Integrated Optical Inspection Measures Robotic Assembly Performance

Trending Industry 4.0. creating intelligent Factories of the Future is slowly becoming a fact as more companies implement solutions in their production facilities as part of this undertaking. The automotive industry is becoming a leader in this field using highly automated processes and innovative solutions for production.

One of the leading German automotive manufacturers requested SMARTTECH for a dedicated optical measuring system to improve its quality control process.  The company was undergoing a process of digital transformation fully automating a production line when a serious problem appeared during the production of vehicle headlining lining roofs..

There are rectangular sponges between the headlining and the metal roof, which are used to cushion the driver’s or passenger’s head in the event of a collision or accident. The arrangement of the sponges is completely regulated and must comply with international ISO standards.

Before the modernization of the production line, sponges were assembled by hand by six employees, who within one hour were able to produce 3 complete headliners. Product was then randomly inspected for quality, which unfortunately increased the risk of producing a product that was not compliant with ISO standards. Automating the assembly line and allowing modern robots to work has shortened the production process of the complete product to just 3 minutes. However, research revealed that variables such as ambient temperature significantly affected the drying speed of adhered sponges, making it difficult for programmed robots to connect the metal roof with the corresponding protective sponges faultlessly. For this reason, the manufacturer gave up selective quality control and decided to make a detailed inspection of every headlining coming from the production line to verify the location of the sponges.

The manufacturer was seeking to install a dedicated optical measuring system that could be fully integrated within the assembly line and become a labor-free production operation. The challenge for the system being to measure the mounted sponges on the headlining and verify their location, and communicate the information upstream to other production areas.

Implementation of Intelligent Optical Measurement

Specialists from the SMARTTECH company created a solution consisting of two measuring devices scan3D surface 10 MPix sensors integrated into a dedicated SMARTTECH3D Position Control System.. The technical requirements of the factory production line assumed inspection of the entire surface of the produced part, which is why the innovative SMARTTECH solution measures 1800 mm x 1250 mm x 350 mm and maintains the specified accuracy specified of 0.7 mm. SMARTTECH engineers also designed a special measuring stand, including a tilt and rotary frame, for installation in the production line.

Measurement with SMARTTECH 3D scanners is based on analysis of the curvature of the fringes displayed on the measured surface. Their deformation is recorded by the detector built into the scanning head. During the measurement, the image from the detector is transformed into a cloud of points due to a special control software algorithm. Each of the points describes the geometry by the X, Y, Z coordinates and this information is used for analysis in the SMARTTECH3D measuring software.

Due to the uniqueness of the project, the SMARTTECH3Dmeasure software control module was expanded to adapt to the customer’s internal standards. A program for performing automatic sponge inspection was adapted, which involved a modification of the measurement algorithm. A customized system for reporting and analysis of controlled headlining to PDF format was also implemented. Detailed reports contain information on the position of sponges and their deviations from the assumed tolerance and data on the headlining itself, including its serial number and measurement result.

As part of Industry 4.0 implementation, the SMARTTECH3Dmeasure software was integrated with existing production systems. It was connected with the implementation of intelligent communication module capable to communicate with other industrial devices and internal factory systems allowing the measurement results to not only be included in the digital ecosystem of the production line, but also stored in a special repository for further analysis.

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