When looking for the best way to measure height or step height, there are a number of important factors to consider, including the shape of the target, the type of measurement system, and the installation environment. Selecting equipment that doesn't adequately meet your needs can lead to insufficient precision and increased man-hours during production, so choosing the right equipment is important. This site is designed to help you discover the best way to perform this measurement with confidence.
Find the best measurement method and the right equipment to measure "Height/Step".
Example Application: Height measurement of dispensers
To efficiently measure the height of a single point, use a reflective laser displacement sensor.
You can measure height at multiple locations by communicating across multiple sensors or by scanning over the target with one sensor.
Example Application: Height measurement of connector terminals
A profile of the surface is obtained where the laser line hits, making it possible to acquire relative measurements such as step height.
Measurement of height difference between the measurement point and the reference point.
Even if the target is tilted, step can be measured accurately because the sensor head features an alignment adjustment function.
2D Triangulation Method.
In-line Multi-point measurement.
World's Fastest sampling rate at 64,000 images/sec.
Multi-color confocal method
Linearrity：From ±0.2μm
Confocal Displacement sensor
Example Application: Camshaft diameter between journals
The silhouette of the target is projected, and the step height between two specified features is calculated.
Even if the shaft is tilted, step can be measured accurately when the alignment adjustment feature is utilized. Measurements are not affected by the color of the target surface.
2D Telecentric Optical Method. Simultaneous measurement of up to 100 with calibrated high-speed measurement.
Example Application: Height measurement of vehicles
To efficiently measure the height of a single point, use a reflective laser displacement sensor.
You can measure height at multiple locations by communicating across multiple sensors or by scanning over the target with one sensor.
If the optical axis is not perpendicular to the target, a measurement error caused by angle θ occurs in the height value, as shown in figure 1.
If θ is greater than 0.8°, the measurement error is approximately 0.01%, so correct the tilt in advance if you are concerned about its effect.
You can easily correct the tilt by preparing one master workpiece and using the scaling settings.
If the target is a transparent object or an object with a mirror finished surface, you have to install the sensor head tilted at an angle that is half the angle of the projected and received light, α, in relation to the target, as shown in figure 2.
(When using the triangulation method.)
Also, if the target is a transparent object, a key point for stable measurement is to have the transparent object be at least as thick as a certain value. If the object is thin, the value measured for the front surface height may be lower than it should be due to the effect of the light reflected from the back surface of the transparent object.
The minimum thickness limits that ensure stable measurement vary depending on the sensor head type, the transparency of the target and the reflectivity of the back surface.
If the optical axis of the 2D laser displacement sensor is not perpendicular to the target, a measurement error caused by angle θ occurs in the step value, as shown in figure 3.
The larger the distance (X) between the two points being measured for the step, the greater the measurement error.
For example, even if the tilt θ is only 0.1°, the measurement error becomes approximately 50 μm if X = 30 mm.
Therefore, the tilt correction function is generally used when performing step measurements.
If at least one of the surfaces being measured in the step measurement is a transparent object or an object with a mirror finished surface, install the sensor head tilted at an angle that is half the angle of the projected and received light, α, in relation to the target, as shown in figure 4.
It is also necessary to prepare a head that is dedicated for use with transparent objects and objects with mirror finished surfaces.
Furthermore, if the target is a transparent object, it must be at least as thick as a certain value in order for the surface height to be measured accurately.
If the object is thin, the value measured for the front surface height may be lower than it should be due to the effect of the light reflected from the back surface of the transparent object.
The minimum thickness limits that ensure stable measurement vary depending on the sensor head type, the transparency of the target and the reflectivity of the back surface.
When the probe comes into contact with a soft target, the target can be compressed, which leads to a corresponding measurement error.
With non-contact measurement, it is possible to measure targets that deform such as soft targets and liquid surfaces.
For targets that are thin and light, it is necessary to hold down the target to ensure that it does not float on an air gap in order to accurately measure the surface height.
With contact measurement, the probe presses down on the target surface, which eliminates errors caused by the target floating in the air. For this reason, the contact method is better suited to this type of measurement than the non-contact method.
With a non-contact laser displacement sensor, the measurement spot (which ranges from a few micrometers to hundreds of micrometers in size) is generally smaller than the probes used in contact measurement. This makes it possible to accurately measure the base height of more narrow indentations with the non-contact method.
