Nomenclature

A = Die set length (for a progressive die); Kdmo/(Kdmo + Kaco)

Ap = Projected area of a part normal to the direction of mold closure
a - Dimension, length; constant
B = Die set width (for a progressive die); Kaco/(Kamo + Kaco)
B m - Width of the part in a direction normal to the direction of mold closure
Bu = Width of an injection-molded or die-cast part with the axis straight = H
b = Dimension, length, thickness, width; rib width; boss width
C - Value obtained from Figures 4.23 or 7.7
Can = Cost to assemble n parts
Cb = Approximate relative tooling cost for an injection-molded or die-cast part
due to size and basic complexity
Ca = Ka/Kdo- Tooling cost for a part relative to the tooling cost for the reference
part
Cac = Kdc/Kaco = Tool construction cost for a part relative to the tool construction
cost for the reference part (= Cb Cs Ct for an injection-molded or die-cast part;
= tac/taco for a stamped part)
Cdci- Relative tool construction cost for the ith part.
Cdcx = Relative die construction cost for a single functionally equivalent part to
replace n parts
C d m -- Kdm/Kdmo- Tool material cost for a part relative to the tool material cost
of the reference part. Value obtained from Figures 4.24 or 7.8 for injection-
molded or die-cast parts. Value obtained from Equation 9.15 for stamped parts.
Cami = Relative die material cost for the ith part
Cdmx = Relative die material cost for a single functionally equivalent part to
replace n parts
C a p -- Kdp/Kdop,Tooling cost of a thermoplastic injection-molded part relative to
the tooling cost of the injection-molded reference part
Gas- Kds/Kdos,Tooling cost of a stamped part relative to the tooling cost of the
stamped reference part
Cdx- Total relative die cost for a single functionally equivalent part
Ce- Ke/Keo = Processing cost for a part relative to the processing cost for the ref-
erence part
C e a = Kea/Keao, Processing cost for an aluminum die-cast part relative to the pro-
cessing cost for the aluminum die-cast reference part
C e p -- Kep/Keop,Processing cost for a thermoplastic injection-molded part relative
to the processing cost for the injection-molded reference part
Ces- Kes/Keos, Processing cost for a stamped part relative to the processing cost
for the stamped reference part
Ch = Machine hourly rate
Cho = Machine hourly rate ($/hr) for the reference part
Chr = Relative machine hourly rate = machine hourly rate for a part relative to
the machine hourly rate of the reference part = Ch/Cho

365
366 Nomenclature

Chr a = Relative machine hourly rate for aluminum die-casting machines

Chrp = Relative machine hourly rate for injection-molding machines
Cm = Km/Kmo, Material cost of a part relative to the material cost of the reference
part
Cmp = Kmp/Kmop, Material cost of an injection-molded part relative to the mate-
rial cost of the injection-molded reference part
Cmr = Kp/Kpo = material cost per unit volume of a part relative to the material
cost per unit volume of the reference part
Cms = Kms/Kmos, Material cost of a stamped part relative to the material cost of
the stamped reference part
Cr = Total cost of a part relative to the total cost for the reference part
Crp = Total relative cost of a thermoplastic injection-molded part
Crs = Total relative cost of a stamped part
Cs = For injection-molded and die-cast parts, a multiplier to account for the cavity
detail (subsidiary complexity) for relative tooling cost.
Ct = For injection-molded and die-cast parts, a multiplier to account for the tol-
erance and surface finish requirements for relative tooling cost.
E = Modulus of elasticity
F = Estimated total force in tons required to form an injection-molded, die-cast,
or stamped part
Fb = Bending force required (stamping)
Fam = Factor to account for the effect of sheet thickness on die material cost for
a stamped part
Feff = Press efficiency
Fout = Force required to separate the stamped part from the trip
Fp = Machine tonnage required to mold or die cast a part; total press force
required to stamp a part
Fst = Stripper force required to remove the strip from around the punches
Fs = Total shearing force required to stamp the part (Fout + Fst)(1 + Xdd)
Ft = Factor to account for the effect of sheet thickness on die construction costs
for a stamped part
fa = Kdo/Ko, Tooling cost of the reference part relative to the total cost of the d
reference part
fdp = Kdop/Kop, Tooling cost of the injection-molded reference part relative to the
total cost of the injection-molded reference part
fe = Keo/Ko, Processing cost of the reference part relative to the total cost of the
reference part
fep = Keop/Kop, Processing cost of the injection-molded reference part relative to
the total cost of the injection-molded reference part
fm = Kmo/Ko, Material cost of the reference part relative to the total cost of the
reference part
fmp = Kmop/Kop, Material cost of the injection-molded reference part relative to
the total cost of the injection-molded reference part
Hm = The height of the part in the direction of mold closure
h = Rib height; boss height; height
Kd = Total tooling cost (mold or die cost) for the part
Kd/N = Tooling cost per part
Kda = Tooling cost for an aluminum die casting
Kdc = Die construction cost for a part
Kdco = Die construction cost for the reference part
Kdi = Total tooling cost for the ith component
Kdm = Die material cost for a part
Kdmo = Die material cost for the reference part
Kdo = Tooling cost for the reference part
 Nomenclature 367

