Determination of Geometry-Based Errors for Interpolated Tool Paths in Five-Axis Surface Machining

2005 ◽  
Vol 127 (1) ◽  
pp. 60-67 ◽  
Author(s):  
O. Remus Tutunea-Fatan ◽  
Hsi-Yung Feng
Keyword(s):  
Tool Path ◽  
Kinematic Chain ◽  
Cnc Machining ◽  
Numerical Control ◽  
Free Form ◽  
Cnc Machine ◽  
Surface Geometry ◽  
Contact Points ◽  
Five Axis ◽  
Deviation Method

Five-axis computer numerical control (CNC) machining is characterized with a multitude of errors. Among them an important component comes from the computer-aided manufacturing software known as the geometry-based errors. A new and accurate method to determine these errors is presented in this paper as opposed to the conventional chordal deviation method. The present method allows establishing the exact linearly interpolated tool positions between two cutter contact points on a given tool path, based on the inverse kinematics analysis of the machine tool. A generic procedure has been developed to ensure wide applicability of the proposed method. Analytical derivation of the geometry-based errors provides insights regarding the origin of these errors and their affecting parameters. Due to the highly non-linear characteristics of the problem, analytical solutions can only be obtained for simple surface geometry. Numerical computation is able to determine the errors for general surface shapes but it would be difficult to uncover further insightful information from the calculated error values. Besides the local surface geometry, the configuration of the kinematic chain of the CNC machine has been found to be the primary factor controlling the resulting value and type of the geometry-based errors. Implementations with a typical complex free-form surface demonstrated that the conventional chordal deviation method was not reliable and could significantly underestimate the geometry-based errors.

Adaptive Tool Path Planning Strategy for 5-Axis CNC Machining of Free Form Surfaces

2019 ◽  
Author(s):  
Hrishikesh Mane ◽  
S. S. Pande
Keyword(s):  
Tool Path ◽  
Cnc Machining ◽  
Memory Storage ◽  
Free Form ◽  
Cnc Machine ◽  
Planning Strategy ◽  
Part Quality ◽  
Tool Paths ◽  
Path Topology ◽  
Free Form Surfaces

Abstract This paper presents a curvature based adaptive iso-parametric strategy for the efficient machining of free form surfaces on 5-axis CNC machine using the flat end mill tool. One iso-parametric boundary of the surface is selected as the initial tool path. Set of cutter contact (CC) points are chosen adaptively on the initial tool path considering desired profile tolerance. Adjacent iso-parametric tool paths are computed adaptively based on the scallop height constraint unlike the traditional iso-parametric approach. The path topology is post-processed to generate the part program for 5-axis CNC machine in ISO format. The system was rigorously tested for various case studies by comparing the results with the traditional 5-axis iso-parametric tool path strategy, iso-scallop strategy and iso-planar strategy of a commercial software. Our system was found to generate efficient tool paths in terms of part quality, productivity and memory storage compared to the conventional strategies.

Proposal of a machining test to evaluate dynamic synchronization error of rotary and linear axes with reversal of rotation direction

2021 ◽  
pp. 1-16
Author(s):  
Qingzhao Li ◽  
Soichi Ibaraki ◽  
Wei Wang
Keyword(s):  
Machine Tool ◽  
Coordinate System ◽  
Numerical Control ◽  
Synchronization Error ◽  
Free Form ◽  
Contour Error ◽  
Surface Geometry ◽  
Rotation Direction ◽  
Machining Test ◽  
Five Axis

Abstract The five-axis machining of a free-form surface often contains the reversal of a rotary axis' rotation direction with linear axis synchronized with it. This paper proposes a machining test to quantitatively evaluate the influence of the reversal of rotation direction on the surface geometry. In the five-axis machining, the trajectory of tool position and orientation is firstly given in the workpiece coordinate system by the CAM (Computer-aided Manufacturing) software, and the CNC (Computerized Numerical Control) system converts it to the machine coordinate system to calculate command trajectories. This paper clarifies that the tool path smoothing in the machine coordinate system can potentially cause a large contour error because of the dynamic synchronization error of rotary and linear axes. Although some academic works in the literature presented the smoothing in the workpiece coordinate system, many commercial CNC systems still employ the smoothing in the machine coordinate system, partly because machine tool users or makers do not clearly see how significant this influence can be on the machining accuracy. The proposed machining test enables a user to quantitatively evaluate it. The machining experiment shows that the geometric error of the finished test piece was as large as 0.16 mm under the conventional smoothing in a commercial CNC system, which can be significantly larger than the influence of other typical geometric errors of a five-axis machine tool. This paper shows, by numerical simulation, that the smoothing in the workpiece coordinate system can completely eliminate this contour error.

