Laser Cutting

What is laser cutting?

Laser cutting is the process of using lasers to cut metals, plastics, dielectrics, and more. A typical laser-cutting machine combines a laser, beam delivery optics, motion hardware to move the part and/or the optics, optional vision system, and integrated control software.

Laser cutting machines use a focused or shaped laser beam to act as a precise tool that selectively removes (ablates) material. The ablation process can be photothermal (using heat) or photoablation (using pressure), depending on the laser parameters and the type of material being cut. Laser cutting can be used to make through-cuts, drill holes, or to scribe—to cut down to a specific depth or material interface. The material can range from thin plastic film to metal several millimeters in thickness. Laser cutting is extremely precise and versatile and is widely used in manufacturing and fabrication.

How laser cutting works

Laser cutting machines move a laser beam over a fixed workpiece or move the workpiece under a fixed laser beam. Some machines use both to create more complex two and three-dimensional shapes. The machines are controlled by software, usually through a user-friendly graphical interface. Some machines include specialized software and hardware combinations for specific tasks. The latest laser cutting machines are compatible with IoT and Industry 4.0.

Let’s take a closer look at laser cutting and how the machines work.

MOVE THE BEAM, THE PART, OR BOTH

A laser cutting machine creates cuts by moving the laser beam relative to the material being machined, just like a mechanical lathe or milling machine. There are three ways to accomplish these cuts:

• Move the part under a stationary laser beam. 
• Move the laser beam relative to a stationary part.
• Do a combination of both. 

Complex cuts and shapes are made by moving both the part and the beam. The two common ways to move a part for laser cutting are xyz translations using linear motion stages, or by rotation using a rotary stage. The former is used for flat parts, the latter for tubular or 3D parts.

The laser beam can be moved using “flying optics” where the focusing lens moves across the part in some type of gantry, or fast scanning by optogalvanic mirrors behind an f-theta lens which gives a flat scanning field.

Moving both the part and the laser beam allows laser cutters to cut just about any geometry: tubular parts, flat patterns, and all kinds of 3D shapes. If you can create it in a CAD file, there’s a laser cutter that can cut it.

COMMON LASER CUTTING TYPES

The three most common types of lasers that are used for laser cutting are sealed CO2 lasers, nanosecond fiber lasers, and ultrashort pulse (USP) lasers. The best choice depends on the type of material you’re cutting, its thickness, and the required edge quality.

Sealed CO2 lasers deliver high power in the mid-infrared making them a great match for cutting materials like ceramics, paper, stone, and plastic. With power from a few watts to hundreds of watts, they can deliver both high power and a high power/cost ratio, so they are well-suited for fast cutting. But these laser-cut parts often require post-processing to remove slag and other defects along their cut edges.

Nanosecond fiber lasers are the most common lasers used for laser cutting. With a choice of infrared and visible outputs, they can be used to cut many different materials: metals, plastics, and other organic materials. They can cut with micron precision, making them suitable for medical devices and re-usables. But some post-processing may be necessary for precision parts like heart stents.

USP lasers with picosecond or femtosecond pulse widths are available with infrared, visible, or UV outputs. Their short pulse widths deliver unmatched edge quality with virtually no heat-affected zone (HAZ). This often eliminates the need for post processing in even the most demanding cutting and scribing applications. But they represent the highest cost per watt and their relatively low power—watts to tens of watts—limits their cutting speed.

Bottom line: If you want to be sure you’re really being supplied with the optimum laser for your cutting application, use a vendor who offers all these laser cutting options and knows how to use them.

LASER CUTTING SOFTWARE, AUTOMATION, AND PROCESS MONITORING

A laser cutting machine should provide a turnkey solution for your cutting application without the need to be an expert on using lasers. Depending on the format, operation ranges from semi-manual to fully automated under closed loop control. With the option of automated part feeders, this enables long runs of unattended operation, cutting hundreds or even thousands of parts without the need for much intervention.

