As the name suggests, laser cutters create patterns and designs by cutting materials. Powerful laser beams are the source of melting, burning or evaporating material.
Essentially, laser cutting is a manufacturing process that uses a thin, focused laser beam to cut and etch material into custom designs, patterns and shapes specified by the designer. This non-contact, heat-based manufacturing process is ideal for a variety of materials, including wood, glass, paper, metal, plastic and gemstones. It is also capable of producing complex parts without the need for custom-designed tooling.
background
The invention of the laser cutter is credited to Kumar Patel, who began his research into the action of lasers when he joined Bell Labs in 1961. In 1963 he developed the first C0 2 laser, a variant with more modern applications than any other type. CO2 lasers are used to engrave materials from acrylic and plywood to cardboard and MDF.
application
Today, laser cutting has found a foothold in industries such as electronics, medicine, aerospace, automotive, and semiconductors. One of the most common applications is cutting metals – whether it’s tungsten, steel, aluminum, brass or nickel – because lasers provide clean cuts and smooth surfaces. Lasers are also used to cut ceramics, silicon and other non-metals.
Perhaps one of the most interesting uses of laser cutting technology is in surgery, where laser beams are now replacing scalpels and being used to vaporize human tissue. This is especially useful in high-precision surgical procedures such as eye surgery.
We’ll discuss more applications in later sections, but for now, let’s see how the laser cutting process works.
What is a laser cutting machine?
How Laser Cutting Works
The Subtle Science of Hairless Stimulating Light Cutting
Laser cutters typically have beam diameters between 0.1 and 0.3 mm and powers between 1 and 3 kW. This power needs to be adjusted according to the material and thickness being cut. For example, to cut reflective materials such as aluminum, you may need up to 6 kW of laser power.
Laser cutting is not suitable for metals such as aluminum and copper alloys because of their excellent thermal and light-reflecting properties, which means they require powerful lasers.
Here are some core components of a laser cutter:
Laser Resonator: The laser beam is emitted from a laser resonator, which is a sealed glass tube with two mirrors facing each other. The tube is filled with CO and other gases such as hydrogen, nitrogen and helium. The mixture of these gases is activated by diodes or discharges that emit energy in the form of light.
Cutting head: The light is reflected in all directions with the help of multiple mirrors, which are carefully arranged to ensure that it reaches the laser cutting head. Once the beam reaches the cutting head, it passes through a curved lens and is magnified and focused to a point. It is within this cutting head that the laser becomes a thin, focused beam that can be cut or rasterized. The focused laser beam passes through a nozzle through which a compressed gas such as nitrogen or oxygen also flows, before hitting the plate. For example, if you are cutting aluminum or stainless steel, the laser beam will melt the material before the high-pressure nitrogen gas blows the molten metal out of the cut. Typically, the cutting head is connected to a mechanical system driven by a chain or belt, which enables precise movement within a limited area. The focus of the lens needs to be on the surface of the material being cut for the laser to actually cut.
Nozzle Distance: An accurate distance is maintained between the plate and the nozzle at all times. This space is crucial because it determines the focal point. Often, changing focus affects the quality of the clip. Several other variables affect cut quality, including beam intensity and speed.
Three types of laser cutting
Flame/Reaction Rut: The auxiliary gas is oxygen, blown into the cut at high pressure (up to 6 bar). The heated material (metal in this case) reacts with the oxygen and begins to burn and oxidize. This reaction expels more energy and assists the laser beam.
Fusion cutting/melting and blow molding: Inert gas (usually nitrogen) blows molten material out of the cut, significantly reducing the power required. The material is first heated until it reaches its melting point, then the gas blows it out
Remote cutting: A high-intensity laser beam partially vaporizes (ablates) the material and cuts thin slices without assisting gas.
Cutting vs Engraving vs Marking
laser engraving
Generally, a laser cutter should also be able to engrave and mark. In fact, the only difference between cutting, engraving and marking is the depth of the laser and how it changes the overall appearance of the material. In laser cutting, the heat from the laser cuts the material all the time. But that’s not the case with laser marking and laser engraving.
Laser marking discolors the surface of the material being laser processed, while laser engraving and etching remove parts of the material. The main difference between engraving and etching is the depth of laser penetration.
The difference between marking and engraving is as follows:
Laser Marking: In laser marking, the laser does not completely penetrate the material, but only changes the properties or appearance of the material. Lasers produce high-contrast marks because the heat of the laser redistributes the carbon in the associated material.
Laser Engraving: In laser engraving, a beam of light physically removes the surface of the material, leaving a cavity that reveals your design. The laser heats the material to very high temperatures, causing it to evaporate and form a cavity.
