Introduction:
A laser is a source of light but unlike anything that had ever been seen or implemented before 1960. Since then, human beings have used the laser in various applications and industries. The technology of laser has grown quickly and efficiently in humans' lives. It would be hard to imagine the modern world without lasers used in everything from CD players and laser printers, fiber-optic and free-space communications, industrial cutting and welding, medical and surgical treatment, holography and light shows, basic scientific investigation in dozens of fields, industrial cutting and welding, and fusion power and star wars weapons research. This research will introduce a very well known use of laser which is called "laser Machining."
What is Laser Machining?
Laser machining has been introduced in different ways. For example, there is laser cutting, laser welding, laser drilling, laser heat-treating, laser scoring and laser scribing. Each of these ways has a different definition from each other according to the task that will be performed in the process. Since lasers are most used in industrial applications, a good definition will be “ The process to cut, weld, drill, score, scribe materials at a very high speed and a very precise specifications.” This definition gives an extended area that allows each task or process that the laser performs.
Basic Types of Laser Machining:
There are many types of laser machining that are commonly used in Industry and technology processing. Each type has its own applications and uses that differ from other types. This research will identify five types of this machining process.
A. Laser Cutting Process:
This process is defined as a machining process in which a laser beam passes over the material being cut. The beam vaporizes the material and the path of the beam determines the shape that is cut. There are two variables that should be considered in this process which are: the specification of the object that will be cut and the speed of cutting.
The above pictures show a laser cutting process that is used in labs and industry usages. This particular machine is used primarily to create architectural models out of plastic. It has a cutting area of 3 feet by 2 feet, but larger machines have cutting areas of 8 feet by 4 feet. The major components are the gas tanks, the laser plotter itself, and the controller. The gas tanks are provided with a nitrogen gas that breaches through the material.
The laser cutting process starts with creating a drawing object on a PC using some graphic software (mostly Corel software). Also, objects can be created by using AutoCAD program and save the file as a DXF format file. After the object is created, the process is ready to perform after setting up the laser-cutting machine.
The laser cutting is used in different applications in the industry and technology. Some examples include, flat panel displays, optical glass, telecommunications, hard disks/storage disks, biotechnology, glass wafer, cuts to final size in online glass production and other types of flat glasses.
B. Laser Drilling Process:
Laser drilling is the process of repeatedly pulsing focused laser energy at a specific material. The drill beam can drill in very difficult locations or areas of materials and the holes that are made by the laser drilling process can be drilled with reliable and consistently good in quality or performance. The picture below illustrates the laser drill process:
There are many benefits associated with the use of laser drilling. First of all, with laser drilling there is no drill breakage or tool wear. Also with laser drilling these are no limitations on the hole sizes or shapes that the operator can create. Laser drilling, also, allows the operator to drill on angled and curves surfaces as well as on both hard and soft materials.
The common applications of laser drilling are in aerospace where cooling holes needs to be formed, nozzle guide vanes, combustion rings and engine blades are common components drilled with lasers. The programmable nature of laser drilling allows for very high speed drilling applications where many thousands of holes are required in short cycle times. By this, laser drilling acquits a very important role in industry and technology due to the mass usage of it in these fields.
C. Laser Heat-Treating Process:
A surface alteration process created to change the microstructure of metals by controlled heating and cooling. The laser, because of its ability to pinpoint focus its energy, can heat treat small sections or strips of material without affecting the metallurgical properties of the surrounding area.
The following pictures identify the laser heat-treating process:
Laser heat-treating is best known in the use of industry due to its advantages and benefits. Some of the advantages include: precision control of heat input to localized areas minimum distortion, minimum stress and cracking, self-quenching, requires no quenching medium and inherently time efficient process. These advantages make this process to be used widely in industry and technology.
D. Laser Scoring Process:
Laser scoring is a process of utilizing a focused spot of laser energy to remove material to specified depth. Laser scoring is useful in designing a crease to be torn or bent easily as with tear away checks, folders, cards, etc. The following pictures illustrate the laser scoring process:
E. Laser Scribing Process:
Laser scribing is a process in which lines and characters of different fonts can be produced on materials. Unlike laser engraving, the line being laser scribed is only as wide as a single laser beam and is set to a specific tolerance depth. The line consists of a series of small, closely spaced holes in the substrate that is produced by laser energy pulses. Ceramics, glass and wood are common laser scribed products.
Safety on Laser Machining
Even though there are advantages from using the laser machining processes in industry and technology, laser is one of the most dangerous tools that can kill users. Here is a list of the danger concerns that users should be aware of:
1. Working on Laser machines while the door open may cause damages in the eyes and burn hands. Therefore, a user should close the door of the machine before starts working.
2. Lasers produce coherent light which when looked at appears to the eye to have come from a very distant source. Consequently, the image formed on the retina by a laser source is always incredibly small and therefore of very high power density.
3. If a laser product is being used to process product, for example cutting, welding and surface treatments, there may also be chemical toxicity risk to address. The processing of organic materials such as thermoplastics is a particular risk that needs careful assessment in the context of local exhaust extraction (LEV) and personal protective equipment (PPE) provision.
4. The wavelengths) of emitted radiation is determined by and a characteristic of the chemical composition of the ‘lasing’ medium. For example, carbon dioxide lasers emit in the far infrared at a wavelength of 10.6 microns. Some media are capable of being made to ‘lase’ at several wavelengths, organic dye lasers being one such example.
5. Additionally, since laser action is essentially an inefficient process, most lasers of class 3B and above will have significant electrical power needs, often at high voltage and three phase. Electrical safety, especially during maintenance and repair, is therefore a significant risk that needs to be adequately controlled by manufacturers and employers that use laser products.
Summary:
Lasers are a fairly new technology. Recognized as a valuable tool in the late 1960s, lasers have become essential in processing for a wide range of industrial applications including automotive, aerospace, medical and manufacturing. Lasers emit light as an almost parallel, single color of light. The laser machining process in its all applications will be a very valuable and important tool in the industry and technology.
