5-axis micro milling machine for machining micro parts

This paper presents a PC-based 5-axis micro milling machine, which can be used for machining micro-sized parts, and be easily constructed a low cost. Micro cutting is a method for manufacturing three-dimensional micro parts; however, machine tools for micro machining are expensive. The micro milling machine presented in this paper is mainly composed of commercially available micro stages, and an air spindle and PC-based control board. An effective method for initializing the spindle position is proposed. Test results of the micro milling machine are presented, which include machining of micro walls, micro columns and micro blades.     

A hybrid 5-axis CNC milling machine

5-Axis CNC milling machines are important in a number of industries ranging from aerospace to consumer-die-mold machining because they can deliver high machining accuracy with a spindle tilting capacity. Most of these machines have serial mechanisms so that modest static and dynamic stiffness become very critical design issues when high speed machining capability is required. Parallel mechanisms have recently received attention from machine tool designers because of their inherent potential for stiffness and because of their compactness. However, much of the promised advantages of parallel machines only occur within a very small region of their workspace. We discuss some of the kinematic and structural challenges to extract machining performance from serial and parallel machines. We compare a hybrid machine, which combines serial and parallel mechanisms, with typical serial and parallel machines such as Euler angle machines and a hexapod. In particular, we consider singularities, reversal characteristics, and manufacturability. We show that hybrid machines can benefit from the advantages of serial and parallel mechanisms while avoiding most potential pitfalls. However, hybrid structures can suffer from the manufacturing problem of over-constraint. We show that the degree of over-constraint depends on machine size. We have designed a small hybrid 5-axis motion platform, the MIT-SS-1, which can tolerate this over-constraint through a novel layout of axes. We show that this structure has potential as a small 5-axis CNC milling machine.     

基于UG的5轴数控高速铣削中心在仿真加工中的应用

基于UG CAM软件强大的仿真加工及后处理功能,运用5轴数控高速铣削中心完成了某框架零件的加工并生成NC代码程序。通过采用先进的数控设备,不仅使零件获得了较高的加工质量,且降低了零件制造的成本,促进了生产率的提高。     

Iso-scallop tool path generation in 5-axis milling

This paper presents a new method of computing constant scallop height tool paths in 5-axis milling on sculptured surfaces. Usually, iso-scallop tool path computation methods are based on approximations. The attempted scallop height is modelled in a given plane to ensure a fast computation of the tool path. We propose a different approach, based on the concept of the machining surface, which ensures a more accurate computation. The machining surface defines the tool path as a surface, which applies in 3- or 5-axis milling with the cutting tools usually used. The machining surface defines a bi-parametric modelling of the locus of a particular point of the tool, and the iso-scallop surface allows to easily find iso-scallop tool centre locations. An implementation of the algorithms is done on a free-form surface with a filleted end mill in 5-axis milling.     

Machining strategy development and parameter selection in 5-axis milling based on process simulations

Fused deposition modeling (FDM) is one of the most popular additive manufacturing technologies for fabricating prototypes with complex geometry and different materials. However, current commercial FDM machines have the limitations in process reliability and product quality. In order to overcome these limitations and increase the levels of machine intelligence and automation, machine conditions need to be monitored more closely as in closed-loop control systems. In this study, a new method for in situ monitoring of FDM machine conditions is proposed, where acoustic emission (AE) technique is applied. The proposed method allows for the identification of both normal and abnormal states of the machine conditions. The time-domain features of AE hits are used as the indicators. Support vector machines with the radial basis function kernel are applied for state identification. Experimental results show that this new method can potentially serve as a non-intrusive diagnostic and prognostic tool for FDM machine maintenance and process control.     

