Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C1/00—Forme preparation
  • B41C1/02—Engraving; Heads therefor
  • B41C1/04—Engraving; Heads therefor using heads controlled by an electric information signal
  • B41C1/05—Heat-generating engraving heads, e.g. laser beam, electron beam
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
  • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
  • B23K26/0604—Shaping the laser beam, e.g. by masks or multi-focusing by a combination of beams
  • B23K26/0608—Shaping the laser beam, e.g. by masks or multi-focusing by a combination of beams in the same heat affected zone [HAZ]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
  • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
  • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
  • B23K26/0643—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising mirrors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
  • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
  • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
  • B23K26/0652—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising prisms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/36—Removing material
  • B23K26/361—Removing material for deburring or mechanical trimming

Definitions

• an optical imaging apparatus for direct engraving flexographic plates comprises at least two laser sources, each emitting laser beams.
• a mirror or prism is placed in front of each of the laser sources to alter an optical path of each of the laser beams.
• the laser beams cut the flexographic plate at different depths and cut out chunks of the flexographic plate.
• the engraving by slicing system (EBS) according to the present invention takes advantage of the fact that while large solid areas need to be processed by the laser to a certain depth relief, fine detail areas can be processed to significantly shallower relief.
• Figure 1 is a prior art schematic illustrating a relief in a flexographic plate showing elevated ink transfer areas and blank areas
• Figure 2 is a prior art schematic illustrating a flexographic plate pressed against a surface. Columns separated by large blank areas are deformed more strongly, and, as a result, large blank areas are noticeably pushed towards the contact surface;
• Figure 5 is a schematic layout of engraving by slicing concept with two laser systems
• Figure 6 is a schematic illustrating a part from a flexographic plate cut out by the engraving by slicing system
• Laser beams 32 and 34 are applied on the flexographic plate to engrave into the plate in two directions 32 and 34 to cut a chunk of the removed non ink transfer area 36 out of the flexographic plate, while the plate is rotating on the drum in the fast scan direction 54, with surface motion vertical to the laser beams.
• the laser beams are further applied at a determined delta step in the slow direction 55 to cut another chunk as is illustrated in Figure 3, by applying laser beams 33 and 35 in order to cut out non ink transfer chunk 38, leaving a relative small residual chunk 37, due to the 2D engraving constraints of the suggested invention.
• the cut non ink transfer chunks 36 and 38 will be removed in one piece from the rotating drum at which the flexographic plate is mounted, due to the drum revolution.
• This invention introduces two major advantages to the flexographic plate production.
• the first is a substantial saving in the energy required to ablate the whole deep non ink transfer areas of a flexographic plate, such as removed non ink transfer chunks 36 and 38.
• the energy saving in engraving these areas can amount to 90%.
• the triangular wedge prism 45 is placed in front of the laser source 43 at the triangle wedge wide part position 41 , prior to entering into the flexographic plate 52.
• the wedge In order to perform the entrance and cut the flexographic plate 52 the wedge is moved relative to the laser source till it is placed in front of the narrow part 42 of the wedge. At the stage when the deep cut is performed, the wedge will not move to form a continuous large cut.
• the triangular wedge prism 45 will be moved till the triangle wedge wide part 41 of the wedge is placed in the front of the laser source 43. This operation will form a cut chunk 46 to be removed from the plate by the act of the rotation of the drum.
• triangle wedge prism 45 in order to diffract the laser beams 44 optical path can be applied by a mirror system.
• the optical diffraction means such triangular wedge prism 45 can be introduced just in front of a single laser source 43, whereas the other laser source will be focused to the maximal depth in the plate material, this will result in a different shape of the cut chunk to be removed 46.
• Figures 7 and 8 show another embodiment for engraving into the flexographic plate 52.
• the pair of laser sources 43 are used without triangular wedge prism 45, the laser sources 43 are focused to the maximal depth of the plate material. This will result in cutting to the deepest cut point inside, to form main cut chunk area 71.
• a high power pulse laser source 74 is deployed to ablate the entrance and the exit of the chunk area 71.
• the entrance and exit areas 72 will be ablated by the pulse laser beams 73 from pulse laser source 74.

Landscapes

• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Manufacture Or Reproduction Of Printing Formes (AREA)
• Laser Beam Processing (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=39865683

Family Applications (1)

Country Status (5)

Cited By (2)

Families Citing this family (15)

Citations (10)

Family Cites Families (7)

• 2007
  • 2007-08-27 US US11/845,141 patent/US8621996B2/en not_active Expired - Fee Related
• 2008
  • 2008-08-12 WO PCT/US2008/009608 patent/WO2009029167A1/en not_active Ceased
  • 2008-08-12 CN CN2008801048072A patent/CN101808823B/zh not_active Expired - Fee Related
  • 2008-08-12 EP EP08795216.4A patent/EP2180997B1/en not_active Not-in-force
  • 2008-08-12 JP JP2010522896A patent/JP2010537848A/ja active Pending

Patent Citations (10)

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