Electron beam pattern generators are nowadays used extensively for the production of masks and for direct writing on wafers. For obvious reasons electron beam pattern generators are optimized for integrated circuit fabrication. However there is also considerable potential for the use of electron beam lithography in other areas. In this paper recent trends in the development of electron beam pattern generators are described and the problems encountered in the application of electron beam machines in other areas e.g. integrated optics are discussed.

Gas lasers have shown to be capable of delivering tens of terrawatt aspeak power or tens of kilowatt as average power. The efficiencies of most high power gas lasers are relatively high compared with other types of lasers. For instance molecular lasers, oscillating on low lying vibrational levels, and excimer lasers may have intrinsic efficiencies above 10%.The wavelengths of these gas lasers cover the range from the far infrared to the ultra-violet region, say from 12000 to 193 nm. The most important properties are the scalability, optical homogeneity of the excited medium, and the relatively low price per watt of output power. The disadvantages may be the large size of the systems and the relatively narrow line width with limited tunability compared with solid state systems producing the same peak power. High power gas lasers group into three main categories depending on the waste-heat handling capacity.

High frequency excitation is increasingly substituting d.c. discharge excitation of CO₂ lasers mainly because of the capability of higher power density and the superior modulation properties. There exist two different modes of high frequency discharges depending on the processes taking place in the boundary layers. The conditions for the existence of both modes will be determined by means of the stationary current density voltage characteristic. Thermal instabilities in high frequency discharges proof to depend on the excitation frequency. The stability limits will be evaluated by a linear stability analysis of a discharge model including gaseous electronics, gasdynamics and Maxwell equations.

A review is presented of the most significant methods and features of RF-excited and DC-excited high power CO₂ lasers. Special attention is given to the symmetry properties of the gain and index of refraction distributions in the active medium and related effects on the laser beam quality. The evolution and the expected trends in this field are also briefly outlined.

There are two major requirements in laser design; sufficient power and correct mode structure. In the design of higher powered lasers the mode structure may suffer. Current designs are often based upon coupled cavities, in which a basic laser module is joined to another to make a single vacuum, optical cavity system. Examples of such an arrangement are the latest Ferranti CLL10, UTRC 25kW and the older Spectra Physics 5kW lasers. An alternative approach is to couple two or more lasers as an oscillator/amplifier system. The results of joining two Fast Axial Flow (FAF) lasers in this way have been discussed previously (1). This paper discusses some results from the coupling of a slow flow (SF) laser oscillator having a near Gaussian mode structure to a FAF amplifier. The result was a more powerful beam with a similar near Gaussian mode. The possibilit ies for laser design and mode engineering by this technique are illustrated by reference to cutting and welding experiments.

In most industrial processes using lasers, the beam generators are fixed, since they are bulky, heavy and subject to misalignment whereas the beam itself can be directed by mirrors or wave guides.

Two commercially available lasers are used to get a high power beam of good optical quality by the way of Amplification. A power level of 3600 Watt has been reached with a quality factor of about 3. The advantage of such beam over a higher power beam extracted from a stable cavity is demonstrated.

The properties of unstable resonators with moderate gain per pass and multipass resonators with various folding mirrors are reviewed with respect to matching the resonator geometry to the discharge volume for small and light weight lasers required for integration into robotics and manufacturing systems.

The temporal behaviour of the laser output characteristics has great influence on the quality and reproducibility of laser material processing. Changes in the transversal intensity distribution and fluctuations of the laser power during machining cause a decrease in processing quality. The interaction of laser medium with radiation field may be responsible for irregular behaviour of the laser beam parameters 1,2. In this paper experimental results concerning the influence of the active medium on the intensity distribution in the laser field and on the output power of the laser are presented. We have measured the stationary radial distribution of small signal gain and refractive index and in addition the instationary disturbance of the radiation field with fluctuations of the refractive index in a turbulent gas flow.

The combination of the fast-axial-flow principle with the RF-excitation method results in the design of high-power CO₂-lasers with low order beam modes and excellent pulsing capability. The rated CW output powers are 2.5 and 5 kW, the transverse beam modes can varied between TEM10* and TEM20, the maximum pulse frequency with approx. 100% modulation depth is 20 kHz.

