Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D1/00—Electroforming
  • C25D1/10—Moulds; Masks; Masterforms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C1/00—Forme preparation
  • B41C1/14—Forme preparation for stencil-printing or silk-screen printing
  • B41C1/142—Forme preparation for stencil-printing or silk-screen printing using a galvanic or electroless metal deposition processing step
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D1/00—Electroforming
  • C25D1/02—Tubes; Rings; Hollow bodies

Definitions

• ABSTRACT OF THE DISCLOSURE A method for the galvano technical manufacturing of a seamless cylindrical thin-walled stencil to be used in the rotary screen printing process, said method comprising two steps viz depositing a layer of nickel prior to, or after the deposition of a layer of zinc or copper upon a cylindrical matrix, so as to obtain a two-ply stencil.
• the invention relates to a method for manufacturing by means of galvanotechnique cylindrical thin-walled screen stencils for the rotary screen printing process, according to which method a layer of nickel, which is under com-.
• pressive stress is deposited by a galvanic process on a cylindrical metal matrix which-at the location of the perforations in the stencil to be manufactured-is inlaid with a nonconductive material, whereupon the stencil formed is removed from the matrix.
• a galvano technical manner of manufacturing of stencils consisting entirely of nickel.
• nickel is deposited by a galvanic process on a cylindrical metal matrix containing dots of non conductive materials like synthetic resins, glass or glaze in order to form the perforations in the stencil.
• the matrix has an outer diameter, which is slightly smaller than the inner diameter of the screen cylinder formed. This can be achieved by admixing substances to the solution of nickel salts in the galvanic bath, which convert the tensile stress normally present in the coat of nickel into a compressive stress.
• Such a substance is e.g. saccharine, which for that purpose is used on a large scale.
• After the formation of the stencil on the matrix it is at first loosened therefrom by mechanical working e.g. with a presser roller and with a considerable pressing force on the whole until the stencil springs loose under the influence of the compressive stress. This operation is further facilitated, when the matrix has been manufactured from a metal with a coefficient of expansion greater than that of nickel.
• the matrix with the stencil formed thereon from the nickel bath with a temperature of about 60 C. into a water bath with a temperature of about 20 C., the cylinder shrinks more than the stencil formed theron, so that the latter springs loose sooner.
• a drawback of such screen stencils entirely made of nickel is in that they consist of a rather hard and brittle metal and owing thereto crease and tear easily.
• the present invention aims to provide a method by which stencils are obtained, which have not this drawback. Consequently the invention proposes that prior to or after precipitation of the Ni-coat, a layer of a soft metal like Cu or Zn is deposited by a galvanic process on the matrix or on the nickel coat, the arrangement being such that the stencil obtained consists for 25% to of its thickness of nickel.
• the invention is based on the experience that if only a percentage ranging from 75 to 25 of the thickness of the wall of the stencil formed consists of nickel, in whichpossibly due to the presence of substances like saccharinea compressive stress is present, while the rest of the thickness of the wall consists of another metal which has no or little compressive stress, the compressive stress in the nickel suffices to slide the stencil from the matrix.
• This is realized after suitable treatment of the matrix with the stencil formed thereon, e.g. by means of the aforementioned presser roller, to enable the stencil to be slid from the matrix without giving rise to injuries, which is due to the difference in diameter between the outer diameter of the matrix and the inner diameter of the stencil formed thereon.
• the invention is further based on the surprising discovery that a stencil consisting for only 25 to 75% of nickel and for the rest of a soft metal, which in itself is not suitable for the manufacture of stencils, like electrolytic copper, represents a useful product.
• a stencil has not only sufiicient strength to allow industrial application at a total wall-thickness ranging from 0.06 to 0.3 mm. for the same purposes as for which so far exclusively nickel made stencils could serve, but that in addition thereto these novel stencils present important advantages since they are not so soon damaged owing to the formation of creases and cracks.
• a -mesh plainmesh screen cylinder was manufactured in a normal way so that the screen was entirely constructed from nickel precipitated by means of a galvanic process from a so-called Watts bath to which saccharine was added in order to obtain the required compressive stress.
• the thickness amounted to 80 microns.
• a new screen cylinder was manufactured by precipitating at first a layer of nickel with a thickness of 40 microns from the aforementioned Watts bath with the same quantity of saccharine. Thereupon the matrix was transferred to an acid copper bath, exclusively containing copper sulphate and sulfuric acid, in which a layer of 40 microns of copper was precipitated on the nickel layer already formed of 40 microns.
• test strips were cut both in the longitudinal and circumferential direction each strip having a width of 15 cm.
• the test strips were thereupon bent in an Amsler bending apparatus at a bias of 6 kg. through an angle of the radius of the curvature of the clamps amounting to 1.25 mm.
• the number of bends was now established at which fracture occurred.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Printing Plates And Materials Therefor (AREA)
• Manufacture Or Reproduction Of Printing Formes (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=19809390

Family Applications (1)

Country Status (6)

Cited By (4)

Families Citing this family (1)

• 1970
  • 1970-02-20 NL NL707002467A patent/NL139565B/xx not_active IP Right Cessation
• 1971
  • 1971-02-18 CH CH237571A patent/CH516406A/de not_active IP Right Cessation
  • 1971-02-19 DE DE2108088A patent/DE2108088C3/de not_active Expired
  • 1971-02-19 FR FR7105779A patent/FR2080669A1/fr not_active Withdrawn
  • 1971-02-22 US US00116718A patent/US3713997A/en not_active Expired - Lifetime
  • 1971-04-19 GB GB1288908D patent/GB1288908A/en not_active Expired

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