Simulating the design of special cutting tools

Abstract

Currently, in simulating the design of special cutting tools, different models (graphs, analytical dependences, functional models) and methods (three-dimensional representation of objects, search methods, etc.) are used. The goal of simulation is to improve the cutting tool at the design stage and to obtain tool characteristics guaranteeing the manufacture of parts of specified quality in different combinations of cutting conditions, machine tools, software, and hardware. A unified design and production system is organized within the framework of a general quality-control system, covering the whole tool lifetime, from obtaining the order for its design to its withdrawal from service. Currently, there are no integrated methods of cuttingtool design within a unified CAD/CAE/CAM/PLM environment based on common algorithms and rules. The method proposed for organizing this environment is based on functional simulation of the design of special cutting tools. The design stage takes the form of processes divided into functions reflecting the current state of these processes and functions permitting their redesign. Automation of the design of manufacturing technologies for cutting tools may be analyzed on the basis of the general principles of computer-assisted systems used in the design of manufacturing processes for general-purpose machine parts [1, 2]. In this approach, in particular, the cutting tool is not considered as an object of design and production, with properties differing from those of machine parts. The cutting tool may be regarded from two points of view, as shown in [3]: as a certain object for which manufacturing processes must be designed; and as a component with a specified function, for producing parts of specified dimensions. In the latter case, a machining method employing a cutting tool selected by the technologist is determined; the tool may be of different designs. Obviously, these perspectives are fundamentally different: in the first, the cutting tool is considered without taking account of the technological-design goals; in the second, it is regarded as a component of this process, permitting different production sequences. Depending on the selected approach, the design of the computer-assisted design system will take different forms. Aspects of the cutting tool that must be taken into account in its design and manufacture were identified in [3]: the many technologically equivalent design options; and the possibility of formulating approximation problems. This calls for the creation of an integrated CAD system for the cutting tool, covering both its design and the formulation of an appropriate manufacturing technology. On the basis of the components of the CAD system, a functional model of cutting-tool design may be created (Fig. 1). In stage 1 (deriving the design constants), the parameters of the tool (tooth geometry, length of the cutting and calibrating sections, tooth spacing, etc,) that guarantee specified quality of the manufactured part are determined, taking account of the initial data for the machined parts (the type of material, the required surface roughness, the optimal cutting conditions, etc.) and the available resources. In stage 2 (determining the variable structural components), technological pathways (TP) of cutting-tool manufacture, operating technologies (OT), and control programs (CP) for the machining of cutting tools on numerically controlled machine tools are developed, taking account of the design standards (I) and also the constraints on the implementation of the new techno