1
Operation Management Case Study
BAYFIELD MUD COMPANY
2
BAYFIRLD MUD
COMPANY
Mud-treating agents
Used to control the pH and other chemical properties of the
core during oil and natural gas drilling operations
Wet land Drilling, Inc.
Warehouse
Houston, Texas
Bayfield Mud
Company
Offices and plant
orange, Texas
3
Product
50 Pound bags of treating agents
An acceptable
standard deviation
is 1.2 pounds.
Past shipments
(October 2007)
The average net weight
is 50.00 pounds
Wet-land randomly
checked 50 bags
Title Four
(November 2007)
The average net weight is
Refers to a good or
47.51 pounds.
service being offered
Short-weight
by a company.
by approximately
5%
4
The lightweight bags might have resulted
from
“growing pains”
Earlier
Energy
crisis
Oil and
natural gas
exploration
activity
increased
Demand for
drilling
mud
increased
5
Bayfield expansion shift
One Shift
Two Shifts
6AM - 2PM
Three Shifts
6AM - 2PM
6AM - 2PM
10PM – 6AM
2PM - 10PM
2PM - 10PM
6
Additional Factors
Occasionally double-check the bag weight feeder
A double check is performed by systematically weighting a bag on a scale to determine if the
proper weight is being loaded by the weight-feeder. If there is significant deviation from 50
pounds, corrective adjustments are made to the weight-release mechanism.
Night shift bagging crew was staffed entirely by new employees
The most experienced foremen were temporarily assigned to supervise the night shift
employees.
To verify this expectation
The quantity control staff randomly sampled 6 bags and weighted
each hour.
Time
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
4
5
A.M.
Noon
P.M.
Midnight
A.M.
Noon
P.M.
Average Weight
(pounds)
49.6
50.2
50.6
50.8
49.9
50.3
48.6
49.0
49.0
49.8
50.3
51.4
51.6
51.8
51.0
50.5
49.2
49.0
Smallest
48.7
49.1
49.6
50.2
49.2
48.6
46.2
46.4
46.0
48.2
49.2
50.0
49.2
50.0
48.6
49.4
46.1
46.3
Range
Largest
50.7
51.2
51.4
51.8
52.3
51.7
50.4
50.0
50.6
50.8
52.7
55.3
54.7
55.6
53.2
52.4
50.7
50.8
48.4
47.6
47.4
48.2
48.0
48.4
48.6
50.0
49.8
50.3
50.2
50.0
50.0
50.1
49.7
48.4
47.2
46.8
45.4
44.3
44.1
45.2
45.5
47.1
47.4
49.2
49.0
49.4
49.6
49.0
48.8
49.4
48.6
47.2
45.3
44.1
50.2
49.7
49.6
49.0
49.1
49.6
52.0
52.2
52.4
51.7
51.8
52.3
52.4
53.6
51.0
51.7
50.9
49.0
Time
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
4
5
Midnight
A.M.
Noon
P.M.
Midnight
A.M.
Average Weight
(pounds)
46.8
50.0
47.4
47.0
47.2
48.6
49.8
49.6
50.0
50.0
47.2
47.0
48.4
48.8
49.6
50.0
51.0
50.4
50.0
48.9
49.8
49.8
50.0
47.8
46.4
46.4
47.2
48.4
49.2
48.4
47.2
47.4
48.8
49.6
51.0
50.5
Range
Smallest
41.0
46.2
44.0
44.2
46.6
47.0
48.2
48.4
49.0
49.2
46.3
44.1
45.0
44.8
48.0
48.1
48.1
49.5
48.7
47.6
48.4
48.8
49.1
45.2
44.0
44.4
46.6
47.2
48.1
47.0
46.4
46.8
47.2
49.0
50.5
50.0
Largest
51.2
51.7
48.7
48.9
50.2
50.0
50.4
51.7
52.2
50.0
50.5
49.7
49.0
49.7
51.8
52.7
55.2
54.1
50.9
51.2
51.0
50.8
50.6
51.2
49.7
50.0
48.9
49.5
50.7
50.8
49.2
49.0
51.4
50.6
51.5
51.9
7
8
Discussion Questions
What is your analysis of
the bag-weight problem?
9
STATISTICAL PROCESS
CONTROL
Setting Mean
Chart Limits: -Charts
S.D. ( )
N
S.D. mean ( )
z (99.73%)
UCL ( +
)
LCL ( )
49.13
1.2
6
0.4898979
3
50.60
47.66
UCL = 50.60 pounds
Mean = 49.13 pounds
LCL = 47.66 pounds
10
Control Chart Factors (R
Chart)
Average Weight
(pounds)
49.6
A.M.
50.2
50.6
50.8
49.9
50.3
48.6
Noon
49.0
P.M.
