Method and device for producing a cutting or embossing roller by means of laser resurfacing welding
A method for producing a cutting or embossing roller having a cutting knife or embossing projection that projects out of the surface of a base body of the roller ensures the greatest possible optimal homogeneity of the cutting knife or the embossing projection, while minimizing production duration and costs. Single-layer or multi-layer application of the cutting knife or the embossing projection onto the roller base body occurs by laser resurfacing welding. Each layer is produced using an additional powdered material, which is melted in a melt bath at the weld point. The heat and/or light radiation emitted by the melt bath is detected, at least during application of each layer. Laser power is controlled or regulated as a function of the heat and/or light radiation emitted by the melt bath, so that melt bath temperature remains essentially constant during application of each layer.
1. A method for producing a cutting or embossing roller having a cutting knife or embossing projection that projects out of a surface of a base body of the roller comprising the following steps:
(a) applying by laser resurfacing welding at least one layer of the cutting knife or the embossing projection onto the base body of the roller, each layer of the at least one layer being produced using an added material in powder form melted in a melt bath at a weld point;
(b) detecting heat or light radiation emitted by the melt bath at least during application of each layer;
(c) controlling or regulating power of a laser used in the laser resurfacing welding as a function of the heat or light radiation emitted by the melt bath so that melt bath temperature remains substantially constant during application of each layer; and
(d) setting a wavelength of a laser beam emitted by the laser as a function of an absorption capacity of powder particles that form the added material in powder form.
2. The method according to claim 1 , wherein a diode laser is used for the laser resurfacing welding.
3. The method according to claim 2 , wherein laser light having wavelengths of 808 nm to 980 nm is generated with the diode laser.
4. The method according to claim 2 , wherein laser light having superimposed wavelengths of 940 nm and 980 nm is generated with the diode laser.
5. The method according to claim 2 , wherein the diode laser generates a laser beam having a cross-section and the cross-section is converted to a circular cross-section by means of a light guide.
6. The method according to claim 1 , wherein the added material in powder form is passed to the weld point by a transport gas that simultaneously functions as an inert gas for shielding the weld point.
7. The method according to claim 1 , wherein a powder composition is used as the added material in powder form, the powder composition containing less than or equal to 90 wt.-% Fe and, in addition, one or more alloy components selected from the group consisting of B, Si, W, V, Cr, C, Co, Mn, Mg, Ti, zirconium oxide and aluminum oxide.
8. The method according to claim 1 , wherein a powder composition is used as the added material in powder form, the powder composition containing less than or equal to 70 wt.-% Co and, in addition, one or more alloy components selected from the group consisting of B, Si, W, V, Cr, C, Co, Mn, Mg, Ti, zirconium oxide and aluminum oxide.
9. The method according to claim 1 , wherein a powder composition is used as the added material in powder form, the powder composition containing less than or equal to 70 wt.-% Ni and, in addition, one or more alloy components selected from the group consisting of B, Si, W, V, Cr, C, Co, Mn, Mg, Ti, zirconium oxide and aluminum oxide.