菌形叶根数控加工程序的开发及试验研究

探讨了菌型叶根的数控加工工艺方法,解决了圆盘铣加工叶根圆弧的瓶颈,为叶根圆弧的加工开辟了新的途径.     

汽轮机叶片菌型叶根圆弧加工方法探讨

阐述了菌型叶根的加工原理,并详细讲述了菌型叶根在数控机床上加工的必要性、重要性和加工方法。描述了在卧式数控加工中心上实现计算机软件自动编制菌型叶根加工程序的过程,提高了菌型叶根的加工效率,提高了产品质量和刀具的利用率,为卧式加工中心增加了一种简单易行的加工应用方式,同时为工厂降本增效起到了不可低估的作用。     

超超临界1000MW汽轮机高压转子菌型叶根槽的加工

介绍了超超临界1000MW汽轮机高压转子菌型叶根槽的结构特点及加工难点,并给出了数控加工方法。     

Cimatron E加工汽轮T型叶根

本文通过对汽轮机T型叶根的结构的分析,制定数控加工工艺,介绍了基于Cimatron E软件加工刀路编程的设置和刀路的修改,探讨了T型叶根数控加工的方法。     

大型枞树型叶根叶片加工工艺的开发

详细介绍了大型能量回收透平发电装置（简称TRT）的关键零件——大型枞树型叶根叶片的加工工艺开发过程。根据加工批量、现有设备以及叶片结构,采用了五轴数控＋高速铣削的方法,以铣代磨,首次实现了大型枞树型叶根以及叶顶剃灰槽的加工。     

菌型叶根动叶片叶根叶冠内径向的加工

菌型叶根动叶片是一种新型的动叶片,采用数控铣加工叶根内径向面时留0.1~0.2mm余量,然后在进行叶根内径向磨削,叶冠直接加工到位,没有后序磨削加工,由于叶根叶冠在加工过程中不是一次装夹完成的,根冠存在一定的落差,在后续的装配中容易产生配合间隙,无法达到要求。文中介绍了一种新的加工工艺,解决了这一问题。     

汽轮机低压转子末级叶轮的齿型叶根槽加工及测量方法

介绍了某重点项目汽轮机低压转子末级叶轮的叶根槽型线(现称之为齿型叶根槽)的加工和测量方法,保证了转子齿型叶根槽型线的对称性和准确性,为同行业转子齿型叶根槽加工提供了经验。     

330MW汽轮机低压模块第三级动叶片的研究与制造

介绍了如何研究解决引进法国技术330MW汽轮发电机低压转子叶片国产化问题，主要介绍了叶片型线，内、背径向面，叶根和围带凸台数控加工的程序编制。     

汽轮机转子T型槽斜承力面测量方法

以新结构斜承力面T型叶根槽为研究对象，研究分析新型叶根槽的结构特征，依托装配原理，提取加工过程中的关键要素，选取合适刀具和加工方法，并通过对刀仪辅助对刀计算补偿数据，制定该型叶根槽加工方案。根据叶根槽精度要求，提出采用中间过程检验和加工完成后专用工装测量两侧斜面对称性的测量方法，保证了斜承力面T型叶根槽的对称性和准确性，顺利完成对该型叶根槽转子的加工，并为相同结构叶根槽加工提供了参考。     

叶根数控加工中欠切问题分析及措施

分析了叶根数控加工中出现欠切的原因，提出了解决办法。实践表明，该方法是一种叶根齿加工的编程小技巧。     

Iso-parametric CNC tool path optimization based on adaptive grid generation

The iso-parametric tool path is broadly used in CAM systems to machine sculptured surfaces. To satisfy tolerance constraints CAM systems usually adopt the smallest intervals across discrete tool paths, leading often to overlap and inefficient tool path. This paper presents a novel optimization scheme based on adaptive grid that can produce the optimal tool path on the basis of iso-parametric tool path and introduces the numerical method of generating the adaptive grid. When the generated optimal tool path has the same number of discrete tool path as the iso-parametric tool path, the optimal tool path will produce smaller machining errors. Or when the generated optimal tool path produces the same errors as the iso-parametric tool path, the optimal tool path will have fewer discrete tool paths and higher efficiency. This optimization scheme is robust, concise, and easy to be integrated into CAM systems to produce the optimal tool path automatically.     

Optimal five-axis tool path generation algorithm based on double scalar fields for freeform surfaces

In order to generate efficient tool path with given precision requirements, scallop height should be kept under a given limit, while the tool path should be as short as possible to reduce machining time. Traditional methods generate CC curves one by one, which makes the final tool path far from being globally optimal. This paper presents an optimal tool path generation model for a ball-end tool which strives to globally optimize a tool path with various objectives and constraints. Two scalar functions are constructed over the part surface to represent the path intervals and the feedrate (with directions). Using the finite element method (FEM), the tool path length minimization model and the machining time minimization model are solved numerically. The proposed method is also suitable for tool path generation on mesh surfaces. Simulation results show that the generated tool path can be direction parallel or contour parallel with different boundary conditions. Compared to most of the conventional tool path generation methods, the proposed method is able to generate more effective tool paths due to the global optimization strategy.     