The difference in laser cutting machines comes from the type of laser in the machine, which determines the type of material thickness the laser may be able to cut. In general, high-power lasers are ideal for professional applications that require cutting large pieces of plastic or metal. On the other hand, low-power lasers are effective on thinner materials such as plastic, cardstock, paper, and wood.
The three main types of lasers are:
- Gas laser/CO 2 laser cutting machine
Cutting is done using electrical stimulation of CO 2 . CO2 lasers are produced in a mixture of other gases such as nitrogen and helium.
The CO2 laser emits at a wavelength of 10.6 millimeters, and the CO2 laser has enough energy to penetrate thicker materials than a fiber laser with the same power. These lasers also provide smoother surfaces when used to cut thicker materials. CO2 lasers are the most common type of laser cutter because they are efficient, inexpensive, and can cut and raster a wide variety of materials.
Materials: Glass, some plastics, some foams, leather, paper products, wood, acrylic
- Crystal laser cutting machine
The crystal laser cutter produces beams from nd:YVO (Nd:Yttrium Orthovanadate) and nd:YAG (Nd:Yttrium Aluminum Garnet). They can cut thicker and stronger materials because they have a smaller wavelength compared to CO2 lasers, which means they have a higher intensity. But because they have a lot of power, their parts wear out quickly.
Materials: Plastics, metals and some types of ceramics
- Fiber Laser Cutting Machine
Here, the cutting is done using fiberglass. The laser light originates from a “seed laser” and is then amplified by a special fiber. Fiber lasers are in the same category as disk lasers and nd:YAG and belong to the “solid state laser” family. Compared to gas lasers, fiber lasers have no moving parts, are two to three times more energy efficient, and can cut reflective materials without worrying about back reflections. These lasers can work with both metallic and non-metallic materials.
Although somewhat similar to neodymium lasers, fiber lasers require less maintenance. As such, they offer a cheaper and longer-lasting alternative to crystal lasers
Material: Plastic and Metal
Of the three lasers, CO2 lasers are most commonly used by manufacturers and professionals. They are mainly used for cutting non-metallic materials, and although they have evolved to cut metals, they are still more suitable for non-metallic and organic materials (wood, leather, rubber) and for carving hard materials.
pros and cons
advantage
Here are the reasons why laser cutting is preferred over other cutting techniques such as CNC milling:
High precision and accuracy
high production speed
More affordable than CNC machines of the same caliber
Broad material compatibility
No risk of contamination (as it is a non-contact process)
Narrower kerf width
shortcoming
High energy consumption
Risk of Toxic Emissions Release (from Plastics)
Thicker materials can be difficult to cut
Risk of burnt edge
Laser Cut Design
A laser cutter works just like your regular inkjet printer. These machines have certain drivers that enable them to pick designs from the computer and convert those designs into a readable format.
Several software packages can support drivers for laser cutters:
What is a laser cutting machine? How does laser cutting work? (image 3)
2D design
AutoCAD
Mojing
Adobe Illustrator
CorelDRAW
While in theory the designer’s imagination is the only limit to what can be created, here are some general guidelines when designing for laser cutting:
The design must match your tool specifications. The completed document must meet the technical requirements of your machine. Otherwise, attempting to convert the file may result in loss of detail or defects.
Know the maximum and minimum laser cutting dimensions and set them correctly. The size of your design is limited by the size of the cutting table. If the table is 1100 x 1100 mm, you can’t design anything beyond that. Likewise, you should also adhere to the minimum size.
Details cannot be smaller than the material thickness. Avoid using details smaller than the material thickness. For example, if a hole is to be punched, its diameter should be greater than the thickness of the material.
Keep the minimum distance between lines. For a given material thickness, there must be a minimum distance between lines. Typically, let the distance between parts be 2 times the thickness of the material
The laws of physics always apply. When you cut a piece of metal, it will come off unless there is a connector in the design.
Show restraint. When multiple lines intersect at the same point, your design will fall apart or become brittle.
Double check the details. Zoom in on the details and make sure the intersections meet where needed.
Note the bend release. Incorrect bend elimination won’t give you a nice straight cut laser.
Once the design is ready and loaded on the machine, the laser cutting head moves over the sheet metal in the direction of the design to cut the part as needed. The laser beam cuts the material along the vector file where the design is saved until the shape/pattern is complete.
Laser cutting machine application
Laser cutters have become a handy tool for prototyping and manufacturing. They are being used:
In rapid prototyping because they allow designers to iterate their designs quickly and cheaply before mass production.
Cut bulk materials in machine shops as well as in industrial manufacturing.
Create prototypes in hardware companies.
In education for prototyping/small projects.
By artists and makers who want to bring their digital designs to life.
