MAN 3504 - Chapter 41 Chapter 4. Flowcharts and Capacity zOutline yA System Perspective yBasic Flowcharting Elements yProcess Capacity xTime Requirements

MAN 3504 - Chapter 4 1

Chapter 4. Flowcharts and CapacityOutline

A System Perspective Basic Flowcharting Elements Process Capacity

Time Requirements Capacity Analysis


A System PerspectiveUnderstanding of the transformation processes System Perspective

A system boundary - depends on the purpose of the analysis

identification of customers and outputs - external or internal

identification of suppliers and inputs - materials, resources, ...

identification of system flows - the activities identification of measures of performance - profits?


ExampleActivit

ies required to prepare tax forms

Attach Document to work package

Tax Documents Arrive

Review that all required documents

are in the package

Request documentsfrom the customer

Prepare alltax forms

Review of formsWait for materials

Take to main office

Partner reviews theforms

Documents Missing

All is OK

Documents Missing

Forms Missingor incorrect

Forms Missingor incorrect

A

A

All OKB

B

End

ADocuments Missing B

Notify Customer


Example 2Points

of customer contact

Customer Calls for Appointment

Appointment is scheduled

Customer satisfiedwith work

Wait for interviewer

Yes

A

End

Fix-up process

Customer Arrives

Customer is interviewedand documents placed

in a folder

Customer Leaves

Must customer becontacted again (needadditional documents/

clarifications)

Customer is contacted toschedule a review

meeting

Customer is contacted + documents

requested

Forms prepared

Wait for interviewer

Customer Arrives

Forms and fees presented to customer

Customer Leaves

No

AYes

No


Basic Flowcharting ElementsOne set of icons. There are many

used in different fields. This is one subset of those.

ACTION/OPERATION

CONNECTOR

DECISIONQUALITYACTION

WAIT

MOVE


Basic Flowcharting: What Flows through the systemOne or more types of entities

People - patients in an hospital or doctor’s office, customers at a bank

Forms - loan application documents at a processing center, admission application at a university

Materials - computers at a store, plastic cups at a factory

Waste/trash - trash collected from offices Vehicles - cars at a concert Information - inventory information at a

supermarket


Determining Process CapacityBased on the analysis of the capacity

for each activityThe capacity of an activity is controlled

by (given a resource set) Time required to complete the activity

- time to fill a form, time to perform a test Space required - number of seats in a

theater, space in the buffer


Estimating Time RequirementsVery popular, lost it, gaining it backMeasurement of activitiesStandard time for an activity

1. Determine the start and end of the activity (bounds)2. Measure (stopwatch) several people several times

(days)3. Analyze the measurements4. ST = NT/(1-Allowances)

Other Standards: Baselines - experience/historical performance


Time Standards ExampleTable 4.1

Date 4/6/97 4/6/97 4/8/97 4/9/97 4/11/97Employee D. Edison R. Ford R. Ford J. Taylor D. EdisonMeasurements 7.3 8.4 8.3 7.2 7.2(minutes) 4.6 7.6 7.8 6.3 6.9

8.1 5.6 8.7 8.1 7.56.8 7.5 6.9 15.2 8.1

02468

10121416

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

02468

10121416

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Eliminating two “variant” pointsPlot of the data and the average


Capacity AnalysisAn evaluation of how forecasted

demand/planned production matches capacityCan be based on a combination of

products/servicesMeasurement of capacity:

Utilization = Required capacity / Estimated Capacity Efficiency = Actual Output / Estimated Capacity

CA can be done at different levels of an organization


Economies of scale/ Diseconomies of scaleLearning/ Experience curveGrowth - capacity additions creates complexity,

bureaucracyDay-to-day factors

Breakdown - equipment failure, employees sick Setup - non producing preparation time Starved - idle time given some input is not available Blocked - cannot produce as there is no space for the new

item Maintenance - idle time for maintenance activity

Factors Affecting Capacity


Table 4.2Equipment Cleaning/move ST Preparation ST Jan FebIV Pump 2.5 min - 104 127Emergency Cart 4.2 min 5.8 min 15 19Single Pump 1.4 min - 37 45Critical Care Cart 3.8 min 11.2 min 4 11

ExampleCalculate

Time requirement per activity for all products (equipment) SUM (Time x

planned use)

Used Equipment Arrives

Wait for equipment personnel

Equipment is cleaned

Yes

Does this equipment

need a preparation process

Take to clean area

Equipment is prep for use

End

No


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