McElroy 28 - Sidewall Fusion Pressure Calculation

9 - 2
Determining Fusion Pressure - Sidewall
Variable Definitions
O.D. = Outside Diameter of Base (not branch)
t = Wall Thickness
∏ = 3.1416
SDR = Standard Dimensional Ratio
IFP = Manufacturer’s Recommended Interfacial Pressure
TEPA = Total Effective Piston Area
Formulas
O.D.
t = ------------
SDR
AREA = (O.D. - t) x t x 
FORCE = AREA x IFP
IFP = 60 PSI for Bead-up
0 PSI for Heat/Soak
30 PSI for Saddle Fusion
ROUND BASE
(O.D. - t ) x t x Π x IFP
TEPA
RECTANGULAR BASE
[ L x W - ( d x d x 0.7854 )] x IFP
TEPA
Example
O.D. of Base = 7.36"
t = 1.10"
DRAG = as measured in PSI (30 PSI for this example)
30 PSI for Saddle Fusion (must calculate for other IFP's also).
Using 28 Combination Unit and calculating the fusion pressure
(O.D. - t ) x t x Π x IFP
TEPA
(7.36 - 1.10 ) x 1.10 x 3.14 x 30
4.71
648.66
4.71
Using the same formula substitute the IFP with the IFP appropriate for the process and recalculate for each
Heat Soak Pressure for this example = 30 PSI
Bead-up Pressure for this example = 306 PSI
TX04270-4-7-11
O.D.t
W
L
d
BASE
END
ROUND BASE
RECTANGULAR BASE
Total Effective Piston Areas
Fusion
Model
High Force
(Standard)
Medium
Force
(High
Velocity)
Low Force
Extra
High
Velocity
Sidewinder 1.00
28 CU 4.71 - 1.66
28 EP Sidewall - - 1.66
18 Sidewall 11.80 - -
36 Sidewall 11.00 - -
+ DRAG
+ 30 PSI
+ 30 PSI = 168 PSI Fusion Pressure