Process engineering and computer applications

Process engineering basics with computer application

1. 4- 110/12/25
Process Engineering
Basics of Process Planning
for computer implementation
IE550 -- Manufacturing Systems
Fall 2008
Dr. R. A. Wysk

2. 4- 210/12/25
Chapter 6 -- Process Engineering

3. 4- 310/12/25
The Engineering Process
Stock Material
Processes
Finished part
Design
specifications
Process planning
Process
capability
Inspection
Need to understand the process capabilities.

4. 4- 410/12/25
PROCESS CAPABILITIES
Process: certain way an operation is carried out, e.g. turning,
drilling, milling.
Tool: physical object which is used to carrying out a process,
e.g. twist drill, spade drill, gun drill.
Machine tool: machine on which process is carried out, e.g.
lathe, drill press, milling machine, machining center.
Process capability: The geometry and tolerance a manufacturing process
can produce, and its limitations, . i.e. shape and size, dimensional and
geometric tolerances, material removal rate, relative cost, other
cutting constraints.

5. 4- 510/12/25
LEVELS OF PROCESS CAPABILITIES
Universal level:
Handbook and textbook level data. Aggregate characterization of what
can be expected. General measures of the process capability such as
shape and size. What the process can accomplish in an average shop
on a typical machine tool.
Shop level:
Specific to a particular manufacturing system. What is the best
attainable capability in one specific shop, e.g. the turning capability of
the student machine shop is far worse than that in the shop of a
precision spindle manufacturer.
Machine level:
Specific to a machine. Machines in the same shop has very different
capability. A table top lathe can machine a small part, yet a large slant
bed lathe may be able to handle a 20"x 10' part.

6. 4- 610/12/25
PROCESS KNOWLEDGE COLLECTION
Few scientific data available or published.
Most process knowledge are gained during actual manufacturing
practice.
Practical manufacturing knowledge is still an art instead of a science.
Certain information can be found in the textbooks, handbooks,
machining data handbook, etc.
Tolerance capability may be obtained from control charts, inspection
reports, and on-line sensor data.

7. 4- 710/12/25
EXPERIENCE-BASED
PLANNING
Relay on one's experience. Most frequently this is the way industry
operates.
Problems:
a. Experience requires a significant period of time to accumulate.
b. Experience represents only approximate, not exact knowledge.
c. Experience is not directly applicable to new processes or new
systems.
Need to automate.

8. 4- 810/12/25
MACHINIST
HANDBOOKS
Universal or shop level knowledge.
e.g. Surface-finish chart - limiting extremes of process
8  in - use grinding, polishing, lapping
Usually not with milling, however, finish milling may achieve the
specification.
The information is general. It does not mean every machine or shop
can achieve that accuracy.
Turning limit (6.3 - 0.4 m or 250 - 16  inch)
Diamond turning at Lawrence Livermore Lab
(12.5 nm or 0.47  inch)

9. 4- 910/12/25
SURFACE FINISH
CHART

10. 4- 1010/12/25

11. 4- 1110/12/25
Dimensional accuracies for Process Planning

12. 4- 1210/12/25
HOLE MAKING KNOWLEDGE
Following data is taken from a manufacturer's process planner's handbook.
I. Dia < 0.5"
A. True position > 0.010"
1. Tolerance > 0.010"
Drill the hole.
2. Tolerance < 0.010"
Drill and ream the hole.
B. True position < 0.010”
1. Tolerance < 0.010"
Drill, then finish bore the hole.
2. Tolerance < 0.002"
Drill, semi-finish bore, then finish bore the hole.
II. 0.05" < dia < 1.00"

13. 4- 1310/12/25
DECISION TABLES
To computerize the decision making, one simple way is to use decision tables.
If the conditions set in an entry are satisfied, the actions in the entry are
executed. The stub contains the condition or action statements. Entries mark
which conditions or actions are applicable. Each entry contain one rule.
Conditions
Actions
Stub
Entries

