How to Align your CO2 Laser Beam for laser cutting machine

Why do we need to calibrate your CO₂ laser engraver?

When we purchased a new laser engraving/cutting machine, even if the machine was assembled in the factory with an accurate optical path, the position of the mirror inside the machine will change due to the collision and turbulence during transportation.,which will lead to a change of the optical path, and the CO₂ laser beam cannot accurately hit the laser focusing lens, so the first thing we did after unpacking was to test and calibrate the CO₂ laser beam. Whether the laser light path can be calibrated will directly affect whether the output power of the machine can reach the optimum power. For many owners of new CO₂ laser engravers, the most difficult task is laser beam mirror alignment. Learning how to align the laser beam of the laser tube with the laser focusing lens and the laser mirror of the workpiece is not always easy.
However, After reviewing the user manual, preparing the work area, and setting up the laser machine, you need to check that the laser beam path is aligned correctly. The mirror alignment of a laser engraver is not as difficult as you might think. If the laser beam is aligned correctly, you will see the laser light from the laser head coincide with the red dot in a circular shape. Also, once your CO₂ laser beam is properly aligned, your laser machine will engrave and cut at peak performance, and you should rarely need to retest and adjust the laser mirror in the future.

laser mirrors and the laser beam path

Laser cutters work by generating a laser beam from a CO₂ laser tube located at the rear of the machine. The laser beam leaves the laser tube and strikes mirror 1 (located near the laser tube output at the rear of the laser machine). Mirror 1 reflects the beam approximately 90 degrees to the front of the machine.

Here, the laser beam hits mirror 2. Note that mirror 2 is mounted on the frame so it can move back and forth in the machine, but not side to side. Mirror 2 also reflects the beam at an angle of about 90 degrees but to the right side of the machine. At this time, the laser beam hits the mirror 3. Note that mirror 3 is mounted on the laser head assembly, which is also mounted on the frame. This means that the mirror can be moved left, right, forward and backward. Mirror 3 reflects the laser beam down into the laser head at an angle of approximately 90 degrees, where it passes through the laser focusing lens (or focusing lens), exits the laser head nozzle, and strikes the workpiece.

How to Align the CO2 Laser Beam?

The three mirrors in the laser cutter are very similar and adjusted in exactly the same way. The mirror is fixed in the middle of the support with a small fixing ring. There are three adjusting bolts (brass) at different corners of the mirror support. They have locks and should be close to the frame. These bolts can prevent the bolts from rotating by themselves when the laser cutting machine moves around. There are two long bolts (steel) with springs on them, which firmly fix the mirror on the adjusting knob.

When you adjust the angle of the mirror, you will affect the position where the laser beam strikes the next mirror in the chain. A piece of target tape attached to the front of the next mirror will display the test point in the new position after adjustment. When the target is as far as possible, the mirror should be adjusted. The small changes in the mirror will be amplified with the increase in distance, and the alignment will be more accurate.

If you turn the top knob clockwise to the right for half a turn, you will see that the position of the new test point is several millimeters lower than before. Turn the knob half a turn to the left (counterclockwise), and the test point will return to its original position. The left-hand adjusting bolt will do the same thing, but it moves the laser left and right. Do not forget to loosen the fixing nut before adjustment, and tighten it again after completion.

There is another way to make the same adjustment. If you turn the two bottom knobs half a turn to the left, you will notice that the test point moves down a few millimeters. You must make sure to turn both knobs by the same amount, otherwise, you will move the laser beam to the left or right at the same time. 

Step 1: Calibrate the co2 laser tube
Stick the shading paper on the dimming target hole of mirror 1, manually turn on the laser (note that the power should not be too high at this time), and fine-tune the base of mirror 1 and the laser tube bracket, so that the laser beam hits the center of the target hole.

Step 2: Calibrate Mirror 1 (Mirror 1 to Mirror 2)
Reflector 2 is fixed on the left side of the machine and can only be moved forward and backward. It is posted on the dimming target hole of reflector 2 with shading paper. Move mirror 2 back and forth and make adjustments to ensure that the laser spot appears in the same position.

Step 3: Calibrate Mirror 2 (Mirror 2 to Mirror 3)
Stick the shading paper on the dimming target hole of mirror 3, move mirror 3 left and right, and make adjustments to ensure that the laser spot appears in the same position.

Step 4: Align the Mirror 3
We need to make sure that the laser beam successfully passes through the center of the focusing mirror and the nozzle after passing through the mirror 3; stick the shading paper on the light outlet, and adjust the adjustment bolts on the mirror frame until a round and straight light spot appear on the shading paper.

Although this process is time consuming, correct alignment of the light path will facilitate future laser engraving. If you have any questions, you can contact us directly: info@cloudraycom