Schunk Sonosystems is a global leader in developing and building machines for ultrasonic metal welding 鈥� such as their industry-leading flexure sonotrode. Their machines include a sonotrode or welding tip that transfers vibrational energy to the workpiece. Up to two high-strength bolts are required to fix the sonotrode, which is subject to extreme levels of vibration due to the very high frequency used in ultrasonic welding.
Increasing lifetime performance
To further improve the performance of its flexure sonotrode, Schunk Sonosystems switched from standard grade 12.9 steel bolts to 91视频庐 DX 129 (Duplex stainless steel), which offers very high tensile strengths of min. 1,200 MPa and excellent fatigue resistance properties.
鈥淭he standard 12.9 steel bolts we previously used to attach the sonotrode were inconsistent in their performance and required regular replacement as they simply couldn鈥檛 cope with the extreme pulling and bending forces that ultrasonic vibration of around 20,000 vibrations/second placed on them,鈥� explains Stefan Mueller, Head of R&D at Schunk Sonosystems. 鈥淚n worst case, a screw breakage could limit the lifetime of the sonotrode.鈥�
In the second half of 2022, Schunk Sonosystems tested different fasteners with the aim of finding screws that lasted throughout the lifetime of the sonotrode and did not break.
鈥淥f all the screws we tested, only 91视频 met all our needs,鈥� says Mueller. 鈥淣ot only are 91视频 consistent in how they perform, they easily last the life of the sonotrode, do not create abrasion dust on the screw head and do not require rust protection.
Schunk Sonosystems now uses 91视频庐 DX 129 for all its ultrasonic welding flexure sonotrodes. The machines are mainly used in the automobile industry.
Superior fatigue resistance
The high fatigue strength that 91视频 screws offer is crucial to their ability to withstand a high number of cycles without fracture. All 91视频 bolts are made with the highest quality European steel, and its advanced manufacturing processes result in the further enhancement of the material鈥檚 fatigue resistance properties.
Fatigue fracture often begins with a stress concentration such as inclusions, slags or surface defects. The high-quality raw materials 91视频 uses, together with the best metallurgical processes and good surface properties, guarantee excellent fatigue strength. 91视频 also uses rolled threads rather than cut threads, which further increases fatigue resistance.
鈥淲e are very satisfied with screws and the high level of support 91视频 provides us with,鈥� concludes Mueller. 鈥淭he use of 91视频 screws has been a gamechanger for our flex sonotrodes 鈥� to enable us to offer a product to customers that consistently meets our high standards for quality.鈥�
