Laser cutting, which is a thermal based non-contact process, is increasingly gain popularity and its applications are expanding beyond the industrial setup. Laser cutting has been used as a substitute for conventional processes because of the technical and economic advantages associated with the process (Clarkson, 2016). The laser cutting technology is ideally capable of cutting sophisticated contour on materials while demonstrating a high degree of accuracy and precision. Although the technology is improving and becoming more complex, the primary concept that laser cutting employs is heating, melting, and subsequent evaporation of material. The process can be employed in cutting of a vast assortment of materials. The flexibility of the method makes it desirable in most industrial applications. In this accord, this in-depth research paper seeks to explore the background, processes, advantages, and disadvantages of laser cutting, as applied in the industrial or small scale setup.
Background of Laser Cutting
The word laser was coined the words light amplification by stimulated emission of radiation. Laser cutting is not a particularly new concept; in fact, the technology has been adopted in many sectors ranging from health care to art spheres (Dewil, Vansteenwegen, & Cattrysse, 2016). In a bid to understand the applicability of laser technology and the reason behind its widespread adoption, it is integral that the history of the technology is understood. The versatility of the usefulness of this technology, owing to the fact that it can be used for drilling, marking, and engraving, makes the endeavor hugely applicable. Although the characteristics of laser cutting have evolved over time, the process wholesomely dates back to the 1960s (Dewil, Vansteenwegen, & Cattrysse, 2016). During the development of the technology, the endeavor did not have vast applications because it was deemed as a technology that is looking for problems. Despite the constricted applications, laser beams were perceived as useful and practical since they deliver a narrow and intense beam of light that was at a single wavelength. Although the technology was viewed as being potentially useful, some scholars in the scientific community were hesitant to embrace the technology, and many newspaper headings labeled the technology the “death rays.”
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The portrayals of laser beams as a useful tool rather than a technology that can be used for mass destruction through television franchises such as start wars inspired the scientific community to take an in-depth look into the usefulness of the technology. By the dawn of 1964, laser beams had already found a myriad of industrial applications. In the same year, a crystal laser process was developed precisely for cutting a vast assortment of materials. The applications of the technology gained further momentum following the publication of a paper written by scientists affiliated to Boeing demonstrate in explicit details how laser cutter can be modified to cut sturdy materials (Clarkson, 2016). Less than a year after the release of the paper, the first laser cutter was built in Scotland. Subsequent innovations in the field resulted in the diversification of the usefulness of laser technology.
Fig 1 : The concept of a laser cutter as per the scientific understanding of the technology in 1969
Understanding what Laser Cutters are and Related Process
Laser cutting is the most crucial industrial process in the production of most goods and services or fabrication processes. Laser technology is an endeavor that was inspired by the need to come up with a technology that would not compromise the speed and the accuracy of the production process (Dewil, Vansteenwegen, & Cattrysse, 2016). Lasers, which are a crucial component of the laser cutting process, are high-powered beams of light at the same wavelength used in the cutting of various materials. In a bid to maintain a high degree of efficiency in the cutting process, lasers are controlled by a computer and used to melt or vaporize material based on the path clearly mapped on the computer program or predetermined instructions. Such an approach not only decreases the margin of error but also improves accuracy and consistency in the output.
Figure 2: An image of Kumar Patel and a carbon dioxide laser cutter
Lasers as a new technology offer industrial process with an entirely new form of energy which has been adopted to perform a myriad of processes in modern medicine and manufacturing. Although laser beams have found vast application in the contemporary world, laser cutting is by far the most popular application of this technology. Laser cutting is principally a thermal process that entails focusing a laser beam to a surface with the aim of melting the material in the focused area. In a bid to accomplish this task, a co-axial gas jet is utilized to eject the molten material; hence creating a kerf at the location that the beam is focused to. In the event that a continuous cut is needed, the laser is moved under CNC control to warrant accuracy and consistency in the cut (Happonen et al., 2015). Typically, laser cutting can be undertaken in three different approaches that include fusion cutting, remote cutting, and flame cutting.
