Abstract: The present invention belongs to the technical field of composite material processing, and relates to a hole making tool for aramid fiber-reinforced plastic and a design method thereof. The drill bit has a step reversed point angle structure, which can reduce a trust force during drilling and effectively cut off a high toughness aramid fiber, thus to improve the hole making quality of an AFRP-related component. It is proved that the new tool can significantly improve the hole making quality of an AFRP component, improve the service life and safety degree, and greatly reduce the processing cost. Therefore, the present invention has a broad application prospect in the fields of aerospace, military industries and civil application.

Abstract: The present invention belongs to the field of friction stir welding (FSW) temperature detection, and relates to a temperature characterization method of FSW weld zone based on infrared thermal imager. The invention combines theory with experiment. A temperature field simulation model of FSW is established based on DEFORM. The data sets of temperature of surface feature points, the maximum and minimum temperatures in weld zone are obtained according to the simulation model result. Then, Support Vector Regression (SVR) is used to establish a temperature characterization model, which represents the correlation between the temperature of surface feature points and the maximum and minimum temperatures in weld zone. In the actual welding process, an infrared camera is used to measure the temperature of the surface feature point in real-time. Combined with the built temperature characterization model, the characterization of the maximum and minimum temperatures in weld zone is achieved.

Abstract: A 3D measurement model and the spatial calibration method based on a 1D displacement sensor are proposed. A 3D measurement system based on a fixed 1D displacement sensor is established; then a spatial measurement model based on the 1D displacement sensor is established; and then based on the high precision pose data of the measurement plane and sensor measurement data, spatial calibration constraint equation are established; a weighted iterative algorithms is employed to calculate the extrinsic parameters of the 1D sensor that meet the precision requirements, then the calibration process is completed. A high precision 3D measurement model is established; a 3D measurement model based on a 1D displacement sensor is established, and the calibration method of the measurement model is proposed, which will improve the precision of the 3D measurement model and solve the problem of inaccurate spatial measurement caused by the errors of the sensor extrinsic parameters.

Abstract: A toolpath topology design method based on vector field in sub-regional processing for the curved surface is disclosed which comprising: finding the functional relationships in feeding direction between the chord error and the normal curvature and between the scallop-height error and the normal curvature; establishing the bi-objective optimization model and calculating the optimal feeding direction at each cutting contact point within the surface through the constructed evaluation function, the space vector field is built; calculating divergence and rotation of the projected vector field and according to whether them are zeros or not to classify different sub-regions, the primary surface segmentation is achieved, etc. The method is applied for the complex curved surface processing, which can reduce the machining error and enhance the feed motion stability.

Abstract: The present invention belongs to the precise and efficient processing field of micro parts, in particular to a deformation prediction method of micro-milling thin-walled parts. Firstly, based on the finite element simulation software, a finite element simulation model of micro-milling thin-walled parts is established. Johnson-Cook material model and failure criterion are used to describe the material properties and damage criteria of the machined materials, so as to realize the prediction of milling force in the micro-milling process. The accuracy of the model is verified by experiments. Then, based on the birth-death element method, a deformation prediction model of micro-milling thin-walled parts model is established, and the milling force output from the finite element simulation model is loaded into the deformation prediction model. Finally, the deformation prediction of d micro-milling thin-walled parts is realized.

Abstract: A large-panel ultrasonic on-machine scanning thickness measurement equipment and method is disclosed. A GNCMT is adopted as the measuring machine main body on which a measured large panel is clamped and conducts scanning measurement motion; a non-contact ultrasonic measurement device is installed on the spindle of the machine tool for realizing transmission and acquisition of ultrasonic signals; a coupling liquid circulation system with the functions of multi-layer filtering, flow monitoring and regulation is set up; a jet flow immersion coupling mode is adopted on the surface of the measured large panel, and micro-emulsion cutting fluid is used as compatible coupling liquid of ultrasonic on-machine thickness measurement; and the coupling liquid is recycled, purified and stably supplied circularly. The thickness measurement equipment has high multi-function integration and reliable performance.

Abstract: This invention, a feedrate scheduling method for five-axis dual-spline curve interpolation, belongs to multi-axis NC (Numerical Control) machining filed, featured a feedrate scheduling method with constant speed at feedrate-sensitive regions under axial drive constraints for five-axis dual-spline interpolation. This method first discretizes the tool-tip spline with equal arc length, thus getting the relation between the axial motion and the toolpath by computing the first, second, and third order derivatives of the axial positions with respect to the tool-tip motion arc length. After that, determine the feedrate-sensitive regions with the constraints of axial drive limitations and the objective of balanced machining quality and efficiency. Finally, determine the acceleration/deceleration-start-point curve parameters by bi-directional scanning.

