Effects of Position and Orientation Errors of Linear and Rotary Axis Average Lines of Five-Axis Controlled Machining Centre Onto its Motion Errors in Testing Method With Truncated Square Pyramid

2020 ◽  
Author(s):  
Koichi Kikkawa ◽  
Naoki Mori ◽  
Yoshio Mizugaki ◽  
Keisuke Ozaki
Keyword(s):  
Motion Error ◽  
Rotary Axis ◽  
Tool Paths ◽  
Squareness Error ◽  
Squareness Errors ◽  
Position And Orientation ◽  
Tool Motion ◽  
Tool Position ◽  
Five Axis ◽  
Flatness Error

Abstract In this paper, ‘position and orientation errors of linear and rotary axis average lines’ is newly named ‘geometrical mechanism deviations.’ This paper presents suggestive simulation results of tool motion error caused by geometrical mechanism deviations of a five-axis controlled machine tool. Firstly, there were assumed seven geometrical mechanism deviations consisting of three positional and four angular deviations. As positional deviations, the error of intersection is set to be 0.01 [mm] off-centre, and the squareness errors of the cross axes as angular deviations are 0.01 [°]. Secondly, there was simulated theoretically the shape of machined pyramidal surface according to the virtual cutter movement of a flat end mill along contouring tool paths. Thirdly, the correspondence of geometrical mechanism deviations and simulated flatness error was analysed and found to have two regularities. One of the two indicated that four pyramidal surfaces wave similarly with left half surface up and right half surface down. The other indicated that the centre of a specific pyramidal surface should be concave in the cases of squareness error between B-Z axes. Through the analysis of grouped flatness error, specific geometrical mechanism deviations seem to cause a particular deformation of pyramidal surface due to the misalignment of tool position and orientation.

Path Planning for Motion Control of Hexapod Machines

2001 ◽  
Author(s):  
Zhiming Ji ◽  
Zhenqun Li
Keyword(s):  
Path Planning ◽  
Machine Tools ◽  
Tool Path ◽  
Local Planning ◽  
Tool Path Planning ◽  
Tool Paths ◽  
Condition Optimization ◽  
Planning Methods ◽  
Tool Motion ◽  
Five Axis

Abstract The dramatic departure in structure of the hexapod machine tools from the traditional five-axis machines leads to the question: can the planning and control methods for the traditional CNC machines be used for the hexapod machine tools? We studied several tool motion characteristics, such as Jocabian matrices, path tracking errors and the extra degree of freedom (e-DOF), and found that the traditional five-axis planning methods cannot take into consideration of the kinematics performance variation and the e-DOF in a hexapod. A kinematics-based tool path planning scheme for the hexapods is therefore proposed. It combines the traditional tool path planning with the kinematic condition optimization. The optimization is a two-step process. First a high accuracy zone of the workspace is identified globally for the placement of the part. Then a set of 5-DOF tool paths is generated and extended to a set of 6-DOF tool paths based on the local planning of e-DOF. Finally the relationship between the e-DOF and the stiffness of the Hexapods, another factor in the use of e-DOF, are discussed.

A Five-Axis Machining Error Simulator for Rotary-Axis Geometric Errors Using Commercial Machining Simulation Software

2017 ◽  
Vol 11 (2) ◽  
pp. 179-187 ◽  
Author(s):  
Soichi Ibaraki ◽  
◽  
Ibuki Yoshida ◽  
Keyword(s):  
Kinematic Model ◽  
Simulation Software ◽  
Geometric Errors ◽  
Machining Simulation ◽  
Machining Error ◽  
Rotary Axis ◽  
Tool Paths ◽  
Numerical Fitting ◽  
Machining Test ◽  
Five Axis

This paper presents a simulator that graphically presents the influence of rotary-axis geometric errors on the geometry of a finished workpiece. Commercial machining simulation software is employed for application to arbitrary five-axis tool paths. A five-axis kinematic model is implemented with the simulator to calculate the influence of rotary-axis geometric errors. The machining error simulation is demonstrated for 1) the cone frustum machining test described in ISO 10791-7:2015 [1], and 2) the pyramid-shaped machining test proposed by some of the authors in [2]. The influences of the possible geometric errors are simulated in advance. By comparing the measured geometry of the finished workpiece to the simulated profiles, major error causes are identified without numerical fitting to the machine’s kinematic model.