离散点云等残留高度数控加工刀轨生成方法

为了最大化刀轨行间距,从而减少刀轨总长度,针对离散点云提出了一种等残留高度刀轨生成方法。提出以点云局部轮廓点集直接生成残留高度点的迭代计算方法,再根据残留高度点和点云局部点集迭代计算出下一行等残留高度刀位点,从而获得等残留高度刀轨。算法无需点云等距或曲面重构,为了提高算法效率,提出了算法所需数据初值的优化计算方法。最后对典型的点云模型生成刀轨,与等行距刀轨相比,提出的算法生成的等残留高度刀轨总长度大幅减少,验证了算法的可行性和有效性。     

对称多型腔粗加工刀轨快速生成算法

对具有对称特性的多型腔零件的刀轨规划方法进行了研究，提出了一种新的算法：首先生成其中一个型腔的刀轨，然后通过阵列生成其余刀轨，并对刀轨的进退刀进行处理，从而快速生成完整的、连续的、有序的刀具轨迹。该算法尤其适用于高速加工的刀轨规划，实践表明，可大大提高编程效率．节省加工时间。     

型腔环切加工的非均匀偏置算法

提出用于型腔加工的一种新型刀轨计算方法－非均匀偏置算法。理论分析及实例计算均证明,在保证遍历加工区域的前提下非均匀偏置刀轨比传的刀轨形式更的加工效率。     

Mesh-based tool path generation for constant scallop-height machining

This paper presents a new approach to mesh-based tool path generation for obtaining constant scallop heights. The mesh surface has recently become the focus of considerable interest, because its geometric computation is simpler and more robust than that of the parametric surface. These advantages make it easy to check and remove interference in the process of tool path generation. The previous tool path generation method based on the mesh surface, however, can generate only one topology of iso-planar type where tool paths have evenly spaced tool path intervals. As constant scallop heights cannot be obtained from evenly spaced tool path intervals, unevenly spaced tool paths based on offset meshes are necessary for reducing the machining time and for easy interference removal. This paper proposes and compares four methods to estimate curvatures from the mesh surface; the curvature is essential for calculating unevenly spaced tool path intervals. This paper also proposes an improved drive surface method to propagate CL-paths unevenly and to generate tool paths with various topologies.     

刀轨环无跳刀尖角垂线过渡连接算法

针对刀轨环如何高效地连接成环切刀轨的问题,提出了刀轨环无跳刀尖角垂线过渡连接算法。首先在基于向量角分线的子域上生成等距环,然后建立刀轨环数组和生成环的多个单向链表,采取顺序取外等距环、逆序取内环的方式生成单根节点刀轨环关系树,提出尖角垂线过渡的连接方式,遍历刀轨环树获得无跳刀刀轨,最后构建加减速数学模型并验证算法的有效性。试验表明,该算法计算效率高,无跳刀,满足实际加工要求。     

Grind-free tool path generation for five-axis surface machining

This paper discusses automatic tool path generation for five-axis filleted end mill finish-surface machining. A new method of automatic five-axis tool path generation is introduced called Grind-Free (GF) tool path generation. GF surfaces result from tool paths that avoid gouging and have scallops that are within the surface profile or waviness tolerances. New algorithms are presented for determining tool forward step and tool path step-over that produce a GF surface. Gouge-free tool paths can be generated directly from CAD data based solely on local and global machining constraints. The proposed methodology for GF tool path generation has been implemented in the C language using the CODE/Robline system. Surfaces were machined on a Boston Digital 505 five-axis milling machine to confirm this method.     

液压连续升降系统研究

为适应大型构件连续升降的施工要求，消除因频繁启停产生的附加惯性载荷和冲击，用运动学观点对连续式液压提升器连续升降的运动机理进行了研究，对影响提升效率的重要参数——速度差和负载转换行程进行最优求解。建立了连续升降控制系统的数学模型，通过MATLAB仿真和连续升降台架试验，证实了连续式液压提升器能实现连续和同步升降。     

Capturing the tacit knowledge of the skilled operator to program tool paths and tool orientations for robot belt grinding

This paper describes a novel methodology for generating grinding tool paths, orientations and grinding parameters based on the captured trajectories of a surface finishing tool operated by the skilled operator. First, a variable frame size moving window principal component analysis is performed on the trajectories. Next, features such as the amplitude, speed of the tool centre point, direction of travel, average position, contact force and orientation of the grinder are calculated. Kernel k-means clustering is applied to the trajectory’s feature vectors for segmentation into the tool path primitives. The robotic tool path primitives would be ordered similar to the manual tool path primitives in the grinding strategy. The robotic tool path primitives are then generated based on the boundaries of the manual tool path primitive in a computer-aided manufacturing software. Anchor points are selected from the corners and at intermediate sections along the robotic tool path to inherit the orientations of the manual tool path. Using the inherited skilled operator tool orientations, spherical linear interpolation and spherical spline quaternion interpolation are used to interpolate the orientations for the robotic tool path points along the cross curves, followed by the flow curves, respectively. A finite element model of the belt grinding process is also introduced to quantify the effect of the contact wheel serrations on the material removal rate. This is to account for the difference in contact wheel design between the handheld and robotic grinding tool. The programmed robotic tool paths generated from the trajectories captured from a skilled operator were proven to be able to grind the workpiece to the desired profile within the desired tolerance in a pre-production environment.