Page 86 - MTW JANUARY 2022 Digital Magazine

TECH INNOVATION

range of red and blue laser scanners covers measuring ranges
from 2mm to 1000mm and measuring rates from 2kHz to
49.14kHz with resolutions down to 0.03µm. High precision laser
sensors from Micro-Epsilon are used in high-tech areas such as
automotive industry and 3D printing, where aircraft components
are also produced.

Car windows
In the automotive industry, measurement tasks in which the
simultaneous detection of multiple measurement values and three-
dimensional detection of measurement objects within short cycle
times are required. For example, when installing the windshield, a
scanCONTROL laser line sensor detects detailed distance values
in all axes. In the installation process, the sensor is mounted
In the automotive industry, there are measurement onto the robot, which fits the window into the vehicle. When the
tasks which require simultaneous detection of several windshield is placed on the car, the scanner detects the complete
measurement values or three-dimensional detection of profile and vicinity of the windshield while all necessary values are
measurement objects within short cycle times. For example, determined with a single run in quick time. It can be determined
when assembling the windshield, a scanCONTROL laser line whether the windshield is placed straight and centered or whether
sensor is used to detect detailed distance values.
it fits perfectly in every plane. The results, which are in this case
the passenger compartment over the robot through the opening, the gap and flushness, are directly generated in the sensor head
which is intended for the driver door and then turned horizontally and output to the PLC.
again. Typically, four optoNCDT laser sensors are used for this Another measurement task concerns the adhesive, which is
measurement task which are installed in the four corners of the already applied before the windshield is fitted into the chassis and
metal frame respectively. They are fixed both on the top and also detected by a laser scanner. Therefore, the scanner is directly
the bottom, i.e. in the four corners of the metal frame, which is mounted onto the robot that applies the adhesive beading. Here,
equipped with the grippers. The sensors measure reference points the sensor moves along the adhesive bead to create a 3D image.
in the vehicle interior in real time. These can be prominences and It reveals whether the adhesive quantity is sufficient, whether it
depressions. The four sensors ensure that the cockpit is properly is applied evenly and whether the bead is applied in the correct
aligned in all directions (x-, y- and z-axes). When all sensors have places. All detected measurement values are stored separately.
detected their respective reference marks, the robot is stopped If an error occurs in the process at a later point in time, these
in order to move the cockpit forward into exactly this position measurement values can be used for analysis purposes.
relative to the car body, to dock it on and to fix it in place. For the
entire process including the fitting of the cockpit, an extremely Gap inspection
short cycle time of less than one minute is required. Furthermore, When assembling a vehicle, numerous gap and flushness
the sensors must operate independently of the surfaces, as measurements are necessary. This includes, among other things,
different reflections occur due to the multitude of different surface the position inspection of airbag stitching. The scanner detects
paints used – from dark to bright colors and from mat to shiny the contour of the stitching while being guided by a robot arm
appearances. and evaluates several features synchronously. The laser scanner
continuously inspects the distance between the stitching and
Strengths of the laser point sensors the separating point between the single stitches and outputs
Considered as one of the best in their class, optoNCDT laser the evaluation directly as 0 (NOK) or 1 (OK) via the Ethernet
point sensors are used for displacement, distance and thickness interface. Beyond that, the height difference between two single
measurements. The Real-Time Surface Compensation feature components is directly inspected in order to immediately recognize
(RTSC) enables the sensors to operate regardless of materials and any faulty assemblies that might impair the safety.
colors. The extremely small measurement spot size also enables Another measurement task involves gap monitoring in car
the measurement of very small objects, while simultaneously interiors. Important parameters of quality are homogeneous gap
providing high accuracy measurements down to the micrometer sizes of cockpit elements and the center console. Depending
range. Measurement data is generally available in real time and so on the inspection situation, a single scanner applied on a robot
can be used to automatically correct and control the production arm can measure different gaps in a static or dynamic mode;
process. Depending on the model, Micro-Epsilon’s wide product alternatively, a special frame on the robot arm is used that enables

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