Chapter
6 Lean Systems
DISCUSSION QUESTIONS
1. a. Many students buy into lean systems as a philosophy until they are faced with the
prospect of having their own work evaluated on the basis of performance of a group
rather than as an individual.
b. This discussion will probably uncover any conflicts between the culture the
students have been raised in and lean systems philosophy. The discussion might be
turned to look for compromises or ways lean systems could be modified to work
with their culture.
2. Aspects of lean systems that have proven troublesome for some U.S. users are
realignment of managerial reward systems, restrictive labor contracts, plant layouts,
and adversarial supplier relationships. Our culture focuses on individuals rather than
groups, and our legal system contains hurdles to forming partnerships that restrict
competition. Many firms have already overcome these obstacles.
3. A lean system requires a low level of capacity slack and increasingly smaller levels
of inventory. In order to reap the waste-reduction benefits of lean uniformly across
the supply chain, all members of the supply chain must participate. Otherwise, one
tier of the supply chain may be holding increasing levels of inventory to decouple
them from their more efficient supply chain partners. This leads to higher costs and
greater inefficiency for the entire supply chain. Thus, it is vital to create close,
collaborative relationships with supply chain partners to ensure that information
planning and problems are shared along the supply chain.
Thus, the pressures of participating in a lean supply chain come from enforcing a
discipline of (1) small lots, (2) frequent shipping, (3) short lead times, (4) accurate
shipping schedules, and (5) high quality from inbound logistics through operations
and outbound logistics. Significant problems within this environment, such as
inventory shortages or labor stoppages, will ripple across the supply chain. If not
corrected quickly, these problems can shut down the entire supply chain.
4. The answer here will vary. Most students will draw a simple process they are very
familiar with. For example ordering an item at a fast food restaurant: Receive order
– gather materials (buns, meat, cheese, condiments) – assemble materials – serve
order.
6-1
Copyright © 2016 Pearson Education, Inc.
, 6-2 • PART 1 • Managing Processes
PROBLEMS
Strategic Characteristics of Lean Systems
1. 1. Swenson Saws
a. The greatest common divisor given the ratios of demand is 2. Thus:
Bow Saw = 1
Frame Saw = 1
Dovetail Saw = 1
Tenon Saw = 2
b. B,T,F,T,D is one possible sequence that will be repeated every 5(6)=30
minutes.
c. The minutes available per shift is 8(60) = 460. The number of saws that can be
produced per shift is (460/6) = 76 saws
2. Harvey Motorcycles
a. What is the cycle time for the assembly line?
1 7 hours hours
c= = = 0.0555
r 126 motorcycles motorcycle
minutes
= 333
.
motorcycle
b. If Harvey uses small-lot mixed model production, what is the batch size of each
model before the production cycle is repeated? The greatest common divisor of
the production requirements for each motorcycle is 6. Therefore,
Golden = 9
LX 2000 = 7
Tiger = 5
c. G L G L T G L G L G L T G L G T G L T G T—other sequences are possible.
d. Now the greatest common divisor is 13. Therefore,
Golden = 4
LX 2000 = 3
Tiger = 2
Cheetah = 1
Unless the setup time is reduced, there may be too much loss of capacity in
performing additional setups per day. There may also be a shift in demand from
the original three motorcycles to the new one, changing the mixed-model
required.
3. Farm-4-Less
a. Each cycle contains 4SM, 2GC and 2 LT. In total each cycle produces 8
machines. Since Farm-4-Less completes a machine every 2 minutes (takt time),
it takes: 8*2= 16 minutes to complete the entire cycle sequence.
b. Per cycle= 4 SM, 2 GC and 2 LT are produced. If there are 480 minutes
available, then there are (480/16) = 30 cycles per shift. Thus, a total of = (30x4)
= 120 SM, (30x2) = 60 GC and (30x2) = 60 LT are produced each shift.
Copyright © 2016 Pearson Education, Inc.