49.0
49.8
50.3
51.4
51.6
51.8
51.0
50.5
49.2
49.0
48.4
Midnight
47.6
A.M.
47.4
48.2
48.0
48.4
48.6
50.0
49.8
50.3
50.2
50.0
50.0
Noon
50.1
P.M.
49.7
48.4
47.2
46.8
Time
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
4
5
Range
Smallest
48.7
49.1
49.6
50.2
49.2
48.6
46.2
46.4
46.0
48.2
49.2
50.0
49.2
50.0
48.6
49.4
46.1
46.3
45.4
44.3
44.1
45.2
45.5
47.1
47.4
49.2
49.0
49.4
49.6
49.0
48.8
49.4
48.6
47.2
45.3
44.1
Largest
50.7
51.2
51.4
51.8
52.3
51.7
50.4
50.0
50.6
50.8
52.7
55.3
54.7
55.6
53.2
52.4
50.7
50.8
50.2
49.7
49.6
49.0
49.1
49.6
52.0
52.2
52.4
51.7
51.8
52.3
52.4
53.6
51.0
51.7
50.9
49.0
R
2.0
2.1
1.8
1.6
3.1
3.1
4.2
3.6
4.6
2.6
3.5
5.3
5.5
5.6
4.6
3.0
4.6
4.5
4.8
5.4
5.5
3.8
3.6
2.5
4.6
3.0
3.4
2.3
2.2
3.3
3.6
4.2
2.4
4.5
5.6
4.9
Time
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
4
5
Midnight
A.M.
Noon
P.M.
Midnight
A.M.
Average Weight
(pounds)
46.8
50.0
47.4
47.0
47.2
48.6
49.8
49.6
50.0
50.0
47.2
47.0
48.4
48.8
49.6
50.0
51.0
50.4
50.0
48.9
49.8
49.8
50.0
47.8
46.4
46.4
47.2
48.4
49.2
48.4
47.2
47.4
48.8
49.6
51.0
50.5
11
Range
Smallest
41.0
46.2
44.0
44.2
46.6
47.0
48.2
48.4
49.0
49.2
46.3
44.1
45.0
44.8
48.0
48.1
48.1
49.5
48.7
47.6
48.4
48.8
49.1
45.2
44.0
44.4
46.6
47.2
48.1
47.0
46.4
46.8
47.2
49.0
50.5
50.0
Largest
51.2
51.7
48.7
48.9
50.2
50.0
50.4
51.7
52.2
50.0
50.5
49.7
49.0
49.7
51.8
52.7
55.2
54.1
50.9
51.2
51.0
50.8
50.6
51.2
49.7
50.0
48.9
49.5
50.7
50.8
49.2
49.0
51.4
50.6
51.5
51.9
R
10.2
5.5
4.7
4.7
3.6
3.0
2.2
3.3
3.2
0.8
4.2
5.6
4.0
4.9
3.8
4.6
7.1
4.6
2.2
3.6
2.6
2.0
1.5
6.0
5.7
5.6
2.3
2.3
2.6
3.8
2.8
2.2
4.2
1.6
1.0
1.9
12
STATISTICAL PROCESS
CONTROL
Setting Mean
Chart Limits: R-Charts
(
LCL (
)
)
2.004
0
3.733
7.482
0
UCL = 7.482 pounds
Mean = 3.733 pounds
LCL = 0 pounds
13
Morning Shift Chart
-Charts
R-Charts
UCL 50.60
Mean 49.13
LCL 47.66
UCL 7.482
Mean 3.733
LCL 0
14
Afternoon Shift Chart
-Charts
R-Charts
UCL 50.60
Mean 49.13
UCL 7.482
Mean 3.733
LCL 47.66
LCL 0
15
Night Shift Chart
-Charts
R-Charts
UCL 50.60
Mean 49.13
UCL 7.482
Mean 3.733
LCL 47.66
LCL 0
16
Discussion Questions
What procedure would you
recommend to maintain proper
quality control?
17
4 procedures
recommended
Hire professional
supervisors
who has expertise and
experiences in quality control
monitors. Set a timetable to
check the quality of product,
collect data, and analyze that
somethings is wrong or not. If
they find any problems, they
would take responsibility to
identify the cause and also
prevent these problems
extending to other process, and
then find the suitable solution.
Educate and train
new employees
Double checked the
bag weight
to increase the new
employees’ knowledge
and skills. Moreover, the
company should create
workshops to make new
employees familiar with
real situation and
environment, so that they
will know more about their
jobs.
to avoid any error in
weight. Moreover,
Bayfield should create a
mean and range charts
guideline, that will
encourage employees to
follow quality control
standard of the company.
Implement
automated testing
device
that can
inspect the
weight of its product in
order that managers can
track every variation more
precise.
18
Thank you