Matching Supply and Demand

Only available on StudyMode
  • Download(s) : 191
  • Published : October 29, 2012
Open Document
Text Preview
Chapter 3: Process analysis

COMFY SHOES INC
Comfy Shoes Inc builds shoes tailored to meet each individual customer’s needs. Customers who visit the downtown offices of Comfy Shoes in Philadelphia can choose one or more of the following four custom-tailoring services. Customers receive their shoes in the mail within a week of their initial visit.

ServiceDescriptionTimeResource used
A. Walking BasicsTake measurements for basic walking shoes.12 min.1 attendant B. Walking PlusChoose specific design (e.g. material, color selection)12 min.1 attendant C. Running BasicsTake measurements for tailor-made running shoes10 min.1 attendant D. Running AdvConsult physical therapist and obtain precise needs for running shoes. Also choose specific design. 40 min.1 attendant

The company offers the following packages to their customers:

1. Package 1: Includes only Walking Basics (Service A)
2. Package 2: Includes Walking Basics and Walking Plus (Services A and B). 3. Package 3: Walking Basics, Walking Plus and Running Basics (Services A, B and C). 4. Package 4: All four services (A, B, C, and D)

Customers of Comfy Shoes visit the store at a constant rate (you can ignore any effects of variability) of 20 customers per day. Of these customers, 45% buy Package 1, 10% buy Package 2, 20% buy Package 3 and 25% buy Package 4. The mix does not change over the course of the day. The store operates 12 hours a day.

What is the implied utilization of the attendant in service D? The calculations are summarized below:

Package
1234TotalUtilization
TaskTime(min)# workersAvail. Cap.0.450.100.200.25 A. Walking Basics121609245200.33
B. Walking Plus12160245110.183
C. Running Basics101603.334.1667.50.125
D. Running Adv40160 16.6616.660.278

Service D has an implied utilization of 28%

Which resource has the highest implied utilization?

Service A (Walking Basics) has the highest implied utilization

At the end of the spring season, Comfy Shoes anticipates an increase in the demand to 50 customers per day. A change in the mix of packages demanded is also expected: 30% of the customers ask for Package 1, 10% for Package 2, 10% for Package 3 and 50% for Package 4. The company will hire an additional attendant to help with Service A (Walking Basics)

At the end of the spring season, Comfy Shoes anticipates an increase in the demand to 50 customers per day. A change in the mix of packages demanded is also expected: 30% of the customers ask for Package 1, 10% for Package 2, 10% for Package 3 and 50% for Package 4. The company will hire an additional attendant to help with Service A (Walking Basics)

What will be the bottleneck in the process given this new demand pattern?

Package
1234TotalUtilization
TaskTime(min)# workersAvail. Cap.0.30.100.100.5
A. Walking Basics12160155525500.833
B. Walking Plus121605525350.58
C. Running Basics101604.16620.83250.4166
D. Running Adv40160 83.3383.331.388

Service D is the new bottleneck
How many customers a day will not be served? *

Service D receives 0.5 * (50/12) * 40 = 83.33 minutes of work every hour. Only 60 minutes of work can be served. Thus, every hour, 23.33 minutes of work, or 23.33/40 customer is not served. Customers not served in a day = [(83.333 – 60) / 40] * 12 = 7 customers a day will not be served

Old City Photographics

Located alongside a cobblestoned street in Old City, Old City Photographics (OCP) specializes in the processing of the traditional 35mm negative film, a once dominant photographic medium now in decline due to the popularity of digital photography. OCP offers three packages to their customers. With the standard package, the customer gets a set of 6”x4” prints for $19.99. The deluxe package adds to the standard package a CD-ROM of high resolution scans...
tracking img