Method and apparatus for forming blind holes in sheet material
A method of forming blind holes in a sheet material is provided. The method includes forming a recessed segment in the sheet material, stamping the recessed segment between a tapered punch and a pad to form a blind hole having a sealed end and a sidewall, wherein the pad includes a profiling pin that is enclosed by the sealed end and the sidewall. The method further includes forming a material channel interposed between the tapered punch and a tapered die, and compressing the material channel to generate a material flow into the sidewall. The material channel may be narrowed to allow more material flow into the sidewall for additional sidewall thickness.
1. A method for forming a blind hole in a sheet of material, comprising;
placing a sheet material between a first upper die and a first lower die;
punching a recess punch into a through opening in said first upper die, to force a portion of said sheet material against a recess pad that inserts into a portion of a through opening of said first lower die to form a recess segment;
placing said sheet material between a second upper die and a second lower die;
punching down a tapered punch into a through opening of said second upper die, scraping a portion of material along a sidewall of said recess segment downwardly;
compressing said portion of material onto said recess segment of said sheet material against a support pad that inserts into a portion of a through opening of said second lower die to form a material channel between said sheet material and recess segment of said sheet material, wherein said tapered punch has an edge that inclines inward, and edges surrounding a top surface of said through opening of said second lower die are chamfered; and
defining a sidewall at an open end of said recess segment with a support portion of said support pad while a profiling pin of said support pad determines a height of said sidewall of an open end of said recess segment to form a blind hole on a bottom surface of said recess segment.
2. The method as recited in claim 1 , wherein a top surface of said recess segment is lower than a bottom surface of other portions of said sheet material.
3. The method as recited in claim 1 , wherein said material channel is constricted to a thickness less than that of a sidewall of said recess segment.
4. A system for forming a blind hole in a sheet material, comprising:
a first upper die with a through opening;
a first lower die with a through opening, wherein said sheet metal is placed between said first upper die and said first lower die;
a recess pad that inserts into a portion of said through opening of said first lower die; a recess punch that inserts into said through opening of said first upper die, wherein said recess punch forces a portion of said sheet material against said recess pad to form a recess segment;
a second upper die with a through opening;
a second lower die with a through opening, wherein said through opening of said second lower die has a chamfered edge;
a tapered punch that inserts into said through opening of said second upper die, wherein said tapered punch has a tapered edge that inclines inward;
a support pad that inserts into a portion of said second lower die, wherein said tapered punch forces a portion of said sheet material placed between said second upper die and said second lower die against said support pad to form a blind hole on a bottom surface of said recess segment.
5. The system as recited in claim 4 , wherein said support pad comprises a support portion.
6. The system as recited in claim 4 , wherein said support pad comprises a profiling pin.