Process Flow Measures

Roadmap

• Flows and Processes• Capacity required to support flows

and processes• Amount of material in flows and

processes• Length of time material is in flows

and processes

How does an IE understand Norcen Industries?By focusing on the material

flows, and information flows.

Important Terminology(domain knowledge)

• Part (part number, part type, sku)• Customer order--one or more part types• Job -- the basic unit of material flow, one

or more parts• Process -- basic unit of conversion capacity• Operation -- particular conversion

performed at a particular process for a particular part

More Terminology

• Process sheet--sequence of conversion operations for a specific part

• Job sheet--history of a specific job• Time card--record of time charged by a

specific worker to specific jobs• Record card--history of orders for a

specific part type from a specific customer, with PO number for each order

Process SheetTechnical data Work standards

Process Sheet

• Tells us what conversion steps are required, and in what order– Q: is this order unique?

• Tells us how long each conversion operation should take

• Does not tell us how long it takes to complete the job!– Q: why not?

Turning

Grinding

Sawing

Milling

Drilling & Deburring

Prep

Inspect

Ship

Figure B7 in Tour B illustrates processes (conversions) for “typical” part

Prep Mill Grind Inspect& Ship

Turn

Turning

Grinding

Sawing

Milling

Drilling & Deburring

Prep

Inspect

Ship

Basic pattern of Job Shop Material Flow

Delay

Setup timeRun time

Transport Time

“Standards”

No “Standards”

Time at this operation = WaitIn + Setup + Run + WaitOut + Transport

Manufacturing Cycle Time(Job Flow Time)

MCT = Σ (WaitIn + Waitout) + Σ (Setup + Run)

+ Σ Transport

ReleaseTime + MCT = DeliveryTime

DeliveryTime - DueDate = Earliness/Lateness

Flow Process Chart

JobChart beginsChart endsChart byDate

Ope

ratio

n Details of Operation Present

Proposed

Ope

ratio

n

Tran

spor

t

Insp

ectio

n

Del

ay

Sto

rage

Dis

tanc

e (ft

)

Qua

ntity

Tim

e

Notes

Process Flow Chart*

* standard “IE” tool

Turning

Grinding

Sawing

Milling

Drilling & Deburring

Prep

Inspect

Ship

Flow Process ChartJobChart beginsChart endsChart byDate

Ope

ratio

n Details of Operation Present

Proposed

Ope

ratio

n

Tran

spor

t

Insp

ectio

n

Dela

y

Stor

age

Dist

ance

(ft)

Qua

ntity

Tim

e

Notes

Prep materials 100

Move to Turning Dept 75

100 2 hour setup time

Turnco Lathe #3

Supervisor inspection 100

Move to Milling Dept

80

Millco Mill #1

Move to Grinding Dept 65

See sheet b for rework process

Grindco Grinder A

Move to QC Department 30

QC sampling inspection

Move to Shipping 100

Pack

Ship

Process Flow Chart

• Documents all the transactionsinvolved in completing a job

• Allows computing the “theoretical” job time, from the standards

• Identifies the delays that must be accounted for

• Provides the basis for estimating actual MCT

Sample of 41 jobs from last week

P T M G I/S 32

P T M G I/S 3

P T M G I/S 3

P T M G I/S 3

What is the total material flow?

From/To Chart*F\T Prep Turn Mill Grind Ins/Ship OutsPrep 32 9 41Turn 32+3=35 3 38Mill 3 32+3+3+3=41 44Grind 3 32+3+3+3=41 44Insp/ShipIns 38 44 44 41 167

What do we learn from this?

* standard “IE” tool

Estimating Mover Capacity

• Suppose jobs moved one-at-a-time by lift truck

• How many “lift truck hours” per day were required?

• Note: lift trucks travel loaded and unloaded

• Visualize lift truck operations...

Estimating Mover Capacity

• Distance traveled unloaded (from last delivery)

• Distance traveled loaded (origin to destination)

• Time required to pick up and set down• Time required to travel, based on velocity

Requires “Standards”

Summary

• Process modeling– input, output, resources– process sheets– process flow charts

• Estimating mover capacity requirement