Laser Bed Cutting

Aluminium honeycomb in laser beds
Oct, 2018
Category: Industry

A laser cutter is a type of CNC (Computer Numerical Controlled) machine, meaning that it is controlled via a computer. A laser cutter is a prototyping and manufacturing tool used primarily by engineers, designers, and artists to cut and etch into flat material. Once a design is sent to a laser cutter, the machine uses a laser beam to cut into or etch into the material on the cutting bed.

When cutting stainless steel or aluminium, the laser beam simply melts the material, and high-pressure nitrogen is used to blow the molten metal out of the kerf (a cut made by the beam). On a CNC laser cutter, the laser cutting head is moved over the metal plate in the shape of the desired part, thus cutting the part out of the plate.

Laser cutting is a manufacturing process which can eliminate the need for machining on many engineering jobs, enabling savings to be made on the manufacturing costs. Laser cutting presents certain advantages over plasma cutting as this process is more precise and uses less energy when cutting steel and aluminium sheets.

When the laser comes into contact with the cutting bed as it slices through the material, debris is deposited onto the reverse face. When laser cutting, the material needs to be supported efficiently from underneath to allow it to remain flat at all times but also allow heat from the laser to escape from underneath. Unfortunately the more contact the reverse of the material has with the laser bed the higher the risk of marks on the reverse. The ideal scenario is to completely float the material so no heat builds up underneath. The ability to do this depends on the artwork and the type of material being cut. Paper for instance needs a lot of support as it is not a rigid material.

Aluminium honeycomb bed

When artwork is very dense, or a less rigid material such as paper or fabric is being cut, a honeycomb bed is required to keep the material evenly flat as the pieces are cut. The aluminium honeycomb cells support the material whilst allowing heat and debris to dissipate from beneath.

Due to the nature of repeat cutting, residues from materials tend to build up on the honeycomb beds. Reverse marks occur when the laser runs over the honeycomb cells. The heat from the laser causes these residues to transfer back onto the material being cut. For this reason, there are alternative honeycomb beds for different classes of material: Plastics, Woods, Papers & card to minimise contamination from material to material. On thicker materials flashback can also sometimes occur. The laser beds are referred to as being sacrificial as they deteriorate with use.

5th Dimension Tooling and Composites

Laser beds Our customer, 5th Dimension Tooling and Composites uses Corex aluminium honeycomb as a sandwich between carbon fibre or glass fibre material which are then water-jet cut into shapes to provide a backing structure to strengthen their mould tools, as shown in the photograph.

Laser cutters are useful tools when it comes to prototyping and manufacturing; they are used in machine shops on the industrial scale to cut large pieces of material, in hardware companies to create cheap, quick prototypes, and artists as a fabrication tool to bring their digital designs to life.

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