Factory Physics

fisica de fabricaIIE Conference: May 2008

®

Factory Physics : A Fast Cycle
Time
Time Story
Presenters
Tim Skowronski

Joan Tafoya

IE Manager

Senior Technologist

Intel Products, Philippines

Intel Products, Vietnam

Factory Physics is a registered trademark of Factory Physics Inc. Our gratitude to Ed Pound
and Mark Spearman of Factory Physics Inc. for their education andsupport.

Tafoya/ Skowronski

May 2008

IIE Conference: May 2008

Let’s Start with the Results:

Tafoya/ Skowronski

May 2008

IIE Conference: May 2008

How Did We Do This?
•Implementing a Lean Culture?
•Install a fancy pull / MRP system?
•Add Automation to our Factories?

NO!.. None of These

Tafoya/ Skowronski

May 2008

IIE Conference: May 2008

Understand HowYour Factory Works
Applying Math And The Scientific
Method - Factory Physics ®

Implementing rigorous engineering methods
that we have all been taught.
» Improves Intuition
» Facilitates Data Based Decision Making

Tafoya/ Skowronski

May 2008

IIE Conference: May 2008

What is Factory Physics

®

» Systematic process to identify areas for factory
improvement
» Focuses heavilyon variability (tool availability, outs,
starts) as the primary source of inconsistent factory
performance
↓ variability = ↑ consistent output = ↓ cycle time
» It is NOT a new catch phrase in the consulting arena.
» The core material is part of most Industrial Engineering
curriculums and is practiced at many other companies
» Text book by Hopp and Spearmam
• Much more information than whatwe will touch of
today…scheduling, forecasting, etc.
Tafoya/ Skowronski

May 2008

IIE Conference: May 2008

A Manufacturing Law
Little's Law: The fundamental relation
between WIP, CT, and TH over the longterm is:

WIP = TH × CT
• Example:
Factory produces 100,000 parts/ week.
To achieve a CT = 5 days and TH = 14,285 units /
day

WIP = 14.3k * 5 days = 71,500 units
Tafoya/Skowronski

May 2008

IIE Conference: May 2008

Illustrating Little’s Law
Cycle Time

& WIP

: Throughput ?
Throughput
TH = 2 gallons/hr

CT = 5 hours
WIP = 10 gallons

CT = 2.5 hours
WIP = 5 gallons

TH = 2 gallons/hr

Tafoya/ Skowronski

May 2008

IIE Conference: May 2008

Definitions
Throughput (TH): Average quantity of good
parts produced per unit time. EG: outputor
outs/ week
Work in Process (WIP): inventory between
the
the start and endpoints of a product routing.
Cycle Time (CT): time between release of
the job at the beginning of the routing until it
reaches an inventory point at the end of the
routing.
Tafoya/ Skowronski

May 2008

IIE Conference: May 2008

Definitions
Definitions
Bottleneck Rate (BNR): Rate (parts/unit
time) ofthe process center having the
highest long-term utilization.
Raw Process Time (RPT): Sum of the
long-term average process times of each
station in the line. This term isn’t
theortical and does not include queue time.

Tafoya/ Skowronski

May 2008

IIE Conference: May 2008

Relationship of Terms:
Critical WIP (CW): WIP level in which a
line having no variability would achieve
maximumthroughput (i.e., BNR) with
minimum cycle time (i.e., RPT).
The ‘ideal’ state

CW = RPT * BNR
So what does this look like?
» CW is the WIP level where … any
additional inventory would cause
material to accumulate queue time.
Tafoya/ Skowronski

May 2008

IIE Conference: May 2008

Make It Simple
Penny Fab
Punch

Stamp

Rim

Deburr

What is relation between CT and WIP?
CTWIP
Tafoya/ Skowronski

May 2008

IIE Conference: May 2008

The Penny Fab

•Characteristics:
»Four identical tools in series.
»Each takes 2 hours per piece (penny).
»No variability.
»Jobs released to maintain target WIP
levels (conwip)

Tafoya/ Skowronski

May 2008

IIE Conference: May 2008

The Penny Fab

Tafoya/ Skowronski

May 2008

IIE Conference: May 2008...