Dalian University of Technology

Jianwei Ma

Wei Liu

Zhenyuan Jia

Fuji Wang

Yu Bai

Rao Fu

Guangzhi He

Dening Song

Siyu Chen

Meng Zhao

Likun Si

Boyu Zhang

Ning Zhang

Xin Ma

Xiao Lu

Wenwen Jiang

Xiaoxuan Zhao

Jiaxuan Hao

Shen Qiu

Bin Niu

Xiao Li

Chunling He

Yi Pan

Multi-adaptive fast loading attached air-cooled dust removal equipment is disclosed. The equipment is mainly composed of five parts: a spindle clamping mechanism, a link mechanism, a bearing connecting mechanism, an axial telescopic mechanism and a dust treatment mechanism. The equipment is connected with a tool holder through an axial connecting mechanism and installed on a machine tool. The axial telescopic mechanism forms a cavity with a processing surface, the gas flow generated by a negative pressure vacuum cleaner forms negative pressure in the cavity, and the telescopic mechanism is fixed to a machine tool spindle housing through the link mechanism to prevent the rotation of the spindle from driving the equipment to rotate and interfere with a workpiece, finally realizing rapid collection and treatment of chips.

Multi-adaptive fast loading attached air-cooled dust removal equipment

The present invention belongs to the technical field of machining of fiber-reinforced composites, and relates to a method for measuring distribution of a thrust force during drilling of a unidirectional composite along with a fiber cutting angle. The method includes: cutting the surface a composite sample piece to form a groove; drilling on an existing experimental platform for measuring a thrust force during drilling, where a through hole obtained through the drilling is required to intersect with the groove; obtaining a curve of the thrust force during drilling, comparing the curve with a conventional curve of the thrust force to find a mutation point, and determining the mutation point, namely a fiber cutting angle at the groove; and calculating fluctuation periods of the thrust force according to machining parameters to reckon the distribution of the thrust force along with the fiber cutting angle in all the periods.

Method for measuring distribution of thrust force during drilling of unidirectional composite

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.

Toolpath topology design method based on vector field in sub-regional processing for curved surface

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. The invented method can effectively make a balance between the feed motion stability and efficiency in five-axis machining, and possesses a high computational efficiency and a good real-time capability.

Feedrate scheduling method for five-axis dual-spline curve interpolation

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. Then, by traversing all the acquired images using the proposed method, we can obtain the six-dimensional motion contour; and the six-dimensional contouring error caused by the imperfect machine interpolation can be computed by comparing the measured contour with the nominal one. The method enhances the measurable dimension of the vision technology through the monocular vision pose algorithm in combination with a datum transformation method, and realizes the six-dimensional measurement of large-range arbitrary contouring error of the CNC machine tool under the small field of view.

Monocular vision six-dimensional measurement method for high-dynamic large-range arbitrary contouring error of CNC machine tool

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. Finally, calculate the three-axis control signals according to the geometry of the equivalent plane, thus realizing the three-axis contouring-error control by using the well-studied two-axis contour controllers.

Equivalent-plane cross-coupling control method

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. The series of drilling tools include the double point angle drill, the twist drill and the stepped drill all of which have the sawtooth structure on the cutting edges. These series of drilling tools can achieve the CFRP holes with minimum drilling defects. The drilling performance of the tools is improved to a great extent, the tool life is extended and the costs are reduced.

Sawtooth structure with reversed cutting function and its drill series

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Dalian, China

Jianwei Ma