14. 4- 1410/12/25
EXAMPLE DECISION TABLE
Dia < 0.5
0.5 < Dia < 1.0
T.P < 0.010
T.P < 0.010
Tol > 0.010
0.002 < Tol < 0.010
Tol < 0.002
Drill
Ream
Semi-finish bore
Finish bore
X X X X
XX
XX X
X
X
X
X
X
X
XX X X
X
X
X X

15. 4- 1510/12/25
DECISION TREES
Node
Branch
To computerize the decision making, one simple way is to use decision trees.
Decision tree is a graph with a single root and branches emanating from the
root. Each branch has a condition statement associate with it. Actions are
written at the terminal. Probabilities may be assigned to the branches. In this
case, the tree represents probabilistic state transitions.
Root
terminal
The node may be "AND" nodes
or "OR" nodes.

16. 4- 1610/12/25
EXAMPLE DECISION TREE
Dia < 0.5
0.5 < Dia < 1.0
T.P < 0.010
T.P < 0.010
Tol > 0.010
Tol < 0.010
0.002 < Tol < 0.010
Tol < 0.002
Drill
Drill, then ream
Drill, then finish bore
Drill, semifinish bore,
then finish bore

17. 4- 1710/12/25
PROCESS-CAPABILITY
ANALYSIS
;
; twist drilling (code 1)
; 111: hole
( ( if
(shape ! 111 = )
( length ! 12.0 diameter ! * <= )
( diameter! 0.0625 >= )
( diameter! 2.000 <= )
( tlp ! diameter ! 0.5 ** 0.007 * >= )
( tln ! diameter ! 0.5 ** 0.007 * 0.003 + >= )
( straightness ! length ! diameter ! / 3. ** 0.0005 * 0.002 + >= )
( roundness ! 0.004 >= )
( parallelism ! length ! diameter ! / 3. ** 0.001 * 0.003 + >= )
( true ! 0.008 >= )
( sf ! 100 >= )
)

PROCESS BOUNDARY Data

18. 4- 1810/12/25
PROCESSES, TOOLS, AND MACHINES
•
Process Sub-Process Cutters
Milling
Plain
Shell end
Hollow end
Ball end
End milling
Peripheral milling Plain
Slittting Saw
Form
Inserted-tooth
Staggered-tooth
Angle
T-slot cutter
Woodruff keyseat cutter
Form milling cutter
Face milling Plain
Inserted-tooth
Drilling
Twist drill
Spade drill
Deep-hole drill
Gun drill
Trepanning cutter
Center drill
Combination drill
Countersink
Counterbore
Reaming
Shell reamer
Expansion reamer
Adjustable reamer
Taper reamer
Boring
Adjustable boring bar
Simple boring bar
Broaching
Form tool
Machines
Vertical milling machine
Horizontal milling machine

Column-and-knee
Bed type
Planer type
Special type

Machining center
Column & upright
Gang drilling machine
Radial drilling machine
Multispindle drilling machine
Bench type
Deepth hole drilling machine
Drill press
Lathe
Lathe
Boring machine
Jig bore
Turning
Turning
Facing
Parting

Knurling

Boring
Drilling
Reaming
Plain
Inserted
Knurling tool
Boring bars
Drills
Reamers
Speed lathe
Engine lathe
Toolroom lathe
Special lathe

Turret lathe
Screw machine
Broaching press
Vertical Pull-down
Vertical Pull-up
Surface broaching machine
Horizontal broaching machine
Surface broaching machine
Rotary broaching machine

19. 4- 1910/12/25
PROCESSES, TOOLS, AND MACHINES
Shaping
Form tool
Planing
Inserted tool
Sawing
Hacksaw
Bandsaw
Circular saw
Process Sub-Process Cutters Machines
Grinding
Cylindrical grinding
Centerless grinding
Internal grinding
External grinding
Surface grinding
Reciprocating saw
Band saw
Circular saw
Shaper
Horizontal & Vertical
Double housing planer
Open-side planer
Edge planer
Pit Planer
Grinding wheels
Points
External cylindrical grinder
Internal cylindrical grinder
Surface grinder
Creep feed grinder
Tool grinder
Disk grinder
Honing Honing stone Honing machine
Lapping Lap Lapping machine
Tapping
Tap Drill press
Milling machine
Machining center

