Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/34—Pretreatment of metallic surfaces to be electroplated
  • C25D5/42—Pretreatment of metallic surfaces to be electroplated of light metals
  • C25D5/44—Aluminium
• • 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
  • C25D1/08—Perforated or foraminous objects, e.g. sieves
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/12—Electroplating: Baths therefor from solutions of nickel or cobalt
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/34—Pretreatment of metallic surfaces to be electroplated
  • C25D5/36—Pretreatment of metallic surfaces to be electroplated of iron or steel

Definitions

• problems occur when it is desired to use a lightweight frame such as aluminum to support a screen to be rigidized. While other frames such as stainless steel are suitable, it is oftentimes preferred to use an aluminum frame for various reasons.
• the aluminum frame has good strength, good dimensional stability, good corrosion resistance besides being light, easy to cast, and generally less expensive than other types of frames.
• the use of an aluminum frame to support a screen to be encapsulated in nickel creates a problem because the aluminum is not passive in the nickel plating solution. Consequently, to plate nickel onto a screen with an aluminum frame produces a secondary reaction in the nickel plating solution that affects the encapsulating properties of the nickel.
• the present invention eliminates the problem of plating on an active metal frame such as aluminum by using two plating solutions, a first zincating solution to plate onto the aluminum frame but not onto the stainless steel screen and a second nickel plating solution to encapsulate and rigidize the screen.
• the invention comprises a process and a method for producing an improved rigidized screen with an aluminum frame for use in the printing industry.
• the invention includes an improved apparatus or screen for use in the printing industry.
• the frame and screen are subjected to a spray rinse to remove any impurities or particles on the screen and frame.
• the screen and frame are then immersed in a nitric acid bath for approximately 30 seconds to remove any remaining impurities on the screen and frame.
• the screen and frame are subjected to a rinse of normal tap water to remove any nitric acid and thus prepare the frame and screen for the zincation step.
• the screen and frame are zincated for one minute in a zincating solution by immersing the aluminum frame and screen in the zincating solution which typically comprises sodium hydroxide and zinc hydroxide.
• the zincating solution typically comprises sodium hydroxide and zinc hydroxide.
• sodium hydroxide and zinc hydroxide are described, other zincating solutions could also be used.
• the outer layer of aluminum oxide is dissolved and replaced with a fine layer of zinc while the stainless steel screen remains unaffected by the zincating solution, i.e., the zinc does not plate onto the stainless steel. Care must be taken in zincating the aluminum frame to ensure that enough zinc is plated onto the aluminum frame to cover all the exposed areas of the frame.
• the screen and frame are removed and washed with a deionized water spray to remove any zincating solution on the frame and screen.
• the final step to rigidize the screen requires plating nickel onto the flexible but taut screen to encapsulate the screen to thereby produce a rigid screen.
• nickel sulfamate bath with a PH of approximately 5.
• the higher PH is desirable and preferred as it does not readily attach the zinc layer on the aluminum frame.
• the nickel forms a harder and stronger deposit around the stainless steel wires which produces a substantially stronger screen.
• the thickness of the nickel layer need only be on the order of 0.1 mil to 0.2 mil to produce a rigidized screen.
• a rigidized self-supporting printing screen comprising:
• a layer of zinc encapsulating said aluminum frame to provide a protective coating around said aluminum frame
• a flexible stainless steel printing screen stretched tautly across the zinc covered aluminum frame, said flexible printing screen and said zinc covered aluminum frame having a layer of nickel thereon, said layer of nickel on said flexible printing screen encapsulating said screen to thereby rigidize said screen, said layer of encapsulating nickel having a thickness on the order of 0.1 mil to 0.2 mils to thereby produce a rigidized printing screen.

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)
• Chemically Coating (AREA)
• Electroplating And Plating Baths Therefor (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=22733210

Family Applications (1)

Country Status (8)

Cited By (2)

Families Citing this family (1)

• 0
  • BE BE788470D patent/BE788470A/fr unknown
• 1971
  • 1971-11-12 US US00198396A patent/US3749010A/en not_active Expired - Lifetime
• 1972
  • 1972-05-29 CA CA143,277A patent/CA940374A/en not_active Expired
  • 1972-08-16 GB GB3816772A patent/GB1379135A/en not_active Expired
  • 1972-09-29 DE DE19722247784 patent/DE2247784A1/de active Pending
  • 1972-11-10 IT IT31554/72A patent/IT970421B/it active
  • 1972-11-10 NL NL7215261A patent/NL7215261A/xx not_active Application Discontinuation
  • 1972-11-13 JP JP47113046A patent/JPS4858901A/ja active Pending

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