Geometric deviation reduction method for interpolated toolpath in five-axis flank milling of the S-shaped test piece

Geometric deviation, defined as the distance between the designed surface and the machined surface, is an important component of machining errors in five-axis flank milling of the S-shaped test piece. Since the interpolated toolpath in practical machining process is the approximation of the theoretical toolpath, the geometric deviation caused by the interpolated toolpath appears. To overcome this problem, a novel geometric deviation reduction method is suggested in this study. First, the features of the S-shaped test piece are analyzed. Second, the theoretical toolpath is generated according to the designed surface and the cutter location data is obtained by discretizing the theoretical toolpath. The linear interpolation of the cutter location data is carried out to obtain the interpolated toolpath. Then, the geometric deviation is modeled by calculating the Hausdorff distance between the tool axis trajectory surface based on the interpolated toolpath and the offset surface of the designed surface. Finally, the geometric deviation is reduced by optimizing the cutter location data without inserting more cutter location points. The machining experiment is conducted to verify the effectiveness of the proposed method. The experimental results agree with the simulation results, and both of them indicate the geometric deviation on the machined surface reduces after optimization.

Precision Sculptured Surface CNC Machining Using Cutter Location Data

Industrial parts with sculptured surfaces are typically, manufactured with the use of CNC machining technology and CAM software to generate surface tool paths. To assess tool paths computed for 3-and 5-axis machining, the machining error is evaluated in advance referring to the parameter controlling the linearization of high-order curves, as well as the scallop yielded as a function of radial cutting engagement parameter. The two parameters responsible for the machining error are modeled and corresponding cutter location data for tool paths are utilized to compare actual trajectories with theoretical curves on a sculptured surface assessing thus the deviation when virtual tools are employed to maintain low cost; whilst ensuring high precision cutting. This operation is supported by applying a flexible automation code capable of computing the tool path; extracting its CL data; importing them to the CAD part and finally projecting them onto the part’s surface. For a given tolerance, heights from projected instances are computed for tool paths created by changing the parameters under a cutting strategy, towards the identification of the optimum tool path. To represent a global solution rough machining is also discussed prior to finish machining where the new proposals are mainly applied.

Path Generation for Robot Polishing System Based on Cutter Location Data

Polishing work is in most cases made by manual labour. It is an extremely laborious operation which demands a lot of time, so it is very expensive. This study aims at rationalizing such difficult polishing work by introducing a robot and CAD technology. Instead of the conventional complicated teaching process. A trajectory generator based on cutter location data generated from the postprocessor of a CAD system is discussed. To realize the smooth interpolation of the tool orientations, a quaternion interpolation algorithm between two CL data is proposed.

A New Compensation Method for Multi-Choice of a Five-Axis Machine with a Tilting Head

Postprocess capable of converting the cutter location data to machine control data is an important interface between the NC programming design and manufacture.Due to the fact that current research on multi-axis postprocess methods mostly deals with machine tool configurations whose linear and rotational movements are orthogonal, an efficient postprocess algorithm for the five-axis machine with a tilting head is presented in this paper.DMU 80P which is a five-axis machine with a tilting head is selected as an example.Its mechanism model is proposed in this paper according to the mechanism theory.The kinematics model is established using coordinate transformation,and the solution of this model is discussed.Based on these,a window-based post-processor with multi-choice function was developed by VS2010 language.Through the verification by the commercial solid cutting software VERICUT,the feasibility of the algorithm proposed is demonstrated.At last,a real impeller cutting experiment has been conducted and the result further verifies the correctness of the algorithm.

NURBS Curve Fitting Based on Arc Centripetal Parameterization for Tool Path Generation

NURBS curve fitting is used for tool path planning for sculptured surface NC machining. The cutter location data is parameterized by equal chord arc length parameterization, and Centripetal Parameterization is improved. It is not only more approach to curves nature equation in theory, but also closer to the interpolated curves in actual fitting. It is directly to reflect the curvature of curves of cutter location in NC machining.

A Five-Axis CNC Machine Postprocessor Based on Inverse Kinematics Transformation

This paper presents a postprocessor for five-axis milling machine that capable of converting CL (cutter location) data to machine control data (NC program). The proposed postprocessor method is based on inverse kinematics transformation and postprocessor module is programmed in Visual Basic language. The Deckel Maho DMU 50 eVoluion five-axis machine with two rotary axes (B and C) on the table is modeled and verified in software VERICUT® to validate the NC data generated by proposed postprocessor.

Design of a Cutting Point Control Algorithm for Five-Axis Machining

Five-axis machine tool with two additional rotary axes has been widely used in defense, aerospace and the consumer industries, and is an important process of precision manufacturing. Traditional five-axis program depends on the machine tool’s configuration and machining setting. This leads to inconvenience of reprogramming five-axis NC code for the end users. This paper proposes a cutting point control algorithm for five-axis machining. Although the commercial advanced controllers provide this function, they are very expensive and restricted to export. The developed algorithm can be embedded to the PC-based controller so that the specific cutter location data can be transformed and employed easily for different cutting tools. Verification using VERICUT solid cutting simulation software demonstrated the correctness of the generated cutter location data.

Creating a Multi-axis Machining Postprocessor

This paper focuses on the postprocessor creation process. When using standard commercially available postprocessors it is often very difficult to modify its internal source code, and it is a very complex process, in many cases even impossible, to implement the newly-developed functions. It is therefore very important to have a method for creating a postprocessor for any CAM system, which allows CL data (Cutter Location data) to be generated to a separate text file. The goal of our work is to verify the proposed method for creating a postprocessor. Postprocessor functions for multi-axis machiningare dealt with in this work. A file with CL data must be translated by the postprocessor into an NC program that has been customized for a specific production machine and its control system. The postprocessor is therefore verified by applications for machining free-form surfaces of complex parts, and by executing the NC programs that are generated on real machine tools. This is also presented here.

Solid Modeling and Machining Approach of the Impeller Based on Five-Axis Machine Tool

An impeller is the core of aviation engine components, the processing quality has a decisive impact on the performance of the engine. An impeller is also one of the most important basic components of centrifugal compressor. When a three-axis CNC machining centre is used for producing an impeller, great difficulties, i.e. collisions between the cutting tool and the impeller, can occur. As the surface is normally twisted in design to achieve the required performance, it can cause overcut and collision problems during machining. To solve these problems, an integrated five-axis machining approach for a centrifugal impeller by combining related machining technologies is developed. As a result, Cutter Location data based on the geometry model of blade and hub of the impeller are generated. Finally, the Cutter Location data is verified through software simulation. The results prove that the machining methodology adopted is useful and efficient.