Dear Nekin Joshua , measuring the tilting angle is a simple trigonometric problem,

you only need to measure a couple of distances:

-Distance between the end part of the laser head and some plane perpendicular to the machine axis (it could be one of the room´s walls or some cardboard or platform you can place normal to the machine axis). Call this distance "a"

- Now turn your laser on, the beam will hit the plane on some point of it, you need to measure the distance between this point and the point where the laser should impact on the wall in absence of tilt. Call this distance "b"

These two distances are the sides of a square triangle, so applying Pythagoras´s theorem, a2 +b2 =c2 , being c the hypotenuse . Applying the sin or cos relation you can obtain the angle of tilting.

Cos θ =a/c, so θ=arccos (a/c) or

Sin θ = b/c, so θ=arcsin(b/c)

If θ is very small, measuring b could be tricky, but the simple solution would be to displace the vertical plane further away, so that the distance b becomes larger and so easier to measure.

Hope it helps.

Project the laser beam on a screen or wall. Mark that spot with a pencil dot. Extend an imaginary line from the machine axis to the same wall. Mark that spot as well. Measure the distance between the spots, call it "s"

Measure the distance of the wall from the laser source, call it "r"

Use the equation s equals r times theta and solve for theta in radians which will be the angle between the laser beam axis and the machine axis

Dear Joshua,

I agree with Prof. Srini Vasan . I would like to add information only.

Actually, Misalignment angle (theta) is about ratio between “laser beam spot in the first to the second position (delta d)” with length (lopt or l).

How to get it?

In the laser interferometry system, you can attach a pointer target at measurement face of the mirror reflector. Generally, the mirror reflector is mounted on moving part. Furthermore, a pointer target is included with the optics set. It was like a metal sheet with a hole and a target logo on it.

In the first step, change shutter control of your laser head to aperture mode and then direct the laser beam to a target on the mirror reflector.

In the second step, move your machine with displacement value is 1000 mm (for example).

Ideally, the laser beam spot in the first step and the second step has same position (delta d = 0). But in practice, the laser beam spot in the first step and the second step has different position (delta d = ? mm). Please see the laser beam spot on the pointer target. You can measure it by ruler (I think enough).

Finally, you can calculate misalignment angle (theta), i.e. delta d = ? mm divided by 1000 mm (for example).