Process for making vacuum fixtures for miniature magnetic memory cores

Claim 1

A PROCESS FOR MAKING A MAGNETIC CORE NEST VACUUM FIXTURE FROM A PHOTOPOLYMER PLATE BONDED TO A RIGID BACKING LAYER WHICH COMPRISES: (A) PHOTOPRINTING A MULTIPLICITY OF THE IMAGES OF RECTANGULAR CAVITY AREAS ON SAID PLATE FROM A NEGATIVE FILM HAVING OPAQUE AREAS DEFINING THE CAVITY AREAS IN CONTACT WITH SAID PLATE BY EXPOSING THE PLATE WHEN IN SAID CONTACT WITH THE FILM TO AN ACTINIC LIGHT SOURCE OF SUFFICIENT INTENSITY TO FORM INSOLUBLE EXPOSED AREAS AND SOLUBLE CAVITY DEFINING AREAS ON THE PLATE AND CONTINUING SUCH EXPOSURE UNTIL THE INSOLUBLE AREAS ARE EXTENDED THROUGH THE PLATE TO THE BACKING LAYER; (B) ETCHING AWAY THE SOLUBLE MATERIAL OF THE PLATE UNDERLYING THE UNEXPOSED AREAS BY SPRAYING THE PLATE WITH A SOLVENT UNTIL STRAIGHT WALLED CAVITIES ARE FORMED THROUGH THE PLATE TO THE BACKING LAYER AT THE UNEXPOSED AREAS, THE CAVITIES HAVING DIMENSIONS SUCH THAT AN ANNULAR CORE NESTING ON EDGE IN THE CAVITY WILL SEAT FIRMLY AGAINST OPPOSITE END WALLS OF THE CAVITY WITH MOST OF THE OPENING THROUGH THE CORE EXTENDING ABOVE THE SURFACE OF THE PLATE; AND (C) ETCHING A SMALL APERTURE THROUGH THE BACKING LAYER INTO EACH OF THE CORE CAVITIES FOR PORVIDING A PASSAGEWAY FOR THE WITHDRAWAL OF AIR FROM THE CAVITY FOR HOLDING THE CORES IN SNUG SEATING ENGAGEMENT WITHIN THE RESPECTIVE CAVITIES.