Process analysis terms

PROCESS ANALYSIS TERMS

• Process: Is any part of an organization that takes inputs and transforms them into outputs.

• Cycle Time: Is the average successive time between completions of successive units.

• Utilization: Is the ratio of the time that a resource is actually activated relative to the time that it is available for use.

PROCESS FLOWCHARTING

• Process flowcharting is the use of a diagram to present the major elements of a process.These basic elements can include:

• tasks or operations• flows of materials or customers• decision points• storage areas or queues.

• It is an ideal methodology by which to begin analyzing a process.

FLOWCHART SYMBOLS

Tasks or Operations

Examples: Giving an admission ticket to a customer, installing a engine in a car, etc.

Decision Points

Examples: How much change should be given to a customer, which wrench should be used, etc.

FLOWCHART SYMBOLS (CONT.)

Storage areas or queues

Examples: Sheds, lines of people waiting for a service, etc.

Flows of materials or customers

Examples: Customers moving to their seat, mechanic getting a tool, etc.

EXAMPLE FLOWCHART:STUDENT GOING TO SCHOOL

Yes

No

Goof off

Go to school today?

Walk to class

Drive to school

1. ApartmentUnit Vacated

2. Trash OutUnit

3. Assessmentto Turn

Unit/MakeReady

4. PerformMajor

Repairs

5. Prepare for Painting

6. Paint 7. Punch Out 8. Replace/Repair Carpet 9. Clean Unit 10. Master Key

Unit

11. ArrangePest

Control

12. Inspect/Light CleanDaily Until

Rented

13. Apt UnitDetermined To

Be Ready

14. ApplicationCompleted/Approved

ApartmentUnit Rented

Process Flowchart - Improving the Apartment Rent-Ready Process

MULTISTAGE PROCESSES

Stage 1 Stage 2 Stage 3

Multistage Process with Buffer

Stage 1 Stage 2

Buffer

MULTI-STAGE PROCESSES

• Buffering• Refers to a storage area between stages where

the output of a stage is placed prior to being used in a downstream stage. Buffers allow stages to operate independently. Work-in-process (WIP) inventory will accumulate in the buffer.

• No Buffering• Blocking: Occurs when activities in a stage must

stop because there is no place to deposit the item just completed.

• Starving: Occurs when the activities in a stage must stop because there is no work.

OTHER TYPES OF PROCESSES

• Make-to-order• Only activated in response to an actual order.• Both work-in-process and finished goods inventory kept to a

minimum.

• Make-to-stock• Process activated to meet expected or forecasted demand.• Customer orders are served from target stocking level.

PROCESS PERFORMANCE METRICS• Operation time = Setup time + Run time• Cycle time = Average time between

completion of units• Throughput rate = 1/Cycle time• Throughput time = Average time for a unit to

move through the system*

* Note: Little’s Law computes throughput time while in (work-in-process) inventory only

CYCLE TIME EXAMPLE

Suppose you had to produce 600 units in 80 hours to meet the demand requirements of a product.

What is the cycle time to meet this demand requirement?

BREAD-MAKING OPERATION

•See pp. 113-114 (102-104 in old text). For homework, construct a table, showing the amount baked, amount packed, and WIP for each hour of the day (3 eight hour shifts).

•Calculate the Throughput Time in WIP Inventory using Little’s Law; then calculate the Total Throughput Time by adding the time in WIP inventory to the baking and packing times.