Self-piercing riveting quality online detection system and method

Abstract

The invention relates to self-piercing riveting quality online detection system and method in the technical field of machining. The system comprises a weighing sensor, a displacement sensor, a weighing sensor amplifier, a displacement sensor amplifier, a data acquisition card and a calculation module. According to the invention, whether the joint quality is qualified or not is judged through acquiring the force-time and displacement-time curves in the self-piercing riveting process according to one feature window and three feature tolerance ranges on the acquired curves and the defect type towhich qualified joints belong is also judged. The method gives consideration to the changes of the displacement and the force in the riveting process, has the characteristics of sensitivity to defects like plate gaps and the like, high defect detection speed and the like and can specifically detect various defects.

Description

technical field [0001] The invention relates to a system and a method in the technical field of mechanical processing, in particular to a self-piercing riveting quality online detection system and a detection method thereof. Background technique [0002] Self-piercing riveting refers to a connection process in which the rivet is pressed into the plate to pierce the upper plate, and then the rivet is opened around to form a mechanical interlock under the combined action of the mold, the lower plate and the shape of the rivet leg. With the energy crisis and environmental pollution getting more and more attention, the environmental protection performance and fuel economy of automobiles are paid more and more attention by major automobile manufacturers. Therefore, as an important way to realize the lightweight of automobiles, various new lightweight materials such as aluminum alloys and magnesium alloys are widely used in body manufacturing. As a mature cold forming process, se...

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Problems solved by technology

This method was developed by companies such as Henrobs, Bollhoffs, and Orbitforms and applied to self-piercing riveting on-line inspection products, but this method has the following shortcomings: 1. The force-displacement curve is used for detection. The tolerance zone is the quality judgment area, so it is not sensitive to the change of the curve along the abscissa (displacement axis) during the riveting process, so that there are some blind spots in the detection of the displacement change during the riveting process; 2. For some specific points in the riveting process Common faults, such as the insensitivity of the gap between the riveted plate and the deviation of the rivet, lead to the limitation of its detection function; 3. Only relying on the deviation degree of the tolerance zone to judge the quality cannot give the cause of the defect and cannot guide the production process. Improve

In addition to the force-displacement curve method, the literature "Online Visual Measurement of Self-Pierce Riveting Systems to Help Determine the Quality of the Mechanical Interlock" (Johnson, P, Cullen, J D., Sharples, L., Shaw, A., Al-Shamma 'a, A I.Journal of Measurement, 2009, 42 (5): 661-667) (on-line visual self-piercing riveting quality inspection method for judging the quality of mechanical interlocking) applies visual recognition technology to self-piercing riveting quality inspection, but This technology is only suitable for detecting the position of rivets to avoid quality problems caused by empty riveting, initial deviation of rivets, etc. The detection range is limited and has not been widely used

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