Lothar Morgenthal

Compact laser machining head with integrated on-line path control for laser machining of material

A compact laser machining head is used for laser machining of material, in particular for laser-supported material machining methods for 2D and 3d laser machining. This laser machining head includes a sensor for geometry recognition and/or following contours, one or a plurality of mirrors and/or mirror systems with a mirror housing and mirror holder, a defined interface with the beam guidance system of the machine, and further required structural elements, connections and lines. In this compact laser machining head, the sensor is structurally completely integrated into the laser machining head, is seated, together with other auxiliary devices of the laser machining head tied to the working direction, rotatable around the rotary shaft of the sensor. The laser machining head contains a protocol memory and a comparator unit which are disposed and connected in such a way that the data of the sensor can be compared and evaluated, in parallel with the control of the machining process, with the data of the protocol memory in the comparator unit for the purpose of quality control and affecting the machining process.

High brightness lasers in cutting applications

Laser cutting machines with linear motor drives provide high contour accuracy and high cutting rates. Thus laser beam cutting has become increasingly competitive compared to mechanical precision cutting [1]. Since the several years, new laser beam sources are available for cutting. One of the promising solutions is cutting with fiber lasers. The fiber laser has several advantages such as absorption rate, power efficiency, fiber delivery, better focusing if compared to the CO2 laser.During the recent years, the system technology for laser beam cutting was upgraded at Fraunhofer IWS Dresden [2]. In particular, a precision 3D-laser cutting system with linear drives, robotic systems and several fiber lasers have been installed.Within the frame of several research projects laser beam cutting with CO2-and fiber lasers has been investigated in order to compare the cutting quality and cutting performance of two beam sources. Objective of these studies was to find out if the cutting quality is sufficient and if the requested cutting rate can be obtained.It could be learned that the cutting quality for both lasers is good. The edge quality is sufficient for most of the materials and thicknesses. However, using single and multimode fiber lasers in the kilowatt range can increase the cutting speed and can thus reduce the cutting time [3][4].This paper describes the gained user experience of Fraunhofer IWS. Various beam sources are compared and evaluated with respect to specific applications. Moreover, the advantages and disadvantages for material processing applications will be explained.Laser cutting machines with linear motor drives provide high contour accuracy and high cutting rates. Thus laser beam cutting has become increasingly competitive compared to mechanical precision cutting [1]. Since the several years, new laser beam sources are available for cutting. One of the promising solutions is cutting with fiber lasers. The fiber laser has several advantages such as absorption rate, power efficiency, fiber delivery, better focusing if compared to the CO2 laser.During the recent years, the system technology for laser beam cutting was upgraded at Fraunhofer IWS Dresden [2]. In particular, a precision 3D-laser cutting system with linear drives, robotic systems and several fiber lasers have been installed.Within the frame of several research projects laser beam cutting with CO2-and fiber lasers has been investigated in order to compare the cutting quality and cutting performance of two beam sources. Objective of these studies was to find out if the cutting quality is sufficient and if th...

Laser welding on the fly with coupled axes systems

The availability of high power high beam quality lasers permits to increase the processing speed for laser welding up to 10 m/min or more. But for complex shaped 3D welding paths conventional laser motion systems restrict the attainable welding speed because of limited dynamic and accuracy.Coupled axes systems can overcome these problems. A handling system with coupled axes consisting of a conventional industrial robot and a high-power beam deflection optics for laser beam welding with high power Nd:YAG – laser beams will be introduced.The example of stitch seam welding combining the deflection optics and a robot will be presented to describe the potential of the new development. Methods of resolution for optimizing the motion of the robot and the synchronized beam deflection will be discussed and evaluated in respect to the increase in productivity.The availability of high power high beam quality lasers permits to increase the processing speed for laser welding up to 10 m/min or more. But for complex shaped 3D welding paths conventional laser motion systems restrict the attainable welding speed because of limited dynamic and accuracy.Coupled axes systems can overcome these problems. A handling system with coupled axes consisting of a conventional industrial robot and a high-power beam deflection optics for laser beam welding with high power Nd:YAG – laser beams will be introduced.The example of stitch seam welding combining the deflection optics and a robot will be presented to describe the potential of the new development. Methods of resolution for optimizing the motion of the robot and the synchronized beam deflection will be discussed and evaluated in respect to the increase in productivity.

Laser processing of siliceous materials

Laser processing of siliceous materials becomes increasingly important. Analogous to the laser processing of conventional materials there are applications in the fields of cleaning, surface processing, cutting, etc. The present paper concerns the state of the art and new applications: (1) Laser cleaning of natural stone surfaces. The good disability allows restoration work to be carried out conveniently, as for example the complete removal of crusts or the removal to such degree that moisture is not trapped beneath. (2) Non-slip finish of polished natural stone surfaces: The excellent focusing of laser beams on spots as small as 100 micrometer and below can be exploited to produce macroscopically invisible structures on the surfaces of different materials. This permits microscopically small craters and lentil shaped depressions to be generated on the stone surface. Therefore it is possible to provide a non-slip finish to polished natural stone surfaces without noticeably impairing the gloss. (3) Concrete cutting: In Europe, and particularly in Germany, there is a growing demand for redevelopment of concrete apartment buildings, involving the removal of non-bearing walls and the cutting of openings. The temporal relocation of residents due to the noise and moisture from the use of diamond tools could be avoided by applying a laser cutting technology. With a 3 kW-Nd-YAG-laser, 70 mm concrete can be cut with rates up to 25 mm/min.

Requirements and potentialities of packaging for bioreactors with LTCC and polymer

The main focus of this article lies on the development of a novel joining technology for LTCC ceramic and polymer sub-assemblies utilising laser radiation. Technical processes and the latest results are presented as well as potential future applications. The developed joining process can be divided into two steps utilizing the same laser system: a surface modification of the joining partners and a thermal process that is melting a small portion of the polymer matrix that is being pressed into the roughness of the ceramic surface.