New type of solid-state laser for several kilowatts is discussed. The main difficulty for the high power solid-state laser is the thermal effects induced in the solid gain medium by the pumping light. As one of solutions to this problem, an annular type of solid gain medium is proposed and its thermal characteristcs are discussed on a concrete example. It is shown that the thermal stress can be drastically redusced by using the annular type of gain medium and that a laser with this annular gain medium is easily scalable to any high power. Several kinds of resonators are considered for the annular type of solid gain medium.

The interaction of picosecond laser pulses with solid surfaces is characterized by ultra-fast energy transfer from the electronic system to the lattice. The present understanding of the elementary mechanisms responsible for carrier thermalization and cooling is briefly reviewed. In semiconductors, the electron hole plasma acts as intermediate energy storage. Recombination limits the maximum density and determines lattice heating in degenerate conditions. Experiments with femtosecond and picosecond laser sources have unraveled the salient features of the energy dissipation routes from photons to lattice.

To describe transient behaviour of experimental laser-material optical coupling, i.e. absorptivity, reflectivity, ..., we propose an original approach based on the distributions theory and Laplace transformation. It allows extent and generalization of the classical definition of stationary parameters to any temporal situation of incident laser beam, including temporal variations of temperature, pressure and surface transformations. Using simple rules of operational calculus as developed for electronic applications, it provides a method for evaluation of the part of laser energy actually absorbed by the material versus time.

The research teams at ETCA have designed and developed more than a dozen transportable analyzers used to characterize high power CO₂ laser beams at 10.6 µm and providing a real time high rate space-time distribution of the beam at all points on a cross-section. For example, in a range of analyzers covering analysis fields up to 200 x 200 mm2, we have developed equipment providing the following performance levels: for a field of 20 x 20 mm2, resolution of 0.4 mm on 50 lines, 50 images per second, and for a field of 5 x 5 mm2, resolution of 50 µm on 100 lines, 5 to 25 images per second, and permissible power of 10 kW/mm2 for another.

A system for temporal and spatial characterization of the laser beam from a very high pulse rate frequency (PRF=1 KHz) XeC1 laser ( X= 308 nm) is described. A one-dimensional Reticon photodiode array of 1024 pixels is coupled to a fast data acquisition system by Lecroy via an home made electronic interface. Then, the data are transfered, via the I.E.E.E. 488 bus, to a micro-computer I.B.M. PC AT for processing. The various components of the system and first results with the LUX laser test-bed are described.

Alignment mechanism for optical components, such as mirrors for manipulating laser beams, frequently require four degrees of freedom: two translations and two rotations, i.e. a four axis system. When the adjustment of one axis influences the others, as often will be the case, alignment procedures can be rather cumbersome. The mechanism, described in this paper, has four mutually independent adjustments, each controlling just one axis. Rotation takes place around a fixed point, which can be located freely in space. A computer simulation program has been developed to determine first and higher order deviations. This program proved to be a useful designer's tool to optimize the construction with respect to other system parameters.

Performance of an advanced XeC1 discharge pumped laser (X=308 nm) using a wire ion plasma X-Ray gun (W.I.P.) for preionisation is presented. This excimer laser optimized both for long use (100 ns), high prf (1 KHz), high average power (200 Watts) and high efficiency is described in details as well as spatial and temporal characteristics of the UV laser beam.

Stimulated Raman scattering has been investigated in H2 and in different H₂ - foreing gas mixtures with a UV - preionized XeCl discharge laser (308 nm) as the pump. Helium, neon and nitrogen have been tested as foreing gases.The energy conversion efficiency of the pump laser beam to Stokes beams has been investigated as a function of the foreing gas concentration and of the pump beam energy. In all the investigated mixtures with 50 percent of H2, the energy conversion efficiency to the first Stokes was more than 70% higher than that obtained in pure H₂ at the same total pressure (40 bar) and pump energy (60 mJ).

Time and spatial distribution of pulsed laser radiation at appr. 5.5 and 10.6 μm with the use of high speed streak camera with reflex optics was studied. Visualization of IR radiation was based on the effect of IR sensitization of a silver halide film with its subsequent exposure to visible light. The suggested high speed phototechnique may be applied throughout the entire middle IR range. To provide recording of a time spatial laser radiation structure a method of obtaining a series of frames at top frequencies of 10² frames per second or more is proposed, using the principles of tomography.

