Study of the stability of the milling tool in die and mould manufacturing.

• Grant number: 12/20816-2
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: March 01, 2013
• End date: June 05, 2016
• Field of knowledge: Engineering - Mechanical Engineering - Manufacturing Processes
• Principal Investigator: Anselmo Eduardo Diniz
• Grantee: Henrique Kull Neto
• Host Institution: Faculdade de Engenharia Mecânica (FEM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Over the past years, milling have been replacing the EDM process in the manufacture of dies and molds for plastic forming processes, metal casting and plastic injection. Milling has several advantages over the EDM, including: shorter cycle times, because it is not necessary to manufacture the electrode, the reduced thermal damage to the machined surface, among others. However, it also presents some drawbacks. The main one is the need of using small diameter cutters for copying the small radii often present in the dies. Moreover, in deeper cavities it is necessary to use slender mills. Consequently, there is the problem of lack of rigidity of the tool, which has high length / diameter ratio (L / D). Therefore, in deeper cavities or in deeper regions of the dies, the EDM process is still used. This study has the objective of evaluating the limits of rigidity of the milling tool. It is intended to test different types of tools in the milling of low hardness dies (P20 steel of 30 HRc) and high hardness dies (D6 steel with a hardness close to 60 HRc), using different cutting speeds and, hence, different tool passing frequencies (which is the main source of vibration in a milling process), with several tool overhangs (L / D). It is intended to verify what are the limits of the tool overhang in each condition. To verify if a particular condition has reached its L/D limit, the process stability will be evaluated by analyzing the cutting force signals in the time and frequency domains and also by analyzing the part roughness. The frequency response function (FRF) of the tools will be found in order to correlate the natural frequency of the tool (which is usually the element of lower rigidity in the tool/workpiece/machine tool system) with the tool passing frequency, the cutting force and cutting conditions. The limit conditions (most stable and the least stable) will also be evaluated in tool life tests, in order to verify how process stability influences the tool life and its wear mechanisms. At the end of the work, it is intended to have constructed a method that permits the user of such process to establish the limits of L / D ratio for each cutting condition.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

KULL NETO, HENRIQUE; DINIZ, ANSELMO EDUARDO; PEDERIVA, ROBSON. The influence of cutting forces on surface roughness in the milling of curved hardened steel surfaces. INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY, v. 84, n. 5-8, p. 1209-1218, MAY 2016. (13/00551-7, 12/20816-2)

KULL NETO, HENRIQUE; DINIZ, ANSELMO EDUARDO; PEDERIVA, ROBSON. Tool life and surface roughness in the milling of curved hardened-steel surfaces. INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY, v. 87, n. 9-12, p. 2983-2995, DEC 2016. (13/00551-7, 12/20816-2)

KULL NETO, HENRIQUE; DINIZ, ANSELMO EDUARDO; PEDERIVA, ROBSON. Influence of tooth passing frequency, feed direction, and tool overhang on the surface roughness of curved surfaces of hardened steel. INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY, v. 82, n. 1-4, p. 753-764, JAN 2016. (12/20816-2)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

KULL NETO, Henrique. Study of machining strategies for minimizing vibration in the milling of convex surfaces. 2016. Doctoral Thesis - Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Mecânica Campinas, SP.