VDI-guidelines combine ISO standards with practice

In the early 2000s, #ISO began work on a comprehensive set of basic standards - the ISO 22514 series. Main title: statistical methods in process management - capability and performance. The working groups are still busy with it and there are now 8 parts. An enormously important work since statistics is the backbone of quality management and especially of Industry 4.0.

When in 2010 the fastening technology experts of the #VDI came together to take care of the capability verification of measuring devices (MEC - Cg/Cgk) – a level below MSA), processes (Process Capability testing – PCT - Cp/Cpk) and fastening tools (machine capability test – MCT – Cm/Cmk) in explicit guidelines for the first time, parts of the fastening assembly world were still in a slumber in this respect. Others, however, were already under enormous pressure. Pressure due to necessary cost-cutting measures, to secure locations in supposedly "high-wage countries", to reduce costs due to assembly errors or to meet worldwide product liability requirements. In addition, with the ISO 22514, the experts once again made it unmistakably clear what statistics must at least achieve in the production environment. The only catch was - the ISO was of course very general and fastening technology was and is very specific. This is true regarding the underlying physics, but also with regard to the associated processes. The task now was to translate the generally valid pragmatically and cleverly into fastening technology. The rest, so to speak, is history. In 2012, the VDI/VDE committee of experts 3.63 published part 3 of the VDI/VDE 2645 on process capability in fastening technology, and in 2014 part 2 on machine capability and built the first bridges between the worlds of aspiration and practice. Part 1 on measurement equipment capability is currently still being worked on at full speed by the volunteer experts to realize a publication of the draft in 2022.

VDI-guidelines as best practice between aspiration & practice

So far so good, but the story is not yet over for this globally unique series of technical standards. In accordance with the rules of the VDI, the MCT guideline is currently being brought up to date. In concrete terms, this means, for example, that the guideline is being brought into line with VDI/VDE 2647 on the type testing of fastening tools and that the homologation regulation is being integrated. Overall, for all current revisions, special attention was paid to improved and consistent applicability across all guidelines. Much more exciting for users, however, is the fact that a statistical aid has been developed that can be used to dynamically adjust test costs by adaptively adjusting the quantity of samples. Just as important as it is special - the so-called joint or position based MCT i.e., the proof of the capability of the production equipment for the specific application, is explained in more detail for the different tools and the procedure required for this in the current production process is explained. This is of particular importance, as this test, in contrast to the conventional or "tool-based" MCT, represents the duty and not the freestyle, as it determines all the essential information for production. The VDI/VDE 2862 part 1 on the minimum requirements of tools and processes in the vehicle and its support industry, which is also currently being revised, will reaffirm this requirement for the MCT related to the bolted joint at the current status. Here, among other things, the MCT for so-called "click-wrenches" will also be brought to the fore as a pragmatic solution. The well-known calibrations for such systems e.g. on basis of ISO 6789-2, which are usually more complex, can also be used for tool-related MCT with additional statistical evaluations, if necessary. However, this again only provides evidence that the tool has a certain repeatability when triggered by a fully automatic system, but what the users need to prove their production, namely the installed torque when used by an averagely qualified worker, is missing. This can be achieved cost-effectively, simply and pragmatically by means of the MCT for click-wrenches, which is related to the specific joint. Speaking of qualification, the reader is warmly recommended to read VDI/VDE MT 2637 parts 1 and 2 – the first comprehensive technical documentation on required qualification and competence in the fastening tech world.

"It must be proven that the wrench does what it is supposed to do."

Internationally, work is also currently still underway on the revision of the performance test method for impulse wrenches, ISO/TS 17104, with active support from VDI experts. Equally interesting are the various activities in the field of interconnectivity and communication. Not only is there a new draft of VDI/VDE 2623 for the definition of the Calibration-Data-Exchange data format, but #OPCUA for fastening technology is also making great strides. Likewise, large corporations are also promoting and demanding proprietary interface solutions that give I4.0 further momentum.

If you have questions about current or upcoming directives and general requirements in fastening technology - SCS is your independent partner and helps you with customized answers & solutions for your concerns and requirements.