Ball pen tip manufacturing machines, ball pen tips, and ball pens

A ball pen tip manufactured by punching the ball pen tip by a punch from a rear end of the ball pen tip along a central axis direction of the ball pen tip to form a plastic flow ridge formed by a plastic flow upheaving radially inward from an inner peripheral wall surface of the ball pen tip to assemble a spring to the ball pen tip by the plastic flow ridge,

• wherein a tip of the punch is formed into a tapered shape and a tip angle of the punch is within a range from 120 degrees to 170 degrees,
• wherein punching energy including the kinetic energy applied per volume of a part to be processed of the ball pen tip, with which the punch comes into contact, is equal to or greater than the processing energy as to meet the conditions that create the plastic flow ridge in the material constituting the ball pen tip,
• wherein the spring is assembled for biasing a ball to the ball pen tip, and
• wherein a front end and a rear end of the spring are wound into a same tapered external shape.

A ball pen tip, comprising:

• a spring for biasing a ball;
• and
• a plastic flow ridge formed by a plastic flow upheaving radially inward from an inner peripheral wall surface of the ball pen tip for assembling the spring to the ball pen tip by the plastic flow ridge by punching the ball pen tip by a punch from a rear end of the ball pen tip along a central axis direction of the ball pen tip,
• wherein a tip of the punch is formed into a tapered shape and a tip angle of the punch is within a range from 120 degrees to 170 degrees,
• wherein punching energy including the kinetic energy applied per volume of a part to be processed of the ball pen tip, with which the punch comes into contact, is equal to or greater than the processing energy as to meet the conditions that create the plastic flow ridge in the material constituting the ball pen tip, and
• wherein a front end and a rear end of the spring are wound into a same tapered external shape.