What You Should Know About Automatic Setting and Feeding of Blind Rivet Nuts

Setting blind rivet nuts involves creating simple threads on one side of a thin-walled object. The nuts used are either round or hexagonal. Unlike the general term “blind rivets,” which are used to create permanent joints, the automated process of “setting blind rivet nuts” involves preparing a removable screw connection.

Phase 1: Threading and positioning the blind rivet nuts

First, the blind rivet nuts are loaded as bulk material into a feeding system. Then, all the blind rivet nuts are separated. Now, each nut is individually blown through a tube into the setting system. When it arrives at the setting system, it is clamped into a small fixture and is ready for the next process step.

Phase 2: Feeding into the part

When threading the nuts, we can identify any nuts with damaged threads and remove them from the line.

Before inserting them into the component, the rotational angle of hex nuts is aligned with the pilot hole using a laser system. While positioning is not critical for round nuts, hex nuts must be aligned precisely. The nut is then “positioned” in the pilot hole.

Phase 3: Retracting the threaded arbour & deforming the blind rivet nut

In the third phase, the blind rivet nut is deformed. For this, the threaded mandrel is retracted to a predefined position without rotation. As a result, the nut is tightened, deforms accordingly, and forms a so-called bulge that encloses the edge of the pre-drilled hole. At WEBER, the quality is reliably monitored, with both the pulling distance and the applied force being continuously controlled and recorded. Only predefined ranges are permitted.

Phase 4: Removing the threaded arbour

Finally, the threaded arbour is removed. The process can start again. The next blind rivet nut can be fed already during the setting process.

What sets WEBER feed systems apart in blind rivet nut setting is their high output and fast cycle times. Thanks to our fully automated process, the insertion head operates continuously while the next blind rivet nut is fed into position. The advantage of WEBER insertion system over other insertion systems lies in its precise alignment. Thanks to extremely precise pre-definition, the insertion system knows the correct position of the blind rivet nut and does not have to “search” for it at the pre-punched hole.

In addition, the WEBER insertion unit utilizes precise monitoring mechanisms. We check for thread damage during the insertion process itself. This allows us to proactively prevent errors that, with other insertion systems, only become apparent afterward, and to automatically reject defective components before the insertion process begins.

Get information about the structure of the WEBER setting unit in the e-mobility application area.