Experimental evaluation of the minimum uncut chip thickness (MUCT) in AISI H13 steel, using the end milling operation

Author(s)

da Silva, Tatiany Mafra ^[1] ; Diniz, Anselmo Eduardo ^[1] ; Coelho, Reginaldo Teixeira ^[2]

Affiliation

^[1] Univ Estadual Campinas, Sch Mech Engn, Campinas, SP - Brazil

^[2] Univ Sao Paulo, Sao Carlos Sch Engn, Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY; v. 113, n. 5-6, p. 1431-1447, MAR 2021.
• Web of Science Citations: 1

Abstract

The increasing market demand for smaller products requires the development of micromachining processes. This, in turn, enhances the importance of knowledge about the phenomenon of chip formation and its characteristics at the microlevel. Conventional machining generally assumes that the tool cutting edge is perfectly sharp, and that it usually does not affect the chip formation process. However, in micromachining, the magnitude of the edge radius (r(e)) is often the same as that of the chip thickness, thus significantly affecting the process. Moreover, the study of chip formation at the microlevel is even more complex. In micromachining, as the chip thickness decreases, it reaches a minimum thickness at which a chip is still formed, called the minimum uncut chip thickness (MUCT). Therefore, the purpose of this work is to use an experimental method, based on milling, to reach the MUCT (h(min)) by simulating a micromilling operation. AISI H13 steel was used in two conditions: hardened and as received, with around 60 and 25 HRc, respectively. The experiments were performed according to a novel method simulating end milling in orthogonal cut. It was found that h(min) varied from 0.56r(e) to 2.5r(e), and that this range depends not only on r(e) but also on the material being machined and on the mechanical compliance of all the equipment used in the test. Based on the theory of contact mechanics, it was possible to explain that a chip is formed only after the cutting edge has attained the necessary stresses to cause failure of the material being tested, and this knowledge is fundamental to understand the occurrence of h(min). In addition, the method used here was successful in reaching h(min) values typically obtained in milling conditions. Using the same method proposed herein, future studies of MUCT can be performed employing even conventional machine tools. (AU)

• FAPESP's process: 13/00551-7 - Milling of dies and moulds: vibration in the process and milling of complex profiles
• Grantee: Anselmo Eduardo Diniz
• Support Opportunities: Research Projects - Thematic Grants