The ability of continuous wave high power CO2 Lasers to generate power densities of up to 108 watts Cm makes them useful for a variety of material processing tasks. Deep-penetration laser welding, high precision laser cutting, surface heat treating by martensitic phase transformation hardening, and surface alloying are the four major areas which are accepting laser processes. This paper will cover these four primary laser applications existing in production within a variety of industries. Each individual area will be discussed in detail, describing the advantages and various parameters to achieve maximum productivity and quality. Beam config-uration, integration, and manipulation are included also. Production examples of laser welding, cutting, surface hardening and surface alloying, are examined to demonstrate the laser processing advantages. This paper also reviews the present and future status of the laser metalsworking industry in respect to the growth potential, research and development, manufacturers responsibilities etc.
Marketing a laser cutting system usually requires a comparison with plasma-arc cutting, Wire EDM (Electrical Discharge Machining), and oxygen-acetylene flame cutting. Each system has its own advantages and disadvantages, however because of its versatility and adaptability, laser is becoming the more sought-after system.
In the past fifteen years, laser technology has expanded from exotic, highly specialized research projects to a broad spectrum of industrial applications. One of the most promising and cost effective of these applications is the use of laser based systems to mark products with alphanumerics, bar codes and symbols during the manufacturing process. This paper is intended to provide an overview of laser marking techniques and their applications in today's manufacturing environment.
Widespread employment of industrial lasers in manufacturing operations has occurred as a result of the technical and economic advantages of the processes. This paper discusses the positive economic factors which singly, or in combination, justify the purchase of a laser for a manufacturing application. Examples of recent industrial installations are cited as evidence of the cost effectiveness of laser processing.
Examples of commercial Nd:YAG systems and their applications in industrial trimming, marking, and drilling are described. Drilling requirements are related to laser variables including pulse energy and duration, number of pulses, focussing parameters, and output beam quality. Performance of Nd:YAG, Nd:Glass, and face pumped TIR slab geometry lasers are compared. As an example of significantly improved beam quality in a high power Nd:YAG drilling laser, Coherent General's new EVERPULSETM M34 is described. The review concludes with current examples and future trends in industrial laser drilling systems and applications.
Use of laser systems in manufacturing facilities has become increasingly important as companies turn to sophisticated technology to solve their production needs. While users are becoming more experienced with this equipment, it remains a major goal for systems manufacturers to develop not only reliable systems, but equipment that meets the user's needs in terms of design, sophistication level and future manufacturing goals.
Present and future development of laser processing as a production technique for modifying semiconductor devices, improving yields, and decreasing developmbnt times are described. Current applications covered include thick-and thin-film resistor trimming, deposited film and polysilicon resistors on silicon trimming and redundant memory repair. Emerging applications include microcircuit mask making and capacitor trimming. Examples of processes still under development include selective annealing, minority-carrier lifetime doping, and device diagnostics by laser imaging.
Industrial application of lasers in the micro electronic industry is an established fact. The most prolific is in resistor trimming and ceramic substrate machining. Though the application has been applied since the 1960's there are still unresolved problems in the economic use of lasers in this area.
Laser heat treatment of iron-base alloys is influenced by factors such as beam intensity profile, beam absorptance, heat conduction, and core microstructure of workpiece. In this article a number of techniques designed to improve the efficiency of laser heat treatment process are presented. Methods to obtain a laser beam profile with uniform intensity involves the use of beam integrating optics with Fresnel number higher than 10. Approaches to increase beam absorptance involve the use of infrared energy absorbing coatings or the use of linearly polarized laser beams. Numerical solution to the three-dimensional time-dependent heat conduction equation is used to calculate and experimentally validate the heat-affected and hardened zone profiles in finite length workpieces. The numerical solution uses an implicit time accurate finite difference procedure based on Newton iteration and triple approximate factorization. Core microstructure influences the hardened depth that can be obtained by laser heat treatment. This is due to the influence of carbon diffusion distance for a specific core microstructure, on the rate of structural transformation for surface hardening.
Lasers create a new challenge in corporations which use them to manufacture parts. This challenge is to find the acceptable accommodation of laser processing within the many disciplines which are a part of the manufacturing operation. This challenge is much more than using the laser to process a part in a development laboratory. The movement of a laser-processed part onto the manufacturing floor is what I will call the challenge of parts design.
Laser cladding techniques and equipment were developed to apply wear/corrosion resistant alloys on valve sealing surfaces. The new techniques allow cladding on flat, cylindrical and contoured surfaces more economically than prior processes and techniques used. The advantages realized by using the laser cladding technique for production parts are: (1) less than 2% dilution of base metal, (2) improved surface wear and corrosion properties, (3) reduced cracking susceptibility, (4) minimal warpage and distortion of clad components, (5) high integrity metallurgical bond, (6) suitability for full automation, (7) considerable savings of expensive cladding materials due to the consistancy and uniformity of applied cladding, (8) low heat input of laser cladding elminates adverse effects on base metal properties.
The ettective application of laser cladding to industrial components has required significant improvements in the process technology, particularly in the techniques for depositing the hardtacing alloy while manipulating the component and laser beam. Advances in equipment such as dynamic powder feeders are reviewed together with the ettects of process parameters on cladding quality. Examples of industrial applications are given.