Abstract: An ultrasonic cutter detection method and device, the method comprises the following steps: preliminary detection: frequency amplitude detection and fall-of-potential detection, if the ultrasonic cutter fails the above two detection solutions in the preliminary detection, repeating the two detections; if the ultrasonic cutter still fails the above two detection solutions, the ultrasonic cutter is judged to be unqualified; and reinspection: free modal detection and pressure modal detection. Using differences of the ultrasonic cutters surface in micro-crack directions that result in different degrees of sensitivity of crack to different ultrasonic vibration modes, combined with the fall-of-potential method and frequency amplitude detection method, a detection rate and a detection velocity of an unqualified ultrasonic cutter can be improved.

Abstract: A monocular vision six-dimensional measurement method for high-dynamic large-range arbitrary contouring error of a CNC machine tool of the present invention belongs to the field of dynamic error detection of machine tools, and relates to a six-dimensional measurement method for high-dynamic large-range arbitrary contouring error of a CNC machine tool using a monocular vision measurement technology with short-time stroboscopic illumination and a priori standard plate. The method designs a measurement fixture and a measurement system, and uses a monocular vision pose algorithm to improve both the visual measurable dimension and range of interpolated contour in combination with priori knowledge. In light of the principle of error distribution, a small field of view is used to enhance the measurement accuracy of the coded primitives in the images.

Abstract: An application method of the thermal error-temperature loop in the spindle of a CNC machine tool. This uses a bar and two displacement sensors to determine radial thermal errors of the spindle. Meanwhile two temperature sensors are used to determine the temperature of the upper and lower surfaces of the spindle box. Then, the thermal error-temperature loop is drawn with the temperature difference between two temperature sensors as the abscissa and the radial thermal error of the spindle as the ordinate. Finally, the loop is employed to analyze the mechanism of the radial thermal deformation of the spindle and the thermal error level is evaluated. Since the method is based on measured data, the results of the analysis are closer to the reality, compared to those from the numerical simulations.

Abstract: A method for machining a drill with tilting blade slot structures for composite machining is provided. In the machining method, a face of the drill produces a downward component force for the inlet material to inhibit the inlet material from turning up; and a cutting edge inclination of an end surface at an outer turning point in a corner region of the drill is a positive value. The face and a flank are firstly partially ground in the corner region of the drill. The face at the outer turning point is ground with a grinding wheel to obtain two tilting blade slot structures. After grinding, a new face and a new cutting edge are obtained; and the cutting edge inclination on the end surface formed by the new cutting edge and a reference plane is a positive angle.

Abstract: A multi-dimensional vibration control method based on piezoelectric ceramic actuator applied to wind tunnel test of aircraft model. The pitch and yaw acceleration sensors arranged on the center of mass of the aircraft model are used to measure the two components of the main vibration acceleration of the aircraft model, and the main vibration vector of the aircraft model is obtained and the real-time vibration plane of the strut is determined. Inertia is introduced to solve the dynamic bending moment on the active section of the multi-dimensional vibration damper, and then the stress distribution on the active section is obtained. The multi-dimensional active vibration control system is adopted to improve the stability and reliability of the active vibration control system of wind tunnel model, extend the service life of piezoelectric ceramic actuator, and ensure the quality of wind tunnel test data and the safety of wind tunnel test.

Abstract: A 3D measurement model and the spatial calibration method based on a 1D displacement sensor are proposed. A 3D measurement system based on a fixed 1D displacement sensor is established; then a spatial measurement model based on the 1D displacement sensor is established; and then based on the high precision pose data of the measurement plane and sensor measurement data, spatial calibration constraint equation are established; a weighted iterative algorithms is employed to calculate the extrinsic parameters of the 1D sensor that meet the precision requirements, then the calibration process is completed. A high precision 3D measurement model is established; a 3D measurement model based on a 1D displacement sensor is established, and the calibration method of the measurement model is proposed, which will improve the precision of the 3D measurement model and solve the problem of inaccurate spatial measurement caused by the errors of the sensor extrinsic parameters.

Abstract: A large-panel ultrasonic on-machine scanning thickness measurement equipment and method is disclosed. A GNCMT is adopted as the measuring machine main body on which a measured large panel is clamped and conducts scanning measurement motion; a non-contact ultrasonic measurement device is installed on the spindle of the machine tool for realizing transmission and acquisition of ultrasonic signals; a coupling liquid circulation system with the functions of multi-layer filtering, flow monitoring and regulation is set up; a jet flow immersion coupling mode is adopted on the surface of the measured large panel, and micro-emulsion cutting fluid is used as compatible coupling liquid of ultrasonic on-machine thickness measurement; and the coupling liquid is recycled, purified and stably supplied circularly. The thickness measurement equipment has high multi-function integration and reliable performance.

