A state-of-the-art and very accurate manufacturing technique called laser beam machining (LBM) uses the extraordinary qualities of laser beams to precisely shape and change materials.
Utilizing the concentrated intensity of coherent light, LBM provides a number of benefits, such as non-contact machining, little material waste, and versatility in handling a variety of materials, including polymers, metals, and ceramics.
This cutting-edge method has been used in a number of sectors, including electronics, medical devices, and aerospace, where complex parts need unmatched accuracy and complexity.
In this article, we will explore what a Laser beam machining is, it’s application, diagram, types, Difference, and how it works. we also discuss it’s advantages and disadvantages
Let’s drive in!
What Is Laser Beam Machining?
Laser beam machining is an unconventional machining technique that uses laser light to accomplish the task. Because of the high temperature at which the laser light reaches the workpiece, the workpiece melts. Material was removed from a metallic surface using heat energy.
One type of machining that makes use of heat emitted from a laser beam is called laser beam machining (LBM). This method removes material from either metallic or nonmetallic surfaces using thermal energy.
High-frequency monochromatic light will strike the surface, causing photons to impinge and cause the material to heat, melt, and evaporate. Although it can be applied to most materials, laser beam machining works best on brittle materials with low conductivity.
Glass can be machined with a laser beam without the surface melting. When using photosensitive glass, the laser modifies the glass’s chemical composition, enabling selective etching. Another name for the glass is photomachinable glass.
The native glass is appropriate for a variety of biological applications, including substrates for genetic analysis, and photomachinable glass has the advantage of producing precisely vertical walls.
Applications Of Laser Beam Machining
- Micro Hole Machining: Ideal for creating small holes for intricate micro-drilling operations.
- Welding Non-Conductive and Refractory Materials: Employed for welding non-conductive and refractory materials.
- Brittle and Low Conductivity Materials: Excels in machining brittle materials with low conductivity.
- Surgical Procedures: Enables precise and minimally invasive procedures in medical science.
- Spectroscopic Science and Photography: Enhances analytical capabilities and diagnostic imaging with laser’s coherent light.
- Mass Macro Machining Production: Offers efficient and consistent machining of large-scale components.
- Cutting Complex Profiles: Valuable for thin and hard materials requiring intricate designs.
- Tiny Hole Fabrication: Used for creating tiny holes with exceptional precision.
Parts Of Laser Beam Machining
Below are the major part of laser beam machining listed:
Workpiece:
The object in which the operation is to be performed is analogous to the workpiece. For instance, we are the workpiece for this machine if the body requires any laser operations. Similarly, in manufacturing, if an item has to be drilled or drilled, the laser machine performed the operation.
Lense:
Here, lenses are offered for visual reasons. To make an action on the specified workpiece mark easier, it displays the picture in a larger scale. To precisely focus the laser beam onto the workpiece, lenses are used. The expanding lens modifies the laser beam to the appropriate size after the laser light passes through an expanding lens and a collimating lens, which aligns the light rays in parallel.
Reflecting Mirror:
Reflecting mirrors come in two main types: internal and external mirrors. Internal mirrors, also called resonators, are crucial for generating, maintaining, and amplifying the laser beam. They direct the laser beam towards the workpiece for material processing.
Capacitor:
A capacitor bank charges and releases energy during the flashing process, forming a significant part of the machining cycle. It operates in pulsed mode, facilitating efficient charging and discharging.
Flash Lamps:
Electric arc lamps, known as flash lamps, produce intense white light that is converted into a coherent high-intensity beam. These lamps are filled with gases that ionise to generate substantial energy, melting and vaporising the material on the workpiece.
Power Supply:
For a laser, a high voltage is necessary. The system receives the power needed to leave the electron. The electron enters an excited state, which indicates that it is prepared to operate, when power is applied.
Ruby Crystal:
In certain types of lasers, like the ruby laser, coherent pulses of deep red light are produced through a concept called population inversion. Ruby lasers belong to the category of three-level solid-state lasers.
Laser Light Beam:
The laser light beam is the focused radiation produced through the process of optical amplification based on the coherence of light generated by bombarding active material.
Diagram
Types of Lasers
- Gas Lasers: Commonly used include He-Ne, Ar, and Carbon dioxide lasers.
- Solid State Lasers: Doped rare elements into host materials, pumped optically by flash or arc lamps. Ruby is a common host material.
- Ruby Laser: A solid-state laser with a synthetic ruby crystal as the laser medium.
- YAG Lasers: Crystals used for solid-state lasers, emit high-energy light waves.
