Patent ID: 7654123

Claim:
A method of forming a slotted wound core having adjacent radial slots separated by an angle α, said method including the steps of: (a) Feeding a length of material through a punch arrangement and attaching an end of the material to a mandrel; (b) Calculating a length BC of the material between a first point B and a second point C, where point B is the point of intercept between a punch center of the punch arrangement and the material and the second point C is the point of contact between material wound on the mandrel and a roll radius measuring means; (c) Determining a next aperture punch point position A on the material, said position A being determined by the steps of: I. Determining the angle θ about a center point of the mandrel between a radial extending to point C and a radial forming a center line of a slot which the aperture at point A will extend when laid against a circumference of the roll of material on the mandrel; II. Determining a length AC of material between a first point A and the second point C, where AC is determined by the equation: AC = θ ( θ × t 4 ⁢ π + r ) Where r is the radius of the roll measured at C by the roll radius measuring means and t is the thickness of the material to be punched; III. Calculating a length of material AB between the first point A and a third point B, where AB is determined by the equation: AB=AC−BC (d) Calculating a mandrel rotation index angle γ required to achieve a feed length AB; (e) Rotating the mandrel by index angle γ; (f) Punching an aperture in the material using the punch arrangement; and (g) Repeating steps (b) to (f) until a desired core radius is achieved.