A new method for establishing the depths of cut for cast iron parts turning

Abstract

It is well known that determining the machining parameters is an important issue of process planning. Machining parameters have a significant influence on the cost and productivity of different machining processes. Among these parameters, special attention comes to the depth of cut. In this respect, the present paper proposes a new method for establishing the depths of cut related to technological sequences-roughing, semi-finishing and finishing-such as to gradually eliminate the errors that occur during surface machining in order to ensure the required accuracy. Hence, depths of cut that are greater than necessary are avoided, thus facilitating certain economic advantages. The operating mechanism underlying the discussed method is based on analysing the roughness of the surface to be machined. Materialization of the method based on the CAPP components is a software tool conceived in Delphi environment and consists of two modules: one for determining the technological sequences and the other one for determining the depths of cut required by the technological sequences. The method also allows the determination of the billet dimensions and of the related tolerances of the analysed surfaces. The software tool includes a database built upon a set of mathematical models for appraising the flaws to be eliminated by removal of the material layer. The paper addresses the turning of cast iron parts and provides a solution for multi-pass turning as well as a case study for exemplification purposes. Keywords Cast iron parts machining • Depth of cut • Machined surface roughness • Cutting sequences • Software tool Abbreviations a(3,15), name(3) Matrices of the database cab Billet casting process accuracy grade Df Clamping surface diameter (mm) Dm Maximum part dimension (mm) Dn cib , fin cib

Determination of the Depth of Cut via Surface Integrity

“…For determining the billet dimensions, there are also necessary data regarding the cylindrical surfaces of the part (the depths of cut). These data have been obtained using another software developed by the authors and presented in [8]. Thus, the billet shape from Figure 7 has been obtained.…”

“…In this way, the authors have developed a new/original software tool named CDFTCI (conceived in Delphi environment). This software is based on a small database associated with the original mathematical relations (2)-( 16), whose role is to model the components of surface integrity and other errors; (h) The CDFTCI software also contributes to the calculation of the billets' dimensions regarding the front faces; with respect to the calculation of the billets' dimensions regarding the cylindrical surfaces, TESEQ and CDCIM software tools must be used [8]; (i) The CDFTCI software tool could be used as a standalone application, and it might be easily integrated into any CAP system and translated, if necessary, into other programming languages.…”

“…This section of the paper develops ideas from previous authors' research [8], approaching the determination of the technological sequences and the depths of cut for the front-face turning of cast iron parts. The considered basic criterion ensures the final surface integrity.…”

“…Surface integrity is specific to each operation. Thus, the concept of Current-Previous Machining Process-CPMP [8] becomes very important. This concept considers that surface roughness Rz p and the components of S p generated during the machining process and caused by the casting process must be considered when calculating d cf (current depth of cut), following Figure 1.…”

Untitled

“…Regression analysis was used. As regards solving the mathematical models of machining parameters optimisation, literature supplies a series of models [3][4][5][6][7][8][9][10][14][15][16][17].…”