Uma contribuição para o estudo das deformações residuais proporcionadas pelo processo de usinagem por fresamento. / A contribution for residual deformation study originated by the face milling machining process.

AUTOR(ES)

Marcelo Acacio Rodrigues

DATA DE PUBLICAÇÃO

2009

RESUMO

The face milling operation purpose is providing flat machined surfaces free from residual strains at the cross section of the workpiece. On the other hand, the evidences presented in this thesis are enough to demonstrate that the strain exists and its behavior can be related to technical measurements such as the cutting tool helical profile, the feed rate, the cutting speed beyond the materials mechanical and metallurgical properties. Several face milling operation under conventional cutting conditions onto two super alloys have been performed. A nickel base alloy and a cobalt base were observed. A titanium base alloy has also been observed. The feed rate, the rake angle and the cutting speed were manipulated aiming the evaluation of the residual strains under different strain rates. The specimen has been evaluated in its strained condition throughout the use of scanning electronic microscopy. Furthermore with the mathematical modeling it has been possible to conclude that the residual strain at the cross sectional surface is supportable and the strained profile can be evaluated through the use of the Slip Line Field plasticity theory. The plastic behavior of the material has been evaluated with the Slip Line Field plasticity theory with the Johnson-Cook´s constitutive material´s model. The cutting force estimation has used the modified parallel shear plane zone machining model assured by P.L.B. Oxley and an ancient Slip Line solution presented by Lee and Shaffer. All of the details of this thesis which collaborate with the contribution concept have been pointed out along this research, especially the derivation of the helical area profile as well as the criticism related with the shear plane initial value definition and temperature estimation. The continuum plasticity has been the main aspect to evaluate the stresses and also the strains in the workpiece and also at the chip. The materials strain hardening index is main point for a new evaluation of the P.L.B Oxley machining model, and the understanding of how the mechanical properties related with this index influence the residual plane strain and the other convergence conditions of strain during the machining are suggested in order to build up the understanding of this contribution.

ASSUNTO(S)

residual deformation ligas refratárias usinagem fresagem machining refractory materials plasticidade das estruturas milling

Documentos Relacionados

• Uma contribuição a melhoria do processo de fresamento de ferro fundido vermicular - CGI
• A contribution to the face milling of irregular grey cast iron surface
• Avaliação da usinagem da liga Ti-6Al-4V pela técnica de fresamento.
• Avaliação de tensão residual gerada pelo processo de usinagem utilizando acustoelasticidade
• A contribution of instrumentation for process monitoring of end mills.