Assomac Machines Limited

Formulas

Our designing team uses various wire drawing formulas for designing a variety of wires with our wire drawing machines such as weight / length relationship formula, surface area formula, zinc coating formula and formula for reduction in area

FORMULA ONE FORMULA TWO
Weight / Length Relationship:

The weight per foot of wire is :
(2) Formula

Example : The Weight per foot os .090" wire is :
Formula

The length per lb of wire is:
(3) Formula

Where:
w = weight per foot (lbs/ft)
d = wire diameter(inch)
L = length per lb (ft/lb)

Example : The length per lb of .090" wire is:
Formula

* Surface Area:
The surface area of one foot of wire is:
(4) a = X 0.090 / 12 = 0.0236 ft2/ft

The surface area of one lb of wire is :
(5) a/w = 1 / (36 X d X y)

Where:
a = surface area of one foot of wire (ft2/ft)
a/w = surface area of one lb of wire (ft2/lb)
d = wire diameter (inch)
w = weight of one foot of wire (lb/ft)
y = specific weight (for steel, 0.283 lbs/in3)

Example : The surface are of one lb of 0.090" diameter wire is :

a/w = 1 / (36 X 0.090 X 0.2836) = 1.088 ft2lb

* Refer to Page 369, Volume 2, Steel Wire Handbook


FORMULA THREE FORMULA FOUR
ZINC COATING

The Percent zinc coating on d" diameter wire coated with coz/ft2zinc is:
(6) Formula

Example : for 0.090" diameter wire coated 0.3 oz/ft2 :

(6) Formula

The weight of zinc on d" diameter wire coated with p% zinc is :

(7) Formula

Where :
p% = weight percent of zinc(%)
c = zinc coating weight (oz/ft2)
d = wire diameter(inch)

Example: for 0.090" diameter wire, 2.00% zinc coating weights :

Formula

* Refer to Page 301, Volume 1, Steel Wire Handbook

Arrow
Graph for Formula Four
Gharph
INCLUDING DIE ANGLE, degrees

Work Sheet for designing tooling geometry to prevent central bursting.
Reduction in Area:

Step reduction, drawing wire from di-1to di
(8) Formula

Examples :drawing from step 3 to step 4:

r4[1-(0.090/0.102)2] X 100

drawing 0.102" wire to 090"
r = [1-(0.090/0.102)2 X 100 = 22.15%
Total Reduction, drawing from d0 to di

(9) Formula

Examples :at step 4: r = [1-(d4/d0)2] X 100
drawing 7/32" rod to 0.102":

r = [1 - (0.102/0.219)2] X 100 = 78.31%
Overall reduction, drawing from d0 to df

(10) Formula

Examples :drawing 7/32" to 0.090" :
rf= [1-(0.090/0.219)2] X 100 = 83.11%

NOTES :
1. Reduction in area is not additive, rf is not f1 + r2 + ... + rn
2. Reduction is always positive.
3. Reduction is never larger than 100%.
4. For ferrous wire, step reduction is usually between 7% and 38% (limits depend on the product).
5. For overall reduction greater than 85%, the process has to be carefully designed.
6. Clue : for final diameter of one half the original, reduction is 75%.

To Compute the diameter from reduction :
(11) Formula

Example:Drawing 7/32" rod 25% reduction:

Formula
Given the small diameter, the large diameter is:

(12) Formula

Where:
r = drawing reduction in area(%)
d = wire diameter(inch)

Example: For an overall reduction of 83.1%, an 0.090" wire will require a starting diameter of:
do =

The Required Percent Reduction Between the Bottom and Top Block of a Double-Draw Single-Block Frame:
Total required reduction at the second hole
(13) = 100% -

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