Punch and stripper assembly for a reciprocating metal-punching press

An integral punch and stripper assembly for a reciprocating metal-punching press in which the punch is an elongated member of predetermined length and maximum transverse dimension having a predetermined cross-sectional shape at the outer extremity, the punch extending outwardly said predetermined length from a punch holder having a substantially planar base of substantially greater area than the cross-sectional area of the punch, the stripper being formed by a process of:

• providing a plastics material initially in a substantially liquid form capable of being poured from a container and capable of setting after a period of time into a substantially non-compressible, deformable, elastic solid shape;
• providing a stripper mold of a material which will not firmly bond to said plastics material and shaped generally in the form of a frusto-conical hollow mold of an axial length greater than the extending length of said punch and with the lower end being open and of an internal diameter substantially equal to the outer diameter of said one end of said punch holder base and with the upper end having an aperture substantially greater in diameter than the maximum diameter of said punch;
• placing said stripper mold onto said punch holder with said lower end of said mold encircling said one end of said punch holder and with said punch within said mold;
• placing said punch holder in an upright position with said aperture of said mold at the upper end thereof;
• thereafter pouring said plastics material through said aperture of said mold into said mold and about said punch until said plastics material fills said mold substantially to said aperture;
• thus creating a totally conforming surrounding relationship between the punch and plastic stripper forming material and a slight axial spacing between the longitudinally outermost extremity of the plastic stripper material and the longitudinally outermost extremity of the punch;
• thereafter maintaining said punch holder in said upright position until said plastics material has set into said solid shape;
• and thereafter pulling said mold upwardly and from engagement with said plastics material creating a closely conforming stripper member completely surrounding the punch, the stripper member defining first peripheral outer sidewall section tapering upwardly and outwardly from its free extremity at a first predetermined angle from the central axis for a first predetermined axial distance, a second peripheral outer sidewall section tapering upwardly and outwardly from the first sidewall section toward the punch holder at a second predetermined angle of taper and for a second predetermined distance, the first predetermined angle of taper being substantially greater than the second predetermined angle of taper and the first predetermined axial distance being substantially less than the second predetermined axial distance so that sufficient lateral and axial bulging of the stripper may occur at the outermost extremity of the stripper providing sufficient resiliency and rebound affect while allowing the stripper to move freely in a turret cavity.