The artificial hip joint is intended to last a long time – over 20 years if possible. This will only work if, in the so-called tribological pairing, the ball and socket fit together with micron precision. These two components form the hip joint, which must withstand many millions of movement cycles after implantation. When it comes to the quality control of medical technology, every single part is measured highly precisely in three dimensions. The probe is moved by FAULHABER motors.
When measuring contours in three dimensions, tactile measurement is the most accurate method. The probe, which is called a stylus, usually has a ball-shaped measuring tip. It moves to defined reference points on the test object and the controller detects the contact on the resistor and uses this to determine the measured value. The best devices work with a measuring tolerance of just one micron (1 µ). With this level of precision, properties such as straightness, flatness, roundness, cylindricity as well as lines and surfaces can be determined.
The stylus can be mounted on the measuring arm in such a way that it is fixed in position or is able to move. It can also measure inside cavities that cannot be accessed by optical systems. Usually, it is positioned by multiple drives. Naturally, the utmost accuracy is required when moving the components. This can be achieved through the interplay of a DC-micromotor with precious metal commutation and a backlash-free gearhead, for example. FAULHABER can provide these from a single source and perfectly tailored to one another.
In this application, it is also important that the device moves smoothly even at low speeds. The interior of the measuring device offers little space; especially in the case of moving styli, very small motors are the only option. They must be able to provide the necessary torque with a minimal volume. In many applications, for example with orthopedic implants, every single part must be measured. This means that the technology must run perfectly in continuous operation and for long periods. Drives from FAULHABER are ideally suited for these strict requirements, for example the motors of the 1524 SR or 1516 SR series together with appropriate gearheads.
