOW PRODUCTION
• Flow production affects lead time in the following ways. – Queue, setup, wait, and move times are minimized. – Run time is compressed as lot sizes are reduced. – Quality processes reduce the risk of increasing actual lead times.
2-32a
MAINTENANCE
There are two types of planned maintenance:
–Preventive
• Adjustments • Replacements • Basic cleanliness
–Predictive
• Nondestructive testing • Statistical analysis
The benefits of maintenance are
? ? ?
Increased flexibility Reduced material handling Improvements in the flow
2-32b
MAINTENANCE
• Maintenance begins with simple housekeeping.
–Simplification –Organization –Discipline –Cleanliness –Participation
2-32c
SUMMARY
– – – – – –
Demonstrate knowledge of scheduling techniques Exhibit the ability to develop a schedule that maximizes throughput Explain bottleneck resource management Demonstrate an ability to use the input/output control technique Explain lead time control techniques Demonstrate the ability to schedule maintenance activities
2-33
doc_247970604.ppt