A tool orientation smoothing method based on machine rotary axes for five-axis machining with ball end cutters

2017 ◽  
Vol 92 (9-12) ◽  
pp. 3615-3625 ◽  
Author(s):  
Rufeng Xu ◽  
Xiang Cheng ◽  
Guangming Zheng ◽  
Zhitong Chen
Keyword(s):  
Smoothing Method ◽  
Tool Orientation ◽  
Rotary Axes ◽  
Five Axis

Studies on the Exchangeability of Different APT Interpreters for 5-Axis Machine Tool Applications

2013 ◽  
Vol 284-287 ◽  
pp. 1924-1928 ◽  
Author(s):  
Hsin Yu Cheng ◽  
Yung Chou Kao
Keyword(s):  
Machine Tool ◽  
Virtual Machine ◽  
Machine Tools ◽  
Contact Point ◽  
Tool Orientation ◽  
Inclined Plane ◽  
Rotary Axes ◽  
Virtual Machine Tool ◽  
Nc Program ◽  
Five Axis

Generally, the NC format is the description for the positioning and/or the movement of its linear and rotary axes. As the multi-axis machine tools have a variety of configurations, their NC codes are not exchangeable. This issue leads to some inconvenience and confounding in the manufacturing processing schedule. Furthermore, when the specifications of tool such as length, diameter or shape are reset, the NC program must be regenerated accordingly. That is to say, the exchangeability of NC program among different five-axis machine configurations is an important issue in making better usage of industrial five-axis machine tools for efficient applications. An APT program records the tool path, tool vector and cutting information, etc. In particular, the recent development of APT format can provide the capability recording the motion posture of the tool such as the tool orientation, the position and its normal vector of the tool contact point. Therefore, it can solve the problems of the exchangeability for the different machine tools as well as the online resetting of tool specifications, even the tool posture. In this paper, a new method was proposed to interpret the APT code into tool movement data including toolpath, location, tool orientation, the contact point and its contact vector, etc., which can be applied to the conversion of different NC codes, or be connected to the controller of the machine tool so as to proceed the interpolation calculation for directly machining control. Moreover, the application scope can be extended to the verification of machining and to drive a virtual machine tool for previewing. Since the APT format varies according to different CAD/CAM systems, a common intermediate interchange standard (CMIS) was proposed, designed and verified in this paper as a feasible solution for the exchangeability of different APT formats. The process of the proposed method includes interpreting a variety of APT program into a common standard format, and then transforming this intermediate standard code into various NC programs for the corresponding machine configurations. An example was used to demonstrate how to convert an APT generated by CATIA software into intermediate code for a Table-Table five-axis machine tool with two rotary axes attached on table (XYZAC configuration). As the APT contains the definition of inclined plane, so the homogeneous coordinate transformation was adopted to transform the coordinate system of the inclined plane into the work coordinate system; it was further transformed into the corresponding NC program via an inverse kinematics transformation. This example has shown the feasibility of the method proposed. Moreover, the research can be applied not only to the exchangeability of different APT format but also to the other related applications such as the verification of machining error and the drive of virtual machine tool.

A Universal Postprocessor of General Table-Tilting Type of Five-Axis Machine Tools Without Rotational Tool Center Point Function for Actual NC Code Generation

2018 ◽  
Author(s):  
Guoqiang Fu ◽  
Hongli Gao ◽  
Tengda Gu
Keyword(s):  
Code Generation ◽  
Machine Tools ◽  
Kinematic Chain ◽  
Rotary Axes ◽  
Nc Code ◽  
Rotation Axes ◽  
Cutting Test ◽  
Center Point ◽  
Rtcp Function ◽  
Five Axis

The postprocessor is essential for machining with five-axis machine tools. This paper develops one universal postprocessor for table-tilting type of five-axis machine tools without rotational tool center point (RTCP) function. Firstly, positions of two rotary axes and the workpiece in the machine coordinate system (MCS) are introduced into the kinematic chain of the five-axis machine tools. The uniform product of exponential (POE) formula of the tool relative to the workpiece is established to obtain the universal forward kinematics. On this basis, the postprocessor of table-tilting type of five-axis machine tools is developed. The calculation of rotation angles of rotation axes is proposed in details, including the calculation of double solutions, the determination of rotation angles of C-axis and the selection principle of the shortest path of rotation angles. Movements of linear axes are calculated with rotation angles of rotary axes. The generated movements of all axes are actual positions of all axes relative to their zero positions, which can be used for machining directly. The postprocessor does not rely on RTCP function with positions of rotary axes and the workpiece in MCS. Finally, cutting test in VERICUT and real cutting experiments on SmartCNC500_DRTD five-axis machine tool are carried out to verify the effectiveness of the proposed postprocessor.