The research of surface waviness control method for 5-axis flank milling

In this paper, the impacts brought by the carbon footprint tax on fashion supply chain systems are analytically examined. First, based on various industrial practices in fashion apparel, we construct the two-echelon manufacturer–retailer analytical fashion supply chain model. Second, by exploring the fashion supply chain with a highly fashionable product, we study how the carbon footprint tax can affect the retailer’s optimal choice of sourcing. We further investigate the significance of carbon footprint tax on fashion supply chain management under two commonly adopted contracts, namely the pure wholesale pricing (WP) contract and the markdown money (MM) contract. Our analytical findings illustrate that: (1) under the WP contract case: A properly set carbon footprint tax, which depends on the product’s manufacturing and shipping costs, and manufacturer’s profit margin, can successfully entice the retailer to source locally. (2) Under the MM contract case where the MM contract is set in a way that the supply chain is coordinated: (a) If the carbon footprint tax is equal to the difference between the product costs from the local and offshore sourcing, then the optimal MM rates and the optimal supply chain product quantities from the local and offshore sourcing modes are the same. (b) Similar to the WP contract case, we prove analytically that a properly determined carbon footprint tax can always entice the retailer to source locally. Further analysis with extended models under the consideration of having a stochastically larger demand with the local sourcing mode is conducted.     

Computation of optimal tool length for 5-axis ball-ended milling of molding die

The research presents an efficient computation of optimal tool-length for 5-axis mold and die machining. The proposed procedure analyzes input NC data generated by a commercial CAM system and computes the minimum feasible tool-length via slight modification of tool orientation at the selected NC blocks where tool-length reduction is required. The test result shows that the research is especially useful in five-axis machining steep wall features of deep cavities in an injection molding die. The developed system is used at a domestic molding die manufacturing company.     

Model for the prediction of 3D surface topography in 5-axis milling

The paper deals with the prediction of the 3D surface topography obtained in 5-axis milling in function of the machining conditions. For this purpose, a simulation model for the prediction of machined surface patterns is developed based on the well-known N-buffer method. As in sculptured surface machining the feed rates locally vary, the proposed model can be coupled to a feed-rate prediction model. Thanks to the simulation model of 3D surface topography, the influence of the machining strategy on resulting 3D surface patterns is analyzed through an experimental design. Results enhance the major influence of the tool inclination on 3D topography. Surface parameters used in the study are strongly affected by the variation of the yaw angle. The effect of the feed rate is also significant on amplitude parameters. Finally, the analysis brings out the interest of using surface parameters to characterize 3D surface topography obtained in 5-axis milling.     

三轴数控铣削仿真系统的研究与实现

切削过程的图形表示方法是数控仿真系统的核心技术,在研究图形表示的关键技术的基础上,采用全局绘制和局部绘制相结合的机制,提出了数控仿真过程中场景绘制的新算法,实验表明该算法有效可行,极大地提高了仿真过程的刷新速率.     

多坐标数控铣削加工图形仿真

针对生产厂在多品种刀具生产中所使用的MAHO800C五坐标四联动数控加工中心,分析实现多坐标数控加工仿真系统的方法及其相关的关键技术.实践表明,所开发的仿真系统可有效地实现加工图形的动态显示.     

A solid modeler based ball-end milling process simulation

A system for geometric and physical simulation of the ball-end milling process using solid modeling is presented in this paper. A commercially available geometric engine is used to represent the cutting edge, cutter and updated part. The ball-end mill cutter modeled in this study is an insert type ball-end mill and the cutting edge is generated by intersecting an inclined plane with the cutter ball nose. The contact face between cutter and updated part is determined from the solid model of the updated part and cutter solid model. To determine cutting edge engagement for each tool rotational step, the intersections between the cutting edge with boundary of the contact face are determined. The engaged portion of the cutting edge for each tool rotational step is divided into small differential oblique cutting edge segments. Friction, shear angles and shear stresses are identified from orthogonal cutting data base available in the open literature. For each tool rotational position, the cutting force components are calculated by summing up the differential cutting forces. The instantaneous dynamic chip thickness is computed by summing up the rigid chip thickness, the tool deflection and the undulations left from the previous tooth, and then the dynamic cutting forces are obtained. For calculating the ploughing forces, Wu's model is extended to the ball-end milling process [21]. The total forces, including the cutting and ploughing forces, are applied to the structural vibratory model of the system and the dynamic deflections at the tool tip are predicted. The developed system is verified experimentally for various up-hill and down-hill angles.     

iTNC 530五轴加工功能在XK2130数控龙门镗铣床上的应用

本文介绍了海德汉iTNC 530五轴加工功能在数控龙门镗铣床上的应用,说明了五轴加工特点及摆角铣头结构和应用.     