- Nd Glass: Neodymium-doped gain media used in fiber lasers.
How Does Laser Beam Machining Works
Electric energy is transformed into light energy and then into heat energy in the complex process of laser machining, which is based on the concepts of laser technology. At the atomic level, electrons move in discrete energy levels around the nucleus, and each orbital is linked to a different energy state.
Electrons inhabit the ground state, which is their lowest potential energy, at absolute zero temperature. However, electrons may absorb energy and vibrate electronically to move into higher energy levels as the temperature increases.
The use of high voltage results in the discharge of gas plasma, which is the basis for the operation of laser beam machining. As energy changes in the system, this leads to a situation known as population inversion, which initiates lasing activity.
Usually, there is one 100% reflector and one partial reflector in the laser configuration. Whereas the partial reflector only permits a certain percentage of the laser beam to be used for material processing, the 100% reflector directs photons inside the gas tube.
The targeted region receives heat energy from the focused laser beam’s interaction with the workpiece throughout the machining process. The substance is thereby heated, melted, vaporized, and removed.
Therefore, by using a coherent beam of light to perform complex machining operations, laser machining provides remarkable accuracy for material removal.
The wavelength of the laser employed in this technique affects the Material Removal Rate (MRR) because it controls the quantity of energy that strikes the workpiece. Laser machining makes it possible to precisely and effectively shape materials for a variety of purposes by comprehending and managing these principles.
Difference between Laser Beam Machining and Electron Beam Machining
The difference between laser beam machining (LBM) and electron beam machining (EBM) lies in their energy sources, beam type, material interaction, and working principle.
The LBM uses thermal energy to melt or vaporize material, while EBM uses kinetic energy of high-speed electrons to remove material. The beam type is coherent and focused, while EBM is primarily suited for conductive materials.
Both methods have different precision, cutting depth, speed, beam control, and application ranges. The difference also lies in the energy efficiency of the beam and the required vacuum environment.
Advantages of Laser Beam Machining
- Material Versatility: Processes any type of material, including non-metallic ones.
- Precision in Small Holes: Machines extremely small holes with exceptional accuracy.
- Low Tool Wear: Contributes to cost-effectiveness and longer tool life.
- Non-Mechanical Processing: Allows easy machinement of delicate materials like plastics and rubber.
- Versatility and Automation: Highly flexible and easily automated.
- Minimal Heat-Affected Zone: Reduces risk of thermal distortion.
- Superior Surface Finish: Provides excellent surface finish.
- Welding of Heat Treated and Magnetic Materials: Ensures integrity of final product.
- Precision Workpiece Location: Ensures accurate and consistent results.
Disadvantages of Laser Beam Machining
- Limited Hole Types: Cannot produce blind holes and is unsuitable for deep drilling.
- Poor Hole Quality: May lead to dimensional inaccuracies.
- High Capital and Maintenance Cost: Implementation and maintenance can be costly.
- Safety Hazards: Requires strict adherence to safety protocols.
- Low Overall Efficiency: Affects productivity and cost-effectiveness.
- Limited to Thin Sheets: Best suited for thin materials.
- Low Metal Removal Rate: Slower removal rate than other machining methods.
- Short Flash Lamp Life: Increases maintenance and replacement costs.
FAQs
What is the working principle of laser beam?
When electrons in atoms in optical materials such as gas, glass, or crystals absorb energy from light or an electrical current, a laser is produced. The electrons are sufficiently “excited” by that additional energy to shift from a lower-energy orbit around the atom’s nucleus to a higher-energy orbit.
What is the principle of LBM?
Electrons inhabit the ground state, which is their lowest potential energy, at absolute zero temperature. However, electrons may absorb energy and vibrate electronically to move into higher energy levels as the temperature increases.
What is the principle of a laser machine?
The term Light Amplification by Stimulated Emission of Radiation is shortened to “Laser.” Light that falls inside or is near the optical region of the electromagnetic spectrum is the energy that a laser produces. The atomic process known as stimulated emission amplifies the laser energy to a very high intensity.
How does laser machining work?
How Do Laser Cuts Operate? Using computer numerical control (CNC) and optics, a high-power laser is used to guide the beam or material during laser cutting. To follow a CNC or G-code of the design to be cut onto the material, a motion control system is usually used.
What is the working principle of EBM?
In order to provide a powerful heat source, it accelerates free electrons in a vacuum and concentrates them using electric and magnetic fields. A power source, an electron gun, an anode, magnetic lenses, work holding apparatus, and a vacuum chamber are needed for the procedure.