Non-contact laser displacement sensors measure the change in displacement and position of an object. Laser displacement sensors do not become mechanically worn out or come into contact with the target, are easy to use and can measure on different surfaces. These sensors are used in robotic applications for industrial automation, control, testing, measurement, quality control and production monitoring.
However, what remains a challenge is to select the ideal laser displacement sensor that fits your requirements within your area of application.
Factors to consider when selecting a laser displacement sensor
Selecting the ideal laser displacement sensors requires a detailed understanding of the measurement applications and expected results. Moreover, how well this sensor functions, when subjected to certain conditions, may be affected by several factors. Therefore, in choosing the laser displacement sensor, the following vital factors need to be taken into account:
Required measuring range
There are laser sensors available for both short and long measuring ranges categorized. A laser triangulation sensor has a fast measuring rate and very high precision with measuring range from 2 to 1000mm. Whereas, the long-range distance laser sensor is used in the measurement of large distances or displacement of up to several km.
Level of Accuracy Required
A laser displacement sensor that uses a red laser diode can be used in almost all industrial applications. When using a red laser sensor, the laser penetrates deeper into the target surface. It is a problem in situations when accuracy cannot be compromised.
The blue laser on the other hand, generates a much more focused laser to the surface and does not penetrate as deep into the object. Therefore, it provides a higher accuracy when measuring on selective surfaces such as translucent, diffusive objects or red hot glowing metals.
Surface Types
The surface of the target object is of prime consideration when selecting a laser displacement sensor. This is because both blue and red laser sensors perform well in distinct surfaces.
For instance, the red laser sensor is best suited for object targets with low reflectivity, matte surface and targets that are fast-moving. However, due to its high intensity red laser light penetrates more in the target and diffuse on the target material. This particularly applies to transparent materials or translucent, where using red laser light lowers the measurement accuracy.
On the other hand, a blue laser sensor performs with higher accuracy when measuring on objects with shiny, reflective or highly-polished surfaces.
Target Materials
Blue laser sensor gains more applications over red laser when measuring on organic, food, transparent and translucent materials. When the red laser is used for measurement on these surfaces, it penetrates deeper into the object which causes the laser to be diffused on the surface. This also generates a blurred spot in the detector due to the lack of focus. The blue laser sensor avoid this issue due to its shorter intensity.
Red laser sensors also have limited use in the measurement of hot and glowing objects. A hotter object generally emits high-intensity light at a wavelength similar to the red laser. This creates undesirable noise when light is reflected to the detector. This effect does not apply to blue lasers as they operate at the opposite end of the visible light spectrum. Thus the blue laser sensor generates stable and accurate signals, unaffected by the object’s temperature.
Measurement Speed
When selecting laser displacement sensors for highly dynamic applications, the red distance laser sensor is an ideal choice as its high-intensity laser provides stable signals when measuring on fast-moving objects. For example, red lasers have been used in production lines for measuring package dimensions in the conveyor belt. They are also better in terms of performance, and availability of measuring ranges and are also more cost-effective compared to the blue distance laser sensors.
Laser displacement sensors come with a wide range of measurement applications based on required range, target surface and measurement speed. When selecting a laser displacement sensor, it is crucial to consider these aspects to get accurate data for test and measurement activities in engineering applications.
If you face difficulties in distance laser sensor measurement and integration applications, contact our engineers at Bestech Australia. We possess considerable expertise in industrial testing and measurement of physical parameters and we offer a comprehensive range of laser displacement sensors from Micro-Epsilon, to serve your industrial application requirements. We can also provide customised systems to adapt to your specific requirement.
Read more about non-contact laser displacement sensor for measurement of distance and position here
