Cognex vision systems guarantee the quality of plastic components for the automobile industry

Citation

(2006), "Cognex vision systems guarantee the quality of plastic components for the automobile industry", Assembly Automation, Vol. 26 No. 3. https://doi.org/10.1108/aa.2006.03326caf.005

Cognex vision systems guarantee the quality of plastic components for the automobile industry

Cognex vision systems guarantee the quality of plastic components for the automobile industry

Keywords: Automotive industry, Image sensors

OCSA S.p.A., a company specialising in moulding plastics, produces plastic parts for major organisations operating both in Italy and Europe-wide. One of the cornerstones of the strategy of this company, located in Creazzo (VI), has been the adoption of the most advanced, innovative technologies for automating production and quality control.

Hundred percent control

OCSA received a major order to produce plastic components for the automobile industry. One of the requirements imposed was total exclusion of faults on the components produced. To meet this requirement, the company's management decided to use a vision system, and their choice was the Cognex^® In-Sight line vision systems. The reasons for this are explained by Marco Milan, the owner of OCSA: “First of all, we were aware of the fact that only a vision system would be able to meet our client's requirement in full, and, in second place, we had already installed a vision solution based on Cognex In-Sight systems to carry out inspection tasks, and this had produced excellent results.”

In this case, the task of the vision system is to check with extreme accuracy the quality of each item produced, and to reject any found to be faulty. In greater detail, this system is able to intercept parts which show imperfections of any kind, such as geometrical defects, excess or lack of plastic material, presence of oil or other impurities on the plastic body (Plate 3).

Plate 3 3 OCSA S.p.A., chose the Cognex^® In-Sight line vision systems

The vision system was installed on equipment expressly dedicated to monitoring the operation described above. The total equipment consisted, in addition to the vision system, of a vibrating unit which sends through the parts to undergo inspection, a conveyor belt which moves the parts under the remote camera, and a pneumatic discharge system which removes faulty parts. The whole system, controlled by a PLC, has been designed and produced by TEC Srl of Lissone (MI), a systems integrator working with Cognex.

As to the vision sensor itself, Ocsa's technical staff opted for the model In- Sight 5100: this device has been selected for its particular efficiency in terms of processing power, and its sturdy, reliable structure, which means that it can be used in particularly severe conditions.

The importance of the software

Another factor which made a decisive contribution to the decision to use the Cognex solution is the excellent software support: like all the other members of the In-Sight family, the 5100 model is supplied with the full Cognex vision tools library, making available advanced functionalities for the processing and analysis of images.

In the case of OCSA, a tool which is particularly useful has turned out to be PatFind^® a function enabling the In- Sight systems to locate the objects being inspected reliably and repeatedly, even in the presence of changes of lighting, angle and scale. Each individual part is recognised and picked up by PatFind. Two geometric options provided by this tool – angle and reference position – make it possible to carry out a detailed in-depth analysis of the geometric characteristics of the object using the edge and blob finding tools.

The results obtained using this vision system have surpassed expectations; all faulty components have been eliminated, while the approved components rejection rate has fallen below 0.5 percent. Thanks to the high speed of inspection, at 120 parts/minute, there is no negative impact on line productivity.

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