Developed CAM System Research Articles

Control of grinding the mandrel working surface of cold-rolling mills

It was found that for maximum performance of grinding the mandrel working surface of cold rolling mills at fulfilling all quality requirements for the machined surface, a graph of the material removal rate (MaterialRemovalRate) throughout the grinding cycle must be located in the region of acceptability, which is limited by the marginal algorithm as close to the boundaries of this region as possible. A problem of determining the material removal rate in grinding the curved surface of the mandrel by the torus-shaped grinding wheel can be solved only by a numerical method using the developed application. To clarify and adapt the cutting process control law to actual conditions, conducting experimental studies to determine the parameters which cause the marginal algorithm restrictions for grinding the mandrel working surface according to the developed methodology is necessary. Automated design of the cutting mode control when grinding the cold rolling mill mandrel is fully provided by the developed CAM system that has been introduced at Nikopol Pipe Plant of JSC Centravis Production Ukraine (Ukraine), where its effectiveness in preparing control programs for grinding a wide range of mandrels with the curved component on the modernized CNC grinding machine was fully confirmed.

Development of CAM system based on industrial robotic servo controller without using robot language

This paper describes the development of a robotic CAM system for an articulated industrial robot RV1A from the view point of robotic servo controller. It is defined here that the CAM system includes an important function which allows an industrial robot to move along cutter location data (CL data) consisting of position and orientation components. In addition, the developed CAM system has a high applicability to other industrial robots whose servo systems are technically opened to end-users. The developed robotic CAM system works as a straightforward interface between a general CAD/CAM and an industrial robot. At the present stage, the relationship between CAD/CAM and industrial robots is not well established compared to NC machine tools that are widely spread in manufacturing industries. The CAM systems for NC machine tools are already established, however, the CAM system for industrial robots has not been sufficiently considered and developed yet. A teaching pendant is generally used to obtain position and orientation data of the arm tip before an industrial robot works. Here, in order to enhance the relationship between a conventional CAD/CAM system and an industrial robot, a simple and straightforward CAM system without using any robot language is developed and implemented. The basic design of the robotic CAM system and the experimental results are presented in this paper.

Development of CAM System Using Linear Servo Motor to Automate Metal Hammering – A Study on Forging-Type Rapid Prototyping System –

This study deals with the use of a linear motor to automate a metal hammering process based on CAD data. In the study, a linear servo hammering system is adopted to automate the hammering work, and a CAM system generating arbitrary tool path modes for metal hammering bases on CAD data is developed. By utilizing the developed CAM system, formability of automated metal hammering using different tool path modes is clarified, and forming characteristics through the integration of discrete deformation throughout the hammering progress is experimentally demonstrated.

5-Axis Control Dexterous Ultraprecision Micromilling of Ruled Surface with Side Cutting Edge

This study deals with 5-axis control tool path generation to create microshapes dexterously and efficiently, while maintaining quality. Concerning 5-axis control machining, the use of ball end mills is generally employed. However, this method needs a lot of time to obtain high quality surface. To solve this problem, a side cutting edge of the ball end mill is positively utilized with its parallel to the ruled surface. Therefore, a new CAM system is developed to detect the surface to be machined with the side cutting edge, and to generate collision-free tool paths between the tool and the work piece. The effectiveness of the developed CAM system is experimentally confirmed by creating a tiny Möbius ring.

Dexterous Machining for a Complicated Shape with Nested Structure

As developing countries gain strength in manufacturing technologies, developed countries have to shift their course in producing highly value-added products. Artistic products, different from conventional industrial products, are considered to be one of high value-added products, which contain a number of skills of experienced operators. However, artistic products in developed countries are requested to be automatically produced by means of efficient machine tools with multifunction and powerful CAD/CAM systems. Such a manufacturing way may be named 'Dexterous Machining'. The Dexterous Machining is an idea to take skills of experienced operators into machining technology. As the first step, a new machining method and a procedure of a complicated shape with a nested structure are devised and developed in the study to establish a CAM system for the Dexterous Machining. The CAM system contrives an efficient machining method by use of a special jig and a support pillar. A machining experiment is conducted to confirm the validity of the devised machining method and the developed CAM system. As a result, it is confirmed that the developed CAM system is effective to create the nested structure.

Layer based micro-machining—New approach for tool-path generation

This paper proposes a new tool-path generation approach for layer-based micro machining (“conventional”, laser or EDM milling). With this approach, the laser spot non-conformity or EDM tool wear is compensated for by varying the layer machining angle and start point while the material removal volumes are represented by a sequence of 2D slices. Tool-path generation is performed taking into account the specific requirements of 3D micro-machining. The capabilities of the developed CAM system have been verified experimentally.

