Laser cutting is a very efficient method for metal fabrication. It uses high-powered laser beams to easily cut and shape the most rigid materials. Its effectiveness has made it a superior fabrication option over traditional cutting methods. However, many people still don’t understand the basics of this process and ask, “What is laser cutting?”
Understanding the basics of laser-based cutting is essential for getting the most out of this process. If you’re one of those and don’t have any know-how of laser cutting, fret not! I will explain everything about this laser-based cutting process in this article. You’ll learn about the history, primary components, and step-by-step working of laser cutting. So, let’s get started!
What is Laser Cutting?
It is an advanced process that utilizes high-energy laser beams. These beams melt or vaporize the target point. The computerized system controls the direction and intensity of these beams to create precise cuts and shapes. This contactless cutting procedure does not cause any waste of materials.
Laser-cutting machines come with laser sources. This source emits lasers of the required energy, which are the workpieces. The history of laser technology dates back to the 1960s. Theodore Maiman first worked on laser technology in 1960. At that time, manufacturers relied on manual cutting methods.
In 1965, Western Electric Engineering Research Center invented the first laser cutting machine. It was a basic machine with no specific precision feature, but it was the first step towards innovation. The initial use of laser machines was to create holes in diamond dies. Remember, cutting hard material was always challenging.
However, manufacturers could cut, shape, and drill holes in the most rigid materials with laser machines. In the 1980s, CO₂ was also developed, which further attracted attention. In the early 1990s, the computerized control system was introduced in the laser cutting machine.
It proved to be a significant advancement in increasing the precision of laser-cutting machines. After that, many manufacturers started using these CNC-based laser machines due to their accuracy and quick speed. Today, these machines are a must-have for advanced manufacturing industries. From automobiles to aerospace, their use dominates everywhere.
Components of a Laser Cutting Machine
The laser cutting machines seem to be a single unit. However, their work is very complex and needs the systematic functionality of various components. Understanding the components and their function is key as they control the working of a whole laser cutting machine. In the section below, I will discuss each of the components of the laser-cutting machine:
- Laser Source: As the name suggests, it is a source that emits high-energy laser beams. Different types of laser sources are available depending on the type of machine.
- Worktable: It is the platform where the workpiece is secured. Generally, a work table clamps the workpiece (material) and allows it to move. As a result, it increases the smooth working of laser-cutting machines.
- CNC Controller: It is the most essential part of a modern laser cutting machine. The operator gives this CNC controller G-coded instructions. These CNC controllers then control the machine’s working according to given instructions. The cutting head of laser cutting machines moves toward a CNC controller.
- Lenses & Mirrors: The laser emitted from the source is generally scattered. The focusing optics, such as mirror and lens, focus this laser beam. These lenses or mirrors concentrate the laser beam at the right point for precise cutting.
- Cutting Head: The lenses and mirrors discussed above are on the cutting head. It also consists of nozzles emitting specific gases, i.e., oxygen or nitrogen. This head moves over the material and directs the laser beam to the right spot.
- Motion System: As said earlier, the cutting head moves above the material. The motion system assists in the movement of the cutting head. The system consists of motors, belts, and rails. This allows the head to move on the X, Y, and Z axes as per computerized instructions.
How Does Laser Cutting Work? Step-by-Step Process
All the components mentioned above work together. A minor defect in any one component will cause the laser-cutting machine to fail. In the section below, I will discuss the step-by-step process of how laser cutting works. So, let’s get started!
1- Generation of Coded Instructions
The operator’s first step is to generate the G-coded instructions. This step is crucial, and small mistakes can lead to imperfection when cutting or shaping. Moreover, it requires a higher level of expertise.
Let me discuss how G-coded instructions are made. First, the required shape is designed. It is a digital model of what manufacturers need. Generally, manufacturers get the help of expert designers to make initial designs. Designers use CAD software to create models. It is a shape that manufacturers want laser-cutting machines to produce.
Once the model is ready, it is then fed to CAM software. The CAM software processes the design given to it. After proper interpretation, this software creates computerized instructions. These instructions are in the form of Codes (G-coded instruction). The operator then feeds this coded instruction to laser-cutting machines.
You might wonder how machines take these G-coded instructions or files. As I discussed above, laser machines come with an interface. The operator uses this computerized interface to transfer the G-coded instruction to the machine. Remember, CNC controllers interpret these instructions and follow them.