20. 4- 2010/12/25
CUTTING EDGE AND FEED
Drill
cutting edge
Boring Reaming
Turning
Peripheral
Milling
minor feed
Face
Milling
feed range
Ball End
Milling
Broaching Sawing

21. 4- 2110/12/25
VOLUME PRODUCING CAPABILITIES
Process Sub-Process Cutters
Milling
Plain
Shell end
Hollow end
Ball end
End milling
Peripheral millingPlain
Slittting Saw
Form
Inserted-tooth
Staggered-tooth
Angle
T-slot cutter
Woodruff keyseat cutter
Face milling Plain
Inserted-tooth
Drilling
Twist drill
Spade drill
Deep-hole drill
Gun drill
Trepanning cutter
Center drill
Combination drill
Countersink
Counterbore
Reaming
Shell reamer
Expansion reamer
Adjustable reamer
Taper reamer
Boring
Adjustable boring bar
Simple boring bar
Broaching
Form tool
Volume Capabilities
flat bottom volume
round hole
round hole
deep round hole
deep round hole
large round hole
shallow round hole
multiple diameter round hole
countersink hole
counterbore hole
thin wall of round hole
thin wall of round hole
thin wall of round hole
thin wall of round hole
thin wall of round hole
thin wall of round hole
Turning
Turning
Facing
Parting

Knurling

Boring
Drilling
Reaming
Plain
Inserted
Knurling tool
Boring bars
Drills
Reamers
?
disk
disk

?

thin wall of round hole
round hole
thin wall of round hole
flat bottom volume
slot
step
polyhedral through hole
formed through volume
flat bottom volume
slot
formed volume



T-slot
Internal groove
pocket, slot, flat
sculptured surface, flat

22. 4- 2210/12/25
VOLUME PRODUCING CAPABILITIES
Shaping Form tool
Planing
Inserted tool
Sawing
Hacksaw
Bandsaw
Circular saw
ProcessSub-Process Cutters Volume Capabilities
Grinding
Cylindrical grinding
Centerless grinding
Internal grinding
External grinding
Surface grinding
?
flat bottom volume, slot
flat bottom volume
Grinding wheels
Points
?
internal wall of round hole
flat bottom volume
Honing Honing stone ?
Lapping Lap
most surfaces
Tapping Tap threaded wall of hole

23. 4- 2310/12/25
PROCESS TOLERANCE
RANGE
ProcessSub-Process
Cutters
Milling
Plain
Shell end
Hollow end
Ball end
End milling
Peripheral milling
Plain
Slittting Saw
Form
Inserted-tooth
Staggered-tooth
Angle
T-slot cutter
Woodruff keyseat cutter
Form milling cutter
Face milling
Plain
Inserted-tooth
Drilling
Twist drill
Spade drill
Trepanning cutter
Center drill
Combination drill
Countersink
Counterbore



Deep-hole drill
Gun drill
Reaming
Shell reamer
Expansion reamer
Adjustable reamer
Taper reamer
Boring
Adjustable boring bar
Simple boring bar
Broaching
Form tool
Turning
Turning
Facing
Parting

Knurling

Boring
Drilling
Reaming
Plain
Inserted
Knurling tool
Boring bars
Drills
Reamers
Tolerances, surface finish, etc. capabilities
roughting finishing
tol 0.002 0.001
flatness 0.001 0.001
angularity 0.001 0.001
parallelism 0.001 0.001
surface finish 50 30
roughting finishing
tol 0.002 0.001
flatness 0.001 0.001
surface finish 50 30
roughting finishing
tol 0.004 0.004
parallelism 0.0015 0.0015
surface finish 60 50
length/dia = 3 usual =8 maximum
mtl < Rc 30 usual < Rc 50 maximum

