Digital Bolting

In 2022, HANNING & KAHL looked at the topic of digital bolting technology. Various manufacturers were compared, and the first new tools were deployed in our assembly departments in October. By Niklas Öster-Winter

As a mechanical engineering company, HANNING & KAHL must follow standards and regulations. DIN 25201 applies for companies active in rail transportation. This standard contains specifications for construction and for assembly.

In the last few months, we concentrated on bolted joints and especially on torque application and documentation of the assembly torque applied. Documentation is particularly important because our customers should be assured that all bolts have been tightened to specifications on every component which leaves our company. 

Proof of the correctness of the assembly torque must also be generated and stored centrally in a database. For simple and reliable creation of such documents, new digital torque wrenches supplied by the Hoffmann Group Oltrogge were implemented in our assembly departments at the end of October 2022. 

These new tools indicate that assembly torque has been reached with triple signalling (haptic, acoustic and visual). With the mechanical torque wrench, the only signal that assembly torque had been reached, was a “cracking” sound. Bolt overtightening can now be more easily recognised and quality problems remedied faster. Assembly staff can now see that bolted joints can also be overloaded and connections may be insecure. These tools also enable documentation of torque application. With a Bluetooth dongle, the data collected is transmitted at the press of button to the all-in-one PCs at the respective workstations and stored. A new file can be created for every order and easily retrieved in case of queries.
Digital torque technology also enables pre-programming of bolting applications. This means that the tools no longer need to be manually set by staff at the respective workstation. All that is required is a click on the respective bolting task in the Windows application. The tool sets the torque and assembly can begin. After assembly, the tool’s digital display indicates if the joint is ok. If not ok, the bolt must be loosened and tightened anew with the assembly torque.

Digital bolting technology achieves higher joint quality and greater customer satisfaction.