The document discusses process planning and engineering. It describes the need to understand process capabilities at different levels including universal, shop, and machine levels. Process capabilities refer to the geometry, tolerances, material removal rates, and costs that manufacturing processes can produce. Decision tables and trees are presented as ways to represent process knowledge and rules for computerized process planning. Specific capabilities of processes like milling, drilling, turning, and grinding are also outlined.

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Process Engineering
Basics of Process Planning
for computer implementation
IE550 -- Manufacturing Systems
Fall 2008
Dr. R. A. Wysk

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Chapter 6 -- Process Engineering

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The Engineering Process
Stock Material Processes Finished part
Design
specifications
Process planning
Process
capability
Inspection
Need to understand the process capabilities.

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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.

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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.

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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.

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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.

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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)

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SURFACE FINISH CHART

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Dimensional accuracies for Process Planning

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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"

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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

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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
X
X
X
X X
X
X
X
X
X
X
X
X X X
X
X
X X

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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.

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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

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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

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PROCESSES, TOOLS, AND MACHINES
•
Process Sub-P
rocess Cutters
Milling
Plain
Shell end
Hollow end
Ball end
End milling
Peripheral milling Plain
Slittting Saw
Form
Inserted-tooth
Staggered-tooth
Angle
T-slotcutter
Woodruffkeyseat cutter
Formmillingcutter
Facemilling Plain
Inserted-tooth
Drilling
Twist drill
Spadedrill
Deep-hole drill
Gun drill
Trepanning cutter
Center drill
Combination drill
Countersink
Counterbore
Reaming
Shell reamer
Expansion reamer
Adjustablereamer
Taperreamer
Boring Adjustableboring bar
Simpleboring bar
Broaching
Formtool
Machines
Verticalmillingmachine
Horizontal milling machine
Column-and-knee
Bed type
Planer type
Special type
Machining center
Column & upright
Gangdrilling machine
Radial drilling machine
Multispindledrilling machine
Bench type
Deepth holedrilling machine
Drillpress
Lathe
Lathe
Boring machine
Jig bore
Turning
Turning
Facing
Parting
Knurling
Boring
Drilling
Reaming
Plain
Inserted
Knurlingtool
Boring bars
Drills
Reamers
Speedlathe
Enginelathe
Toolroomlathe
Special lathe
Turretlathe
Screwmachine
Broaching press
VerticalPull-down
VerticalPull-up
Surface broaching machine
Horizontal broaching machine
Surface broaching machine
Rotary broaching machine

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PROCESSES, TOOLS, AND MACHINES
Shaping Form tool
Planing
Inserted tool
Sawing
Hacksaw
Bandsaw
Circular saw
Proce ss Sub-Proce ss 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 cylindricalgrinder
Surface grinder
Creep feed grinder
Toolgrinder
Disk grinder
Honing Honing stone Honing machine
Lapping Lap Lapping machine
Tapping Tap Drill press
Milling machine
Machining center

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CUTTING EDGE AND FEED
Drill
cu tting edge
Boring Reaming
Turning
Peripheral
Milling
minor f eed
Face
Milling
f eed range
Ball End
Milling
Broaching Sawing

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VOLUME PRODUCING CAPABILITIES
Proc ess Sub-P
rocess Cutters
Milling
Plain
Shell end
Hollow end
Ball end
End milling
Peripheralmilling Plain
Slittting Saw
Form
Inserted-tooth
Staggere d-tooth
Angle
T-slotcutter
Woodruffkeyseat cutter
Face milling Plain
Inserted-tooth
Drilling
Twist drill
Spade drill
Deep-hole drill
Gun drill
Trepanningc utter
Centerdrill
Combination drill
Counters ink
Counterbore
Reaming
Shell rea mer
Expansion re amer
Adjustable re amer
Tape rreamer
Boring
Adjustable boring ba r
Simple boring bar
Broa ching Formtool
Volume Capabilities
flatbottomvolume
roundhole
roundhole
deep round hole
deep round hole
large roundhole
shallow round hole
multiple diameter roundhole
counters inkhole
counterbore hole
thin wall ofround hole
thin wall ofround hole
thin wall ofround hole
thin wall ofround hole
thin wall ofround hole
thin wall ofround hole
Turning
Turning
Facing
Parting
Knurling
Boring
Drilling
Reaming
Plain
Inserted
Knurling tool
Boringbars
Drills
Reamers
?
disk
disk
?
thin wall ofround hole
roundhole
thin wall ofround hole
flatbottomvolume
slot
step
polyhedralthrough hole
forme dthrough volume
flatbottomvolume
slot
forme dvolume
T-slot
Internal groove
pocket, slot, flat
sculptured surface , fla t