Dia Tolerance
0 - 1/8 +0.003 -0.001
1/8-1/4 +0.004 -0.001
1/4-1/2 +0.006 -0.001
1/2- 1 +0.008 -0.002
1 - 2 +0.010 -0.003
2 - 4 +0.012 -0.004
usuall best
True position 0.008 0.0004
roundness 0.004
surface finish 100
Dia Tolerance
< 5/8 0.0015
>5/8 0.002
surface finish > 100
straightness 0.005 in 6 inch
Dia Tolerance
0 - 1/2 0.0005 to 0.001
1/2- 1 0.001
1 - 2 0.002
2 - 4 0.003
roughting finishing
roundness 0.0005 0.0005
true position 0.01 0.01
surface finish 125 50
length/dia 5 to 8
Dia Tolerance
roughing finishing
0 - 3/4 0.001 0.0002
3/4- 1 0.0015 0.0002
1 - 2 0.002 0.0004
2 - 4 0.003 0.0008
4 - 6 0.004 0.001
6 - 12 0.005 0.002
straightness 0.0002
roundness 0.0003
true position 0.0001
surface finish 8
diameter tolerance
to 1.0 0.001
1 - 2 0.002
2 - 4 0.003
surface finish 250 to 16
tolerance 0.001
surface finish 125 to 32

24. 4- 2410/12/25
PROCESS TOLERANCE
RANGE
Shaping Form tool
Planing
Inserted tool
Sawing Hacksaw
Bandsaw
Circular saw
ProcessSub-Process Cutters
Grinding
Internal grinding

Cylindrical grinding
Centerless grinding

External grinding
Surface grinding
Honing Honing stone
Lapping Lap
Tapping Tap
Tolerances, surface finish, etc. capabilities
length tol squareness surface finish cutting rate material
0.01 0.2 200 - 300 3-6 sq in/min to Rc45
0.01 0.2 200 - 300 4-30 sq in/min to Rc45
0.008 0.2 125 7-36 sq in/min to Rc45
roughting finishing
location tol 0.005 0.001
flatness 0.001 0.0005
surface finish 60 32 (cast iron)
surface finish 125 32 (steel)
Dia Tolerance
roughing finishing
0 - 1 0.00015 0.00005
1 - 2 0.0002 0.00005
2 - 4 0.0003 0.0001
4 - 8 0.0005 0.00013
8 - 16 0.0008 0.0002
Dia Tolerance
roughing finishing
1 +0.0005-0.0 +0.0001-0.0
2 +0.0008-0.0 +0.0005-0.0
4 +0.0010-0.0 +0.0008-0.0
surface finish 4
roundness 0.0005
roughing finishing
tolerance 0.000025 0.000015
flatness 0.000025 0.000012
surface fin 4-6 1-4
tolerance 0.003
roundness 0.003
surface fin 75
roughing finishing
tolerance 0.0005 0.0001
parallelism 0.0005 0.0002
roundness 0.0005 0.0001
surface fin 8 2
roughing finishing
tolerance 0.001 0.0001
parallelism 0.001 0.0001
surface fin 32 2
center ground
flat
and centerless
Internal

25. 4- 2510/12/25
AUTOMOTIVE PARTS REQUIREMENTS
•Cylinder bore 13 - 25 in honed
•Main bearing bore 63 - 200 in
•Crankshaft bearing 3-13 in polished
•Brake drum 63-125 in turned
•Clutch pressure plate25-100 in turned

