Mr. Stangl, at first glance it doesn’t sound all that difficult: clamping a part in a chuck?
In reality, the opposite is true. Not every part that enters a production line is a perfect, round raw piece. There are delivery specifications for semi-finished products such as bar stock or forged parts that must be met. But that doesn’t mean every component is identical or that round bars are actually perfectly round.
And what happens when a part isn’t “perfect”?
This can lead to problems during the clamping process, and even slight misalignment can have serious consequences. For example, machining results may be compromised due to uneven cuts or inconsistent surface finishes.
The danger when clamping out-of-round raw parts lies in eccentric alignment. The resulting imbalance can cause the part to be thrown from the chuck, tools to break due to interrupted cuts, excessive tool wear from overly high or irregular cutting depths, or – over time – damage to the main spindle bearings due to vibration.
Not only do higher scrap and rework rates drive up costs, but the risk of excessive wear on tools and machines increases as well – up to the point where the workpiece may come loose, fly uncontrollably around the machine enclosure, and cause damage.
Automation plays a particularly important role in precision clamping, doesn’t it?
Exactly. In modern manufacturing, automation has become a cornerstone of efficiency, consistency, and scalability.
While automation – especially through the integration of collaborative robots, or cobots – can significantly streamline loading and unloading processes, precise clamping remains absolutely essential. Cobots are highly effective at repetitive tasks like loading and unloading, but they are still limited in their ability to feel or detect alignment errors, especially when dealing with eccentric or slightly out-of-round parts.
This means that when such parts are loaded by a cobot, the risk of eccentric clamping can lead to major issues during machining, affecting safety, quality, and productivity.
And this is where RÖHM’s award-winning intelligent clamping jaw, the iJaw, comes into play.
Exactly. The iJaw is the world’s first sensor-equipped clamping jaw capable of measuring the clamping force directly at the workpiece in real time. It provides access to data that was previously unavailable – making machining processes safer and more efficient. In practical terms: with the iJaw, productivity and safety increase while costs decrease. In short: Smarter Clamping.
Our iJaw won the “Best of Industry Award 2022” and the “Industry 4.0 Award 2023.” Since then, we’ve continued to refine it, and it is now available in various versions for different jaw geometries.
So how exactly does the iJaw work?
Unlike a conventional clamping jaw, the iJaw contains a sensor, electronics for evaluating and transmitting sensor data, and a battery. Everything is sealed to be waterproof and protected against chips. The iJaw is mounted into standard clamping devices just like any other jaw. The antenna of the external wireless receiver is placed inside the machining area. A blue LED on the mainboard indicates that the iJaw is active and connected to the receiver, to which it transmits clamping force data.
So the clamping force measured directly at the workpiece in real time…
…always corresponds precisely to the maximum allowable process force that can act on the workpiece during machining without compromising its stable position – and therefore without compromising safe clamping.
As spindle speed increases, centrifugal force reduces the clamping force – by as much as 60 percent of the original static clamping force. This means only smaller machining forces can act on the workpiece without causing it to shift or become insecurely clamped.
A very important point: even if the hydraulic pressure at the clamping cylinder remains constant, the actual clamping force at the workpiece depends heavily on lubrication and wear conditions of the clamping device. With poor maintenance, clamping force can drop by up to 50 percent. Simply measuring hydraulic pressure is not enough to ensure safe clamping. It does not account for these factors and only provides a rough indication of the true clamping condition.
Let’s summarize the functionality again in the context of cobot-assisted part loading.
Of course. The cobot places the part into the chuck. As soon as the part is positioned, the iJaw immediately begins measuring clamping force and part geometry – and instantly detects whether the part is clamped off-center or whether eccentricity is present. If the iJaw identifies a problem, it sends a real-time signal to the cobot instructing it to readjust the part to ensure proper centering and secure clamping. This guarantees that every part is clamped precisely, preventing costly machining errors before they occur.
The iJaw offers a wide range of benefits for manufacturers.
Traditionally, operators must “feel their way” toward the minimum and maximum clamping forces specified by design. This takes time and can result in damaged parts. With the iJaw, this effort is reduced to a minimum. Operators can immediately set the optimal clamping force – repeatably, for every clamping cycle. The result: faster setup times.
Continuous monitoring of the machining process by the iJaw – including warnings when clamping forces exceed or fall below allowable limits – improves machining safety and cutting speeds. The effects are substantial: up to 50 percent shorter cycle times, no downtime or lost parts, higher machine availability, and ultimately lower part costs.
And what about clamping delicate, thin-walled workpieces?
This is where the iJaw truly shines. Operators can preset the clamping force reproducibly, which means deformation of the workpiece caused by clamping becomes reproducible as well. The iJaw can detect even the slightest relative movement of the workpiece, enabling controlled adjustment toward the minimum required clamping force. This helps determine the optimal clamping force and prevents clamping marks on the surface.
Let’s return once more to automated part loading with the iJaw.
The roundness of raw material is defined in DIN EN 10060, which allows radial out-of-roundness of up to two millimeters. If such material is incorrectly aligned during clamping, it can cause severe imbalance during machining.
In cobot-assisted loading of turning and milling machines, the iJaw becomes indispensable because it measures the clamping force at the workpiece and detects whether it is distributed symmetrically. This makes it possible to clearly identify – and, as mentioned, correct – eccentric clamping.
Can the iJaw system for automated loading and unloading be retrofitted into existing equipment?
Absolutely. At the recent EMO trade show in Hannover, four of our technology partners –GROB, HERMLE, INDEX, and WFL – demonstrated the smart clamping jaw live on their machines. With seamless integration into their systems, manufacturers can improve their clamping processes without major interruptions or investments in new infrastructure.
RÖHM provides a comprehensive package that includes:
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an iJaw case with a three-jaw set for a chuck
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the iJaw Connect control cabinet, mounted externally on the machine, containing an IO-Link Wireless Master with edge computing capability. It receives sensor data and forwards it to an industrial PC, also part of iJaw Connect, where the data is processed. A Wi-Fi router completes the setup and transmits data for visualization
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a tablet equipped with the iJaw Mobile app for displaying and automatically analyzing recorded data
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a flange that connects the grippers to the cobot and wirelessly transmits stroke‑monitoring data to the IO-Link Wireless Master
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a wide range of grippers and jaws covering all conceivable raw-part sizes, each of which can be retrofitted with sensors for stroke monitoring or part measurement
Naturally, we also handle on-site installation and provide comprehensive training during commissioning. Our service includes support during ramp-up production as well as ongoing after-sales support.
