What is CNC Laser Cutting?

Laser Cutting is the process of using a Laser beam to vaporize, melt, or otherwise gradually remove material. Computer Numerical Control (CNC) Laser Cutting commonly uses optics, an assist gas, and a guidance system to direct and focus the Laser beam into the workpiece. The many benefits of CNC Laser Cutting include:

  • Speed.
  • Less waste.
  • Broad Range of Materials.

Although Laser Cutting has been used industrially since the early 1970s, CNC Laser Cutting has recently become the production tool of choice in makerspaces, in schools, and with hobbyists.

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CNC laser cutting through thin sheet metal.
CNC Laser Cutting through thin sheet metal.

How CNC Laser Cutting Works

Laser beams are generated by electrically exciting a lasing material. This beam is internally reflected and amplified inside its container with a partial mirror. Once it has generated enough energy to escape the container, it may be focused towards the workpiece. Three main types of Lasers are used for CNC Laser Cutting:

  1. Carbon dioxide (CO₂)
  2. Neodymium-doped yttrium aluminum garnet (Nd:YAG, or YAG)
  3. Fiber

CO₂ and YAG Lasers are similar in construction but are used differently. C0₂ Lasers with lower power levels are used for engraving, while ones with higher power levels are used in industrial applications for welding and cutting because of their reasonably low price. YAG Lasers, with their higher peak output, yield exceptional results for metal marking and etching. Fiber Lasers, with their solid-state construction and high-power output, reduce consumable costs and effectively cut a wide variety of materials.

Why Use CNC Laser Cutting?

CNC Laser Cutting features:

  • Faster processing and production times.
  • Minimal warping.
  • Greater accuracy when compared to Flame or Plasma Cutting.
  • More parts per sheet of material due to the Laser beam’s small cutting diameter (kerf).
  • Great for thing materials, but thicker and denser materials may be cut by replacing the collimating lens in order to change the Laser’s focal point.

CNC Laser Cutting has many advantages over Flame, Plasma, and Waterjet Cutting methods. As the Laser’s heat application is tightly focused, it requires less power and the material’s heat-affected zone (HAZ) is reduced. Many high-end industrial Laser Cutting machines are accurate to 10 micrometers and have a repeatability of 5 micrometers. CNC Lasers can affordably cut and etch a wide variety of materials, even the non-metallic materials that typically cannot be cut by Flame or Plasma processes.

Small CNC Laser cutting machine.
Lasers can cut various materials, including natural materials like leather.

Choosing CNC Laser Cutting

With the rise of the maker, do-it-yourself (DIY), and hobbyist communities, CNC Laser Cutting continues to surge in popularity. The broad range of cutting capabilities and superior dimensional accuracy make CNC Laser Cutting an ideal manufacturing tool for end users. Read more about how CNC Laser Cutting could work for you on our Customized CNC Cutting Services page.

About the author:
Colin Worobetz is the owner of DUB MFG, a CNC Laser, 3D Printing, and CNC Machining shop based out of British Columbia, Canada.
Facebook: @DubMFG
Prototype Hubs Profile: Dub Manufacturing

Computer Numerical Control (CNC) is a manufacturing process in which tools or cutting head paths are pre-programmed with the use of computer software. Before CNC equipment existed, machining and cutting were completed by operating hand wheels, levers, or mechanical cams that followed a fabricated pattern.  The earliest models of numerically controlled machines utilized punch cards or tapes that would be fed into an analog system to guide the machine to specific points. Nowadays, CNC machines are controlled using G-Code, a computer programming language generated with the use of a computer software program. G-Code was once commonly programmed from scratch with the use of a part drawing, but it is now produced using a post processor program and a Computer-Aided Design (CAD) part file. Newer CNC cutting machines allow the operator to observe each individual line of G-Code and the position of the tool in real time while performing its work.

CNC plasma cutting became a more popular, cleaner, and more productive option to oxy-fuel cutting around the 1980s, about the same time when personal computers were first in demand. The plasma cutting process uses a compressed gas, forced through a focused nozzle, combined with an electric arc that is produced from an electrode within the cutting torch head. The arc creates an electrically conductive channel of plasma, which delivers enough heat to melt through an electrically conductive work piece. The compressed gas then aids in blowing away the molten material, creating a cutting kerf through the work piece. CNC plasma tables operate on a 2-dimensional (and sometimes 3-dimensional) axis and have come very far from the original older, bulkier, and expensive machines of the 1980s and 1990s.

The bigger plasma power units, upwards of 800 amps, are able to sever as thick as 6 inches and pierce 4 inches of stainless steel, whereas the smaller and more common machines found in many workshops can easily cut material around 0.5-1 inches thick. Many electrically conductive materials including steel, stainless steel, and aluminum can all be cut with a plasma torch, since the plasma cutting process relies on an electrical arc to cut through material. Because of the heat produced by the plasma arc to melt and cut through the material, all CNC plasma cut parts will have a Heat Affected Zone (HAZ).

In recent years, CNC plasma cutting technology has advanced in leaps and bounds as its demand has steadily increased. Consequently, it is now more affordable for smaller shops and can be easily purchased and used by the hobbyist Do It Yourself (DIY) community. This overall cost reduction is easily passed along to clients and is a large reason why CNC plasma cutting has become extremely popular. With the rise of the DIY community, home built CNC plasma tables are now a reality. While the differences between laser and waterjet cutting used to be miles apart, plasma technology has made tremendous strides and advancements in terms of cut quality and accuracy. Although CNC plasma is still considered less accurate than its laser and waterjet counterparts, it can be an incredible tool for those who know how to program and use it properly.

About the author:
Andy Gschwend is the owner of Viking Metal Worx based out of Ontario, Canada.
[email protected]
Instagram: @vikingmetalworx
Facebook: @VMX