Often times when the laser does not produce an even burn over the entire workspace, the laser is out of alignment. This procedure will explain to you how to align the laser for optimal cutting.

Overview

The image above shows the laser path. The laser beam travels from the laser tube, bounces on the stationary mirror then travels down to the Y axis mirror. It bounces off the Y-axis mirror into the hole of the laser head assembly. Inside the laser head assembly, there is another mirror which makes the laser beam bounce down into the lens and out the bottom hole onto the work.

Step 1

Use a red laser pointer use it to make sure the Y axis mirror and the laser head are aligned. The best way to do this is to but a round laser pointer inside a machinist V-block then rest the V-block against the X-axis gantry as shown above. This will ensure the laser pointer is parallel to the X-axis as shown above. You can also use a ruler and ensure the laser pointer beam is parallel to the X-axis gantry. Raise the laser pointer off the floor with some shims so it is the same height as the center of the laser head hole. Here the laser pointer inside the V-block is raised with some 123 blocks and pieces of copper clad.

Once you are sure the laser pointer is parallel to the X-axis gantry and is raised to the correct level, loosen the screws holding down the laser head as shown on the right. The laser head will slide up and down. Adjust it so that the center of the hole is aligned with the laser pointer dot. Twist the laser head so that the spot falls exactly onto the center.

Next flip the laser pointer 180 degrees so it shines on the Y-axis mirror. Adjust the screws holding down the Y-axis mirror and slide it until the beam is in the center of the mirror. Don't worry about the 4 thumbscrews right now, simply adjust the sliding direction so that the Y-axis mirror and the laser head form a line parallel to the X-axis.

Tighten the screws and add some epoxy and or loctite. Be sure to doublecheck it with the laser pointer to make sure the line was not disturbed as you tighten the screws.

Step 2

Cover the hole of the laserhead with some thermal thermal receipt paper with some blue masking tape. Turn it so that the side that has some writing on it faces out.

Turn the power off to the motors and slide the laserhead so that it is closest to the Y-axis mirror. This ensure there is the least distance for a laser beam coming in at an angle to diverge. Press the laser test button and you should see a dot appear on the receipt paper.

Now turn down the laser power to the minimum possible so that the paper will get dark but not burn through. Burning through the paper will leave a residue on the laser mirrors which should be avoided. Press the laser test button and see where the laser hits the paper.

Loosen the 4 thumbscrews on the mirror and adjust the height and pivot until the dot is dead center on the laserhead receipt paper.

The thumb screws should be adjusted in pairs.

If you tighten the top two thumb screws, the mirror will tilt down which will make the laser dot lower on the receipt paper. If you loosen the top two thumb screws, the mirror will tilt up.

If you tighten the right most thumb screws, the mirror will tilt inward and the dot will move to the left. If you loosen them it will move to the right.

Keep adjusting them thumb screws until you are happy with the laser spot.

Now push the laser head slightly away from the Y-axis mirror and fire another test shot. This time the distance between the mirror and the laser head is greater so that any angle error will become more apparent. Repeat the thumbscrew adjustment until it is in the center.

The ultimate test will be when you push the laser head all the way to the right, furtherest away from the Y-axis mirror. The laser beam will travel the longest distance.

It is not necessary to have exact dead center spots for all the locations. As long as the laser beam goes into the hole, it will reflect off the mirror and the lens focusing will correct any small errors. However, the better aligned you have the laser the better your result will be for detailed work.

Aligning the laser should only need to be done once unless you bump the lens or mirror.