Method and apparatus for cutting a laminate made of a brittle material and a plastic

Abstract

A method and an apparatus for cutting a laminate made of a brittle material and a plastic with a cutting tool is described. The plastic is heated up, thereby lowering its viscosity, at least in the region of a predetermined cutting line. A cutting tool is placed onto the plastic side of the laminate, the loading pressure being adjustable. By moving cutting tool relative to the laminate along the predetermined cutting line, the plastic is severed; at the same time the brittle material is scored, thereby inducing a mechanical stress. If appropriate, the mechanical stress along the cutting line is subsequently increased to exceed the rupture strength of the scored brittle material. A preferred application is the cutting of thin glass or glass-ceramic/plastic laminates.

We claim:  
     
         1 . A method of cutting a laminate comprising a brittle material and a plastic on one side of the laminate, said method comprising the steps of: 
 a) heating the plastic in the vicinity of a predetermined cutting line on the plastic, whereby a viscosity of the plastic is lowered;    b) engaging the cutting tool on the plastic on said one side and adjusting a loading pressure of the cutting tool on the plastic;    c) moving the cutting tool relative to the plastic and along the predetermined cutting line on the plastic, whereby the plastic is severed and the brittle material is simultaneously scored, thereby inducing a mechanical stress; and    d) additionally, if appropriate, increasing the mechanical stress along the predetermined cutting line to exceed a rupture strength of the brittle material.    
     
     
         2 . The method as defined in  claim 1 , further comprising providing the laminate with the plastic on another side of the laminate opposite to said one side in addition to said one side; heating the plastic in the vicinity of another predetermined cutting line on said another side, thereby lowering the viscosity of the plastic on said another side as well as on said one side; engaging another cutting tool or said cutting tool on the plastic on said another side and adjusting a loading pressure on said plastic on said another side; moving said another cutting tool relative to said plastic along the another predetermined cutting line on the plastic on said another side, whereby the plastic on said another side is severed and the brittle material is simultaneously scored on said one side or on both of said sides, thereby inducing a mechanical stress; and additionally, if appropriate, increasing the mechanical stress along the another predetermined cutting line to exceed a rupture strength of the brittle material.  
     
     
         3 . The method as defined in  claim 1  or  2 , wherein the heating is performed by irradiating the plastic.  
     
     
         4 . The method as defined in  claim 1  or  2 , wherein the heating is performed by irradiating the plastic with radiation from at least one of an infrared radiation source and a laser.  
     
     
         5 . The method as defined in  claim 1  or  2 , wherein the heating is provided by a hot-gas jet.  
     
     
         6 . The method as defined in  claim 1  or  2 , wherein the heating of the plastic takes place by heating said cutting tool or said another cutting tool.  
     
     
         7 . The method as defined in  claim 1  or  2 , wherein the heating of the plastic takes place by heating as lower end of said cutting tool or said another cutting tool.  
     
     
         8 . The method as defined in  claim 1  or  2 , wherein the laminate is heated in its entirety during the heating.  
     
     
         9 . The method as defined in  claim 1  or  2 , wherein the cutting tool or the cutting tools is or are each provided with a diamond tip.  
     
     
         10 . The method as defined in  claim 1  or  2 , wherein the cutting tool or cutting tools is or are each provided with a cutting blade or a cutting wheel.  
     
     
         11 . The method as defined in  claim 1  or  2 , wherein the cutting tool or the cutting tools is or are each provided with a cutting blade or a cutting wheel and said cutting blade or cutting wheel is made of a hard metal or of a ceramic material.  
     
     
         12 . The method as defined in  claim 1  or  2 , wherein the cutting tool or the cutting tools is or are each provided with a cutting blade or a cutting wheel and the cutting wheel or the cutting blade is made of tungsten-carbide and/or diamond-containing sintered metal.  
     
     
         13 . The method as defined in  claim 1  or  2 , wherein the cutting tool has or the cutting tools each have a lower end and further comprising vibrating the cutting tool or tools so that the cutting tool or tools including said lower end execute axial ultrasonic vibrations.  
     