Free-Form Surface Five-Axis Machining G-Code Automatic Generation System Based on Path Messages for the Different CNC System

2011 ◽  
Vol 55-57 ◽  
pp. 1441-1446
Author(s):  
Shu Kun Cao ◽  
Jia Jia ◽  
Wei Wei Song ◽  
Kai Feng Song ◽  
Jie Lv
Keyword(s):  
Control System ◽  
Tool Path ◽  
Automatic Generation ◽  
Numerical Control ◽  
Free Form ◽  
Processing Route ◽  
Numerical Control System ◽  
G Code ◽  
Free Form Surface ◽  
Five Axis

For the free-form surface 5-axis computer numerical control processing field, we can obtain the processing route information according to the secondary development of UG , it also based on the free surface 5-axis numerical control machining tool path and synchronization of posture multi-objective optimization algorithms, then develops a software module according to the analysis comparison of features and programming instructions of the Fanuc and Siemens numerical control system, This module can be realized according to the information from the path for the two numerical control system, this module generates the proper or absolute matching G-code, it also can generate the automatic G-code for many different numerical control system .

A Real-Time C3 Continuous Local Corner Smoothing and Interpolation Algorithm for CNC Machine Tools

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Qin Hu ◽  
Youping Chen ◽  
Xiaoliang Jin ◽  
Jixiang Yang
Keyword(s):  
Real Time ◽  
Machine Tools ◽  
Tool Path ◽  
Control Period ◽  
Cnc Machining ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Interpolation Algorithm ◽  
Cnc Machine ◽  
Highly Nonlinear

Linear tool path segments of computer numerical control (CNC) machine tools need to be smoothed and interpolated in order to guarantee continuous and steady machining. However, because of the highly nonlinear relation between arc lengths and spline parameters, it is difficult to develop algorithms to simultaneously achieve real-time corner smoothing and interpolation with high-order continuity, although it is important to guarantee both high calculation efficiency and good dynamic performance of high-speed CNC machining. This paper develops a computationally efficient real-time corner smoothing and interpolation algorithm with C3 continuous feature. The corners at the junction of linear segments are smoothed by inserting Pythagorean-hodograph (PH) splines under the constraints of user-defined tolerance limits. Analytical solutions of the arc length and curvature of the smoothed tool path are obtained by evaluating a polynomial function of the spline parameter. The smoothed tool path is interpolated in real time with continuous and peak-constrained jerk. Simulations and experimental results show that the proposed tool path smoothing and interpolation algorithm can be executed in real time with 0.5 ms control period. Acceleration and jerk continuity of each axis are achieved along the tool path. Comparisons with existing corner smoothing algorithms show that the proposed method has lower jerk than existing C2 algorithms and the real-time interpolation algorithms based on the Taylor series expansion.

Research on Path Optimization Technology for Free-Form Surface Five-Axis NC Machining

2012 ◽  
Vol 443-444 ◽  
pp. 202-208 ◽  
Author(s):  
Shu Kun Cao ◽  
Li Song ◽  
Ke Dong ◽  
Kai Feng Song ◽  
Zhi Ming Sui
Keyword(s):  
Tool Path ◽  
Simple Calculation ◽  
Nc Machining ◽  
Cnc Machining ◽  
Path Optimization ◽  
Free Form ◽  
Surface Boundary ◽  
Scallop Height ◽  
Free Form Surface ◽  
Five Axis

In view of all sorts of questions existing in CNC machining, such as machining vibration, so proposed a new method of free-form surface NC machining path optimization based on constant scallop height. This method first discrete surface boundary into the knife touch point based on the maximum tolerance, then in accordance with the maximum allowable scallop height generates circular trajectory with the same scallop, and finally connects adjacent curve path using the diagonal to achieve a continuous cutting scallop height tool path. This method can reduce the number of tools cut in and out parts, reduce the processing vibration and tool wear, and the surface processed has the same precision. This method has simple calculation, suitable for free-form surface of CNC highspeed and precision machining.

Adaptive spiral tool path generation for computer numerical control machining using point cloud

2021 ◽  
pp. 095440622199007
Author(s):  
Mandeep Dhanda ◽  
Aman Kukreja ◽  
SS Pande
Keyword(s):  
Tool Path ◽  
Cnc Machining ◽  
Numerical Control ◽  
Numerical Control Machining ◽  
Form Errors ◽  
Spiral Tool Path ◽  
Novel Method ◽  
Mesh Grid ◽  
Cloud Of Points ◽  
Cam Software

This paper reports a novel method to generate adaptive spiral tool path for the CNC machining of complex sculptured surface represented in the form of cloud of points without the need for surface fitting. The algorithm initially uses uniform 2 D circular mesh-grid to compute the cutter location (CL) points by applying the tool inverse offset method (IOM). These CL points are refined adaptively till the surface form errors converge below the prescribed tolerance limits in both circumferential and radial directions. They are further refined to eliminate the redundancy in machining and generate optimum region wise tool path to minimize the tool lifts. The NC part programs generated by our algorithm were widely tested for different case studies using the commercial CNC simulator as well as by the actual machining trial. Finally, a comparative study was done between our developed system and the commercial CAM software. The results showed that our system is more efficient and robust in terms of the obtained surface quality, productivity, and memory requirement.

scholarly journals Study of Machining of Gears with Regular and Modified Outline Using CNC Machine Tools