Abstract: A toolpath topology design method based on vector field in sub-regional processing for the curved surface is disclosed which comprising: finding the functional relationships in feeding direction between the chord error and the normal curvature and between the scallop-height error and the normal curvature; establishing the bi-objective optimization model and calculating the optimal feeding direction at each cutting contact point within the surface through the constructed evaluation function, the space vector field is built; calculating divergence and rotation of the projected vector field and according to whether them are zeros or not to classify different sub-regions, the primary surface segmentation is achieved, etc. The method is applied for the complex curved surface processing, which can reduce the machining error and enhance the feed motion stability.

Abstract: The invented equivalent-plane cross-coupling control method belongs to high-precision and high-efficiency intelligent multi-axis CNC (Computer Numerical Control) machining filed, featured a three-axis cross-coupling controller based on the equivalent plane which can be used for improvement of the three-dimensional contour-following accuracy. This method first find the foot point from the actual motion position to the desired contour using a tangential back stepping based Newton method. Then, establish an equivalent plane which containing the spatial contouring-error vector by passing through the actual motion position and the tangential line at the foot point. After that, estimate the three-dimensional contouring error in a scalar form, thus controlling the signed error using a PID based two-axis cross-coupling controller.

Abstract: Disclosed is an ultrasonic cutting method employing a straight-blade sharp knife. The ultrasonic cutting method employing the straight-blade sharp knife includes the following steps: S1, measuring parameters of the straight-blade sharp knife; S2, initially rotating, by the straight-blade sharp knife, around an axis thereof, such that a rear knife surface of the straight-blade sharp knife is attached to or is away from a machined surface, and performing ultrasonic vibration cutting on a material according to a machining track; S3, performing quality detection on the machined material surface obtained by the ultrasonic vibration cutting, completing the machining if the surface passes the detection, and performing step S4 if the surface does not pass the detection; S4, further increasing an amount of rotation of the straight-blade sharp knife during initial rotation around the axis thereof, performing the ultrasonic vibration cutting on the material according to the machining track, and performing step S3.

Abstract: A multi-dimensional vibration control method based on piezoelectric ceramic actuator applied to wind tunnel test of aircraft model. The pitch and yaw acceleration sensors arranged on the center of mass of the aircraft model are used to measure the two components of the main vibration acceleration of the aircraft model, and the main vibration vector of the aircraft model is obtained and the real-time vibration plane of the strut is determined. Inertia is introduced to solve the dynamic bending moment on the active section of the multi-dimensional vibration damper, and then the stress distribution on the active section is obtained. The multi-dimensional active vibration control system is adopted to improve the stability and reliability of the active vibration control system of wind tunnel model, extend the service life of piezoelectric ceramic actuator, and ensure the quality of wind tunnel test data and the safety of wind tunnel test.

Abstract: A kind of sawtooth structure with reversed cutting function and its drill series are presented in this invention. This invention is suitable for drilling low-damage holes on carbon fiber reinforced polymers (CFRP). The sawtooth structure is comprised of sawteeth and grooves located on the cutting edges of drill. And the sawtooth structure is helically arranged with a specific helix angle around the axis of the drill. It can be classified as the left-hand helix sawtooth structure and the right-hand helix sawtooth structure based on the helix angle value. The bottom edges of the left-hand helix sawtooth structure are the cutting edges, and the rake angles are positive; while the top edges of the right-hand helix sawtooth are the cutting edge with the positive rake angles. The sawtooth structure can be applied to various drilling tools, which proves to be universal. And it can effectively reduce delamination at both hole entrance and hole exit as well as burrs defects.

Abstract: A comprehensive performance evaluation method for the CNC machine tools based on an improved pull-off method belongs to the technical field of performance evaluation of CNC machine tools. A linear proportional method is used to standardize the performance index data of machine tool. The entropy weight method and mean variance method are used to determine the two objective weights of each level of indicator. Based on the principle of vector A comprehensive evaluation of three-level index is obtained from the linear weighted evaluation function. Finally, a similar method was used to calculate the comprehensive evaluation of a large system layer by layer. The present invention is used for the comprehensive performance evaluation of various CNC machine tools and also for a lateral comparison of specific performance of different machine tools, providing a scientific and possible evaluation method and process for the comprehensive performance evaluation of machine tools.