2- Laser Beam Generation
The second step is the generation of laser beams. As I said earlier, laser-cutting machines come with laser sources. These sources consist of gases that create laser beams. Generally, those gases include carbon dioxide, nitrogen, and helium. Inside the source, electrical energy is released. This energy excites the atoms of those gases.
Remember, when an atom absorbs energy, it moves to a higher energy state. The same happens in laser machines. The atoms of those gases absorb electrical energy and go to a higher energy state. But when these electrons return to a lower energy shell, they release energy. The release of energy is in the form of light, which we know as a laser beam.
3- Laser Amplification
The laser (light energy) we get when an atom comes to a lower energy state is scattered. This scattered energy is useless and cannot help in the cutting process. Therefore, laser-cutting machines use specialized focusing optics. The lenses and mirrors concentrate the laser beam and don’t allow it to scatter.
Due to these lenses, the laser beam becomes very focused and narrower. It can easily hit tiny targets or spots due to its focus and concentration. Remember, the machines come with laser resonators, which amplify the laser beam’s energy. The laser resonator consists of a series of mirrors that reflect the light.
When the laser beam (photon) strikes the mirrors, it moves back and forth due to reflection. Remember, these mirrors are in series. Due to continuous binding, the energy of the photon increases. There is one mirror in the series, which is partially reflective. When a photon strikes it, this mirror allows it to escape with amplified energy.
These escape photons are laser beams that machines use. These beams are directed at the workpiece. They have higher energy to cut and shape any material of any thickness. The interface of laser cutting machines allows operators to adjust the level of amplification of laser beams.
4- Beam Focus Through Cutting Head
As I said earlier, the laser comes out through the cutting head. This heading consists of mirrors and lenses that amplify the laser. After amplifying the laser beam, it comes out through the nozzle of the cutting head. This head comes over the material or workpiece. The laser comes out and strikes directly on the surface of the material.
Due to the beam’s higher energy, it melts and evaporates the material. As a result of melting, the material is cut smoothly. The stronger and thicker material requires a higher level of laser beam amplification, and vice versa. The movement of the cutting head is significant. If this motion is not correct, manufacturers will never get precision cutting.
Therefore, laser-cutting machines come with a CNC controller. This component controls the movement of the cutting head according to computerized instructions. All manufacturers who use CNC-based laser cutters have in-house designers who create CAD designs. Remember, a wrong design will result in a wrong G-coded instruction, ruining the precision.
5- Role of Assist Gas in Laser Cutting
Generally, the laser beam melts the material and cuts it. However, the melted part can look ugly and affect the finishing of cuts, right? In such cases, modern laser cutting machines come with assist gas options like nitrogen or oxygen. These gases come out of the nozzle of the cutting head and clean the cut part. They do not allow the melted residual to remain on the cut.
In this way, the laser beam can continue cutting the workpiece smoothly. Moreover, these assist gases eliminate the chances of oxidation, which could be a big problem for the quality of the cut. The nozzle of the cutting head has a small opening. When a laser comes out to cut the material, the second opening opens up. As a result, the assistant comes out to clean the cut part.
What Materials Can Be Laser Cut?
Laser-cutting machines are very versatile in terms of compatibility. They can easily cut and shape any material of any thickness. However, the ease of cutting some materials is better than others. However, there is no material that cannot be cut with modern laser-cutting machines.
Remember, all the metals can be cut using laser cutting machines. However, the thickness of the material affects the operation of laser machines. For example, thicker material will need a high-energy laser beam, and vice versa. Interestingly, modern machines come with adjustment features. Operators can easily adjust the intensity of laser beams.
Manufacturers can cut metal and non-metal of any thickness. However, some reflective materials pose challenges to laser-cutting machines. They reflect the laser beam (light), wasting some energy from the laser beam. However, such materials can also be cut using the proper technique and laser types.
Quick Highlight: Some material fumes when they undergo laser cutting. Some examples include PVC and chlorinated plastics. These fumes can be toxic to humans. Therefore, I recommend wearing safety equipment such as gloves and masks. Inhaling such fumes can cause allergies and other health issues.
Conclusion
The laser cutting process is complex and confusing. Understanding it requires basic knowledge of the machine’s components. I have explained both these machines’ components and working in this article. Even if you are a newbie, understanding how laser machines work won’t be hard anymore.
Remember, there is a difference between old and modern laser-cutting machines. However, those differences lie in their additional features. The three essential workings of both machines are almost similar. The old machines without CNC controllers are less expensive and require more human effort. On the flip side, modern laser-cutting machines offer exceptional precision.