СТРУКТУРА ДОСЛІДЖЕННЯ ЕНЕРГОСИЛОВИХ ПАРАМЕТРІВ ПРОЦЕСІВ ЛИСТОВОГО ШТАМПУВАННЯ

One of the main tasks of theoretical research is to identify optimal conditions for deformation. The greatest interest for practice is determination of main technological parameters of shaping process and their connection with external factors. The solution to the problem is a very important and crucial stage of theoretical investigation. It is inextricably linked with choosing theoretical method of analysis and design scheme, which most fully meets requirements and particular case of shaping conditions. The article discusses structure of complex theoretical and experimental investigations sheet drawing energy-power parameters of technological processes. Mathematical model has been proposed based on the constructed structural-logical scheme for effective forecasting of energy-power parameters, which determines methods and sequence of theoretical and experimental researches. It reflects correlation between functional characteristics of machining and technological parameters of the sheet stamping-drawing. The character of shaping has been determined, which is provided by plastic deformations in the processes of metal working by pressure. It has been determined that loss workpiece stability or its destruction impose restrictions on allowable deformation degree, which is defined in the deformation zone by stress field. Method for calculating processes of plastic deformation metals is proposed which it is using to theoretical investigation energy-power parameters of technological processes of sheet stamping. It is based on closed system equations of continuum mechanics. The form of particles velocity functional dependence of plastically deformable material on coordinates in stamping-drawing process of sheet has been determined. Expressions are analyzed which make it possible to make the spatial picture distribution of deformation in metal during sheet stamping. This allows visualizing deformation mechanism and simplifying the analysis material deformed state. The relationship between velocity and energy dissipation function is shown at total work deformation is found, which makes it possible to determine force parameters of sheet stamping-drawing process. A functional relationship between the deformation power and the parameters of processing modes during sheet stamping has been investigated. Approaches to determining deformed material state are considered.

Expert System Based on Integrated Fuzzy AHP for Automatic Cutting Tool Selection

Cutting tool selection plays an important role in achieving reliable quality and high productivity work, and for controlling the total cost of manufacturing. However, it is complicated for process planners to choose the optimal cutting tool when faced with the choice of multiple cutting tools, multiple conflict criteria, and uncertain information. This paper presents an effective method for automatically selecting a cutting tool based on the machining feature characteristics. The optimal cutting tool type is first selected using a proposed multicriteria decision-making method with integrated fuzzy analytical hierarchy process (AHP). The inputs of this process are the feature dimensions, workpiece stability, feature quality, specific machining type, and tool access direction, which determine the cutting tool type priority after evaluating many criteria, such as the material removal capacity, tool cost, power requirement, and flexibility. Expert judgments on the criteria or attributes are collected to determine their weights. The cutting tool types are ranked in ascending order by priority. Then, the rule-based method is applied to determine other specific characteristics of the cutting tool. Cutting tool data are collected from world-leading cutting tool manufacturer, Sandvik, among others. An expert system is established, and an example is given to describe the method and its effectiveness.

A Deterministic Method of Application Region of Clamping Forces for Fixture Design

After being located, cutting force and torques will exert on a workpiece during the machining operation. In order to guarantee the location accuracy and production safety, the feasible clamping forces must be planned to stabilize the workpiece in the entire processing. Therefore, the workpiece stability is taken as a core to create a deterministic algorithm to the application region of clamping forces for the complex workpiece. Firstly, on the basis of the combination of the screw theory with the linear programming technology, an analysis algorithm is subjected to judge the workpiece stability. Secondly, according to the surface discretization method, a deterministic algorithm is further established to plan the application region of clamping force by analyzing the workpiece stability at all nodes in sequence. The proposed method can be utilized for the determination of the application region of clamping forces as well as the verification of the feasibility of the magnitudes of clamping forces.