A new era has opened in the manufacture, machining and use of ceramics. Throughout the industrialized world, advances in products and competition in performance, cost and reliability are driving materials, including ceramics, to new levels of sophistication.

Ceramics and silicon are brittle materials, a fact that may cause problems and at the same time be helpful while machining with lasers. After giving a short introduction to ceramics different ways of cutting and drilling alumina (Al203) and silicon (Si) are discussed and compared to conventional methods. Examples from electronics industry with regard to types of laser, quality and velocity of process are presented.

The HF laser radiation is absorbed in-depth by glass. It allows for radiation-controlled heating of glass and can be used in glass working. An investigation has been conducted about the welding and the cutting of glass plates by this laser, which has been compared to the CO₂ laser.

An experimental investigation of laser cutting of a number of polymer composites of current interest is presented. Axial flow CO₂ lasers with a power up to 3 kW were used. The influence of high gas jet stagnation pressure and Mach number was studied with a nozzle of unconventional design. A simple "ansatz" for description of the laminate anisotropy was tested as well as a method for cut quality diagnosis. Gases and particles produced in the cutting operation were sampled and analysed with the aim of elucidating the disintegration mechanisms involved as well as from the point of view of possible environmental health risks.

Thin films of Ge or/and Se are irradiated by means of an excimer KrF laser beam. It is evidenced that such an irradiation gives rise to different transformations, when the energy density and the number of laser pulses are varied. Depending on the irradiation parameters and the starting stoichiometry of the films, either synthesis or ablation are observed. In the case of ablation, evaporation rates are very high. This cannot be explained via a purely thermal effect. A model based on electronic excitation is proposed.

Laser-induced surface modification and chemical etching of insulators, semiconductors and metals is reviewed. Special emphasis is placed on new results concerning the metallization and the etching of piezoelectric oxides and the etching of silicon with chlorine.

In addition to the conventional use of metal coatings on glass for mirrors, the electrical and electronic industries have increasing demand for patterned metal films on polymer substrates.

Static and dynamic measurements of the incident laser power, of the diffuse and specular reflected power have been performed in order to determine the absorption behavior of various metals and semiconductors during the interaction with powerful CO₂-and Nd:YAG-laser-radiation. The absorptivity of the vapor and laser-induced plasma was probed by high-speed photography and measurements of conductivity transients as a function of intensity, composition, and pressure of the ambient atmosphere. For I<Iv the intensity-independent energy coupling is given by the temperature-dependent refractive index and absorption coefficient of matter. For I>IB the intensity-dependent energy coupling is governed by the generation of photon-induced plasma in the surface region in combination with the dynamics of the molten and vaporized material within the interaction zone giving in addition indication for capillary waves.

In different laser applications the laser induced plasma governs the process of energy coupling into the workpiece particularly in laser welding. Using a cw-0O2-laser, the plasma shows temporal and spatial fluctuations with typical frequencies. During these fluctuations the Plasma disappears completely for approximately 0.2 ms. Amongst other things it is demonstrated that there is a strong correlation between the plasma fluctuations and the dynamics of the molten metal.

The phenomena related to deep penetration welding by means of concentrated energy beams are, in a first approximation, similar, even if the beam sources (electron and laser beams) and the irradiated materials (metals, quartz) differ. Clearly however, if the temperature distribution and the material flow dynamics are to be calculated, it can be seen that these similarities are merely qualitative, and consist of the presence of a vapour tube (key-hole) in the processed material. The mathematical models hitherto developed correspond exactly to experiments at a certain distance from the interaction point. Although several authors have investigated the physical condition of the key-hole, both theoretically and experimentally, additional data are needed in order to obtain satisfactory data of the temperatures and flows of the vapour and liquid metal, at least as far as the most common laser welding application is concerned. In the RTM laser centre, the data obtained by the various investigation methods are being correlated systematically. The devices most widely used are a fast framing camera, a fast slide to intercept the laser beam and a vacuum chamber for welding in a controlled atmosphere. The two CO2 laser sources used can vary their power from 1 kW to 15 kW. Data regarding stainless steel are dealt with in the greatest detail since this is the principal application of laser welding.