26. 4- 2610/12/25
BASIC MACHINING
CALCULATIONS

t
m=
L+L
v
f
Machining time
Total amount of time to finish a workpiece.
For drilling, one pass turning, and milling:
L: clearance or overhang distance.
For multipass turning

n
p=
D
o–D
i
2a
p
+
integer round up
For milling

n
p=
h
a
p
+
w
D
+

n
p:#ofpasses

h:totalheightofmaterialtoberemoved

w:workpiecewidth

:cutteroverlappingfactor
=effectivecuttingwidth/tooldia1.0

27. 4- 2710/12/25
BASIC MACHINING
CALCULATIONS
Machine control parameters are: f, V, ap.
a. Feed and feedrate

f:inch/rev
turning or drilling
milling
rpm

N:
#ofteechinmilling
1indrilling

n:rpm

V
f=fnN

V
f=fn

V
f:inch/min

V
f

28. 4- 2810/12/25
BASIC MACHINING
CALCULATIONSCutting speed
D: Diameter
Depth of cut

a
pinch

a
p=
D
o–D
i
2
D
V
surface speed

Vinsfpm
D
i
D0

V=
Dn
12

29. 4- 2910/12/25
BASIC MACHINING
CALCULATIONSMetal removal rate

MRRcuttingtimetoollife

MRR
in
3
min
in
3
min
Drilling
Turning
Milling
W
v
f
a
p

MRR=
D
2
4
v
f
=3DfV

MRR=
(D
2
o–D
2
i)
4
v
f
=6(D
o–D
i)fV
v
f
(D
2
o–D
2
i)
4

MRR=a
pwv
f
=
12a
pwn
D
fV
D
2
4
v
f

30. 4- 3010/12/25
BASIC MACHINING
CALCULATIONS

t
m=
L+L
v
f
Machining time
Total amount of time to finish a workpiece.
For drilling, one pass turning, and milling:
L: clearance or overhang distance.
For multipass turning

n
p=
D
o–D
i
2a
p
+
integer round up
For milling

n
p=
h
a
p
+
w
D
+

n
p:#ofpasses

h:totalheightofmaterialtoberemoved

w:workpiecewidth

:cutteroverlappingfactor
=effectivecuttingwidth/tooldia1.0
L

31. 4- 3110/12/25
CUTTING FORCE AND POWER
ProcessSub-Process
Milling
End milling
Peripheral milling
Face milling
Drilling
Reaming
Boring
Shaping
Planing
Broaching
Turning
Facing
Turning
Cutting Force F Power (hp)
KF f
F
ap
F
Dt
F
bwz
KF v
F
a
f
F
a
p
F
bw
F
z
F
Dt
F
KF f
F
a
p
F
KF f
F
a
p
F
Dt
F
KF a
p
F
Dmzc
c
(lb)
Fc Vc
33,000 m
Fc Vc
33,000 m
Fc Vc
33,000 m
Ts rpm
63,030 m
where:
Vc :: cutting speed fpm
m : machine efficiency
Ts : Torque
torque

32. 4- 3210/12/25
MATERIAL REMOVAL RATE
ProcessSub-Process
Milling
End milling
Peripheral milling
Face milling
Drilling
Boring
Shaping
Broaching
Turning
W: width of the cutter
ap : depth of cut
f : feed
n : number of teeth
N : spindle rpm
D : tool
diameter
tr : rise per tooth
W : Width of the tool
V : cutting speed
n : number of tooth in
contact with part
12 tr W V n
( D
2
/4) f N
12 V f ap
12 V f ap
Facing
Turning
6 V f ap
L t f Ns
L : strock length
Ns : number of strock per minute
W ap f n N
MRR

33. 4- 3310/12/25
CONSTRAINT
S

n
minn
wn
max

n
tminn
tn
tmax

F
cF
c,max
Spindle-speed constraint:
workpiece
tool
Feed constraint:
Cutting-force constraint:

P
mP
max
Power constraint:

R
aR
a,max
Surface-finish constraint:
 f
minff
max

34. 4- 3410/12/25
MODELS
Multiple pass model

t
prt
h+(t
i
m
i=1
n
p
+
t
i
m
t
t
t
)

c
pr
c
b
n
b
+c
mt
h+c
i
pr
i=1
n
p
i : pass number
Additional constraint:
depth of cut
: number of passes is a function of the depth of cut.

a
p

n
p
Productivity model:

p
r
s–c
pr
t
pr
s: sale price/piece