A 3D curvature gouge detection and elimination method for 5-axis CNC milling of curved surfaces

Based on the concept of Eular-Meusnier Spheres (EMS) that portrays the generic curvature model of surfaces, a new three-dimensional (3D) method for curvature gouge detection and elimination in sculpture surface machining is presented. The new method is superior for presenting one-dimensional (1D) and two-dimensional (2D) approaches for curvature gouge detection and curvature gouge-free machining due to its capability to consider both normal and osculate curvatures of the cutter and machined surfaces and their interactions. The method can be applied to all three types of commonly used milling cutters (end, torus and spherical mills) and all concave curved surfaces. Test results from machining simulations are presented to demonstrate the new method and its advantages. The work forms the foundation for further research on the automated generation of highly efficient and high quality 5-axis CNC tool paths for machining curved surfaces.     

Adaptive method of 5-axis milling of sculptured surfaces elements with a curved line contour

Journal of Mechanical Science and Technology - In this paper, an attempt to develop a new adaptive method of controlling the axis orientation of a toroidal milling cutter (leading angle α)...     

Quadtree-array-based workpiece geometric representation on three-axis milling process simulation

A workpiece hybrid representation method based on quadtree-array is presented to improve the geometric simulation efficiency on three-axis milling process. The method takes the advantages both of Z-Map and quadtree in simulation model representation. The discrete points managed by using Z-Map algorithm is to represent the whole model, while the points used to represent the simulated surface detail are managed with quadtree-array. The method can reduce the levels of a quadtree without losing simulation accuracy. A dynamic optimization algorithm to the quadtree structure is highlighted to reduce its total nodes in simulation process. As a result, the simulation efficiency can be improved significantly. A three-axis milling process simulation system based on quadtree-array representation was developed and used to evaluate the performance of the presented method. The evaluated results show that quadtree-array-based hybrid representation method of workpiece can improve the simulation efficiency significantly, and reasonable division number of array cells is also recommended.     

基于LS-DYNA的铣削过程三维仿真研究

金属铣削是一个弹塑性变形和断裂的复杂过程，基于LS-DYNA对铣削加工系统建模，对系统进行动态三维仿真，并对7075铝合金材料进行铣削力动态实验测试，将其与仿真结果进行比较，验证仿真计算可靠性，对铣削温度分布进行了分析，通过调整仿真铣削模型的参数，对铣削过程进行优化，降低铣削力的大小，保证铣削过程的稳定和加工的质量，提高切削效率。     

四坐标侧铣方法加工叶轮的数控实验

提出了四坐标侧铣方法加工叶轮等不可展直纹面理论,并按相对接触条件确定了圆柱刀具与工件的相对位置.相对于端铣加工,该方法大幅度减小了切削余量.最后,通过数控实验验证了该方法的可行性,并结合了径流式叶轮机械轴-径型叶轮抛物面叶片的成型设计计算方法,使设计计算和加工计算更方便,加工效率更高.     

铣头可自动交换的高速龙门五轴加工中心设计研究

介绍了一种铣头可自动交换的桥式高速龙门五轴加工中心的总体设计方案,对国内外现有的类似机床的性能指标作了详细的对比,其中,主要阐述了机床的机械结构、特点和关键零部件的设计及选型,对三个直线轴驱动方式、两个摆动轴的驱动方式以及数控操作系统的的设计选型作了深入的分析探讨,重点介绍了大推力直线电机的应用和双摆铣头可自动交换技术的应用;为大推力直线电机的应用以及高速龙门机床的设计研究提供了重要的理论依据和实践经验。     

A dimension-driven adaptive programming for tool-path planning and post-processing in 5-axis form milling of hyperboloidal-type normal circular-arc gears

Hyperboloidal-type normal circular-arc gears (HNCGs) are a latest application of circular-arc tooth profile in the gearing with perpendicular non-intersect