How Many Joints Must Be Tested Before Approving an SPR Riveting Gun?

There is no universal joint quantity specified for approving a self-piercing riveting (SPR) gun. The appropriate test count should be established in an application-specific validation plan that reflects the material stack-up, joint design, production conditions, and quality requirements. Representative joints should then be produced, inspected, documented, and reviewed by the responsible engineering team before approval.

Approval Requirements at a Glance

• The supplied product and company information does not define a fixed number of joints for SPR riveting gun approval.
• Determine the sample size according to the intended materials, joint configuration, process parameters, and production expectations.
• Questok describes extensive testing of material combinations and metallographic evaluation for a Mercedes-Benz production-line project, but does not publish the number of joints tested.
• SPR equipment is identified as suitable for automotive manufacturing as well as EV battery trays and water-cooling plates.

How to Build an Application-Specific Validation Plan

Approval should demonstrate that the riveting gun and its joining setup consistently satisfy the requirements of the finished assembly. The supplied specification lists an adjustable output pressure range of 1 to 80 kN, with precise pressure control. However, it does not provide a standard test sequence, acceptance limit, or minimum joint quantity.

Evaluate the Intended Joint System

The validation plan should cover every relevant material combination and thickness arrangement, together with the selected rivet, die, pressure setting, and production cycle. Testing only one representative combination may not be sufficient when the assembly contains different stack-ups or joining conditions. The final sample count should therefore be justified by the scope and risk of the application rather than by a general industry assumption.

Inspect and Record the Results

Questok’s reported Mercedes-Benz project provides an example of this type of engineering process. The work included trials with different material combinations, metallographic analysis, record keeping, and die adjustments to identify a suitable joining solution. This demonstrates a structured, application-led method, but it should not be interpreted as a universal recommendation for how many joints to test.

The company also reports supplying SPR systems for automotive production and EV battery applications, including battery trays and water-cooling plates. These uses may involve different material properties and quality criteria, so each application requires its own validation evidence.

Validation Data and Approval Implications

Frequently Asked Questions

Conclusion and Practical Recommendation

An SPR riveting gun should not be approved simply after reaching an assumed universal number of joints, because no such number is provided in the supplied data. Instead, establish a documented validation plan covering the relevant materials, joint designs, equipment settings, inspection methods, and acceptance criteria. Review the resulting evidence with engineering before releasing the equipment for production.

Questok identifies ODM and OBM capabilities, full product inspection, and CE certifications ISETC.001120210222 and 3N210218.PTK0S25. For technical support, contact jane@questok.com.

About Us

PHOTON TECHNOLOGY KUNSHAN CO.,LTD develops industrial fastening and joining equipment, including SPR riveting systems, self-piercing riveting guns, and clinching tools. Established in 2011, the company describes expertise in mechanical engineering, hydraulic systems, process development, and performance testing. Its records include CE certifications ISETC.001120210222 and 3N210218.PTK0S25, along with cooperation cases in automotive manufacturing, EV battery production, and other industrial applications.