Materials processing utilizing excimer lasers is enjoying rapidly increasing interest due to the growing number of promising fields of application. Especially processes like ablation and micro-processing gain more and more attention. However, little is konwn about the mechanisms involved in the interaction of UV-radiation with matter and experimental data on process parameters such as ablation rate, wavelength, puls rate of operation etc. are not sufficient for controlled applications with high quality and reproducibility. Therefore plain and clear criteria have to be found in order to garantee the desired standard.

In laser materials processing systems, power densities or fluences may reach levels which can endanger optical elements located in the beam path. In this paper, laser-induced damage to optical elements is reviewed in a general sense without reference to specific wavelengths or modes of operation. Emphasis is put on the distinction of functional vs. catastrophic laser damage, and on laser damage test procedures.

When a semiconductor is irradiated many times by means of a medium power laser beam, it is expected that the cumulative effects of small phenomena occuring per pulse may give rise to dramatic effects. The problem is approached here via a theoretical analysis of the behaviour of defects under repetitive pulsed laser irradiation. Preliminary results indicate how demixing depends on the thermodynamical parameters for diffusion of defects. The roles of temperature gradients are analyzed carefully. The effects of optical excitation of localized states on the lifetime of devices are also discussed.

Many applications of high power lasers require wide aperture focusing optics preferably with a long back focus. The upscaling and updating of the Schwarzschild microscope objective design leads to a useful concept for applications such as in laser material processing.

Deformation energy, accumulated under optical surfaces during the manufacturing process was studied. The deformation energy and its distribution in depth as a function of the process parameters was determined in a series of optical materials. The influence of deformation energy under polished surfaces on the damage threshold of optical components exposed to high energy laser radation was examined.

The role of convection in controlling laser melted pool geometry such as pool shape, undercut and ripples; defects such as variable penetration, porosity and lack of fusion; and properties such as homogeneity has been studied by a number of researchers. This paper will review the state-of-the-art research in this area.

Material cutting techniques with a focussed c/w CO₂ laser beam use a gas jet from a nozzle to assist ejection of material from the cut kerf. Traditional techniques use a circular tipped nozzle mounted coaxial with the focussing beam. It is usual for these nozzles to be operated at low pressures (<100 kPa-gauge). Higher pressures can give higher cutting speeds but this can be associated with lack of reproducibility of cut quality. One of the reasons for the unreliable behaviour is the complex nature of the shock fronts and associated phenomena that can occur in a supersonic gas jet impinging on a workpiece. Shocks can result in a reduction of the stagnation pressure on the surface of the workpiece. Experiments are described that demonstrate a strong correlation between the local stagnation pressure and the maximum laser cutting speed. Measurements of this cutting pressure and flow visualisation techniques have been used to investigate a number of nozzle and workpiece geometries. The formation of a strong normal shock (the Mach shock disk, MSD) in underexpanded cutting jets is found to impair cutting performance. Not only does a MSD cause a significant reduction in the cutting pressure but it can also encourage the formation of a stable stagnation bubble on the surface of the workpiece. It is suggested that the adverse flow conditions in the bubble could impede cut debris removal. Two new nozzle designs are described whereby the formation of a MSD and stagnation bubble is prevented at normal operating pressures. Examples are given of nozzles which can exert cutting pressures in excess of 500 kPa-gauge at damage resistant stand-off distances of 4 to 7mm. The flow characteristics of nozzle designs used by other investigators is reported. These include the flat-tip nozzle, the tri-jet off-axis array and the ring or annular nozzle.

Plume generation and the effects of the plume on the welding process and three methods for suppression of the plume are discussed. An experimental nozzle for Nd-YAG laser welding is presented. The nozzle is used for welding experiments with Stainless Steel and Titanium. Results show that the nozzle is suited for creation of a shielding gas atmosphere and for protection of optic components. No significant effect of the plume suppression is found. This may be due to the low power densities used throughout the experiments.

Quality of laser cuts is mainly determined by the roughness of the cut edges. That roughness is caused by nearly periodic striations that are typical for laser cutting and appear during laser cutting without reactive gas flow as well as for reactive gas assisted laser cutting and also for other thermal cutting processes /1/.

In this paper, the numerical simulation method and results of dynamic response of the material which is irradiated by X-rays are given, and an analytic solution has been found.

