n a co-operation project between AFT Aikawa Fiber Technologies and Savroc Ltd the aim was to test the suitability of trivalent hard chromium TripleHard® in a demanding application of brushing machine shafts in a machining device. During operation, plenty of water cutting abrasive is mixed into the closed water circulation. This abrasive cannot be totally removed with filtering. In addition, a very high pressure of 350-600 bars is applied to high pressure pump, rotating nozzle head to remove swarf from work pieces. The overall impact of these factors causes severe wear and leaks especially in the sealing surface of the shaft. Because of the wear, currently used shaft with 200 µm of hexavalent hard chromium needs to be changed every few months. TripleHard® was plated on a few shafts and the results are prominent.
– First two TripleHard®-plated shafts were installed in the early Fall and are used in our regular production. So far everything works as expected and no leaks have been detected in the shaft, so the expectation to reach longer lifetime for the shafts has been fulfilled thanks to TripleHard® chromium. For this application the coating has proven to be functional, Markku Luukkonen from AFT Aikawa Fiber Technologies states.
Currently, the shafts are manufactured and plated in Finland with hard chromium, and normally the sealing surfaces are electroplated with hexavalent chromium and grinded. The final HCr6 thickness is about 200 µm. Savroc plated the shafts directly to desired measurements without the need of grinding, the final TripleHard® thickness being approximately 20 µm. With a TripleHard®-layer of only 10 % of HCr layer thickness guarantees longer lifetime, decreased maintenance need and thus steadier production. In addition, the plating process is cost-effective, faster, safer and more environmentally friendly than current hexavalent chromium process.
Osmo Jahkola | CEO | +358 45 123 6643 | osmo.jahkola[at]savroc.com
Markku Luukkonen | Director of Manufacturing Technology | AFT Aikawa Fiber Technologies | markku.luukkonen[at]aikawagroup.com
Savroc TripleHard® chromium coating is a cost-efficient alternative to commonly used, but carcinogenic hexavalent chromium coating whose use will be subject to authorization by European Chemical Agency in the near future. TripleHard® coating is industrially proven to meet the requirements of demanding industrial applications and is based on non-toxic trivalent chromium that is safe for the environment and people involved in the plating process.