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VOLUME PRODUCING CAPABILITIES
Shaping Form tool
Planing
Inserted tool
Sawing
Hacksaw
Bandsaw
Circular saw
Process Sub-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 ?
Lapp ing Lap most surfaces
Tapping Tap threaded wall of hole

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PROCESS TOLERANCE RANGE
Process Sub-Proc ess Cutte rs
Milling
Plain
Shell end
Hollowe nd
Ball end
End milling
Peripheral milling
Plain
SlitttingSaw
Form
Inserted-tooth
Staggered-tooth
Angle
T-slotc utte r
Woodruffke yse atc utte r
Form millingc utte r
Fa ce milling
Plain
Inserted-tooth
Drilling
Twist drill
Spade drill
Trepa nningc utte r
Center drill
Combina tion drill
Countersink
Counterbore
Deep-hole drill
Gundrill
Rea ming
Shell re amer
Expansionream er
Adjustable rea mer
Taper reame r
Boring
Adjustable boring bar
Simple boringba r
Broac hing Form tool
Turning
Turning
Fa cing
Parting
Knurling
Boring
Drilling
Rea ming
Plain
Inserted
Knurlingtool
Boringba rs
Drills
Rea mers
Tolerances ,surface finish,etc.capabilities
roughting finishing
tol 0.002 0.001
flatness 0. 001 0.001
angularity 0.001 0.001
pa ra llelism 0.001 0. 001
surface finish50 30
roughting finishing
tol 0.002 0.001
flatness 0. 001 0.001
surface finish50 30
roughting finishing
tol 0.004 0.004
pa ra llelism 0.0015 0.0015
surface finish 60 50
le ngth/dia = 3 usual =8 maximum
mtl < Rc 30usual < Rc 50 ma ximum
Dia Tolera nce
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 be st
True position 0.008 0.0004
roundne ss 0.004
surface finish 100
Dia Tole ranc e
< 5/8 0.0015
>5/8 0.002
surface finish > 100
straightne ss 0.005in 6inch
Dia Tolera nce
0 - 1/2 0. 0005to 0.001
1/2- 1 0. 001
1 - 2 0. 002
2 - 4 0. 003
roughting finishing
roundne ss 0.0005 0.0005
true position 0. 01 0.01
surface finish 125 50
le ngth/dia 5to 8
Dia Tolera nce
roughingfinishing
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
straightne ss 0.0002
roundne ss 0.0003
true position 0. 0001
surface finish 8
diamete r tolerance
to 1.0 0.001
1 -2 0.002
2 -4 0.003
surface finish 250 to 16
toleranc e 0.001
surface finish 125 to 32