The design and performance of an inexpensive compact repetitively pulsed TEA CO₂ laser is described. The device uses a modified corona preionization technique and a fast transverse gas flow to achieve high repetition rates. An output energy of 500 mJ per pulse and an out-put power of 6.2W at 40Hz have been obtained. Due to the small energy needed for preionization, the efficiency of the device is high, whereas the gas dissociation is low when compared with commercial laser systems. This results in the relatively small fresh laser gas exchange of 20 ltr h-1 for long term operation.

An experimental investigation into the cutting of mild steel up to 20 mm thick was carried out using a 2.5 kW CO₂ laser with a good quality T.E.M. 00 mode. The results show that cutting was possible in sections up to 20 mm although the quality of the cut edge decays between 15 and 20 mm. Explanations of this decay in quality and of the reduction in cutting efficiency with increasing thickness are put forward concerning the effect of the cut slot depth on the action of the oxygen jet. The technical and commercial possibility of cutting a stack of two or three layers of steel at once was investigated. This method was found to be less efficient than single sheet cutting.

This investigation mainly reports about the practicable processing of alumuina ceramics (Al203) with a pulsed 150 W CO2-laser with a focus diameter of about 80 um- The optimal parameters like pulse length, pulse space and the laser power had been determined to work on plates of alumina ceramics with variable thickness of up to 2 mm.

This paper deals with investigations of the spatial structure of the electrical potential, the current density, the gas temperature and the reduced electrical field strength in the discharge volume of a transverse gas flow CO₂-laser in dependence on the geometry of the electrodes. The data were obtained by means bf Langmuir double probes. The results are compared with optical measurements applying a probe laser resonator. A calculation of the laser output power of a transverse flow laser is carried out on the base of rate equations including the convective losses. The position of the laser cavity in the gas flow direction is discussed to find optimum conditions.

Local soft annealing experiments with CO₂ - lasers of 0.6 or 4 kW power respectively were carried out to obtain local softening of sheets for different materials. Preliminary results of such treatments and a mathematical description of the processes are given. Possible applications are discussed.

Using a large section of a laser beam delivered by a pulsed power laser (Nd doped glass), we calibrated a piezo-electric transducer device to record the acoustic signals produced by shock-hardening laser treatments and observed the influence of the incident laser energy density (or fluence) on the magnitude of signals.

A study of surface treatment by laser generated shock waves was carried out on various materials. A plasma trapping device enabled intense shock waves to be obtained with attenuated thermal effects. A hardening of 50 % over 1 mm of thickness was obtained on aluminium samples. Amongst the different surface treatment techniques which seem the most promising is that using a high power pulse laser. With the new technique it is possible to obtain intense shock waves over large surfaces of whatever form at the same time as attenuated thermal effects without creating bulk deformation. An experimental study of surface treatment by shock waves generated by an Nd-YAG pulse laser (30 J, 25 ns) was carried out on metals (aluminium, titanium, steel). To obtain high pressures (40 Kbar) with moderate energies and not very high laser intensities (109 W/cm2), a containment device for the plasma resulting from the interaction and the easily vaporizable materials was used. A analysis showed a hardening of more than 50 % over a surface of 0.6 cm2 throughout the thickness of an aluminium sample (1 mm). No hardening effect was observed for the other metals. These results were obtained without optimization of the trapping technique. Better control of this will enable a hardening effect to be obtained on other metals.

The time-development of a laser irradiated surface in the case of a high ablation rate is given by the local energy balance. The analytical solution is found by the method of characteristics. The macroscopic shape of the metal decays into a self-similar surface shape. The ablation rate depends on the amplitude and the spatial period of the surface such that the contour is smoothed out in the course of time. Linear polarization of the laser beam induces an anisotropy of the irradiated surface.

The microscopic and macroscopic working quality attainable during production of finished component parts are discussed in both relationships, the beam-workpiece and the workpiece-motion system interactions. Influences on working accuracy of laser beam characteristics, beam shaping (focussing) system and the guiding behaviour of the NC-machine tool are dealt with. Sheet metals chosen are austenitic, ferritic and carbon steel.

In laser gas cutting an appreciable fraction of the required energy flow density is contributed by the chemical reactions. As known from autogenous gas cutting two different mechanisms are possible: direct chemical reaction at the gas/metal interface and diffusion controlled reaction within an oxide layer. The interdependencies of gas flow, chemical reaction process, laser power, cutting speed, and plate thickness are studied.

