Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
  • B29C59/007—Forming single grooves or ribs, e.g. tear lines, weak spots
• • 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
  • B23K26/08—Devices involving relative movement between laser beam and workpiece
  • B23K26/083—Devices involving movement of the workpiece in at least one axial direction
  • B23K26/0838—Devices involving movement of the workpiece in at least one axial direction by using an endless conveyor belt
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
  • B29C59/16—Surface shaping of articles, e.g. embossing; Apparatus therefor by wave energy or particle radiation, e.g. infrared heating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
  • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
  • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
  • B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
  • B29C2035/0838—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using laser

Definitions

• the present invention relates generally to a system for use in laser treating material and more particularly to a method and apparatus for rapidly providing half-cuts or score lines or various other laser treatments in material.
• a continuous web feed of uncut material into a process For example, in the packaging industry, a continuous web of material is fed through a printing system and later is cut into individual packaging units to be folded into a desired package configuration.
• a newspaper printing press is another example of a continuous feed of material (i.e. paper) passing through a printing process, later to be cut into individual sections.
• the present invention provides a process and system wherein shingled sheets of material are passed through a section where a laser system may treat the material.
• the source of the sheets may be a stack of sheets, or may be a web system sheeter output, or various combinations thereof
• the power requirements of a laser system may be reduced.
• the lower power requirements permit the use of laser systems previously thought impracticable for such laser treating systems.
• Many C0 2 laser systems may now be used along with state of the art garvos systems having finite power handling capabilities.
• Shingling allows the conveyor speed to be reduced dramatically.
• the speed of the shingled blanks riding on a conveyor can be reduced by a factor of 10 if a 90% overlap is used, as compared to the web speed.
• the shingling conveyor speed will be 20rrVmin. This example assumes that the laser treatment to be performed is to be done on the 10% exposed surface. Because the speed is reduced to 20m/rnin. on the shingling system, it travels 1/10 the distance during the cut cycle. Thus the galvo tracking distance need only be 1/10 of what would be needed on a web system This in turn allows the use of shorter focal lengths.
• the shorter focal length is significant since it is directly proportional to the focused spot diameter.
• the gah/o focal length is reduced by a factor of 10. This reduction in the spot diameter will have a large impact on the power densities achieved. Since the power density is related to the spot size area, any reduction in the spot diameter will increase power density by the square of the diameter change. The power requirements for the optics can also be decreased accordingly.
• the optic path (Le., gah/o, optics, mirrors) need only to carry this lower power requirement.
• the present invention may be utilized to provide scores or cut lines in predete ⁇ nined places in containers to contribute to the consumer-fiiendliness of a container. Such containers may be easily opened without the use of tools such as scissors or knives.
• Figure 1 is a schematic view of one embodiment of the present invention
• Figure 2A is a plan view of a shingled stack of material cards of the present invention
• Figure 2B is a plan view of a continuous web method of transporting material cards that are not yet cut
• Figure 3 is a plan view of one embodiment of a card processing system of the present invention.
• Figure 4 is a schematic view of yet another embodiment of the present invention.
• a laser cutting system of the present invention is shown generally at 10.
• a stack of material cards 12 may be fed to a shingle transfer 14. This process can be implemented in any physical plane.
• the cards can be shingled at 90 degrees right or left to the web, or as well as in-line with the web. This allows for selective exposure of all edges of the card.
• Shingle transfers are well known in the art and may be purchased from Multifold International of Milford, Ohio.
• An example of one shingle transfer sold by Multifold International is the Model 4026 TOTF (Turn Over Top Feeder).
• the shingle transfer 14 may shingle each individual card from the stack to expose a portion of a surface of each card and may then convey the shingled cards to another stack 16.
• a laser beam may be directed onto the surface of individual cards to cause local evaporation of material from the cards.
• a laser system 20 may generate a laser beam and supply it to a Z-axis focus 22. The laser beam then travels through two axis laser gah o 24, which may comprise X and Y axis positioning mirrors.
• Figure 2A shows a plan view of a portion of shingled cards 26. Each individual card may expose a portion of its surface 28 when shingled. Sensors may be utilized to detect a leading edge of each card 30 to trigger the laser system. Each individual card need only expose enough area to allow the laser beam to contact the area to be treated with the laser beam, as shown at 32.