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PROCESS TOLERANCE RANGE
Shaping Formto ol
P lan in g Inserted tool
Sawing Hacksaw
Ban dsaw
Circular saw
Process Sub -Pro cess Cu tters
Grin ding
Internal grinding
Cylindrical g rinding
Cen terless grindin g
External grinding
Surface grinding
Ho ning Ho ning stone
Lap ping Lap
Tapping Tap
Tolerances, surface finish, etc. capabilities
len gth tol sq uareness su rface finish cutting rate material
0.0 1 0.2 200 - 300 3 -6 sq in/min to Rc45
0.0 1 0.2 2 00 - 3 00 4-30 sq in/min to Rc45
0.0 08 0.2 125 7-36 sq in/min to Rc45
rough ting finishing
location tol 0.0 05 0.001
flatness 0.001 0 .0005
surface finish 60 32 (cast iron)
surface finish 125 32 (steel)
Dia Tolerance
roug hing finishing
0 - 1 0 .0001 5 0.00 005
1 - 2 0 .0002 0.00005
2 - 4 0 .0003 0.0001
4 - 8 0 .0005 0.00013
8 - 16 0.0008 0.00 02
Dia Tolerance
roug hing finishing
1 +0.0 005-0.0 +0.00 01-0.0
2 +0.0 008-0.0 +0.0005-0 .0
4 +0.0 010-0.0 +0.0008-0 .0
surface finish 4
roun dness 0.0005
rou ghing fin ishin g
tolerance 0.000 025 0.00001 5
flatness 0.000 025 0.00001 2
surface fin 4-6 1-4
tolerance 0.003
roun dness 0 .003
surface fin 75
ro ughing finish in g
tolerance 0.00 05 0.00 01
parallelism 0 .0005 0 .0002
roun dness 0.00 05 0.00 01
surface fin 8 2
ro ughing finish in g
tolerance 0.00 1 0.00 01
parallelism 0 .001 0 .000 1
surface fin 3 2 2
center grou nd
flat
and cen terless
Internal

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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 plate 25-100 :in turned

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BASIC MACHINING CALCULATIONS

tm = 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 =
Do – Di
2 a p
+
integer round up
For milling

n p = h
a p
+
w
 D
+
n p : # of passes

h : total height of material to be removed
w : workpiece width

 : cutter overlapping factor
= effective cutting width / tool dia  1.0

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BASIC MACHINING CALCULATIONS
Machine control parameters are: f, V, ap.
a. Feed and feedrate
f
: inch / rev
turning or drilling
milling
rp m
N:
# of teech in milling
1 in drilling
n : rpm
V f = f nN
V f = f n
V f : inch / min
Vf

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BASIC MACHINING CALCULATIONS
Cutting speed
D: Diameter
Depth of cut
a p inch
a p =
Do – Di
2
D
V
surface speed
V in sfpm
Di
D0
V = p D n
12

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BASIC MACHINING CALCULATIONS
Metal removal rate

MRR cutting time tool life
MRR in3
min
in3
min
Drilling
Turning
Milling
W
v f
a p
MRR = pD
2
4
v f
= 3D f V
MRR =
p ( D
2
o – D
2
i)
4
v f
= 6(Do – Di ) f V
v f
p (D
2
o –D
2
i)
4
MRR = a p w v f
=
12 a p w n
p D
f V
pD
2
4
v f

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BASIC MACHINING CALCULATIONS

tm = 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 =
Do – Di
2 a p
+
integer round up
For milling

n p = h
a p
+
w
 D
+
n p : # of passes

h : total height of material to be removed
w : workpiece width

 : cutter overlapping factor
= effective cutting width / tool dia  1.0
L

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CUTTING FORCE AND POWER
Process Sub-Process
Milling
End milling
Peripheralmilling
Face milling
Drilling
Reaming
Boring
Shaping
Planing
Broaching
Turning
Facing
Turning
Cutting Force F Power (hp)
KF fF
ap
F
Dt
F
bw z
KF v Faf
F
ap
F
bw
F
zF
Dt
F
KF fF
ap
F
KF fF
ap
F
Dt
F
KF ap
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

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MATERIAL REMOVAL RATE
Process Sub-Process
Milling
End milling
Perip heral 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 rp m
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
(p 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

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CONSTRAINTS

nmin  nw  nmax

ntmin  nt  ntmax

Fc  Fc,max
Spindle-speed constraint:
workpiece
tool
Feed constraint:
Cutting-force constraint:

P
m  Pmax
Power constraint:

Ra  Ra,max
Surface-finish constraint:
f min  f fmax

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MODELS
Multiple pass model

t pr  th + (ti
m

i =1
n p
+
ti
m
t tt)

c pr 
cb
nb
+ cmth + ci
pr

i = 1
n p
i : pass number
Additional constraint:
depth of cut
: number of passes is a function of the depth of cut.
ap
np
Productivity model:

p
r 
s – c pr
t pr
s: sale price/piece