A continuous control of the laser cutting process is necessary to guarantee a continuously high level of the cut quality. In order to achieve an on-line control, the mirror that leads the laser beam to the focussing optics is replaced by a beam splitter. This configuration makes a direct observation of the cutting process possible. The advantages and first results are shown.

The first practical demonstration of a laser device was in 1960 and in the following years, the high power carbon dioxide laser has matured as an industrial machine tool. Modern carbon dioxide gas lasers can be used for cutting, welding, heat treatment, drilling, scribing and marking. Since their invention over 25 years ago they are now becoming recognised as highly reliable devices capable of achieving huge savings in production costs in many situations. This paper introduces the basic laser processing techniques of cutting, welding and heat treatment as they apply to the most common engineering materials. Typical processing speeds achieved with a wide range of laser powers are reported. Accuracies achievable and fit-up tolerances required are presented. Methods of integrating lasers with machine tools are described and their suitability in a wide range of manufacturing industries is described by reference to recent installations. Examples from small batch manufacturing, high volume production using dedicated laser welding equipment, and high volume manufacturing using 'flexible' automated laser welding equipment are described Future applications of laser processing are suggested by reference to current process developments.

In the field of lasers for welding and surface processing, we need to measure the map of temperatures in order to control the processing in real time by adjusting the laser power, the beam pointing and focussing and the workpiece moving speed. For that purpose, we studied, realized and evaluated a model of thermal imaging system at 2 wavelengths in the mid-infrared. The device is connected to a 3 axis table and to a 3 kW CO₂ laser. The range of measured temperatures is 800 C to 1 500 C. The device includes two AGEMA infrared cameras fixed to the welding torch each operating with a choice of filters in the 3, 4 and 5 micrometre band. The field of view of each is about 14 mm by 38 mm. The cameras are connected to an M68000 microprocessor family based microcomputer in which the images enter at the rate of 6. 25 Hz with 64 x 128 pixels by image at both wavelengths. The microcomputer stores the pictures into memory and floppy disk, displays them in false colours and calculates for each pixel the surface temperature of the material with the grey body assumption. The results have been compared with metallurgic analysis of the samples. The precision is about 20 C in most cases and depends on the sample surface state. Simplifications of the laboratory device should lead to a cheap, convenient and reliable product.

Radio frequency excited fast-axial-flow CO₂-lasers in the power range between 2.5 and 5.0 kWatts offer new possibilities in material processing, because of their excellent mode structure, low divergence and good pulsing capability. Due to the minimum required maintenance, they are specially suitable for industrial use. The welding properties of these lasers are characterized by a high depth to width ratio (up to 7:1) and fast welding speed, achieved by electron beam welding. Because of their' good mode structure and excellent pulsing capability (up to 20 kHz) these lasers can also be used for cutting.

Mathematical models are widely used to simulate the thermal field inside the workpiece during laser hardening. Simple analitycal models allow to identify the range of working parameters, otherwise numer ical methods may produce more accurate predictions. In particular, the results obtained with two-dimension, finite elements code to design laser hardening process of actual workpieces are reported.

Twenty years ago the first laser system was installed to solve a manufacturing problem, the drilling of precise holes in diamonds to produce a wire drawing die. The early system installations either for laser technology or end use reasons, were categorized as specials, that is units which differed in specification and performance from previous units. During the first ten years it was quite common for industrial applications to be processed by a customized unit. As the number of common applications grew, and as the specific application needs began to dictate a uniform approach to successful resolution, the number of customized systems began to decline. Coupled with this was the system suppliers' efforts to standardize product design to reduce manufacturing complexity and cost. Today the users of industrial laser systems have a choice when considering the laser in a manufacturing operation. within certain categories such as sheet metal cutting, turbine blade drilling, and ceramic scribing users can choose from a representative number of stan-dard systems. For other applications such as marking, hermetic sealing, and transmission component welding suppliers can provide variations of designs which are known as semi-standards. The third and last category, specials, makes up a reasonable share of the units currently being installed in production applications. These specials are the subject of this paper. Identification of a specific manufacturing problem and exploration of the reasons why a laser could be cost effective are presented. Illustrations of a number of these manufac-turing problems will show how a custom laser design provided a practical, satisfactory, solution. The novel system concepts employed to effect the solution will be discussed. Applications selected include: oven liner cutting, transmission gear welding, exhaust pipe cutting, and aircraft engine part processing.