Rohm's REAL-TIME MEASUREMENT OF CLAMPING FORCE DURING PROCESSING

By Niraj M Wanikar, Chief Editor, CNCTimes.com, 2022-02-15 09:20:00

Even on the most modern machine tools, workpieces are still clamped in the same way as it was a hundred years ago: the operator clamps "by feel". Due to a lack of sensors, the machine tool can only support him to a limited extent. And so that workpieces are really "safely" clamped - nobody wants to risk being thrown out - the clamping force is often set too high. Especially with thin-walled components or sensitive surfaces, this quickly leads to deformation and crushing.

With the iJaw, the clamping device specialist Röhm presents a clamping jaw with integrated sensors for measuring the clamping force directly at the clamping point. Between the sensor and the workpiece there is only a clamping insert that is only a few millimeters thick. In this way, Röhm eliminates almost all falsifying influencing factors and the iJaw can provide information about the actual clamping force applied to the workpiece. The iJaw wirelessly transmits the measured data to a gateway via the robust IO-Link wireless protocol with a high sampling rate of 100 Hz. This means the iJaw measures in real time during processing. For this purpose, it is made of hardened steel and is waterproof (IP 68). To protect against glowing chips, the transmitting antenna has a cover made of high-temperature plastic. The iJaw can be mounted and used on all lathe chucks with a suitable (standard) jaw interface like any other clamping jaw. For the market launch, the iJaw is available as a stepped jaw for lathe chucks with straight or helical teeth in sizes 215, 260 and 315. Suitable lathe chucks from Röhm are the power chucks with the quick-change jaw system Duro-A RC, Duro-NCSE and Duro-NC as well as the counterpart to the conventional one range the Duro-T. To adapt the jaws to different workpiece geometries, there are various interchangeable hard and soft clamping inserts that are locked on the jaw with screws. For the market launch, the iJaw is available as a stepped jaw for lathe chucks with straight or helical teeth in sizes 215, 260 and 315. Suitable lathe chucks from Röhm are the power chucks with the quick-change jaw system Duro-A RC, Duro-NCSE and Duro-NC as well as the counterpart to the conventional one range the Duro-T. To adapt the jaws to different workpiece geometries, there are various interchangeable hard and soft clamping inserts that are locked on the jaw with screws. For the market launch, the iJaw is available as a stepped jaw for lathe chucks with straight or helical teeth in sizes 215, 260 and 315. Suitable lathe chucks from Röhm are the power chucks with the quick-change jaw system Duro-A RC, Duro-NCSE and Duro-NC as well as the counterpart to the conventional one range the Duro-T. To adapt the jaws to different workpiece geometries, there are various interchangeable hard and soft clamping inserts that are locked on the jaw with screws.

Gateway as data hub

The gateway with IO-Link wireless receiver is used to receive and forward the data. The gateway offers a Profinet interface for connection to the machine. The data is also available on the machine control and can be displayed on the machine tool's HMI and/or further processed by the machine control. The iJaw can be connected to the Internet via a LAN interface on the gateway, making it a real IoT solution. The data can be sent to a cloud and archived and processed there.

Seven application scenarios identified

"We have identified seven very different scenarios in which the iJaw offers significant added value," says Claus Faber, Head of Product Management and Marketing at Röhm. The first three scenarios deal with the 'feeling' before and during processing. Before processing, the iJaw provides support when feeding workpieces and setting up the clamping system. If errors occur, the measured clamping forces deviate from the target values ??and manual or automated responses can be made. During processing, clamping forces that are too high (risk of damaging the workpiece) and clamping forces that are too low (insufficient holding forces up to the point of the workpiece being ejected) can be detected. Three other scenarios offer solutions for the evaluation of series and series measurements. Here, trends can be identified early on through changing clamping forces. This includes the early detection of pending maintenance to maintain the clamping force or tool wear. Reject parts can already be identified in the processing process, ie during their manufacture.

"In the last scenario, we primarily see the documentation," explains Claus Faber: "On the one hand, this is extremely interesting for components that require documentation - such as in aerospace technology - but on the other hand also for product and process optimization tasks. If, after a long period of time, I want to know how a component was manufactured, I can research the manufacturing situation in the data in the cloud. The iJaw essentially archives the fingerprint of the processing”.

Claus Faber adds: “But we are sure that our customers will have a large number of other applications. Even in the wildest brainstorming sessions, we will not have even thought of most of them.”

Development partners for machine tool manufacturers DMG Mori, WFL Millturn and EMCO

Since the end of 2020, Röhm has had an exclusive development partnership with the machine tool manufacturers DMG MORI, WFL and EMCO. They tested the iJaw on their machines in the final phase of development and accompanied Röhm until it was ready for series production. DMG Mori presented the iJaw on a CTX beta 1250 TC 4A to invited guests at the Pre-EMO in Pfronten from 20.-25. September 2021. WFL will present the iJaw on an M50-G at the EMO 2021 trade fair in Milan in Hall 4/Stand D09.

IO-Link Wireless as the upcoming industry standard

Röhm sees the IO-Link wireless protocol as the upcoming standard in wireless communication in the industrial environment. Compared to Bluetooth, which is widely used today, IO-Link Wireless is significantly more robust and stable. Röhm is convinced that IO-Link wireless will become increasingly popular in future IoT products. Röhm has therefore secured exclusive use for applications in clamping technology with the IO-Link wireless specialist CoreTigo for the development period of the iJaw technology. CoreTigo is a development partner for hardware components for wireless transmission.

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