Dalian University of Technology

Fuji Wang

Wei Liu

Zhenyuan Jia

Jianwei Ma

Yu Bai

Meng Zhao

Rao Fu

Guangzhi He

Siyu Chen

Ning Zhang

Boyu Zhang

Dening Song

Bin Niu

Chunling He

De Cheng

Chong Zhang

Jiaxuan Hao

Shen Qiu

Dekun Yin

Hongwei Zhao

Zegang Wang

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.

Hole making tool for aramid fiber-reinforced plastic and design method thereof

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

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

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

A vertical-edge double-step sawtooth cutter for preparing high-quality holes of composite material and thereof hybrid stack structure, and has three parts which are a major cutting edge region A, a minor cutting edge region B and a shank region C. The minor cutting edge region B comprises a step vertical-edge region D and a sawtooth cutting region E. This has the step structure and the sawtooth structure which is distributed in the first step, has a recutting function at the inlet and a reverse cutting function at the outlet in the direction opposite to the main cutting motion. The cutter has the vertical edge structure distributed in the second step, and the angle of the second step is a negative value, thereby realizing chip breaking and crushing, reducing scratch to the upper-layer composite material and metal hole walls.

Vertical-edge double-step sawtooth cutter for preparing high-quality holes of composite material and hybrid stack structure thereof

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Dalian, China

Fuji Wang