Sub zero laser cutter Offline#

Those used for material processing can generate beams of many kilowatts in power. Such a laser is electrically pumped using an electric discharge.ĬO 2 lasers typically emit at a wavelength of 10.6μm. The CO 2 laser (carbon dioxide laser) is generated in a gas mixture, which mostly consists of carbon dioxide (CO 2), helium and nitrogen. Nowadays most of industrial sheet metal laser cutting is carried out using two types of lasers: CO 2 and fibre. What Types of Laser Cutting are Used for Sheet Metal? In reality, changing the lens is avoided and a compromised cutting speed used, unless a specific job has special requirements. In fact, it would be possible to optimise focal length for each material thickness, but this would involve additional set-up time when changing from one job to another, which would have to be balanced against the increased speed. The only other consideration is that the shorter the focal length, the closer the lens is to the workpiece, and therefore more likely to get damaged by spatter from the cutting process. The requirements for cutting are as follows:Ī) high power density and therefore small focused spot sizeī) long depth of focus to process thicker materials with a reasonable tolerance to focus position variation.īecause these two requirements are in conflict with each other, a compromise must be made. To allow comparison between lasers with different beam diameters we therefore use a factor called the focus f-number, which is the focal length, F, divided by the incoming raw beam diameter, D. For a constant focus length lens, increase in the raw beam diameter also reduces both the spot diameter and the depth of focus. For a constant raw laser beam diameter, decrease in the focal length lens of the focusing lens results in a smaller focal spot diameter and depth of focus. The laser focal spot diameter and the depth of focus is dependent on the raw laser beam diameter on the lens and the focal length of the lens. It can be defined as the distance over which the area of the focused spot does not increase beyond 50%. The depth of focus is the effective distance over which satisfactory cutting can be achieved. The critical factors which govern the efficiency of the process are the focused spot diameter (d) and the depth of focus (L). The lens is defined by its focal length, which is the distance from the lens to the focused spot. The laser cutting process involves focusing a laser beam, usually with a lens (sometimes with a concave mirror), to a small spot which has sufficient power density to produce a laser cut. How Does the Lens Used Affect the Thickness of the Cut? Low heat input – small HAZ, low distortion.Ultra flexible – simple or complex parts.Cuts thermoplastics, wood and many non-metals.Cuts carbon manganese steels up to 20mm.Improvements in accuracy, edge squareness and heat input control means that the laser process is increasingly replacing other profiling cutting techniques, such as plasma and oxy-fuel. There are many state of the art laser machines on the market for cutting purposes, which can be used to cut metals, woods and engineered woods.

Sub zero laser cutter Offline#

The laser cutting process lends itself to automation with offline CAD/CAM systems controlling either three-axis flatbed systems or six-axis robots for three-dimensional laser cutting. In remote cutting, the material is partially evaporated (ablated) by a high-intensity laser beam, allowing thin sheets to be cut with no assist gas. In addition to exerting mechanical force on the molten material, this creates an exothermic reaction which increases the energy input to the process. In flame cutting, oxygen is used as the assist gas. Nitrogen gas does not exothermically react with the molten material and thus does not contribute to the energy input. In fusion cutting, an inert gas (typically nitrogen) is used to expel molten material out of the kerf. There are three major varieties of laser cutting: fusion cutting, flame cutting and remote cutting. A continuous cut is produced by moving the laser beam or workpiece under CNC control. A co-axial gas jet is used to eject the molten material and create a kerf. Laser cutting is mainly a thermal process in which a focused laser beam is used to melt material in a localised area.

Click here to see our latest technical engineering podcasts on YouTube.īy far the most popular use of lasers is for cutting. Able to heat, melt and even vaporise material, lasers are seen as the ideal medium for channelling intense but controllable energy. They offered an entirely new form of energy which in turn lent itself to uses in manufacturing, medicine and communications.

National Structural Integrity Research CentreĬoined from the words Light Amplification by Stimulated Emission of Radiation lasers have been a byword for efficiency and quality in materials processing since their advent in the sixties.

Structural Integrity Research Foundation.