For processing a workpiece held by a chuck table with branched pulsed laser beams, if it is assumed that branch intervals at which adjacent ones of the branched pulsed laser beams are spaced from each other on a surface of the workpiece are represented by L, a value calculated by dividing a processing feed speed at which the chuck table is moved with respect to a condensing lens by a processing feed unit by the frequency of the pulsed laser beam at a processing point where the branched pulsed laser beams are applied to the workpiece is represented by S, and any integer is represented by n, then the branching intervals, the processing feed speed, and the frequency of the pulsed laser beam are established to satisfy the relationship of L≠n×S.

Provided is a crack repair method of melting and eliminating a crack generated in a steel material, the method including holding a tab plate in surface contact with the steel material in which the crack is generated, thereafter continuously irradiating the tab plate to a first end portion of the crack in the steel material with a laser beam, and subsequently continuously irradiating the crack with the laser beam along the crack to a second end portion of the crack to melt and eliminate the crack. Consequently, when eliminating the crack generated in a constituent member of an existing structure or a constituent member such as a machine component, the crack can be eliminated without forming a through hole in the constituent member.

A workpiece processing method includes a protective film forming step of coating an upper surface of a wafer with a protective film including a water-soluble resin, a laser processing step of applying a laser beam of such a wavelength as to be absorbed in the wafer to the upper surface to subject the wafer to ablation, and a cleaning step of removing the protective film from the upper surface of the wafer together with debris generated in the laser processing step. The cleaning step includes a first cleaning sub-step of spinning a spinner table holding the wafer and supplying a cleaning fluid to the upper surface of the wafer and a second cleaning sub-step of supplying a mixed fluid of gas and the cleaning fluid to the upper surface of the wafer held by the spinning spinner table, to clean the wafer.

A workpiece processing method includes a protective film forming step of coating an upper surface of a wafer with a protective film including a water-soluble resin, a laser processing step of applying a laser beam of such a wavelength as to be absorbed in the wafer to the upper surface to subject the wafer to ablation, and a cleaning step of removing the protective film from the upper surface of the wafer together with debris generated in the laser processing step. The cleaning step includes a first cleaning sub-step of spinning a spinner table holding the wafer and supplying a cleaning fluid to the upper surface of the wafer and a second cleaning sub-step of supplying a mixed fluid of gas and the cleaning fluid to the upper surface of the wafer held by the spinning spinner table, to clean the wafer.

In a three-dimensional printing method example, a metallic build material is applied. A positive masking agent is selectively applied on at least a portion of the metallic build material. The positive masking agent includes a radiation absorption amplifier that is compatible with the metallic build material. The metallic build material is exposed to radiation from a spatially broad, high energy light source to melt the portion of the metallic build material in contact with the positive masking agent to form a layer. The radiation absorption amplifier i) has an absorbance for the radiation that is higher than an absorbance for the radiation of the metallic build material, or ii) modifies a surface topography of the at least the portion of the metallic build material to reduce specular reflection of the radiation off of the at least the portion of the metallic build material, or both i) and ii).

In a three-dimensional printing method example, a metallic build material is applied. A positive masking agent is selectively applied on at least a portion of the metallic build material. The positive masking agent includes a radiation absorption amplifier that is compatible with the metallic build material. The metallic build material is exposed to radiation from a spatially broad, high energy light source to melt the portion of the metallic build material in contact with the positive masking agent to form a layer. The radiation absorption amplifier i) has an absorbance for the radiation that is higher than an absorbance for the radiation of the metallic build material, or ii) modifies a surface topography of the at least the portion of the metallic build material to reduce specular reflection of the radiation off of the at least the portion of the metallic build material, or both i) and ii).

A method of forming a separator for a lithium-ion battery includes arranging a polymer film in contact with a sacrificial layer to form a cutting stack. The method includes disposing the cutting stack between a first vitreous substrate and a second vitreous substrate. The method includes applying an infrared laser to the cutting stack through the first vitreous substrate to generate heat at the sacrificial layer. The method also includes transferring heat from the sacrificial layer to the polymer film to thereby cut out a portion of the polymer film and form the separator. A method of cutting a polymer film and a cutting system are also explained.

A method of forming a separator for a lithium-ion battery includes arranging a polymer film in contact with a sacrificial layer to form a cutting stack. The method includes disposing the cutting stack between a first vitreous substrate and a second vitreous substrate. The method includes applying an infrared laser to the cutting stack through the first vitreous substrate to generate heat at the sacrificial layer. The method also includes transferring heat from the sacrificial layer to the polymer film to thereby cut out a portion of the polymer film and form the separator. A method of cutting a polymer film and a cutting system are also explained.

Fluorescent rare earth glass frits are suitable for laser marking. A marking composition including fluorescent glass frits is disclosed that is capable of emitting fluorescence under irradiation of ultraviolet rays. A method of forming marks or indicia on a substrate using the fluorescent rare earth glass frits is also disclosed.

A grain-oriented electrical steel sheet incudes a groove formed on a surface and a solidified alloy layer formed under the groove, wherein the solidified alloy layer includes particles of a certain average diameter.