An Analytical C3 Continuous Local Corner Smoothing Algorithm for Four-Axis Computer Numerical Control Machine Tools

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Qin Hu ◽  
Youping Chen ◽  
Jixiang Yang ◽  
Dailin Zhang
Keyword(s):  
Machine Tools ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Smoothing Algorithm ◽  
Linear Motion ◽  
Tool Orientation ◽  
Cnc Machine ◽  
B Splines ◽  
Rotary Axes ◽  
Tip Position

Linear motion commands of multi-axis computer numerical control (CNC) machine tools need to be smoothed at the transition corners, because the velocity discontinuities at corners can result in fluctuations on machine tool motions and lead to poor surface quality. However, no research has been reported on local corner smoothing algorithm for four-axis CNC machine tools with two rotary axes by considering their special kinematic characteristics. To this end, this paper proposes an analytical C3 continuous local corner smoothing algorithm for four-axis CNC machines with two rotary axes. After coordinates transformation, the tool tip positions and tool orientations are smoothed by locally inserting specially designed three-dimensional (3D) quintic B-splines and one-dimensional (1D) quintic B-splines into the corners between linear motion segments, respectively. The smoothing algorithm guarantees C3 continuity of the tool tip position and C3 continuous synchronization of the tool orientation related to the tool tip position, through analytically evaluating control points of the inserted microsplines. The maximum error tolerances of the tool tip position and tool orientation are mathematically constrained. Experiments on an in-house developed four-axis machine verify the efficacy of the proposed algorithm, where maximal errors caused by the local corner smoothing algorithm are constrained, the synchronization of the tool orientation and the tool tip position are achieved, and the proposed C3 continuous corner smoothing algorithm has lower jerk and jounce but higher tracking and contour accuracy than C2 continuous algorithm.

scholarly journals Geometric Error Identification and Analysis of Rotary Axes on Five-Axis Machine Tool Based on Precision Balls

2019 ◽  
Vol 10 (1) ◽  
pp. 100 ◽  
Author(s):  
Chuandong Li ◽  
Xianli Liu ◽  
Rongyi Li ◽  
Shi Wu ◽  
Houwang Song
Keyword(s):  
Machine Tool ◽  
Error Term ◽  
Geometric Error ◽  
Contact Method ◽  
Error Measurement ◽  
Spatial Error ◽  
Term Operation ◽  
Rotary Axes ◽  
Geometric Error Measurement ◽  
Five Axis

This paper presents the design of a precise “ball-column” device to efficiently and accurately measure the geometric error terms of both rotary axes of the five-axis machine tool. A geometric error measurement method of spherical contact was proposed based on the influence of the geometric error term from a five-axis machine tool rotating axis on the integrated geometric error of the machine tool. A multiple degree of freedom, step-by-step contact method based on on-machine measure for measuring the spherical center point is proposed, and the solution formula of each geometric error term of the rotating axis is established, respectively. This method can identify 12 geometric errors based on the influence of one rotating axis on another rotating axis after long term operation. The spatial error field of the five-axis machine tool was constructed by analyzing the error law of the two rotating axes of machine tools based on various positions and postures. Finally, after the comparison of the experiment, the results showed that the accuracy of the developed error measurement device reached 91.8% and the detection time was as short as 30–40 min.

scholarly journals Collision-free tool orientation optimization in five-axis machining of bladed disk

2015 ◽  
Vol 2 (4) ◽  
pp. 197-205 ◽  
Author(s):  
Li Chen ◽  
Ke Xu ◽  
Kai Tang
Keyword(s):  
Tool Path ◽  
Poor Quality ◽  
Reference Plane ◽  
Jet Engines ◽  
Tool Orientation ◽  
Worst Case ◽  
Machine Vibration ◽  
Tool Positioning ◽  
Bladed Disk ◽  
Five Axis

Abstract Bladed disk (BLISK) is a vital part in jet engines with a complicated shape which is exclusively machined on a five-axis machine and requires high accuracy of machining. Poor quality of tool orientation (e.g., false tool positioning and unsmooth tool orientation transition) during the five-axis machining may cause collision and machine vibration, which will debase the machining quality and in the worst case sabotage the BLISK. This paper presents a reference plane based algorithm to generate a set of smoothly aligned tool orientations along a tool path. The proposed method guarantees that no collision would occur anywhere along the tool path, and the overall smoothness is globally optimized. A preliminary simulation verification of the proposed algorithm is conducted on a BLISK model and the tool orientation generated is found to be stable, smooth, and well-formed.

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