Tool-Path Planning Method For Kinematics Optimization of Blade Machining On Five-Axis Machine Tool

Planning tool-paths on free-form surfaces is a widely discussed issue. However, traditional methods of generating paths capable of meeting all the requirements of blade machining remain challenging. In this study, a new iso-parametric path-planning strategy based on a novel parameterization method combined with the conformal transformation theory was proposed. The proposed method could adapt to the curvature characteristics of the blade surface, improving the kinematic performance of the machining process, reducing multi-axis coordinated motion control complexity, and improving machining quality. The proposed method was then compared with three traditional methods. The influence of the tool-path on the kinematic performance of the machine tool was quantitatively examined based on the kinematics models of two different machine tools. A large cutting depth milling experiment was conducted to verify that kinematics optimization could improve machining quality. The proposed method provides a more reasonable path-planning approach for blade machining on a five-axis machine tool, which is of great significance in reducing the cost of blade machining and the risks of blade failure. Moreover, it is of great significance for the large-scale automated production of blades.

Investigation of Cutting Forces for Thin Layers when Planing and Milling

The problem of machining structural elements with removal of metal layers with thickness less than 0.01 mm by carbide tools, when the conditional radius of the blade rounding is less than or equal to the thickness of the cut layer, is considered. These cutting conditions can be considered constricted which requires research into cutting forces and chip shape. The problem of recording and measuring small cutting forces arising during blade machining of small grooves that serve for gas drainage in the manufacture of rubber products is solved. To measure forces, a lever fixed in a universal dynamometer, which has a supporting support with small friction, is used. Value of force moment measured with dynamometer can be used for optimization of cutting conditions, selection of tool geometry when processing small relief elements. Dependences of lever system cutting forces and displacements on the use of lubricant-cooling liquids, values of front angles during planing and milling with small-size tools are investigated. Experimental discrepancies between theoretical calculations of cutting forces according to classical and modern reference data and fixed results with the use of cutting liquids during cutting with small values of feed for carbide tools are found

Self-Tuning Algorithm for Tuneable Clamping Table for Chatter Suppression in Blade Recontouring

The production and repair of blades for aerospace engines and energy turbines is a complex process due their inherently low stiffness and damping properties. The final recontouring operation is usually performed by milling operations where regenerative chatter is one of the main productivity limiting factors. With the objective of avoiding specific stiffening fixtures for each blade geometry, this paper proposes a semi-active tuneable clamping table (TCT) based on mode tuning for blade machining. The active mode of the device can be externally controlled by means of a rotary spring and eddy current damping modules. Its in-series architecture allows damping to be introduced to the critical mode of the thin-walled part without any direct contact in the machining area and enables a more universal clamping. Its chatter suppression capabilities are maximized by means of a novel self-tuning algorithm that iteratively optimizes the tuning for the measured chatter frequency. The benefits of the iterative algorithm are validated through semidiscretization and initial value time-domain simulations, showing a clear improvement in blade recontouring stability compared to regular broad-bandwidth tuning methods.

Calculation of Deviations of Shape, Size and Location of Flat Surfaces

The development of computerization allows the development of mathematical models of physical processes with different methods of blade machining of machine parts. Modern programmable CNC machines have the ability to produce parts in an automated cycle, ensuring the requirements of the drawing. Control of the quality of processing of the main flat surfaces, which are technological and Assembly bases, should be considered in more detail. Their accuracy in accordance with the standards is determined by the shape deviations from the adjacent planes, size and relative position. The standards have instructions on how to create a virtual adjacent plane using adjustable supports and further scan the ordinates of its individual points to calculate the deviation of the form. To quantify the deviations of shape, size and location is not enough to have a field f, the vectors of which are defined from the geometric plane, given the nominal size, it is necessary to establish a base for their reference. The question of establishing bases for reference is not only of fundamental importance, since different bases can be obtained different values of deviations. The paper proposes a mathematical model for determining the named parameters of accuracy from the middle planes, which are determined by the calculated vectors at specific points of the treated surface when processing batches of blanks on milling machines face milling.

Constructing Process Models of Engine Blade Surfaces for Their Adaptive Machining: An Optimal Approach

In a new blade manufacturing process, manufacturers precisely forge blade billets with the blade suction and the pressure surfaces within tolerance. After that, only two blade edge billets should be machined to the leading- and the trailing-edges within tolerance. If these edge design surfaces are used to generate tool paths for machining the edge billets, the machined edges are not continuous with the suction and the pressure surfaces. To address this problem, an optimal approach to constructing process models of edge surfaces is proposed for adaptive blade machining. Specifically, the modified edge surfaces are optimized within the design tolerance and are continuous with the billet suction and pressure surfaces. These surfaces are used to generate tool paths for machining the edge billets. This approach addresses the current technical challenge in the new blade manufacturing process and can substantially promote this process in blade mass production.

Research on Key Process Technology for Profile Electrolytic Finishing of Large Marine Propeller Impeller

An electrolysis process method for free-form blade surface finishing is proposed for a free-form surface impeller, and a stepwise method is used to process the inter-blade channel of the overall impeller. The forming cathode is then used to finish the blade to meet the blade processing requirements. In the design, the forming cathode structure was improved by using motion simulation software, and the flow field simulation software was used to simulate and analyze the cathode flow channel. The cathode shape and the electrolyte flow rate between the electrodes meet the processing requirements. In the process of processing experiments, the motion path of the cathode was analyzed and optimized. The effect of the feed direction on the uneven distribution of the blade machining gap was reduced through optimization, and high-frequency pulse power processing was used to reduce the machining gap and improve the machining accuracy of the blade. The experimental results show that the process scheme is feasible and the precision of the processed impeller free-form surface is significantly improved. The material is a monolithic turbine disk of high-temperature alloys, and its large twisted blade processing has always been a problem in the manufacturing industry.