     
         14 . The method as defined in  claim 1  or  2 , wherein the cutting tool has or the cutting tools each have a lower end and further comprising vibrating the cutting tool or tools so that the cutting tool or tools including said lower end execute axial ultrasonic vibrations and wherein the ultrasonic vibrations have amplitudes of from 5 μm to 40 μm.  
     
     
         15 . The method as defined in  claim 1  or  2 , wherein the cutting tool has or the cutting tools each have a lower end and further comprising vibrating the cutting tool or tools so that the cutting tool or tools including said lower end execute axial ultrasonic vibrations and wherein the ultrasonic vibrations have amplitudes of from 5 μm to 40 μm and frequencies in the range from 20 kHz to 100 kHz.  
     
     
         16 . The method as defined in  claim 1  or  2 , wherein the cutting tool has or the cutting tools each have a lower end and further comprising vibrating the cutting tool or tools so that the cutting tool or tools including said lower end execute transverse ultrasonic vibrations longitudinally and/or transversely with respect to a cutting direction of the cutting tool or tools.  
     
     
         17 . The method as defined in  claim 1  or  2 , wherein the cutting tool has or the cutting tools each have a lower end and further comprising vibrating the cutting tool or tools so that the cutting tool or tools including said lower end execute transverse ultrasonic vibrations longitudinally and/or transversely with respect to a cutting direction of the cutting tool or tools and wherein the ultrasonic vibrations have amplitudes of from 5 μm to 40 μm.  
     
     
         18 . The method as defined in  claim 1  or  2 , wherein the cutting tool has or the cutting tools each have a lower end and further comprising vibrating the cutting tool or tools so that the cutting tool or tools including said lower end execute transverse ultrasonic vibrations longitudinally and/or transversely with respect to a cutting direction of the cutting tool or tools and wherein the ultrasonic vibrations have amplitudes of from 5 μm to 40 μm and the ultrasonic vibrations have frequencies in the range from 20 kHz to 100 kHz.  
     
     
         19 . The method as defined in  claim 1  or  2 , wherein the plastic is a plastic film or a sprayed-on polymer film.  
     
     
         20 . The method as defined in  claim 1  or  2 , wherein the plastic is a polyethylene or polycarbonate film.  
     
     
         21 . The method as defined in  claim 1  or  2 , wherein the plastic has a thickness of from 1 μm to 300 μm.  
     
     
         22 . The method as defined in  claim 1 , wherein the brittle material is glass, a glass-ceramic material or a ceramic material.  
     
     
         23 . The method as defined in  claim 22 , wherein the glass is flat glass.  
     
     
         24 . The method as defined in  claim 1 , wherein the brittle material has a thickness of up to 30 mm.  
     
     
         25 . The method as defined in  claim 1 , wherein the brittle material is a glass sheet, a glass-ceramic sheet or a ceramic sheet.  
     
     
         26 . The method as defined in  claim 25 , wherein the sheet has a thickness of from 10 μm to 300 μm.  
     
     
         27 . The method as defined in  claim 1  or  2 , wherein the brittle material and the plastic are bonded to one another by means of a respective layer of adhesive.  
     
     
         28 . The method as defined in  claim 1  or  2 , wherein the brittle material and the plastic are bonded to one another by means of a respective layer of adhesive and the layer of the adhesive has a thickness of from 2 μm to 50 μm.  
     
     
         29 . The method as defined in  claim 1  or  2 , wherein the laminate is made by applying the plastic to the brittle material by extrusion, casting, spraying, roller-coating or laminating a plastic film onto the brittle material.  
     
     
         30 . An apparatus for cutting a laminate comprising a brittle material and a plastic on one side of the laminate, said apparatus comprising 
 means for heating the plastic in the vicinity of a predetermined cutting line, whereby a viscosity of the plastic is lowered,    means for engaging a cutting tool on the plastic on the one side with an adjustable loading pressure on a surface of the laminate,    means for moving the cutting tool relative to the laminate along the predetermined cutting line on the plastic for the purpose of severing the plastic and simultaneously scoring the brittle material, thereby inducing a mechanical stress, and    means for additionally increasing the mechanical stress along the cutting line to exceed the rupture strength of the brittle material, if appropriate.    
     
