Perpendicular or at an angle? Tips for installing industrial lasers

Updated: May 7

One of a laser’s customisable features is the fan angle (also known as the beam opening angle), which affects the projected line’s length. A greater fan angle yields a longer line. The user can also affect the length using the distance and installation angle of the module in relation to the illuminated surface.

Read this blog post for tips regarding laser installation, and don’t hesitate to contact us if you have any questions.


Perpendicular installation of laser

A laser can be positioned perpendicular to the illuminated surface, as shown in Figure 1.


Installing a laser perpendicular to the surface.
Figure 1. Installing a laser perpendicular to the surface.

Placing the laser further from the surface increases the line length.


This layout is suitable, for example, for installation and assembly lines with sufficient overhead space for lasers.


Line length can easily be planned out by noting the fan angle (α) and the laser’s distance in relation to the illuminated surface.


Chart 1 shows how line length increases in relation to fan angle and distance.






Lasersäteen pituus
Chart 1:Line length of a laser with different fan angles.

Slanted installation of laser

A laser can also be positioned at an angle above the surface. This significantly increases the line length compared to perpendicular installation.


A laser is installed at a slanted angle when the distance to the surface is shorter than would be optimal, due to limited space. Applications include various devices such as automatic welding machines and machine vision solutions, where the laser is mounted on the frame of the apparatus.


Changing height, distance, and position in relation to the illuminated surface can affect where the line begins and where it ends. See L1 in the figures below.


Chart 2 shows how line length changes when the fan angle is either 75° or 90° and the installation angle of the laser module is either 55° or 70°.


If the fan angle is smaller than in the previous examples, such as 45° or 60°, the line is projected as shown in the figure above (the figure on the right side).

The effect of angle on the laser line length.
Chart 2. The effect of angle on the laser line length.

Value L1 in Chart 3 denotes the distance from the laser where the line begins. When the laser is installed at a 60° angle, using a lens with 60° fan angle, the line begins perpendicular to where the laser is positioned.

The effect of different angles on the laser line length.
Chart 3. The effect of different angles on the laser line length.

Can line width be affected?

Not really. The laser line is made as sharp and as thin as possible by focusing and choosing a surface that scatters light minimally. The laser can be specifically focused when the laser module is positioned perpendicular above the illuminated surface and when distance is constant and less than five (5) metres. Roughly estimated, the line width is about 1–3 mm depending on the wavelength and surface material.


Do you have questions about our industrial lasers?

Contact us, and I’ll be glad to help.


Jari Paajanen

Product Manager

+358 50 3400 381

jari.paajanen@keypoint.fi