By Dr. Cameron Chai
Scientists from the Fraunhofer Institutes for Production Systems and Design Technology (IPK) in Berlin and Mechanics of Materials (IWM) in Freiburg have discovered a novel way of straightening out distorted ceramics.
Shot is fired from a blasting gun at a ceramic leaf spring to correct its shape or cause specific warping as desired.
The shot peening technique uses small pellets called shot, which are fired from a blasting gun at the surface of a ceramic component to correct the shape of the outermost, thin layer of the material. In addition, researchers strived to reduce undesirable warping by moving the blasting gun on the ceramic component along an accurately calculated path.
Shot peening process is commonly used for transforming metals and it has never been applied on ceramics, as they are too fragile and can break easily. Hence, the peening technique needs to be implemented on ceramic with high precision, said Dr. Wulf Pfeiffer of IWM. Initially, the research team started investigating the size of shot that will be ideal for application on ceramic because larger size pellets can damage the material surface. Another major factor that impacts the application is the pellet speed. If the speed is too fast, the material gets damaged and if it is too slow, the shape of the ceramic surface is not modified sufficiently.
Prior to a new component production, the researchers initially perform experimental analysis on the ceramic involved in the manufacturing. They shoot a beam of pellets at the material and evaluate the resultant stresses to observe the type of possible deformation and the path in which the beam has to be fired. Several prototypes have already been produced, including a concave mirror and a ceramic leaf spring. IWM researchers are now developing a computer simulation method that will enable working of components in multiple axes. Their IPK colleagues are working on automating the process with a robot.