• Figure 2B shows a plan view of a web of material. A print repeat may also be used to trigger a laser system to contact an area 32. In some systems the entire surface 28 of each repeat of material is exposed, and the entire surface must pass by before a new material piece can be started.
• the process rate (Le., number of cards per minute) would be the same, but that the time to process can be only equal if the laser and the gah/o system is allowed to track the print repeat for its entire elapsed time, thus requiring a larger field of view equal to the print repeat.
• the material cards of the system of Figure 3 may be comprised of multiple layers of different materials together forming each material card.
• Each card may have an inside surface and a printed side.
• a web of material may be supplied to a rotary knife 42 which cuts the web of material into individual cards.
• the cards may then be separated by splitter wheels 44 and supplied to a conveyor 46. In this embodiment the cards are shingled orthogonally to the web.
• the cards may abut stop plates 48 and pass by squaring plates 50 which position the cards as they are being conveyed.
• the cards are shown with a printed side 52 facing upwards.
• a laser system 54 treats the cards while a shield and ventilation system 56 operates.
• the cards are then stacked and turned at station 58 where they may be turned over to have the printed side facing down 60.
• a shingle conveyor 100 may convey cards 102 under a laser system which may comprise a laser 104, and a galvo 106 (plus a field flattening lens 108 in one embodiment or a z-axis focus lens 109 in another embodiment).
• a tachometer 110 may be used to provide a speed input to a control system 112 which allows the processor to track the cutting surface.
• the control system 112 starts the laser and guides the laser beam through its desired pattern by controlling the placement of gah/o mirrors 106 in combination with z-axis focus compensation.
• a leading edge trigger 120 senses the leading edge of a card and provides a signal to initiate the lasering process.
• the control system 112 Upon receiving the signal, the control system 112 tracks the material via tachometer 110 signal and initiates lasering 104 and beam positioning 106.
• the field flattening lens (or in another embodiment, the z-axis focus lens) provides a means for enabling the laser beam to maintain focus over the gafvos mirrors' entire field of view.
• the discrete sheets of material may be shingled in a straight ahead, right side or left side orientation from the loading point to the shingling conveyor. If a web of material is cut into discrete sheets prior to the loading point, the discrete sheets may be rotated 90° and then conveyed. This arrangement allows for different edges of each sheet to be exposed to the laser.
• the discrete sheets may also be conveyed at any angle past a laser system while the discrete sheets are vertically inclined or inclined in any plane through 360° rotation.
• the vertical arrangement (as well as other arrangements) still allows for shingling (overlap) of adjacent sheets and provides the same advantages as shingling the sheets in the horizontal plane.
• Gah/o Max Angle plus or minus 15 degrees
• the web is cut into blanks and the blanks are transferred to a shingling conveyor.
• the shingled blanks would need to have an exposed area of ,033m (90% overlap). It can be shown that the resultant shingling conveyor speed would be reduced by a factor of ten (10):
• the laser system In order to rnaximize the cut time in a web system, the laser system would track the part during the cut time.
• the field of view for a web system would need to be .3m while the work area is only .033m
• Focal Length Field of view ⁇ 2 x Inv Tan 15 degrees
• the focal length reduction on a shingling system is a factor of 10.
• the spot diameter is directly proportional to the focal length as shown in the following formula:
• Wave Length (L) In Microns is 10.6 for C02 laser.
• Focal Length (f) in Millimeters is 567 for the Web System and 56.7 for the
• Beam Diameter (W) In Millimeters is 30 for either system.
• the respective spot diameters are as follows:
• Shingling System Spot Diameter 25 microns
• the overall focused spot diameter is reduced by a factor of 10.
• the power density of the shingling system is increased significantly over the web system power density:
• the power density for the shingling system is increased by a factor of 100 times.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Mechanical Engineering (AREA)
• Plasma & Fusion (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Laser Beam Processing (AREA)
• Cell Separators (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
• Treatment Of Fiber Materials (AREA)
• Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
• Manufacturing Of Electric Cables (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Soil Working Implements (AREA)
• Removal Of Insulation Or Armoring From Wires Or Cables (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)

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• 1995
  • 1995-10-11 US US08/541,047 patent/US5688463A/en not_active Expired - Fee Related
• 1996
  • 1996-06-11 DE DE69623021T patent/DE69623021T2/de not_active Expired - Lifetime
  • 1996-06-11 CA CA002224248A patent/CA2224248C/en not_active Expired - Lifetime
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  • 1996-06-11 BR BR9608757A patent/BR9608757A/pt not_active IP Right Cessation
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  • 1996-06-11 WO PCT/US1996/010138 patent/WO1996041713A1/en not_active Ceased
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• 1997
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• 1998
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