6 Lean Systems
DISCUSSION QUESTIONS
1. a. Many students buy into lean systems as a philosophy until they are faced with the
prospect of having their own work evaluated on the basis of performance of a group
rather than as an individual.
b. This discussion will probably uncover any conflicts between the culture the
students have been raised in and lean systems philosophy. The discussion might be
turned to look for compromises or ways lean systems could be modified to work
with their culture.
2. Aspects of lean systems that have proven troublesome for some U.S. users are
realignment of managerial reward systems, restrictive labor contracts, plant layouts,
and adversarial supplier relationships. Our culture focuses on individuals rather than
groups, and our legal system contains hurdles to forming partnerships that restrict
competition. Many firms have already overcome these obstacles.
3. A lean system requires a low level of capacity slack and increasingly smaller levels
of inventory. In order to reap the waste-reduction benefits of lean uniformly across
the supply chain, all members of the supply chain must participate. Otherwise, one
tier of the supply chain may be holding increasing levels of inventory to decouple
them from their more efficient supply chain partners. This leads to higher costs and
greater inefficiency for the entire supply chain. Thus, it is vital to create close,
collaborative relationships with supply chain partners to ensure that information
planning and problems are shared along the supply chain.
Thus, the pressures of participating in a lean supply chain come from enforcing a
discipline of (1) small lots, (2) frequent shipping, (3) short lead times, (4) accurate
shipping schedules, and (5) high quality from inbound logistics through operations
and outbound logistics. Significant problems within this environment, such as
inventory shortages or labor stoppages, will ripple across the supply chain. If not
corrected quickly, these problems can shut down the entire supply chain.
4. The answer here will vary. Most students will draw a simple process they are very
familiar with. For example ordering an item at a fast food restaurant: Receive order
– gather materials (buns, meat, cheese, condiments) – assemble materials – serve
order.
6-1
Copyright © 2016 Pearson Education, Inc.
, 6-2 • PART 1 • Managing Processes
PROBLEMS
Strategic Characteristics of Lean Systems
1. 1. Swenson Saws
a. The greatest common divisor given the ratios of demand is 2. Thus:
Bow Saw = 1
Frame Saw = 1
Dovetail Saw = 1
Tenon Saw = 2
b. B,T,F,T,D is one possible sequence that will be repeated every 5(6)=30
minutes.
c. The minutes available per shift is 8(60) = 460. The number of saws that can be
produced per shift is (460/6) = 76 saws
2. Harvey Motorcycles
a. What is the cycle time for the assembly line?
1 7 hours hours
c= = = 0.0555
r 126 motorcycles motorcycle
minutes
= 333
.
motorcycle
b. If Harvey uses small-lot mixed model production, what is the batch size of each
model before the production cycle is repeated? The greatest common divisor of
the production requirements for each motorcycle is 6. Therefore,
Golden = 9
LX 2000 = 7
Tiger = 5
c. G L G L T G L G L G L T G L G T G L T G T—other sequences are possible.
d. Now the greatest common divisor is 13. Therefore,
Golden = 4
LX 2000 = 3
Tiger = 2
Cheetah = 1
Unless the setup time is reduced, there may be too much loss of capacity in
performing additional setups per day. There may also be a shift in demand from
the original three motorcycles to the new one, changing the mixed-model
required.
3. Farm-4-Less
a. Each cycle contains 4SM, 2GC and 2 LT. In total each cycle produces 8
machines. Since Farm-4-Less completes a machine every 2 minutes (takt time),
it takes: 8*2= 16 minutes to complete the entire cycle sequence.
b. Per cycle= 4 SM, 2 GC and 2 LT are produced. If there are 480 minutes
available, then there are (480/16) = 30 cycles per shift. Thus, a total of = (30x4)
= 120 SM, (30x2) = 60 GC and (30x2) = 60 LT are produced each shift.
Copyright © 2016 Pearson Education, Inc.
