OUTER DIAMETER

MEASURING THE OUTER DIAMETER OF TUBES USING LASER-SCAN MICROMETERS

 

Laser-scan-micrometer consist of emitter and receiver. LAP METIS sensors use a light plane generated by a laser beam, which is deflected by a rotating prism and directed by a lens. 

In the receiver, the laser is focused on a diode. For each pass, the laser needs a fixed time interval.

 If there is an object in the laser plane, the receiver is shadowed for a certain amount of time. This time is proportional to the dimension of the object. 

One micrometer can measure one axis of an object, e.g. the diameter. To get the ovality or further dimensional values, several measuring axes are necessary. These multi-axes systems in round steel housings form are LAP RDMS systems. 

 

 

Animation

Short demonstration of the measuring principle
of laser-scan micrometers.

 

Play

OUTER DIAMETER

MEASURING ThE OUTER DIAMETER OF TUBES USING BACKLIGhT AND CAMERA

A long light source emits a band of light which is detected by a camera. Any tube crossing the light causes a shadow which is recorded by the camera. For a fixed distance, the diameter can be calculated in relation to calibration values.

Using two perpendicular systems, the parallax error can be compensated automatically and the ovality can be calculated.

OUTER DIAMETER

MEASURING THE OUTER DIAMETER OF TUBES USING LIGHT-SECTION

Light-section

Light-section sensors can do a lot more than only measuring diameter. Because of this, they are normally used, when more dimensional values need to be collected.

A camera detects a laser line emitted by the sensor. The laser line plane is perpendicular to the transport direction of the tubes to be measured.

If a tube crosses the plane, the laser line follows its surface contour. Thus, the camera records the surface profile in her detection area. To cover the whole surface and diameter, several sensors need to be placed around the tube.

Camera view
Camera view