Multi-tasking Machine Research Articles

Decision Method of Target Shape Position and Orientation Corresponding to Actual Objects

Multi-tasking machine tools are popular owing to properties such as high flexibility and productivity. It is essential for an operator to avoid collisions between the machine structure and workpieces as machine tools realize complicated motions. Thus, a machine simulator is widely used prior to machining operations to solve this problem. However, unexpected collisions often occur in a commercial machine simulator when the setup of a workpiece or a jig differs from the 3D models created in advance. Therefore, this study proposes a machine simulator that utilizes 3D models created by measuring the shape and position of the workpiece and jig on the machine tool. In a case in which the workpiece differs from the desired workpiece, it is necessary to determine a suitable position and orientation of the target shape based on the obtained objects to modify NC (Numerical Control) programs. In this study, a decision method of the position and orientation of target shape is devised such that it corresponds to actual objects obtained by on-machine measurement.

複雑形状に対応した工程設計支援システムの加エフィーチャ認識に関する研究

Manufacturing industry tends to high-mix low-volume production in recent years. Therefore, it is strongly required to develop a computer aided process planning (CAPP) system to shorten the preparation time and to generate NC program. Feature recognition has been treated as a key technology to develop a CAPP system. In authors’ previous study, novel machining features for multi-tasking machine tools have been proposed. The machining features can correspond to several alternative machining methods. However, complex target shapes of practical mechanical parts have not been considered. In order to solve this problem, special shapes such as chamfer part and freeform surface are firstly approximated and machining features such as cylinder or cuboid are recognized from the converted simple shapes in this study. From the results of conducted case study, it is found that the proposed feature recognition method has a potential to deal with complex target shapes of practical mechanical parts.

COMPLETE MACHINING OF GEARS ON 5X MULTITASKING MACHINES

The objective of industry is to produce components in the shortest possible time, to the lowest costs and in the required quality. It isn´t only demanded in the machine development, but also in the technology development and in the technology integration. Another requirement of industrial production is the order-based production of components. These objectives require very high standards in the development of new machine-concepts. They lead to the concentration of technological machining processes in a single machine. The actual development of special CAM software additionally extends the range of applications. Profound machining Know-how and technological knowledge in the different fields of action e.g. in kinematics, workpiece material, machining strategies etc., are essential.This paper shows you, our work on the optimization of the gear manufacturing process chain on 5X multitasking machines.

Study on analytical technique in a smooth design of multi-tasking machine

Study on analytical technique in a smooth design of multi-tasking machine

Polishing of Large-Sized Spiral Bevel Gears Using Elastic Grindstone

A manufacturing method of large-sized spiral bevel gears has been developed using a multi-axis control and multi-tasking machine tool in recent years. As a result of trial manufacturing of large-sized spiral bevel gears in a cyclo-palloid system using a multi-axis control and multitasking machine tool, and the surfaces roughness and tool mark of the machined gears were compared with those using a special generator, the surfaces were rough and leprous tool mark occurred. In this paper, the tooth surfaces are polished using a PVA elastic grindstone in order to improve the surface roughness and leprous tool mark. As a result, the surface roughness was improved after polishing although the wear and clogging of the elastic grindstone occurred.

Cloud-DPP for distributed process planning of mill-turn machining operations

Abstract Today, the dynamic market requires manufacturing firms to possess a high degree of adaptability to deal with shop-floor uncertainties. Specifically targeting SMEs active in the metal cutting sector who normally deal with intensive process planning problems, researchers have tried to address the subject. Among proposed solutions, Cloud-DPP elaborates a two-layer distributed adaptive process planning based on function-block technology and cloud concept. One of the challenges of companies is to machine as many part features as possible in a single setup on a single machine. Nowadays, multi-tasking machines are widely used due to their various advantages such as reducing setup times and increasing part accuracy. However, they also possess programming challenges because of their complex configuration and multiple machining functions. This paper reports the latest state of design and implementation of Cloud-DPP methodology to support parts with a combination of milling and turning features, and process planning for multi-tasking machining centers with special functionalities to minimize the number of setups. The contributions of this work are: representation of machining states and part transfer functionality, support of multi-tasking machines in adaptive setup merging, development of special function blocks to handle sub-setups and transitions, and finally generation of function-block network for the merged setups. The developed prototype is validated through a case study.

