Jari Hovikorpi

Laser cutting of paper

It is commonly known that CO2 laser beam is suitable for paper and board cutting. However there exists quite little published research work about paper cutting with laser. Lasers at paper industry are mainly used to different perforating and scoring applications. There exists only few paper slitting applications. Water jet cutting is widely used edge trimming applications at paper plants. Laser cutting could be substation process for water jet cutting.This paper concentrates on understanding parameters that are characteristic to the laser cuttability of coated and uncoated papers. Also economical aspects, for edge trimming of paper web, are studied. This study was performed within a national project in Finland about laser cutting of pulps, papers and boards. The research was carried out with a Trumpf 2.7 kW HQ laser and a work cell designed and manufactured for the project.The cutting experiments contained the cutting tests of how different laser parameters like power, focal point position, and focal length affected the cutting speed and the cut edge quality. Papers used in study could be laser cut with acceptable quality. Highest cutting speeds were noted with 127 mm focal length. It was also found that the cut edge quality and kerf width were stable for each grammage and paper types produced with parameter combinations on cutting limit (laser power/cutting speed).It is commonly known that CO2 laser beam is suitable for paper and board cutting. However there exists quite little published research work about paper cutting with laser. Lasers at paper industry are mainly used to different perforating and scoring applications. There exists only few paper slitting applications. Water jet cutting is widely used edge trimming applications at paper plants. Laser cutting could be substation process for water jet cutting.This paper concentrates on understanding parameters that are characteristic to the laser cuttability of coated and uncoated papers. Also economical aspects, for edge trimming of paper web, are studied. This study was performed within a national project in Finland about laser cutting of pulps, papers and boards. The research was carried out with a Trumpf 2.7 kW HQ laser and a work cell designed and manufactured for the project.The cutting experiments contained the cutting tests of how different laser parameters like power, focal point position, and focal leng...

Laser Cutting of Birch Pulp

Laser cutting offers unique possibilities for different production systems. So far the utilisation has been most advanced in cutting of metal products. Lasers have also been used for paper and board cutting in some specific applications. This document, which concentrates on the physical phenomena of laser cutting of birch pulp, is part of a national project performed in Finland about laser cutting of pulp, paper and board. The research was carried out with a 2.7 kW HQ laser, with a focal point diameter of 80 μm and a work cell designed and manufactured for the project. These experiments were carried out with a pure birch pulp manufactured for the experiments, and with three different densities. The experiments cover the effect of laser power, focal point position, material thickness, direction of the polarisation plane, cutting gas pressure and nozzle stand-off distance on the cutting speed and cut edge quality. From the experiments it can be seen that all of the variables have an effect on both the cutting speed and the cut quality.

Laser cutting of pulps

Laser cutting offers unique possibilities for different production systems. So far the utilization has been most advanced in cutting of metal products. The laser has also been utilized for paper and board cutting in some specific applications. This study is performed within a national project in Finland about laser cutting of pulp, paper and board. The research is carried out with a Trumpf 2.7 kW HQ laser, with focal point diameter of 80 µm and a work cell designed and manufactured for the project. The study concentrates on the physical phenomena of laser cutting of different pulps. These experiments covered the effect of pulp type and weight per square meter (grammage g/m2). The experiments covered also the effect of laser parameters on the cutting speed and cut edge quality. By the experiments it can be seen that all of the variables have an effect on both the cutting speed and the cut quality.Laser cutting offers unique possibilities for different production systems. So far the utilization has been most advanced in cutting of metal products. The laser has also been utilized for paper and board cutting in some specific applications. This study is performed within a national project in Finland about laser cutting of pulp, paper and board. The research is carried out with a Trumpf 2.7 kW HQ laser, with focal point diameter of 80 µm and a work cell designed and manufactured for the project. The study concentrates on the physical phenomena of laser cutting of different pulps. These experiments covered the effect of pulp type and weight per square meter (grammage g/m2). The experiments covered also the effect of laser parameters on the cutting speed and cut edge quality. By the experiments it can be seen that all of the variables have an effect on both the cutting speed and the cut quality.

Laser cutting of pigment coated boards

It is commonly known that laser cutting is suitable for paper and board cutting. Anyhow the use of laser technology in this application is minimal. This paper concentrates on defining the parameters that affect the laser cuttability of pigment coated boards and outlook of cut edge. This study was performed within a national project in Finland about laser cutting of pulps, papers and boards. The research was carried out with a Trumpf 2700 W HQ laser and a work cell designed and manufactured for the project.The materials used in study were calcium carbonate and clay coated boards. The grammage of base board was kept constant when coat weight varied. The cutting experiments contained tests of how different laser parameters like power and focal point position affected the cutting speed and the cut edge quality.Coated boards used in study could be laser cut with distinguished quality. It was noticed that cutting speed was linearly dependent on laser power. However, it was found that with mineral pigment coated materials, like not with uncoated materials, in certain parameter point this linear behaviour turned to nonlinear behaviour. This was due to type of pigment and amount of coating. In addition, it was found that fastest cutting speeds and narrowest kerfs were reached with optimal positions of focal point.It is commonly known that laser cutting is suitable for paper and board cutting. Anyhow the use of laser technology in this application is minimal. This paper concentrates on defining the parameters that affect the laser cuttability of pigment coated boards and outlook of cut edge. This study was performed within a national project in Finland about laser cutting of pulps, papers and boards. The research was carried out with a Trumpf 2700 W HQ laser and a work cell designed and manufactured for the project.The materials used in study were calcium carbonate and clay coated boards. The grammage of base board was kept constant when coat weight varied. The cutting experiments contained tests of how different laser parameters like power and focal point position affected the cutting speed and the cut edge quality.Coated boards used in study could be laser cut with distinguished quality. It was noticed that cutting speed was linearly dependent on laser power. However, it was found that with mineral pigment coated...

Case studies of industrial applications of high-power diode laser in Finland

The high power diode laser is a new industrial tool. It has several advantages and disadvantages compared to the conventional industrially used CO2 and Nd:YAG laser. The most promising areas of application of diode laser have been considered to be thin sheet welding and hardening. Quite a few feasibility studies of the use of diode laser have been carried out in Finland. So far there has been some application in which diode laser is the most suitable laser. Typically, the HPDL is integrated to an industrial robot. The welding of stainless steel housing, car door lock and catalytic converters are typical examples of applications in which diode laser has technological as well as economical advantages over the conventional laser and welding techniques. The welding of these products requires good control over the heat input, short through put time and low investment. The weld cross-section of a diode laser weld is, because of conduction limited welding process, more suitable for these applications than the keyhole welding. Hardening of a large gear wheel presents also a good example of an application in which the diode laser makes it possible to economically produce structures that have not earlier been possible. Hardening requires a special form of heat delivery in order to ensure evenly hardened zone and acceptable quality. The application was performed with two high power diode lasers. The case studies of these four applications are presented and discussed in details in this paper.