The error analysis of the NC machined free form surfaces in reverse engineering

In this paper a feasible methodology that deals with the issues in reverse engineering is reported. It starts by introducing the cubic polynomial to construct the CAD model in accordance with the points measured from the original object by using the optical non-contact scanning system. The needed control points for reconstruction are sifted from the tight squeezed scanned point cloud. Next, based on the control point, the interference-free algorithm connected with the developed CAM system is used to generate the fine-cutting tool paths for NC machining to avoid over-cut. When carrying out the error analysis, points scanned from the machined replica are compared to the reconstructed CAD model to investigate the error distribution. The test-point is sampled statistically from the scanned points due to analyzing the large number of points. The suitable sample size can stand for the entire population with sufficient confidence and accuracy. Meanwhile, a datum is needed to unify both the coordinate systems of the test-point and the reconstructed CAD model to make sense of the aftermath of error detection. For fulfilling the tasks of coordinate alignment and error detection, the test-point is transformed iteratively by means of the rigid-body transformation matrix, so as to minimize the sum of squares distance. The Nelder–Meade simplex method is used in resolving the parameters of the rigid-body transformation matrix in an optimal fashion, where the trouble that arises from resolving the derivates of non-linear equation can be prevented. Once the sum of squares distance in the normal direction converges to a preset value, the coordinate system of the reconstructed CAD model and that of the test-point are treated as consistent. As a result, the margin of error and the error distribution are evaluated. An example for system implementation was also demonstrated to show the validity of the proposed methodology .

CAM System for Layer-Based EDM

This paper proposes a new tool-path generating approach for layer-based EDM milling. With this approach, electrode wear is compensated for by varying the layer thickness while the material removal volumes are represented by a sequence of 2-D slices. Tool-path generation is performed taking into account the specific requirements of 3-D micro-EDM milling. The capabilities of the developed CAM system have been verified experimentally.

倣いシミュレーションに基づくCAMシステムの開発

A CAM system which is based on simulating the servo data generation method of a copy milling machine was developed. In this system, the tool path data can be directly calculated using the coordinates of the contact point between the defined shape and the imaginary stylus, without preceding processes of offset surface generation and tool interference checking. For application of this algorithm to the model which is expressed by the boundary representation method, the algorithm has been modified slightly. As the contact point is regarded as the nearest point to the center of the imaginary stylus, and which is on the model surface, all intervals between the center of the imaginary stylus and the constructing surfaces which are close to it are calculated. The point which has the shortest interval is the representative nearest point of the model data and the contact point in the case that the interval is equal to the radius of the tool. A roughing tool path which is constituted with imaginary block and a spiral finishing tool path which tool feed with smoothly cutting have been developed using the algorithm. Tool path simulations and cutting tests show that the developed CAM system was able to generate appropriate CL data with high accuracy and reliability.

Development of CAM System Based on Simulation of the Copy Operation.

For a high speed machining and a new type surface finishing with non-rotating cutting tools, it is necessary to develop a CAM system that can generate accurate CL data with high speed and high reliability. In order to extend CAM functions, a unified algorithm for CL data generation that can be applied for both rotating cutting tools and non-rotating ones was developed which is based on simulating the servo data generation method of a copy milling machine. The model and the stylus head are represented by a CSG data structure, and the tool path is defined in a calculation of contact points between the model and the stylus head, and normal vector at contact point. Therefore, preceding processes of offset surface generation and tool interference check can be abbreviated. The developed system has following four tool path modes; (1) the scanning line mode, (2) the contour line mode, (3) the 3D profile mode, (4) the contour line roughing mode. The contour line mode is suitable for high-speed machining because it will provide stable cutting with a small variation in cutting loads. Tool path simulations and cutting tests show that the developed CAM system can generate CL data of various types of tool path mode with high accuracy and reliability.

５軸加工用ＣＡＭシステムの開発

The purpose of this study is to improve the productivity of the molds and dies for plastic injection by means of developing and utilizing the CAM system which can generate CL data for 5-axis controlled machine tools. In case of machining the molds and dies which have complicated and deep shape in Z-direction, the EDM system is widely used. On the other hand, the 5-axis controlled machine tools are not used effectively even if they have the same machining potential as the EDM system because the CAM system which has the following basic functions for multi-axis machining has not been developed; (1) high speed collision detection between machine tool components and the work material, (2) exact position control to avoid the collision, and (3) high speed and high accurate generation of the tool path for rough cutting, semi-finishing and finishing. In the developed CAM system, the Inverse Offset Method has been used for discerning the cutting area previously where the collision may take place. The new rough cutting method on the basis of the contour line tool path with down cut operation has been developed. The results of the actual machining test show that the developed system has the proper functions of collision detection and position control, and the complicated shape machining with high efficiency is possible.