자동차 파워 트레인 샤프트 가공용 8축 복합가공기의 고 강성 구조설계에 관한 연구

자동차 파워 트레인 샤프트 가공용 8축 복합가공기의 고 강성 구조설계에 관한 연구

Development of Cutting Force Prediction Method Using Motion Information from CNC Controller

Five-axis machines and multi-tasking machines are widely used because they facilitate integration of work processes and simplification of jigs and set-ups. Along with effective machine use, development of optimum machining such as research on tools and cutting methods to achieve high-speed cutting and increase of material removal rate is being investigated. While these efforts have greatly contributed to furthering of automation and cost reduction at the manufacturing site, complex machine motions and increased demanding work processes can lead to unexpected collisions and tool breakages. To prevent tool breakage caused by unexpected overloading or to improve the inefficient feed rate on the basis of safety considerations, simulations based on numerical control (NC) data are usually performed in advance to evaluate the cutting force. In high-speed, high-efficiency machining, however, the machine does not always execute movements as instructed by the NC data and the predicted cutting force does not always agree with the actual cutting forces. In this study, therefore, we developed an off-line system in which the motion information of each axis of an actual machine is acquired from a computer numerical control (CNC) controller, and is then used to predict the cutting force. The effects of using the proposed method are described in this article.

Development of A Hybrid Multi-tasking Machine Tool: Integration of Additive Manufacturing Technology with CNC Machining

Reduction in manufacturing cost and total in-process time is critical for industries in developed countries in order to maintain competitive advantage. At the same time, high added value manufacturing is also required. If not addressed, it will become increasingly difficult for the manufacturing industries in high-wage countries who are at a competitive disadvantage to survive in the future. In order to meet these requirements by creating a new possibility for machine tools, a Hybrid Multi-tasking machine tool has been developed by equipping Laser Metal Deposition functionality in addition to existing integrated turning and milling capabilities. The concept of a Hybrid Multi-tasking platform enables a further evolution of Done-in-One processes enabling building near-net shape components to be produced by additive manufacturing and then quickly generating the net shape through high-precision finish machining operations. It is particularly well suited to small-lot production of difficult-to-cut materials, such as aerospace alloys, high-hardness materials used in the energy sector, production tools and components and high-precision, specialty alloy designs common in medical device manufacturing. This paper introduces the features of the Mazak Hybrid Multi-tasking machine tool with application examples and demonstrates possibilities and tasks for the next generation manufacturing.

把持替えと同時加工を可能にする複合加工機用工程設計支援システムの開発

把持替えと同時加工を可能にする複合加工機用工程設計支援システムの開発

Effects of tool axis offset in turn-milling process

The orthogonal turn-milling process draws increasing attention parallel to the developments in multi-tasking machine tools. However, the effects of process parameters used in orthogonal turn-milling are not fully understood. The basic objective of this study is to describe one of the most important and unique cutting parameters which is the tool axis offset, and determine its effects on process outputs such as cutting force, surface quality and tool wear. In order to achieve this objective, the effect of the tool axis offset is defined based upon geometrical relationships which are used to develop a mechanistic force model. Surface quality including the tool axis offset effect is examined by both analytical and experimental methods. Additionally, tool wear experiments were conducted to obtain the tool life under different settings for the tool axis offset. It is found that the process outcomes such as cutting forces, surface quality and tool life can be improved by taking into account the tool axis offset in orthogonal turn-milling operation. As a valuable conclusion, the proposed models and experimental results can be used to select a proper tool axis offset value while performing orthogonal turn-milling process in order to improve the process outcome.

A Numerical Simulation Study on Machining Performance for Front Face Circular Grooving Using Special Structure Milling Cutters — Part 2: Simulation Results and Discussions for Machining a Groove with Rectangular Sectional Profile

This paper proposes a simple and convenient numerical simulation approach to examining the characteristics and machining capacity of the manufacture process to machine a front face circular groove on a multi-tasking machine tool by a side milling cutter with special structure. In the second part of the paper, the practicability of the process to machine a groove with rectangular sectional profile is discussed based on the simulation results, and then an improved process is developed for correctly machining the groove profile in the required shape. Furthermore, the effect of cutter feed motion on the profile precision of machined groove is studied; at the same time, a main disadvantage of the process as a finishing cutting method is also identified.

A Numerical Simulation Study on Machining Performance for Front Face Circular Grooving Using Special Structure Milling Cutters — Part 1: Simulation Method and Examination of Machining Capacity

This paper proposes a simple and convenient numerical simulation approach to examining the characteristics and machining capacity of the manufacture process to machine a front face circular groove on a multi-tasking machine tool by a side milling cutter with special structure. In the first part of the paper, the simulation method is explained and then based on the simulation results, several important problems in applications are discussed such as how to design the cutter profile and determine the cutter position in grooving. Furthermore, an improved process is also developed for correctly machining a groove with specific profile in the required shape.

