CNC Laser Q&A.

Questions and Answers

Q. What are Cnc laser cutters used for? What is Cnc Laser? What does a Cnc laser cutter do? What is Cnc laser? Cnc laser cutting machine applications?

A. Cnc laser cutting machines are used to cut and engrave sheet materials using a powerful laser beam. There are many different types of CNC laser machines for different purposes.
ART sell high performance CNC FIBRE LASER machines which are designed to cut sheet metal using a solid state laser with a light frequency in the infrared range of 1064nm wavelength. The output power of the laser ranges from 3kW up to 40kW with increasingly higher power lasers becoming available.
Other types of CNC Laser include CO2 Laser machines which use a glass tube laser generator which generates a visible frequency of laser beam. These are used for cutting and engraving plastics and timber. CO2 laser cutters range from 10W to several kW. They often require a lot of maintenance and mirror adjustments to keep them cutting optimally.
Also in the CNC Laser category are galvanometer based scanning laser engravers which use pivoting mirrors to scan a laser over a surface to create patterns. These are mainly used for promotional engraving on products. They are of limited application for cutting as the laser beam is not vertical for most of its range.

Q. Laser vs. CNC? Difference between CNC and Laser Cutter? CNC Laser and Router? CNC and Laser Machine? CNC or Laser Cutter? CNC Laser vs Router?

A. CNC is a term that applies to ALL computer controlled cutting machines, as it stands for Computer Numerical Control. There are CNC Routers, CNC Milling Machines, CNC Plasma Cutters, CNC Lasers and so on. However, in the hobby industry, CNC has become ubiquitous with CNC Routers in particular.
A CNC Router uses a high speed rotating spindle with a round tool with a sharp cutting edge to physically remove material in a systematic manner. This is a mechanical process and requires the material to be securely clamped in place. CNC Routers can cut a wide range of materials including timber, plastic and soft metals. They have the advantage of being able to cut 3D surfaces and cut thick materials. Higher quality Cnc router machines such as those from ART can efficient and accurately machine aluminium and even mild steel. Many ship and boat builders use ART CNC routers to mass produce their hull components accurately and efficiently.
A Cnc laser cutter instead uses a high intensity beam of light to cut or engrave sheet material. It is much harder to control depth of cut so it is best used for cutting all the way through, or for marking the surface at a lower power.
The advantages of CNC Lasers over CNC Routers are usually higher speed and a very fine cut width which can cut intricate patterns. However they do not excel at 3D surfaces or cutting thick material. They are also more limited in the materials they can cut.
The following section describes the operation of a Cnc laser in more detail.

What is CNC Laser cutting machine? How CNC Laser cutting machine works? How does a Cnc laser cutter work? What is Cnc fiber laser cutting machine?

A CNC Laser Cutter uses a high intensity beam of light to burn material away. The Laser Beam is generated by a CO2 or Fibre Laser power source, and is fed to the Focusing Head by, either a series of mirrors, or a flexible glass fibre. It has a motion controller that moves the Focusing Head over the material to burn away the material being cut. CO2 lasers use a glass tube laser generator and lots of mirrors and lenses to direct the beam through the air to the focusing head where it is directed down through the material being cut. They cut timber and plastic mostly with very limited application in metals.
Fibre Lasers use a flexible glass fibre to deliver the laser beam energy from the solid state laser diodes to the focusing head. Fibre Lasers use higher frequency light which is absorbed better into metal and can cut stainless and carbon steel as well as aluminium and brass and other metals. They do not cut plastic and timber very well as the whole mechanism is designed around metal cutting.  A Fibre Laser focusing head will usually include a very highly tuned height control mechanism that uses capacitance to accurately measure the surface of the material and keep the cutting tip at precisely the required distance from the material.
An assist gas is usually injected through the cutting nozzle to keep the material around the cut cooler and help blow the burnt material out of the cut. With metal cutting, this assist gas is very critical and must be controlled precisely by a pressure regulator. When cutting carbon steel it is possible with the correct settings to create an exothermic reaction between the steel and the oxygen gas to increase the cutting capacity beyond what the heat of the laser alone could produce.
Fibre Laser is extremely fast and accurate in thin sheet and plate metal, however it requires much higher power to cut thicker metal. Recently fibre lasers have become available in 20kw up to 40 or even 60kW to achieve cuts in steel up to 50mm thick, or even more. However the facility must have access to very high power electrical supply. For perspective, a mere 6kW CNC fibre laser cutting machine may require up to 150 amps from a 3 phase 400v ac supply.

Q. Can a CNC LASER cut metal? What is CNC laser Metal?

Only Fibre Lasers can cut metal effectively. This is because the frequency of light is much higher and is absorbed into the metal much more quickly and can burn away the metal efficiently. This results is a narrow cut. It requires a very high power laser to cut metal however. Laser generators are notoriously inefficient and lose a lot of their incoming energy in heat. Fibre Lasers are more efficient than CO2 lasers, but still require a large electrical power supply. They can cut stainless steel, carbon steel and alloys. However fibre laser is not suitable for cutting plastic or timber.