Evaluation Method for Behavior of Rotary Axis Around Motion Direction Changing

2017 ◽  
Vol 11 (2) ◽  
pp. 171-178 ◽  
Author(s):  
Tadahiro Nishiguchi ◽  
◽  
Shogo Hasegawa ◽  
Ryuta Sato ◽  
Keiichi Shirase ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Motion Trajectory ◽  
Machined Surface ◽  
Motion Direction ◽  
Motion Error ◽  
Rotary Axes ◽  
Rotary Axis ◽  
Synchronous Motion ◽  
Five Axis

Several methods for evaluating the motion accuracy of the rotary axes in five-axis machining centers have been proposed till date. As it is known that particular motion errors exist around the motion direction changing points, it is important to evaluate the behavior of the rotary axes around these points. However, the influence of the motion error in the translational axes is included in the conventional evaluation results, as the translational axes reverse at the motion direction changing points about the rotary axes. In this study, an evaluation method which can assess the behavior of a rotary axis around motion direction changes by synchronous motion of translational and rotary axes is proposed. In this method, the direction of translational axes does not change when the motion direction of a rotary axis changes. A measurement test and actual cutting tests are carried out to clarify the influence of the behaviors of rotary axes on the motion trajectory and machined surface, caused by the change in the motion direction of the rotary axis. Simulations of the motion are also carried out to discuss the causes of inaccuracy.

The Stiffness Field Modeling and Analyzing of Tool Position and Orientation of Five-Axis NC Machining System

2013 ◽  
Vol 589-590 ◽  
pp. 692-695
Author(s):  
Shi Wu ◽  
Da Qu ◽  
Xian Li Liu ◽  
Hong Xu ◽  
Zheng Chun Wang
Keyword(s):  
Virtual Work ◽  
Analytical Calculation ◽  
Complex Surface ◽  
Field Modeling ◽  
Machining System ◽  
Nc Machine ◽  
Position And Orientation ◽  
Tool Position ◽  
Composite Stiffness ◽  
Five Axis

The transformation of tool position and orientation has impact on processing performance of the system when processing complex surface. Five-axis NC machine center was taken for example in this article. Semi-analytical calculation method was taken for stiffness field of system. Based on virtual-work principle, the composite stiffness field modeling of system was built by methods of Jacobian matrix, point transformation matrix and finite element, etc. For the key point of workpiece surface which is needed analyzed, 3D space force ellipsoid was introduced, composite stiffness field was modeled and composite stiffness performance of system was analyzed by force ellipsoid with different tool position and orientation. Guiding conclusion was obtained for following works by analyzing influence of tool position and orientation on stiffness performance.

The Research of Nonlinearity Error Control on Five-Axis Machining Post Processor

2011 ◽  
Vol 311-313 ◽  
pp. 2353-2357 ◽  
Author(s):  
Qing Chun Tang ◽  
Jun He ◽  
Lan Lan Gao ◽  
Yu Huo Lai ◽  
Xue Ming Fang
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Error Control ◽  
Estimation Method ◽  
Linear Interpolation ◽  
Nonlinearity Error ◽  
Motion Error ◽  
Nonlinear Error ◽  
Tool Motion ◽  
Five Axis

Abstract：This paper analyses the causes and effective estimation method of nonlinear error; By machine tool motion solution, established a five-axis machine tool BV100 motion transformation mathematical models, combined with linear interpolation principle established the error compensation and nonlinear motion error model of the machine tool .by VB language, developed nonlinear error compensation function of special post process; and through the impeller cutting experiment validate the processor is correct and practical.

Basic Research on Five-Axis NC Machining of Subdivision Surface

2010 ◽  
Vol 139-141 ◽  
pp. 1237-1240
Author(s):  
Hong Yuan ◽  
Xiao Li Lu ◽  
Rong Jing Hong
Keyword(s):  
Tool Path ◽  
Basic Research ◽  
Nc Machining ◽  
Normal Vector ◽  
Subdivision Surface ◽  
End Mill ◽  
Rough Machining ◽  
Position And Orientation ◽  
Tool Position ◽  
Five Axis

Basic research on five-axis NC machining of subdivision surface is presented. Research on Catmull-Clark subdivision surface, a method is presented by using computational geometry techniques to determine optimal tool position and orientation for 5-axis machining with torus end-mill: The normal vector of the subdivision surface vertex and the offset surface calculation are discussed firstly, then the rough machining model of subdivision surface is built and machined by using five-axis machining with the motion of the torus end-mill position and orientation according to the normal line of the surface. The tool position and orientation, cutting radius and tool path are calculated. Finally a computer simulation instantiation is given. This method improves the machining ability of subdivision surfaces.

