Laser Machining Systems Research Articles

Dose Rate Measurements in Pulsed Radiation Fields by Means of an Organic Scintillator

A deficiency in the implementation of current radiation protection is the determination of the ambient dose equivalent H*(10) and the directional dose equivalent H´(0.07) in pulsed radiation fields. Conventional dosimeter systems are not suitable for measurements in photon fields comprising short radiation pulses, which consequently leads to high detector loads in short time periods. Nevertheless, due to the implementation of advanced medical accelerators for cancer therapy, new medical diagnostic devices as well as various laser machining systems, there is an urgent need for suitable dosimeter systems for real time dosimetry. In this paper, a detector concept based on an organic scintillator and a full digital data analysis with the aim of developing a portable, battery powered measurement system is presented.

Metal Optics — New Chances for Laser Focusing Mirrors

AbstractAll reflective laser focusing heads have been in use for industrial high‐power laser machining systems for more than thirty years now. Originally inevitable for multi‐kilowatt “macro” lasers, now better metal mirror machining technologies open the field for metal optics to mid‐power and even to low‐power applications. Especially the advantage of cost effective flexible manufacturing of aspherical and free form surfaces even in lowest quantities gives the optical engineers the versatility to manufacture laser focusing systems for interesting new applications: Bessel beams will go beyond the diffraction limit, polygon scanners with smallest focus spots will deliver high power densities, e.g. for dicing, extremely compact focusing for 3D metal printing or remote welding is realized with a few mirrors only. Complete “focusing‐boxes” or just single mirrors as well as matched mirror sets are available and help laser machine builders and system integrators to realize never‐seen‐before products.

Strong Market Growth in 2006 – World Market for Laser Systems Reaches New Record High

AbstractIn 2006, the world market volume of laser machining systems reached a new record high. After the record high in 2000 the market saw decreasing numbers first and recovered then in 2004 and 2005 to a level of 4.8 billion euro. In 2006 the market saw a remarkable 27 percent increase to 6.1 billion euro (Fig. 1).

Strong market growth in 2004 – World market for laser systems narrowly misses the record high of 2000

In 2004, the world market volume of laser machining systems reached 4.65 billion euro, a 27% increase over the previous year's level of 3.65 billion euro and within a few percent of the record 4.75 billion euro achieved in 2000 (Fig. 1). What makes this result more surprising is that between 2000 and 2004, the value of a US dollar fell from an average of 1.08 euro to 0.81 euro; meaning that, from a US dollar standpoint, 2004 actually surpassed the 2000 level.

Patterning of optical coatings by laser ablation for the fabrication of dielectric masks and diffractive phase elements

Excimer laser ablation is a versatile method to generate 2- or 3-D microstructured devices for mechanics, fluidics, and optics. Particularly, if in 1-D the structure is predefined by a layer design, and the other two dimensions are defined in the layer ablation process by mask projection, very precise structure definition in three dimensions and ablated surfaces with optical quality can be achieved. By patterning optical layers or layer stacks, a variety of applications is possible. Two examples are demonstrated. 1. Dielectric masks (amplitude masks) are fabricated by structuring a highly reflective dielectric layer stack. These masks can be used in high power laser machining systems. 2. Diffractive optical elements (phase elements) are generated by structured ablation of a transparent layer. The performance of these elements in shaping excimer laser beams is demonstrated.

Heating mechanism in relation to the laser machining process

Laser workpiece interaction mechanism is an important phenomenon which will assist in the development of laser machining systems. The interaction mechanism is generally complicated and depends on the laser and workpiece properties. In the present study a mathematical analysis for the laser material removal by evaporation and radial ejection of liquid is carried out. In the analysis the time unsteady problem is solved and nucleation explosions are predicted.

Grid attenuators in laser machining systems

General equations for the attenuated and focused intensity distribution of a gaussian beam at the focal region are derived for two-dimensional arbitrary shaped grid attenuators. Assuming a circular aperture grid, calculations of the intensity distribution in the focal plane and at several planes of the focal region were done. Results of calculations and relevant experiments are reported and discussed, in view of the application of these types of attenuators in laser machining systems.