The machining of sintered ceramic parts is a difficult process, mainly due to the hardness and brittleness of these materials, which implies in high production costs. Therefore, great efforts have been made to improve the forming processes of green ceramics, or create new processes to obtain the near net shape parts. The production of ceramic parts with complex shapes, free of defects, is a task that involves great difficulties. Ceramic springs exhibits shapes extremely difficult to be molded and therefore are currently commercially produced mainly by machining, a process which is difficult and expensive. An alternative for the production of ceramic springs is by low-pressure injection molding. For the development of ceramic springs for technological applications, it is required in addition to getting parts intact and free of defects, to measure some of its properties, including the spring constant. Since these springs are usually applied at high temperatures, it becomes important to carry out the measurement of resistance imposed by the spring to elastic deformation at different temperatures. Accordingly, in this work we describe the assembly of an experiment for the measurement of the spring constant of low-pressure injection molded ceramic springs, both at ambient temperature and at high temperatures, using the dynamic impulse excitation method to measure the frequency of vibration of a suspended spring inside a furnace. Results are presented for a helical spring of alumina from room temperature to1100 ºC to illustrate the application of this technique.
low-pressure injection molding; ceramic springs; spring constant