Kdop = Tooling cost for the thermoplastic injection-molded reference part

Kdp = Tooling cost for a thermoplastic injection molding
Kds = Tooling cost for a stamped part
Kdx = Total tooling cost for the single functionally equivalent part to replace the
n parts
Ke = Processing cost per part (approximately the product of the machine hourly
rate and the cycle time)
Kea = Processing cost for an aluminum die casting
Keao = Processing cost for the die-cast aluminum reference part
K~i = Processing cost for the ith component
K~o = Processing cost per part for the reference part
Kep = Processing cost for a thermoplastic injection molding
Kepo = Processing cost for the thermoplastic injection-molded reference part
Kes = Processing cost for a stamped part
Kex = Processing cost for the single functionally equivalent part to replace the n
parts
K m = Material cost per part
Kma = Material cost for an aluminum die casting
Kmi = Material cost for the ith component
Kmo = Material cost per part for the reference part
Kmop = Material cost per part for the thermoplastic injection-molded reference
part
Kmp = Material cost for a thermoplastic injection-molded part
Kms = Material cost for a stamped part
Kmx - Material cost for the single functionally equivalent part to replace the n
parts
Ko = Manufacturing cost of the reference part
Kop = Manufacturing cost of the thermoplastic injection-molded reference part
K p = Material cost per unit volume
Kpo = Material cost per unit volume for the reference part
K t = Total production cost of a single part
Kta = Total cost to produce a part as an aluminum die casting
Kti = Total cost of producing the ith component
Ktp - T o t a l cost to produce a part as a thermoplastic injection molding
Ktx = Total cost of producing the single functionally equivalent part to replace
the n parts
L, B, H = Lengths of the sides of the basic envelope (L > B > H)
Lbt = S u m o f all straight bend lengths
Ldb = Die block width (progressive die)
Ldl = Die block length (progressive die)
Lm = The length of the part in a direction normal to the direction of mold closure
Lout = Peripheral length of an unfolded part
Lu = Maximum length of an injection-molded or die-cast part with the axis
straight = L + B
Lub = Envelope dimension of a stamped part parallel to the direction of strip feed
Lubn = Envelope dimension of a stamped part perpendicular to the direction of
strip feed
Lul = Flat envelope length of a stamped part
Luw = Flat envelope width of a stamped part
1 = Length
Ma = Projected area of the mold base normal to the direction of mold closure
M t = Thickness of the mold base
Mwf = Thickness of core plate
Mws = Thickness of the mold's side walls
368 Nomenclature

N = Production volume
N a = N u m b e r of active stations for progressive die
Nal, Na: = N u m b e r of active stations required for shearing and local forming, and
wipe forming and side-action features, respectively
Nil, Ni2 = N u m b e r of idle stations required for shearing and local forming, and
wipe forming and side-action features, respectively
No = Production volume of reference part
Ns = Total number of stations required for a progressive die = Na + Ni
n = Strain hardening coefficient; number of parts in an assembly
nc = N u m b e r of cavities in a multiple cavity mold
Ra = Surface finish
r = Radius
Sds = die set area = AB
Ta = Tolerance; difference between the maximum and minimum limit of size
t = Machine cycle time (processing time) for a part; sheet thickness for a stamped
part; thickness; time
tb = Basic relative cycle time for an injection-molded or die-cast part; tool build
hours for a stamped part
td = Tool design hours for a stamped part
ti = Build hours for a progressive die station
tdc = Total die construction hours for a stamped part
tcy = Effective cycle time of a press (stamping)
te = Additional relative cycle time due to inserts and internal threads
teff = Effective cycle time (injection molding) = machine cycle time, t, divided by
the production yield, Y
to = Cycle time (processing time) for the reference part
tp = A time penalty factor to account for surface requirements and tolerances on
the relative cycle time
tr = t/to = Relative cycle time of a part
trp = Relative cycle time for a thermoplastic injection-molded part
tra = Relative cycle time for a die-cast aluminum part
tsetup = Approximate setup time in hours (stamping)
V = Part volume
Vo = Volume of the reference part
w = Wall thickness; width
Xdd ~-~A force factor to account for die detail in stamping
Y = Production yield = usable parts/total parts produced
ACdm -- ]~Cdmi- Cdmx
ACdc m ]~Cdci- Cdcx
AK = Cost to produce and assemble n parts minus the cost of producing one func-
tionally equivalent part
AK~p = Difference in cost to produce a part as an aluminum die casting and as a
thermoplastic injection molding
AK~ = Difference in processing cost
AKps = Difference in cost to produce a part as a thermoplastic injection molding
and as a stamping
/" 1 "x

ln(1) ; 1 is the final length of the specimen, and lo is the initial length of the
X. x O /

specimen
~ e = l n ( 1 - lo
1~ ;1 is the final length of the specimen, and lo is the initial length of
the specimen
 Nomenclature 369

P
o=~-;P is the tensile load applied to the specimen, and A is the cross-
sectional area of the specimen
P
Oe = ~oo; P is the tensile load applied to the specimen, and Ao is the initial cross-
sectional area of the specimen
Oy = yield stres