For quick replacement

When designers want to replace the threaded nuts of spindle drives with PFAS-tested alternatives, many face a dilemma: there are hardly any variants that are free of the controversial chemical, meaning that expensive adjustments would be necessary. Igus is changing this with a new PTFE-free and PFAS-tested universal flange threaded nut made of iglidur high-performance plastic. It allows for a quick 1:1 conversion and promises an above-average service life thanks to a special thread geometry..

A packaging machine designer has been given a new task: to replace all plastic components with variants that do not contain PFAS chemicals. These could be subject to stricter regulations in the future, as they pose a potential risk to humans and the environment. The change is intended to proactively ensure legal certainty in the future. But the devil is in the details. The designer cannot find an alternative for the small plastic nuts used in a threaded drive. There are hardly any PFAS-tested threaded drives on the market. And the few that are available have a flange with different connection dimensions for the nut mount.

“To solve this dilemma, we have developed a universal flange threaded nut that is PTFE-free and has been tested for the 96 most critical PFAS compounds,” says Thorben Hendricks, Head of dryspin Thread Technology at Igus. “The injection-molded component has a flexible hole pattern with closed and open holes, which enables a quick 1:1 replacement without any design adjustments.” The universal flange threaded nut from the dryspin series is now available with thread diameters of 6.35, 8, and 10 mm.

Special thread geometry ensures longer service life

Another special feature is the flexibility of the threads: Igus first manufactures blanks for the universal flange threaded nuts using an injection molding process from a material called iglidur JPF. Different thread types can be incorporated into these blanks according to customer requirements. “Our patented dryspin thread is enjoying increasing popularity in the industry,” explains Thorben Hendricks. The reason: in contrast to classic sliding threads, where the spindle and nut have symmetrical profiles, with dryspin the thread teeth of the nut are enlarged by up to a factor of 1.3. “Thanks to the asymmetry, we have been able to increase the service life by around 30 percent compared to classic trapezoidal threads, as tests in our in-house laboratory have shown,” emphasizes Thorben Hendricks.

No PTFE coating of the spindle required anymore

The new universal flange threaded nuts also enable dry running. Microscopic solid lubricants are integrated into the iglidur JPF material, which make the material slippery. The advantage: External lubrication is no longer necessary. This reduces maintenance and the system's susceptibility to dirt. “Another advantage of low-friction dry running is that the spindles no longer require PTFE sliding coatings. This means our customers receive complete, PTFE-free and PFAS-tested system solutions,” says Thorben Hendricks.