     
         31 . The apparatus as defined in  claim 30 , further comprising means for heating the plastic on another side of the laminate in the vicinity of another predetermined cutting line when the plastic is provided on said another side as well as said one side, thereby lowering the viscosity of the plastic on said another side as well as on said one side, means for engaging another cutting tool on the plastic on the another side with an adjustable loading pressure on a surface of the plastic on the another side; means for moving the another cutting tool along the another predetermined cutting line for the purpose of severing the plastic along the another predetermined cutting line and simultaneously scoring the brittle material on said one side or on both of said sides, thereby inducing a mechanical stress, and means for additionally increasing the mechanical stress along the predetermined cutting lines to exceed the rupture strength of the brittle material, if appropriate.  
     
     
         32 . The apparatus as defined in  claim 30 , wherein the means for heating the plastic is a radiation source.  
     
     
         33 . The apparatus as defined in  claim 32 , wherein the radiation source is a heat source.  
     
     
         34 . The apparatus as defined in  claim 33 , wherein the heat source is an infrared heater and/or a laser heater.  
     
     
         35 . The apparatus as defined in  claim 30  or  31 , wherein the means for heating the plastic is a hot-gas jet.  
     
     
         36 . The apparatus as defined in  claim 30  or  31 , wherein the means for heating the plastic heats the cutting tool including a lower end of the cutting tool.  
     
     
         37 . The apparatus as defined in  claim 30  or  31 , wherein the cutting tool has or cutting tools each have a lower end and a diamond cutting element is mounted in said lower end.  
     
     
         38 . The apparatus as defined in  claim 30  or  31 , wherein the cutting tool has or cutting tools each have a tip and said tip comprises a cutting wheel or a cutting blade.  
     
     
         39 . The apparatus as defined in  claim 30  or  31 , wherein the cutting tool has or cutting tools each have a tip and said tip comprises a cutting wheel or a cutting blade made of a hard metal or of a ceramic material.  
     
     
         40 . The apparatus as defined in  claim 30  or  31 , wherein the cutting tool has or cutting tools each have a tip and said tip comprises a cutting wheel or cutting blade made of a tungsten-carbide and/or diamond-containing sintered metal.  
     
     
         41 . The apparatus as defined in  claim 30  or  31 , further comprising a piezo- or magnetostrictive modulator and a coupling element coupling the modulator with the cutting tool or each of the cutting tools and wherein said modulator includes means for inducing ultrasonic vibrations in an axial, longitudinal or transverse cutting tool direction in the cutting tool or in each of the cutting tools including a lower end thereof.  
     
     
         42 . The apparatus as defined in  claim 30  or  31 , further comprising a piezo- or magnetostrictive modulator and a coupling element coupling the modulator with the cutting tool or each of the cutting tools, said modulator including means for inducing ultrasonic vibrations in an axial, longitudinal or transverse cutting tool direction in the cutting tool or in each of the cutting tools including a lower end thereof, and means for controlling amplitudes and frequencies of the ultrasonic vibrations in an open-loop and closed-loop manner.  
     
     
         43 . The apparatus as defined in  claim 30  or  31 , further comprising a piezo- or magnetostrictive modulator and a coupling element coupling the modulator with the cutting tool or each of the cutting tools, said modulator including means for inducing ultrasonic vibrations in an axial, longitudinal or transverse cutting tool direction in the cutting tool or in each of the cutting tools including a lower end thereof, and means for controlling amplitudes and frequencies of the ultrasonic vibrations in an open-loop and closed-loop manner; and wherein the amplitudes of the ultrasonic vibrations are from 5 μm to 40 μm and the frequencies of the ultrasonic vibrations are from 20 kHz to 100 kHz.  
     
     
         44 . The apparatus as defined in  claim 30  or  31 , wherein the means for heating the plastic comprise at least one heating element for heating the cutting tool or cutting tools, a thermocouple arranged to measure a temperature of the cutting tool or tools and a heating element voltage control device.  
     
     
         45 . The apparatus as defined in  claim 30  or  31 , wherein the cutting tool or each of the cutting tools is pivotable by means of at least one axial element perpendicular and parallel to a cutting plane thereof, at least in a cutting direction.