Lean Aircraft Initiative
Plenary Workshop
Factory Operations Team
October 16, 1996
Presented by:
Tom Shields
MIT
LEAN AIRCRAFT
INITIATIVE
Factory Operation Benchmarking
w Review of benchmarking activities
w Results
w Analysis of data
w Conclusions
w Next steps
w Focus group status report
FO10/16/96- 2 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Benchmarking Objective
Develop comparative benchmarking
on member factory flow measures.
Flow Variables:
* Touch Labor
* Cycle Time
* Router Queuing
* Batch Sizes
Support Variables:
* IE Hours
* Part Characteristics
* Distance Traveled
* # of Process Steps
* Process Controls
* Quality
FO10/16/96- 3 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Benchmarking Ground Rules
w Specific parts and data to be collected
determined by sector representatives
w Questionnaire based
w Data verification
FO10/16/96- 4 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Metric Definitions
w Cycle Time (Hours)
– The total time from initiation of work order to
completion of manufacturing process on work
order.
w Waiting Time (Hours)
– Cycle Time - Touch Labor. The time the work
order spends on the floor without work being
charged to the work order.
w Router Queuing (Hours)
– Time between creation of work order and first
process step.
FO10/16/96- 5 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Part Manufacturing Timeline
Cycle Time
Router Queuing
Issued to
Floor
First
Operation
Touch
Labor
Work Order
Completed
FO10/16/96- 6 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Touch Labor Measurement
Process #1: One Person/Operation per Batch
Process #2: Multiple Persons/Operations per Batch
FO10/16/96- 7 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Flow Efficiency Metric
w Flow Efficiency in principle (Unitless)
=
Fabrication Time
Cycle Time
w Flow Efficiency surrogate (Unitless)
=
Touch Labor/part/crew size
Cycle Time - Router Queuing
FO10/16/96- 8 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
w
Extruded Sheet Metal Part
–
–
–
–
w
Airframe Sector
Straight, aluminum
< 2 ft long
< 1/4” thick
“T”, “L”, “C” or “Z” cross
section
Brake-Formed Part
– Aluminum
– 2 ft long
– < 1/4” thick
w
Machined Prismatic Part
– Aluminum
– 3 Axis machine
– < 1 ft3
FO10/16/96- 9 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Airframe Sector - Extrusions
700
600
Hours
500
400
Waiting Time
Touch Labor
300
Router Queue
200
100
0
A
B**
C*
* Estimated router queue times
** Estimated router queue and cycle times
D
E**
Respondents
G
Note: Bar length is
total cycle time
FO10/16/96- 10 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Airframe Sector - Brake-formed Parts
1600
1400
1200
Hours
1000
Waiting Time
Touch Labor
800
Router Queue
600
400
200
0
A
B**
C*
* Estimated router queue times
** Estimated router queue and cycle times
D
E
G
Respondents
Note: Bar length is
total cycle time
FO10/16/96- 11 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Airframe Sector - Machined Parts
6000
5000
Hours
4000
Waiting Time
3000
Touch Labor
Router Queue
2000
1000
0
A
B**
C*
* Estimated router queue times
** Estimated router queue and cycle times
D
E
F
Respondents
G
Note: Bar length is
total cycle time
FO10/16/96- 12 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Airframe Sector - Flow Efficiency
Airframe Sector - Flow Efficiency (Router Queue
removed)
Flow Efficiency (touch labor/(cycle
time-router queue time))
0.80%
0.70%
0.60%
0.50%
0.40%
Maximum
0.30%
Mean
Median
0.20%
Minimum
0.10%
0.00%
Extrusions
Brake-formed
Parts
Machinings
FO10/16/96- 13 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Electronic Sector
w Printed wiring assembly
– Component insertion through
final test
– Does not include wafer board
fabrication
w Electronic Chassis
– Less chassis fabrication
w Cable / Harness
– All assembly operations
FO10/16/96- 14 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Electronic Sector - Printed
Wiring Assembly
1200
1000
Hours
800
waiting time
600
touch labor/part
400
200
0
A
B
* Based on planned cycle time
C
D
Respondents
E
F*
NOTE: Bar length is
total cycle time
FO10/16/96- 15 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Electronic Sector - Chassis
1000
900
800
700
Hours
600
waiting time
500
touch labor/part
400
300
200
100
0
A
B
* Based on planned cycle time
C
D
E
Respondents
F*
NOTE: Bar length is
total cycle time
FO10/16/96- 16 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Electronic Sector - Cable / Harness
1200
1000
Hours
800
waiting time
600
touch labor/part
400
200
0
A
B
C
Respondents
D
E
NOTE: Bar length is
total cycle time
FO10/16/96- 17 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Electronic Sector - Flow Efficiency
20%
18%
Adjusted Flow Efficiency
16%
14%
12%
maximum
mean
10%
median
minimum
8%
6%
4%
2%
0%
Printed Wire
Assemblies
Chassis
Cables/
Harnesses
FO10/16/96- 18 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Engine Sector
Items Benchmarked
◗ Turbine Disk
◗ Combustor
w
w
w
w
Three companies responded
Usable data from one company
Results not reported by sector
Used in total data analysis
FO10/16/96- 19 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Summary Observations After
Data Collection
w Each respondent’s data collection system
was different
w Multiple work methods observed
w Questionnaire method insufficient for
gathering detail data
w Few respondents tracked their actual
elapsed cycle times
w Work order lot size not the batch size used
for processing
FO10/16/96- 20 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Analysis
w Hypotheses
– Higher flow efficiencies with lower lot sizes