Q. CNC Laser for Wood? CNC Laser for Woodworking? CNC laser for plastic? CNC laser for acrylic? CNC laser for engraving?

For the above materials it is best to use a CO2 Cnc laser cutter or engraver. These are economical but require regular maintenance. Many cheaper imported CO2 laser machines are of poor quality and fail prematurely. It is common to purchase spare laser tubes as they are a consumable item that fails after a period of time.
Recently, solid state laser heads have become available in power levels up to 40W for cutting and engraving. These may be an option but also require replacement when they wear out from use.

Q. Are Cnc Fibre Laser Cutters safe? Do I need safety glasses to operate a laser cutter? What is a class 4 laser? What is a Cnc laser operator?

A. DEFINITELY NOT SAFE! Fibre Lasers are Class 4 laser devices which emit a particularly harmful frequency of light that can quickly make you go blind or damage your skin. This is not just from direct exposure to the laser beam, but also from reflected light from the material, from the floor under the work piece, or any other surfaces that may redirect light to the operator or others in the vicinity. The minimum safe distance from a class 4 laser device is in excess of 70 meters. Class 4 laser devices MUST be fully enclosed by a fully sealed enclosure. Any opening must have an optically filtered window that is 100% opaque to the 1064nm wavelength laser light.
Fibre Laser machines produce an invisible light at the frequency of 1064nm wave length. This is not the bright light that you see at the point of cutting. That is a secondary light generated by the burning material. The actual laser light cannot be seen by the human eye. This means if the light enters the eye it will not respond by closing the iris, and your blink reflex will not be triggered. You may be absorbing hazardous laser radiation into your retina and not even realise it. This can permanently damage your retina. It cannot be repaired.
Unfortunately, many unscrupulous suppliers are selling open style Cnc fibre laser tables which do not comply with safety standards or provide a safe working environment for workers. This leaves supervisors, managers and company owners liable for litigation if people are injured by laser equipment that does not meet the safety standards.
Do not purchase open type Cnc Fibre Laser machines! Do not operate open type CNC Fibre Laser machines even if you are assured it is safe. It must be fully enclosed with safety interlocks that instantly disable the laser as soon as they are opened.
Laser Safety Glasses DO NOT make a CNC fibre laser cutter safe or make it meet the safety standards.
Remember! Class 4 Laser devices must be fully enclosed. It’s the law. You may lose your eyesight, or you may be sued for injury to a worker or bystander.
The answer to the question “What is a Cnc laser operator?” could be “Blind!” if the correct safety enclosure is not used.

Q. Is metal cutting laser better than plasma? Cnc Fibre Laser vs. CNC Plasma?

A. This is a complex question. You must consider your actual requirements, your available funds, and power supply to answer the question.
Plasma cutting is very efficient and cost effective. however the cut quality on a base model plasma cutter can be less than ideal for some applications. Air plasma is the most affordable method to cut sheet metal for air conditioning ducting and other general sheet metal fabrication. To achievee better cut quality, high definition plasma cutters have been developed with cut very effectively and efficiently, particularly in carbon steel. The cut quality of a high definition plasma cutter can be excellent for most fabrication applications with accuracy and straight, smooth cuts in steel top to 50mm a greater depending on the power rating, however the cost is significantly higher than a simple air plasma cutter, and requires various gases such as oxygen, nitrogen, argon etc. High definition plasma cutting machines may also include secondary tools such as drilling and tapping heads, bevel cutting capabilities and more for a very flexible machine.
Fibre Laser cutting machines are an excellent choice for precision cutting in thin stainless sheet due  to the fine cut, shiny cut edges, and fast processing. The initial cost is higher than plasma but this is compensated by the higher performance in thin material. There are some companies selling open type fibre laser at a similar price however there cannot meet safety standards and are dangerous. A fully enclosed fibre laser must be chosen, and these do cost more.
When it comes to cutting thicker metal it is harder to differentiate between high definition plasma and fibre laser.
Here is an example:A 6kW fully enclosed fibre laser will cost up to double the price of a 170 amp high definition plasma machine. There 6kW laser will cut up to 25mm mild steel but becomes quite slow, therefore losing the advantage of speed. The cut quality also drops off with laser in thicker material, often leaving vertical lines in the cut face. Therefore it may be necessary to move to a higher power laser such as 12kW or 20kW to achieve the desired cut quality in thicker steel. This of course increases the purchase price and power requirements.
A high definition plasma actually cuts better in thicker materials with excellent cut quality in 30mm material or thicker. However hole quality is not as good with plasma so an optional drilling head may be beneficial if small holes are required to be perfect. Generally excellent holes with diameters equal to the material thickness can be achieved with plasma and laser.