Chapter I. Introduction To Cam: Dr. Tien-Chien Chang School of Industrial Engineering Purdue University
Chapter I. Introduction To Cam: Dr. Tien-Chien Chang School of Industrial Engineering Purdue University
Chapter I. Introduction To Cam: Dr. Tien-Chien Chang School of Industrial Engineering Purdue University
Chang
11/11/18 1- 1
©T.C. Chang
Definition
What is CAM?
11/11/18 1- 2
©T.C. Chang
11/11/18 1- 3
©T.C. Chang
11/11/18 1- 4
©T.C. Chang
INVENTIONS IN MANUFACTURING
1750 Screw-driven lathe
1751 Slide lathe - 1st metal lathe
1770 Screw-cutting lathe
1775 Boring mill
1813 Interchangeability of parts
Simon North horse pistols
1817 Planing machine
1845 Turret lathe
1847 Milling machine - Brown & Sharpe
making twist - drill helical grooves
11/11/18 1- 5
©T.C. Chang
THE TREND OF
MANUFACTURING INDUSTRY
Facts:
1. Rapid changing market place
2. Fast development of new technologies
Vacuum Tubes ->: Transistor -> IC -> VLSI
Wiring -> thru-hole PCB -> Surface Mount Component
Quality product -> precision engineering -> nano-engineering
3. Fierce competition
Failing automotive industry, steel mills, Wang Lab, ...
4. A "use brain" generation, not willing to learn the trade which
requires hand skill.
To survive:
1. Lower cost
2. Higher quality
3. Lower product development cycle
11/11/18 1- 6
©T.C. Chang
Tolerance
0.25 Cost
0.025
0.0025
11/11/18 1- 7
©T.C. Chang
SOLUTIONS DEVELOPED
1. Small batch production 95% in lot size of 50 or
less.
2. Just in time production, reduce inventory
(union?)
3. Automation - quality, labor cost
Automated lathe, screw machine (Swiss
machine), transfer line
4. Flexible automation - further reduce lead time,
automation of small batch
(NC, FMS, FMC, Robotics, ...)
5. Integration - CAM, CIM, concurrent engineering,
TQM, etc.
11/11/18 1- 8
©T.C. Chang
BENEFITS OF CAM
90% Inventory reduction
50% more efficient use of factory & warehouse
space
75% reduction in machine setup time - item setup
(re-measurement, repositioning, and
replacement of cutting tools,..)
Does not change product specific set-up.
25% reduction in direct and indirect labor
90% reduction in lead time
11/11/18 1- 9
©T.C. Chang
Too small a batch size is cited by 3/5 of all non-adopters as the reason
of not implementing computerized automation.
11/11/18 1- 10
©T.C. Chang
11/11/18 1- 11
©T.C. Chang
CURRENT
PROBLEMS
1. Manufacturing not emphasized enough
2. Designer tend to design for functionality
along
3. Manufacturing engineers lack overall concept
in manufacturing
4. Systems are not integrated.
11/11/18 1- 12
©T.C. Chang
CONCURRENT ENGINEERING
(SIMULTANEOUS ENGINEERING)
Design product and process simultaneously.
"Do not focus on only one aspect of the product
realization process."
11/11/18 1- 13
©T.C. Chang
EFFECT OF TOLERANCE
Tolerance
value
11/11/18 1- 14
©T.C. Chang
FUTURE
Alvin Toffler, Power Shift, 1990
(two other books by him: The Future Shock, 1970
The Third Wave, 1980)
Sources of power:
Force
Money
Knowledge
THREE LEVELS
OF COMPUTERIZATION
Data processing
Information processing
Knowledge processing
11/11/18 1- 16
©T.C. Chang
BASIC TAXONOMY
OF MANUFACTURING
1. Discrete vs. Continuous Mfg
Discrete - finite number of discrete steps
parts & product separable entities
TV, car,.....
11/11/18 1- 17
©T.C. Chang
MATERIAL PROCESSING
Machining - In This Class We Do Not Cover Forming
Turning
Drilling
Reaming
Boring
Tapping
Milling
Grinding
Broaching
Planing
Shaping
Sawing
EDM/ECM
Laser
11/11/18 1- 19
©T.C. Chang
MATERIAL HANDLING
11/11/18 1- 20
©T.C. Chang
MATERIALS PLANNING
mtl type
mtl shape
mtl preprocessing methods
eg. shape:
stock, casting,....
11/11/18 1- 21
©T.C. Chang
MATERIALS SELECTION
COST MODEL
Other than the strength consideration the cost is another major
one
NC1 + N C I VI = CM + N C I VI' + N C1'
I I
N: batch size
C1 : cost for preparing one workpiece from stock
Cm : cost of mold
': volume being machined by process i from the
Vi
casting
C1 ': incremental cost of making one casting
11/11/18 1- 22
©T.C. Chang
BREAK-EVEN
POINT
Cm
N* N
11/11/18 1- 23
©T.C. Chang
Automation
1. Process layout - individual m/c, NC.....
2. Product layout - transfer line technology
3. Group layout - FMS, FMC
11/11/18 1- 24
©T.C. Chang
PROCESS LAYOUT
(functional layout)
• transportation problem
radom route
Milling Lathe • scheduling problem
Job Shop complex flow
Drilling Grinding • most flexible, no new
layout for new prod.
• for batch production
11/11/18 1- 25
©T.C. Chang
PRODUCT LAYOUT
(flow layout)
• may need redundant m/c's
• simple scheduling, easy to
automate the mtl transportation
function
Production Line • less flexible
• for mass production
11/11/18 1- 26
©T.C. Chang
GROUP LAYOUT
(cellular layout)
• combination of 1 & 2
• tradeoff interdepartment mtl
handling w/ intradepartment
M.H.
Each cell produces one or a few
families of parts.
11/11/18 1- 27
©T.C. Chang
Final product
assembly Products quality
station
performance
inventory average
level tardiness
profit
ability
11/11/18 1- 28