– Higher flow efficiencies with shorter
distance traveled
– Higher flow efficiencies with fewer process
steps
w
w
w
w
Analysis by sector
Analysis with all sectors combined
Influence of process type
Wait time analysis
FO10/16/96- 21 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE Flow Efficiency vs. Lot size (Combined)
0.2
0.18
0.16
Flow Efficiency
0.14
PWA
Chassis
Cable
Disk
Combustor
Extruded
BrakeFormed
Machined
0.12
0.1
0.08
Flow Efficiency = 1 / Lot Size
0.06
0.04
0.02
0
0
100
200
300
400
500
600
Lot Size
FO10/16/96- 22 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Flow Efficiency vs. Travel Distance
(Combined)
0.2
0.18
0.16
Flow Efficiency
0.14
PWA
Chassis
Cable
Disk
Combustor
Extruded
BrakeFormed
Machined
0.12
0.1
0.08
0.06
0.04
0.02
0
0
2000
4000
6000
8000
10000
12000
Distance Travelled (ft)
FO10/16/96- 23 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Flow Efficiency vs. Process Steps
(Combined)
0.2
0.18
0.16
Flow Efficiency
0.14
PWA
Chassis
Cable
Disk
Combustor
Extruded
BrakeFormed
Machined
0.12
0.1
0.08
0.06
0.04
0.02
0
0
10
20
30
40
50
60
Process Steps
FO10/16/96- 24 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Process Type
0.2
0.18
0.16
Dedicated Line
or Flow Shop
Flow Efficiency
0.14
0.12
PWA
Chassis
Cable
Disk
Combustor
Extruded
BrakeFormed
Machined
0.1
0.08
Flow Efficiency = 1 / Lot Size
0.06
0.04
Job Shop
0.02
0
0
100
200
300
400
500
600
Lot Size
FO10/16/96- 25 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Job Shop Considerations
Factors that influence performance of
job shops
w
w
w
w
What the facility has optimized
Operations may be capacity limited
Machine utilization effect on set up
Numbers of parts that are processed in
this area
w Production environment
FO10/16/96- 26 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Wait Time Components
w Transportation delay
w Lot delay (while all parts are processed)
w Storage delay
FO10/16/96- 27 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Wait Time Analysis - Airframe Sector
Extrusion
Brake Formed
Machining
Wait Fraction
Lot Delay
95%
97%
94%
2%
2%
3%
FO10/16/96- 28 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Wait Time Analysis - Electronic Sector
w Could not determine wait times directly
w Bounded the problem
– Defined maximum wait times
– Defined I. E. factor necessary to achieve
zero wait time
w Process defined one respondent in each
type of part that was doing at least twice
as good as the other respondents
FO10/16/96- 29 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Dedicated Lines or Flow Shops
Dedicated Line or Flow Shop Process
Efficiencies
0.2
0.18
0.14
0.12
0.1
0.08
0.06
0.04
0.02
14
13
12
11
10
9
8
7
6
5
4
3
2
0
1
Operation Efficiency
0.16
Operations Deemed to be a Flow Shop or Dedicated Line
FO10/16/96- 30 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Wait Time Analysis
Efficiency versus Travel Distance
0.7
0.6
Efficiency
0.5
0.4
0.3
0.2
0.1
0
0
500
1000
1500
2000
2500
3000
Travel Distance
FO10/16/96- 31 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Wait Time Analysis Conclusions
w Dedicated line or flow shop
– All wait time in dedicated line or flow shop is waste
– Transportation delay does not predominate
– Predominate wait time component is storage delay
w Job shop
– Storage and transportation delay predominate
– research could not differentiate other contributing
factors
w Most opportunity for lean improvement is to
concentrate on wait time reduction
FO10/16/96- 32 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Cycle Time Reduction
Wait Time = Waste
w Gather data to understand wait time
– part/assembly/product ACTUAL cycle time key
– part/assembly/product ACTUAL fabrication time
– Determine wait time and their components
w Analyze causes of wait time
w Implement steps to reduce wait times
w Evaluate results to the production system
w Standardize the improvement across the system
w Reflect on the process and select next effort
FO10/16/96- 33 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Observations
w Few respondents tracked actual cycle times
w Router cueing time ranged from 4 to 42% of
total cycle time in the airframe sector
w Wait fraction for airframe sector averages
96%
w Wait fraction for engine sector averages 87%
w Could not determine wait times in electronic
sector
– Comparison of wait time bounds
– One electronic sector company showed at least two
times better performance
FO10/16/96- 34 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Conclusions
Wait time reduction = cycle time reduction
w Within sectors apples to apples comparison achieved
for each type of part
w Flow efficiency varied inversely with lot size and
travel distance
w In job shops storage and transportation delay greater
than lot delay times
w For dedicated lines or flow shops the largest
component of wait time was storage delay
FO10/16/96- 35 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Next Steps
w Report to respondents
w Application of lessons learned into
future research
FO10/16/96- 36 ©1996
Massachusetts Institute of Technology
©
LEAN AIRCRAFT
INITIATIVE
Factory Operations Status Report
w Focus on LEM overarching practice - Identify
and Optimize Enterprise Flow
w Concentrate on factors that effect “Order to
point of use delivery cycle time”
w Use LEM to classify results
w Focus Group Identified field research site
w Data collection methodology developed at
MIT
w Site introductory visit completed
w Data collection to commence next week
FO10/16/96- 37 ©1996
Massachusetts Institute of Technology
©