Laser-cutting software usually has an object-driven, user-friendly graphical interface. Laser Framework, supplied with many of the cutting machines from Coherent, has streamlined visual process design, execution, and monitoring. That means faster job setup, higher operator productivity, fewer production errors, and reduced personnel training.

Advanced laser cutting machines also offer the option of laser monitoring to ensure the beam is working exactly to specification. Thanks to AI, the monitoring system can even tell you the probable reason for laser errors.

SPECIALIZED LASER CUTTING

There are general-purpose, jack-of-all-trades laser cutting machines and laser cutting machines designed for a specific purpose.

General purpose machines like the MPS family from Coherent give you lots of choices and options. You can pick the size of the machine, the details of the cutting platform, the choice of laser, and the motion axes (linear and rotary). These machines can be used to do a wide variety of laser cutting and can be reconfigured when new laser cutting needs arise.

Other laser cutting machines are optimized for a specific set of applications. For example, the Coherent  StarCut Tube series are popular in medical device manufacturing (MDM), where they’re often used to cut small parts with fiber or USP lasers. They are mainly intended for tubular parts but can also cut flat sheets of material.

Some laser cutting machines are even more specialized, designed from the ground up to perform a specific task as efficiently as possible. An example of the “single task” machine type is the NA Needle Drilling System. This product series is configured solely to drill blind holes in traditional and miniaturized surgical needles with no undesirable thermal damage.

REVOLUTIONIZING MANUFACTURING

Laser cutting has revolutionized manufacturing in virtually every industry imaginable. It has allowed engineers to create precision parts using new materials, and even created entirely new manufacturing methods. 

Here are some common uses of laser cutting: 

1. Industrial Manufacturing:
   • Metal Cutting: Laser cutting is widely used for cutting metals like steel, aluminum, and titanium in the manufacturing of automotive parts, aerospace components, and machinery. It offers high precision and can handle complex shapes.
   • Textile Cutting: Laser cutting is used in the textile industry to cut fabrics and create intricate patterns for clothing, upholstery, and other textile products.
2. Signage and Advertising:
   • Acrylic and Plastic Cutting: Laser cutting is used to create precise cuts in acrylic and other plastics for signage, displays, and promotional materials. It allows for intricate designs and smooth edges.
3. Prototyping and Rapid Manufacturing:
   • Prototyping: Laser cutting is employed in the creation of prototypes for product development. It enables the quick and accurate fabrication of prototype parts and models.
   • Custom Manufacturing: Small-scale and custom manufacturing benefits from laser cutting due to its ability to produce low volumes of specialized components economically.
4. Electronics Industry: 
   • PCB Manufacturing: Laser cutting is used in the production of printed circuit boards (PCBs) to precisely cut and shape the boards. It aids in creating intricate patterns for electronic components.
5. Medical Applications:
   • Medical Devices: Laser cutting is utilized in the production of medical devices, such as stents and surgical instruments, due to its precision and ability to cut delicate materials.
6. Paper and Cardboard Cutting:
   • Packaging: Laser cutting is employed to create intricate and precise cuts in paper and cardboard for packaging, promotional materials, and artistic projects.
7. Jewelry Manufacturing:
   • Precious Metals: Laser cutting is used in the jewelry industry to cut and shape precious metals like gold and silver. It allows for intricate designs and precise detailing.
8. Automotive Industry:
   • Interior Components: Laser cutting is used to cut and shape materials for automotive interior components, such as leather, fabric, and plastic.
9. Woodworking:
   • Custom Furniture: Laser cutting is employed in the production of custom furniture and woodworking projects. It allows for detailed and intricate designs in wood.
10. Architectural Models:
    • Model Making: Architects and designers use laser cutting to create detailed architectural models with precision and accuracy.

Laser cutting offers high-precision, minimal material waste, and the ability to cut a wide range of materials. It has become essential in modern manufacturing and design and our world wouldn’t be the same without it.