Fusion cutting is a process that utilizes an inert gas, usually nitrogen, to expel molten material out of the location that the beam is focused to. Fusion cutting is safer and sustainable because nitrogen does not react with the molten material. The inert characteristics of nitrogen allow the process to be conducted with relatively low energy input. Conversely, if a reactive gas is used, more energy will be required to serve as the activation energy for the chemical reaction, and the reaction could yield harmful products that may have far-reaching ramifications on the wellness of the workers. In the case of flame laser cutting, oxygen is primarily utilized as the assist gas (TWI n.d.). Oxygen is responsible for exerting more mechanical strain on the material that has been melted as well as creating an exothermic reaction which increases the energy available to the cutting process. Contrary to the aforementioned process, a remote laser cutting process employees the usage of a high-intensity laser that partially vaporizes the material. The process is useful in the cutting of thin sheets without the need to use an assist gas. Current technological modifications that have improved the accuracy of the laser cutting process have promoted the presentation of laser cutting as a viable alternative to cutting techniques such as oxy-fuel and plasma.
In the cutting process, it is crucial to note that the lens used directly affects the thickness of the cut. The cutting process entails focusing of light on a predetermined path or point. By using lenses, the process can focus the light on a small surface area hence improving the accuracy of the cut. The focal length usually dictates the thickness or the thinness of the lens; the distance between the lens and the focused spot (TWI, n.d.). By manipulating the focal distance to achieve the desired focal diameter and depth of focus, laser cutting can be used to produce cuts that meet the desired specifications. As a means to achieve a small spot size a high power density beam should be preferred. Also, extended depth of focus should be used when the material to be processed is thick.
For the purposes of cutting sheet metal, a myriad of processes can be used. Some of the lasers that will be preferred in cutting metal sheets include carbon dioxide lasers, fiber lasers, and direct diode lasers. Although the methods differ significantly in terms of the technology employed and ingenuity, the choice of the ideal model can be informed by the cost differences.
Advantages and Disadvantages
Laser cutting, just like any other engineering process, has its upsides and downsides. The advantages of the process include the ease by which the work-piece can be kept in position, the method is accurate and relatively quick, the risk of contaminating the material is relatively low because the cutting tool does not come into contact with the material, and laser cutting is also better that traditional cutting techniques that melted the material because in focus sport in relatively small in laser cutting reducing the possibility of deformation of the material (Clarkson, 2016). The method requires relatively less energy as compared to traditional cutting methods. Also, the material can be used to cut a vast array of materials ranging from wood to rubber; hence, it is apparent that laser cutting is a versatile technology. Furthermore, the fact that a computer controls the process reducing errors and improving the quality of the output.
However, laser cutting has some disadvantages. The energy consumed by the tool is usually dependent on the type of material to be cut. As a result, when a lot of energy is consumed, the process becomes costly. Moreover, fumes released when plastic is cut using the technology are harmful and toxic to the human populace. Also, not all metal can be cut using the technology; thus limiting the applicability of the technique (Clarkson, 2016). Also, failure to correctly set the distance and temperature may result in the combustion of some materials.
Efforts to improve laser cutting technology currently are focused on increasing efficiency, reducing energy consumption, and improving the applicability of the process. Most importantly the development of computer programs to control the cutting process has massively improved the efficiency and precision associated with laser cutting (Happonen et al., 2015).
In conclusion, laser cutting is a technology that has revolutionized industrial activities. Although the technology was feared to be a precursor for disaster, in the beginning, the technology has turned out to be instrumental to industrial activity. The approach is precise, versatile, cost-effective, and does not contaminate the material being cut; thus, improving productivity in an industrial setup.
References
Clarkson, G. (2016). Laser cutting and 3D printing tools. Journal of Australian Ceramics, The , 55 (3), 40.
Dewil, R., Vansteenwegen, P., & Cattrysse, D. (2016). A review of cutting path algorithms for laser cutters. The International Journal of Advanced Manufacturing Technology , 87 (5-8), 1865-1884.
Happonen, A., Stepanov, A., Piili, H., & Salminen, A. (2015). Innovation Study for Laser Cutting of Complex Geometries with Paper Materials. Physics Procedia , 78 , 128-137.
TWI (n.d.). Cutting processes – Laser cutting. Retrieved from: https://www.twi-global.com/technical-knowledge/job-knowledge/cutting-processes-laser-cutting-052 .
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