cover story Seals for
cover story Seals for the global market Handling high pressure Razor-sharp: the wedge angle of the inserts resembles a blade Hydraulics, gas and water. Seals are found wherever high pressures are involved or to prevent the tap at home from dripping. The inconspicuous parts are installed in a large number of devices. The Prädifa Technology division of Parker Hannifin Corporation is a leader in the development and production of sealing solutions. A seal with two axial grooves can be machined in a single clamping The site in Boom, Belgium, specializes in seals made from machinable materials such as PTFE. The specialists rely on tool solutions from Paul Horn GmbH for machining. The Supermini and Mini systems are mainly used on the machine tools. “Due to the variety of our different seals, we use special tools 90 % of the time. The materials and the different sealing profiles require very sharp tools with special cutting edge profiles”, explains Peter Schockaert. He is responsible for production at Parker Prädifa, together with Johan Willems. “HORN’s ability to design the cutting edge profiles according to our wishes and requirements is very important to us. That’s why we’ve been relying on the tools from Tübingen since years”, says Willems. Leading supplier of polymer seals Parker Prädifa Technology Division’s product portfolio includes a wide range of standard sealing elements and sealing systems, customized and application-specific seals and other technical components. Customers include companies from the aerospace, automotive, pharmaceutical, chemical, hydraulics and other industries. The company is recognized as a leading supplier of polymer sealing solutions made from a variety of sealing materials and in a wide range of sizes. This diversity also applies to the sizes of the seals, which range from a diameter of a few millimeters to the world record seal having a diameter of over four meters. 6 no. 2, May 2025
cover story The miniature seal requires sharp tools “We often just call the tools blades, as they are ground with a very sharp wedge angle”, says Schockaert. Such a tool is used in the following application example. An axial thread has to be turned on a steering shaft seal made from a carbon fiber-Teflon material. The thread is needed to make the sealing ring axially flexible. This allows it to be slid over the shaft during subsequent assembly and remain securely attached after it is screwed on. Razor-sharp blade The first tests were carried out and orders fulfilled with tools that were ground in-house. “We grind prototypes and small quantities of tools ourselves. Then when volumes increase, we look for an appropriate tool solution”, says Willems. In this case HORN supplied a Supermini with a ground blade for axial machining. The thread to be produced has a depth of 0.2 mm. The tool machines the thread at a high feed rate. “At first glance, the machining process looks very easy. But the required absence of burrs demands a very sharp cutting edge”, says Schockaert. No chips flow during machining. The Supermini insert cuts or scores the thread into the surface. Micromachining The Supermini system is also used for producing another plastic seal having a diameter of just under 4 mm. In addition to having a face groove, a hole of 1 mm diameter must be bored. “The sharpness of the tools is also very important in this application, as the walls are very thin and could warp if During machining no chips are produced, the insert of the Superminis cuts or scores the thread into the surface no. 2, May 2025 7
