Roctech CNC Router: Introduction to Laser Cutting / Etching Machine -Part 2

Although seemingly high end, classy and high grade, laser cutting / etching machines are quite simple in the way they work. The lens system that controls the position of the laser is itself moved by a motorised slide control system. This allows movement in any direction. The control system moves according to the programme being used by the machine. The diagram shows the LID open - however, the laser will not operate unless the lid is closed. This is a safety feature.

The work/material being engraved or cut by the laser is held firmly in position on a vacuum bed. The work/material is normally positioned in the top left corner as shown on the diagram below. The machine operates with three axis, X, Y and Z. The top left corner is regarded as coordinates (0,0,0), this is sometimes called zero point or the start point.

The diagram below shows a coat of arms being etched on a sheet of transparent glass. The lens unit focuses the laser in exactly the right position as it cuts / etches.

A close up of a typical lens system can be seen below. The lens system slides up and down the motorised slide control system.

The laser is deflected from it source within the machine through a series of precision lenses/mirrors and focussed accurately on the area to be cut/etched. The laser removes small dots of material, up to 1200 dots per inch. This means that it is able to cut extremely accurate shapes and produce astonishingly detailed etchings. The laser cutter is similar to an ink jet printer. The printer sprays ink onto the paper in a series of dots that make up a picture or text. The laser cutter removes material in a series of dots producing pictures / etchings and shapes cut away from the surface of the material.

The microprocessor controlled height guide ensures that the laser cuts to the correct depth.

If a circular or curved product such as a glass container is to be etched then a motorised roller system is used. The rollers are controlled by the microprocessor, rotating the glass at exactly the right speed and direction. This allows etching to be produced accurately on the surface. The height guide ensures that the laser is set to the correctly at all times. This system allows uneven surfaces to be etched as well as surfaces that are uniform.