Medical technologie

Flexible clamping concept from EMUGE-FRANKEN for the production of rotors for X-ray devices.

Clamping technology in the manufacture of X-ray equipment

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A brief review to get you started: X-rays were discovered 125 years ago, in 2020. This happened rather by chance. At the time, Wilhelm Conrad Röntgen was a professor in Würzburg and held the chair of experimental physics. At that time, it was known that a high electrical voltage in a glass flask pumped empty of air produced a weak light. Röntgen experimented with it and noticed that suddenly a fluorescent screen and other objects began to glow.

The discovery was the starting signal for the development of X-ray machines. These devices are highly complex in their function, so we will remain on the "surface" when explaining them.

In a nutshell: The essential components of an X-ray machine include a rotor and a stator, which ensure the rotation of an anode. Modern X-ray machines produce high-resolution images within a very short time and need only a fraction of the radiation dose required by earlier models.

EMUGE-FRANKEN's clamping technology has developed and successfully implemented a concept which can clamp rotors of X-ray machines with high precision for turning and milling. We briefly highlight the challenges, the corresponding solution and show the advantages for our customers.

Clamping concept for thin-walled workpieces

First challenge: The workpiece is thin-walled and therefore requires a special clamping concept. On the one hand, the workpiece must not be deformed, but on the other hand, the clamping should guarantee the necessary holding torques for machining. The solution: "We use a clamping sleeve that covers the entire length of the workpiece," explains our colleague Bernd. "We thus enable the rotors to be machined to be fixed with little deformation and with precision". Clamping is initiated via a pull and push rod on the machine side. The clamping bolt is pulled and thus ensures the expansion of the clamping bush.

"One factor regarding the deformation of the workpiece was the actuating force of the customer's machine. As the machine can only move with a fixed force, we integrated precisely defined spring assemblies into the clamping concept. These restrain the actuating force of the machine to the necessary extent!"

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Modular system: flexible and quick to implement

Furthermore, the customer wants to machine several workpieces with one clamping concept. The workpieces are visually almost identical, but differ in the clamping diameters. "In order to cover three different workpieces, it was clear that we needed a kind of 'modular system'. The result is a clamping concept consisting of three clamping mandrels with the matching interchangeable parts in each case." Our colleague points out another technical feature: "The clamping sleeves feature a highly accurate internal contact on the workpiece. A rather unusual case and technically more complicated than an external system!"

The three clamping mandrels are connected to the machine spindle via a quick-change flange to facilitate flexible usage. The change is simple and quick: "Loosen three cylinder screws, twist the mandrel and pull it off. The other clamping mandrel is mounted just as quickly in reverse order. Markings on the clamping mandrel and quick-change flange support this process!" Alignment options on the quick-change flange and clamping mandrel provide the decisive micrometres of accuracy.

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Our colleague adds: "With the modular system, tailored to the customer's requirements, the clamping concept developed enables high-precision clamping of several, similar workpieces. For internal machining of these workpieces, three clamping devices can also be accommodated on the quick-change flange."

Cooling lubricant is supplied during internal machining of the rotor workpieces: "The quick-change flange is already prepared for this. The transfer of coolant to the machining area takes place via the central pulling elements and the end stop of the clamping chuck."

In order to avoid workpiece deformation as best as possible, even in the case of the external system, the clamping bush is in contact over almost the entire length of the workpiece. The axial tightening of the workpiece against the end stop ensures even more stable fixing. Flexibility is also required for the parts that come into contact with the workpiece: "There are separate interchangeable parts for the different workpiece lengths, which can be quickly exchanged with auxiliary tools."

Accuracy is also important: "The repeatability of the change is 0.003 mm, i.e. 3 microns.

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Flexible clamping concept with added value - from EMUGE FRANKEN

We ask about the advantages our clamping concept offers the customer: "Our customer benefits from high holding torques with thin-walled workpieces, a quick change of the clamping devices and highest accuracy due to several alignment options on the entire clamping system. In addition, the customer can load the clamping fixtures automatically thanks to the high lead-in clearance!"

If you want to receive more information about our modular systems or about clamping technology in general, our contact persons are ready to answer your questions and meet your challenges!