Análise das variáveis existentes na usinagem de blocos de Zircônia estabilizada com 3% de Ítria e a possível reutilização do cavaco produzido

Abstract

The production of biocompatible microcomponents has driven areas such as medical and dental ones requiring the delivery of high or ultra-precision custom prostheses and microcomponents. Polycrystalline Tetragonal Zirconia stabilized with Itria (Y-TZP) are preferably oxide ceramics which present in their composition a vitreous phase and one or more crystalline phases, which play an important role in dental restoration and machining of crowns and fixed partial prostheses. To this end, previously pressed and partially sintered parts are machined until it reaches the ideal format, using a defined geometry manufacturing process called milling, comparing the efficiency of hard metal top milling (WC-Co) of two cutting edges in relation to four cutting edges. The swarf generated after Y-TZP, which is usually discarded in the manufacturing process, was the object of study in order to demonstrate the feasibility of reuse. For this, rectangular bars were constructed according to ISO 6872 using uniaxial pressing and a pressure of 100 Mpa. These bars were sintered using a microwave energy oven at a temperature of 1450 ºC for 15 minutes. The total process time between heating and cooling was 2 hours and 30 minutes. After sintering, the specimens presented an average volumetric reduction of 49%. The bars were submitted to the destructive vickers microhardness test. When performing the prints, hardness of up to 1305 HV was detected. These values found are compatible with commercial sintered blocks, dimensional and geometric controls of the samples were performed to characterize the recycling viability of this industrial refuse.