Development of Online Real-Time Collision Free Machining Using Simulation with CNC Openness

In recent years, 5-axis machine and multi-tasking machine have seen wide spread use. These tools can contribute to the enhancement of machining efficiency and precision. Conversely, their complex motion can cause numerous collision accidents between machines, tools, materials, and other parts. To prevent such accidents, it is now common to verify numerical control (NC) data using a machine motion simulator before performing the actual machining. However, the actual machining process is not always conducted in the expected manner. In some cases, the machining process is manually defined or altered, possibly causing a collision accident. In the present study, an online real-time collision free system was developed for the prevention of unexpected collisions. The effects of using this system are described in this article.

자동차 파워트레인 샤프트 가공용 8축 복합가공기 베드의 유한요소 해석에 관한 연구

To build a high precision machine tool and increase its productivity, structural analysis needs to be carried out for vibration and stiffness of the machine tools before any detailed design. Therefore, in this paper, static and dynamic analysis is carried out to evaluate 8-axis multi tasking machining beds for automotive power train shafts; then, selection of an appropriate device is made for application to bed design. The results of structural and modal analysis confirmed the structural characteristics of the 8-axis multi tasking machine for automotive power train shaft beds: and the second shape bed is the safest is considered secure.

二重らせん経路での摩擦攪拌形バニシングによる高硬度・圧縮残留応力を両立する表面強化層の創成

Frictional Stir Burnishing (FSB) is a surface enhancement method after machining without using additional device. The FSB process can be utilized on the machine tool which uses the rotation tools such as a machining center and a multi-tasking machine. Therefore, the FSB process can be applied just after the cutting process on the same machine tool. FSB was applied to the shaft materials of 0.45%C steel by using a multi-tasking machine in this paper. FSB is a process where the burnishing tool rotates at high revolution speed. Then the thin surface layer is rubbed and stirred with a temperature elevation and reduction. However it is difficult to achieve both high hardness and high compressive residual stress by FSB on 0.45%C steel shaft with helical path. In order to overcome this problem, FSB process with double helical path was proposed in this paper. As a result, both high hardness (600 HV) and compressive residual stress (-400 MPa) could be achieved.

Graph based automatic process planning system for multi-tasking machine

Multi-tasking machine is capable of performing both milling and turning operations, it contributes to highly efficient machining and space conservation. However, prior to machining a lot of lead time is consumed in deciding efficient process plan, and generating machining tool path. Although the current CAM systems are highly integrated, the efficiency of the generated tool path is highly relied on the experience of the CAM programmer. In this research, an automatic process planning system for multi-tasking machine was developed. It is capable of recognizing manufacturing features and deciding efficient process plan from CAD model automatically. In this developed system, the CAD model is described as Attributed Adjacency Graph (AAG), and each feature is defined by AAG and its geometrical properties. Totally 8 milling features and 9 turning features can be recognized. The optimal machining plan is calculated based on machining cost evaluation. In addition, in this research a new method based on subfeature combination is proposed in order to recognize intersecting features. Furthermore, in this research the connection relationship of each feature is classified, and machining priority is assigned to adjacent features. It prevents the time consuming evaluation for checking all possible machining sequences. Finally, according to the experiment results, it is confirmed this developed system is capable of obtaining optimal machining plan properly and rapidly.

S1310203 R-testを用いた複合加工機の補間運動精度に関する研究

Multi-tasking machine tools are rapidly expanding because they can do both turning and milling processes. There is no accuracy test standard because multi-tasking machine tool is not defined exactly. However, it can be tested by referring to the accuracy test standard for turning centers and the newly revised one for 5-axis machining centers. In this research, three axes simultaneous interpolation motion measurement with R-test was performed and the motion errors for the multi-tasking machine were evaluated. Moreover, measurement with two-dimensional scale was also performed. The result was revealed much more information at once by performing data processing similar to the R-test.

複合加工機用工程設計支援システムのための加工フィーチャの提案

複合加工機用工程設計支援システムのための加工フィーチャの提案

Current State of the Art of Multi-Axis Control Machine Tools and CAM System

<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00260005/01.jpg"" width=""300"" />Asymmetric curved grooving</div> Multi-axis numerical control (NC) machine tools such as 5-axis control machining centers and 5-axis control multi-tasking machines are widely used in machine shops. NC data, which are prepared using computeraided manufacturing (CAM) systems, are used with multi-axis control NC machine tools that have a variety of advantages. This article describes the advantages ofmulti-axis control machining. The structure of CAM systems used for multi-axis control machining and the important role of collision avoidance in generating cutter location (CL) data are then explained. The transformation of CL data to NC data for use in machining, which is performed by a post-processor, is presented. Finally, an efficient machining method and unique shape creation via 6-axis control machining are explained. </span>