Investigation of Motion Control of Liner Axes and a Rotary Axis Under Constant Feed Speed Vector at Milling Point With a Five-Axis Machining Center

2013 ◽  
Author(s):  
Yuma Maruyama ◽  
Takayuki Akai ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
Keiji Ogawa
Keyword(s):  
Surface Roughness ◽  
Present Report ◽  
Sudden Change ◽  
Machining Accuracy ◽  
Feed Speed ◽  
Motion Error ◽  
Rotary Axis ◽  
Machining Center ◽  
Five Axis ◽  
Cutting Point

Recently, a novel manufacturing technology has spread out with a five-axis machining center. It is especially important to keep the surface roughness on an entire machined surface constant. Thus, we proposed a novel method for maintaining a constant feed speed vector at the cutting point between the end-mill tool and the workpiece surface by controlling two linear axes and a rotary axis with a five-axis machining center. In the present report, we focused on machining the combined inner and outer radius curvature and investigating the influence of synchronous control error between the linear axes and rotary axis on the machining accuracy and surface roughness. As a result, we determined that it is possible to suppress sudden change in the synchronous motion error by accurately aligning the motion direction of the linear and rotary axes and the feed speed vector at milling point at the contact point of the inner and outer circles.

Linked Ball Bar for Flexible Motion Error Measurement for Machine Tools

2017 ◽  
Vol 11 (2) ◽  
pp. 188-196 ◽  
Author(s):  
Daisuke Kono ◽  
◽  
Fumiya Sakamoto ◽  
Iwao Yamaji
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Measurement Range ◽  
Motion Error ◽  
Ball Bar ◽  
Displacement Direction ◽  
The Difference ◽  
Tool Motion ◽  
Five Axis ◽  
Analytical Resolution

A measuring instrument, Linked Ball Bar (LBB), is developed to measure machine tool motion errors quickly, flexibly, and robustly. The LBB employs the concept of double ball bar (DBB) and measures the distance between two balls attached to the spindle and table. The problem of short measurement range, the drawback of the DBB, is solved using a link. The measurement accuracy of the LBB is investigated. The analytical resolution of displacement measurement using the LBB is under 30 nm when the displacement direction coincides with the sensitivity direction. The difference between the LBB and the laser interferometer is less than 1 μm in the center measurement range of 75 mm. The repeatability of the LBB is ±0.4 μm and is at the same level as the interferometer. The kinematic error of a five-axis machine tool is measured using the LBB to demonstrate its validity. The parallelism between the C-axis and Z-axis identified using the LBB agrees with the result measured using the cylindrical square. The difference between the LBB and the cylindrical square is about 10 μm/m at the maximum. The LBB can provide quick and flexible measurements of the motion errors of five-axis machine tools.

Defects Cause Analysis Generated by Five-Axis NC Machine Tool and Optimization

2014 ◽  
Vol 687-691 ◽  
pp. 353-358
Author(s):  
Jin Wei Fan ◽  
Hong Xia Yan ◽  
Yu Hang Tang ◽  
Yi Song
Keyword(s):  
Machine Tool ◽  
Motion Error ◽  
Nc Machine Tool ◽  
Analysis Theory ◽  
Great Responsibility ◽  
Nc Machine ◽  
Error Terms ◽  
Tool Motion ◽  
Multi Body ◽  
Five Axis

In view of defects-"chew cutting" generated by the five-axis nc machine tool in the process of machining the S sample, the machine tool motion error model is established based on multi-body system theory. After that,combining sensitivity analysis theory with the research of machine tool processing defect causes.Then find out the main error terms which take great responsibility of machining defects and optimize related motion components,to meet accuracy requirements before leaving the factory.

Investigation of Synchronous Accuracy of Dual Arm Motion of Industrial Robot

2012 ◽  
Vol 516 ◽  
pp. 234-239 ◽  
Author(s):  
Wei Wu ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama
Keyword(s):  
Rotational Motion ◽  
Manufacturing Systems ◽  
Industrial Robot ◽  
Circular Path ◽  
Stable Operation ◽  
Motion Error ◽  
Ball Rolling ◽  
Arm Motion ◽  
Five Axis ◽  
Dual Arm

Recently, new needs have emerged to control not only linear motion but also rotational motion in high-accuracy manufacturing fields. Many five-axis-controlled machining centres are therefore in use. However, one problem has been the difficulty of creating flexible manufacturing systems with methods based on the use of these machine tools. On the other hand, the industrial dual-arm robot has gained attention as a new way to achieve accurate linear and rotational motion in an attempt to control a working plate like a machine tool table. In the present report, a cooperating dual-arm motion is demonstrated to make it feasible to perform stable operation control, such as controlling the working plate to keep a ball rolling around a circular path on it. As a result, we investigated the influence of each axis motion error on a ball-rolling path.

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