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2913
Author(s):  
Rafał Gołębski ◽  
Piotr Boral
Keyword(s):  
Machine Tools ◽  
Coordinate Measuring Machine ◽  
Optical Microscope ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Milling ◽  
Cnc Machine ◽  
Cylindrical Gears ◽  
Measuring Machine ◽  
Five Axis

Classic methods of machining cylindrical gears, such as hobbing or circumferential chiseling, require the use of expensive special machine tools and dedicated tools, which makes production unprofitable, especially in small and medium series. Today, special attention is paid to the technology of making gears using universal CNC (computer numerical control) machine tools with standard cheap tools. On the basis of the presented mathematical model, a software was developed to generate a code that controls a machine tool for machining cylindrical gears with straight and modified tooth line using the multipass method. Made of steel 16MnCr5, gear wheels with a straight tooth line and with a longitudinally modified convex-convex tooth line were machined on a five-axis CNC milling machine DMG MORI CMX50U, using solid carbide milling cutters (cylindrical and ball end) for processing. The manufactured gears were inspected on a ZEISS coordinate measuring machine, using the software Gear Pro Involute. The conformity of the outline, the tooth line, and the gear pitch were assessed. The side surfaces of the teeth after machining according to the planned strategy were also assessed; the tests were carried out using the optical microscope Alicona Infinite Focus G5 and the contact profilographometer Taylor Hobson, Talysurf 120. The presented method is able to provide a very good quality of machined gears in relation to competing methods. The great advantage of this method is the use of a tool that is not geometrically related to the shape of the machined gear profile, which allows the production of cylindrical gears with a tooth and profile line other than the standard.

A Novel Method for Automated Tool Path Optimisation for CNC Machining Operations

2010 ◽  
Vol 166-167 ◽  
pp. 357-362
Author(s):  
Shahed Shojaeipour
Keyword(s):  
Tool Path ◽  
Target Location ◽  
Imaging System ◽  
Optimal Path ◽  
Digital Camera ◽  
Basic Program ◽  
Cnc Machining ◽  
Cnc Machine ◽  
Current Location ◽  
Tool Diameter

In this article, a new method for rapid tool movement in CNC machines is presented. Firstly, a single digital camera, installed on the Z-axis, captures the image of the workpiece on the work table. Image processing techniques, implemented using MATLAB, are then used to convert the image into a binary black and white image. This allows the locations of protruding edge sections on the workpiece, which could impede tool movement, to be identified. Quadtree decomposition is then performed on the binary image, and possible paths from the tool current location to its target location are found. These paths are then analysed based on the tool diameter clearance and the distance to the goal, and the shortest path with sufficient tool clearance is selected. A Visual Basic program then converts the selected path into G-code commands that provides instructions to the CNC machine tool such that this path is followed. With this method, the workpiece fixture location would not have to be precise as the imaging system would be able to automatically identify the target location with respect to the tool current location, along with the optimal path to reach it.

Tool Path Generation for Five-Axis Controlled Machining of Free-Form Surface Using Barrel Tool: Control of Contact Point on Cutting Edge

2020 ◽  
Author(s):  
Tomonobu Suzuki ◽  
Koichi Morishige
Keyword(s):  
Tool Path ◽  
Contact Point ◽  
Cutting Edge ◽  
Free Form ◽  
End Mill ◽  
Ball End Mill ◽  
Surface Machining ◽  
Free Form Surface ◽  
The Cost ◽  
Five Axis

Abstract This study aimed to improve the efficiency of free-form surface machining by using a five-axis controlled machine tool and a barrel tool. The barrel tool has cutting edges, with curvature smaller than the radius, increasing the pick feed width compared with a conventional ball end mill of the same tool radius. As a result, the machining efficiency can be improved; however, the cost of the barrel tool is high and difficult to reground. In this study, a method to obtain the cutting points that make the cusp height below the target value is proposed. Moreover, a method to improve the tool life by continuously and uniformly changing the contact point on the cutting edge is proposed. The usefulness of the developed method is confirmed through machining simulations.

Application of Convex Hull for Tool Interference Avoidance in 5-Axis CNC Machining

1996 ◽  
Author(s):  
Yuan-Shin Lee ◽  
Tien-Chien Chang
Keyword(s):  
Convex Hull ◽  
Tool Path ◽  
Correction Method ◽  
Nc Machining ◽  
Cnc Machining ◽  
Free Form ◽  
Interference Avoidance ◽  
Tool Interference ◽  
Free Form Surface ◽  
Free Form Surfaces

Abstract In this paper, a methodology of applying convex hull property in solving the tool interference problem is presented for 5-axis NC machining of free-form surfaces. Instead of exhausted point-by-point checking for possible tool interference, a quick checking can be done by using the convex hull constructed from the control polygon of free-form surface modeling. Global tool interference in 5-axis NC machining is detected using the convex hull of the free-form surface. A correction method for removing tool interference has also been developed to generate correct tool path for 5-axis NC machining. The inter-surface tool interference can be avoided by using the developed technique.

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