Bitcoin is probably the best known implementation of a blockchain technology. However, blockchain is about much more than digital currency: It’s about guaranteeing confidence in data, ensuring the immutability of data, and resource-saving, localized storage systems and networks. All three properties will allow data to be handled like commercial goods in the future, perhaps even independently between the specific processing machines.
Exploring this step was the aim behind the establishment of the Industrial IOTA Lab Aachen (IILA) at RWTH Aachen’s Laboratory for Machine Tools and Production Engineering (Werkzeugmaschinenlabor, WZL). IOTA is a technology similar to blockchain, but it works without blocks and without a chain. The Director of the IILA, Dr. Daniel Trauth, outlines the advantages of this new technology.
The Industrial IOTA Lab Aachen
The Industrial IOTA Lab Aachen is the name of a pilot project at the WZL of RWTH Aachen University. It is part of the established digitization strategy at the WZL, which hosted, among other things, the Industrial Internet of Things Hackathon in January 2017, in which Feintool was involved as a sponsor ((Verlinkung ). The IILA serves as a safe space with an error culture that is practiced explicitly, in which young technologies and risky feasibility studies prompted by the university’s day-to-day research and project work can be explored and implemented. It was established to challenge classic project management structures and address future-oriented questions in interdisciplinary teams. It thus offers academic assistants, graduate students, PhD students and industry representatives an informal platform for artificial intelligence, industrial Internet of Things, Internet of Production, machine communication and machine economics, in each case relating to industrial questions of production technology. For this purpose, the WZL provides a range of equipment for use at its location in Rotter Bruch, see video.
The potential of IOTA for fineblanking
Fineblanking technology is the subject of the first feasibility study, whereby a Feintool XFT 2500 speed from Feintool is being used. The study aims to save a counterfeit-proof digital twin for each blanked part produced via a secure network connection in the IOTA network. The digital twin can be recalled via a website and the integrity of its data checked, which ensures that the data set has not been manipulated and thus, generates confidence in the piece of data itself.
The background to the feasibility study is that fineblanked parts are identical only in theory. In reality, no two parts are alike, since neither the time nor the place they were blanked can be the same. Elongations in the tool, temperature changes over time as well as tool wear and tear make it impossible to draw conclusions about all the parts from just one of them. While these always remain within a certain tolerance, parts that almost reach the tolerance limits that can lead to problems in subsequent stages of processing. Against this background, a digital twin to the blanking process offers the potential to treat each part individually or to arrange them in logical clusters, whereby the processing strategy is adapted to the properties of the component.
The following video shows how, for example, 500 fineblanked components were digitized during the fineblanking process and the maximum punching force, the maximum punching distance, the workpiece material, the time stamp and the component ID were encoded and uploaded securely to the IOTA network:
Data acquisition in fineblanking
For the purposes of data acquisition, a twin punch tool made by Feintool was equipped with piezoelectric force sensors in the area of the blank holder, the punch and the counter punch. The type Kistler 9021A was used for the blank holder, Kistler 9041A for the punch and Kistler 9031A for the counter punch. Furthermore, the laboratory-charging amplifier Kistler LabAmp 5167A was used in connection with the software LabVIEW 2018 from National Instruments.
The IOTA network
With the help of software, the maximum amount for each of the tool forces were extracted from the time series data, which were then attached to the IOTA network. Each component is consequently a transaction in the IOTA network, and the network grows like a tube over time. One advantage of the IOTA network is that it gets faster the more participants there are. The following video shows the transactions or components attached at the point of fineblanking. Once transactions have been confirmed in the IOTA network, they can be recalled from there at any time.
User-friendly dashboard – focus on the user
Attaching transactions to the IOTA network is one thing, but extracting the data is quite another. To this end, a dashboard was developed that is able to visualize the stored transactions based on the location and window of time. In the development of the dashboard, there was a consistent focus on the user so that all data can be made available in one platform.
Outlook – M2M with integration of the digital twin
In future work, the IILA aims to further expand the stored data set. The plan is to take those pieces of data that are required for the development and implementation of a finite-elements simulation, store them separately, and to develop secure machine-to-machine communication to an FE server. This would allow storing a digital FEM-twin additionally to the digital twin based on the machine data. The FEM makes it possible to simulate physical state variables that cannot be measured experimentally. Alongside geometric data, strains, elongations and temperatures would then be available for each blanked part for the first time.
In detail – IOTA compared to blockchain
The IOTA network is a development by the non-profit IOTA Foundation, based in Berlin. In contrast to blockchain technology, the IOTA network is built on a directed acyclic graph. This means that transactions do not have to be collected in blocks before they can be attached to the existing blockchain. The attachment of entire blocks clearly requires considerably more processing power than attaching just one transaction, so following on from this, the advantage of IOTA is that, unlike blockchain, it permits transactions without charges. The mining common to Bitcoin and the many hours, days and sometimes weeks this can take no longer apply, and thus nor does the mining fee.