Process planning based on cylindrical or conical surfaces for five-axis wire and arc additive manufacturing

2020 ◽  
Vol 26 (8) ◽  
pp. 1405-1420
Author(s):  
Fusheng Dai ◽  
Haiou Zhang ◽  
Runsheng Li
Keyword(s):  
Additive Manufacturing ◽  
Path Planning ◽  
Process Planning ◽  
Flat Surface ◽  
Welding Process ◽  
Planning Method ◽  
Content Type ◽  
Tool Paths ◽  
Conical Surfaces ◽  
Five Axis

Purpose The study aims to fabricate large metal components with overhangs built on cylindrical or conical surfaces with a high dimensional precision. It proposes methods to address the problems of generating tool-paths on cylindrical or conical surfaces simply and precisely, and planning the welding process on these developable surfaces. Design/methodology/approach The paper presents the algorithm of tool-paths planning on conical surfaces using a parametric slicing equation and a spatial mapping method and deduces the algorithm of five-axis transformation by addressing the rotating question of two sequential points. The welding process is investigated with a regression fitting model on a flat surface, and experimented on a conical surface, which can be flattened onto a flat surface. Findings The paper provides slicing and path-mapping expressions for cylindrical and conical surfaces and a curvature-speed-width (CSW) model for wire and arc additive manufacturing to improve the surface appearances. The path-planning method and CSW model can be applied in the five-axis fabrication of the prototype of an underwater thruster. The CSW model has a confidence coefficient of 98.02% and root mean squared error of 0.2777 mm. The reverse measuring of the finished blades shows the residual deformation: an average positive deformation of about 0.5546 mm on one side of the blades and an average negative deformation of about −0.4718 mm on the other side. Research limitations/implications Because of the chosen research approach, the research results may lack generalizability for the fabrication based on arbitrary surfaces. Originality/value This paper presented an integrated slicing, tool-path planning and welding process planning method for five-axis wire and arc additive manufacturing.

A Voxel Model-Based Process-Planning Method for Five-Axis Machining of Complicated Parts

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Yamin Li ◽  
Kai Tang ◽  
Long Zeng
Keyword(s):  
Process Planning ◽  
Planning Method ◽  
Dynamic Problems ◽  
Tool Paths ◽  
New Process ◽  
Part Surface ◽  
Voxel Model ◽  
Voxel Representation ◽  
Complex Features ◽  
Five Axis

Abstract This paper presents a new process planning method for five-axis machining, which is particularly suitable for parts with complex features or weak structures. First, we represent the in-process workpiece as a voxel model. Facilitated by the voxel representation, a scalar field called subtraction field is then established between the blank surface and the part surface, whose value at any voxel identifies its removal sequence. This subtraction field helps identify a sequence of intermediate machining layers, which are always accessible to the tool and are free of self-intersection and the layer redundancy problem as suffered, respectively, by the traditional offset layering method and the morphing method. Iso-planar collision-free five-axis tool paths are then determined on the interface surfaces of these machining layers. In addition, to mitigate the deformation of the in-process workpiece and avoid potential dynamic problems such as chattering, we also propose a new machining strategy of alternating between the roughing and finishing operations, which is able to achieve a much higher stiffness of the in-process workpiece. Ample experiments in both computer simulation and physical cutting are performed, and the experimental results convincingly confirm the advantages of our method.

Feature-based five-axis path planning method for robotic additive manufacturing

2018 ◽  
Vol 233 (5) ◽  
pp. 1412-1424 ◽  
Author(s):  
Gang Zhao ◽  
Guocai Ma ◽  
Wenlei Xiao ◽  
Yu Tian
Keyword(s):  
Additive Manufacturing ◽  
Path Planning ◽  
Planning Method ◽  
Manufacturing Strategy ◽  
Feature Extraction Method ◽  
Manufacturing Method ◽  
Feature Based ◽  
Five Axis ◽  
Subtractive Machining ◽  
Manufacturing Features

Additive manufacturing has been developed for decades and attracts significant research interests in recent years. Usually, the stereolithography tessellation language format is employed in additive manufacturing to represent the geometric data. However, people gradually realize the inevitable drawbacks of the stereolithography tessellation language file format, such as redundancy, inaccuracy, missing of feature definitions, and lack of integrity. In addition, it is almost impossible to apply the simple polygonal facet representation to the five-axis manufacturing strategy. Hence, there are quite few researches and applications on the five-axis additive manufacturing, in spite of its common applications in the subtractive machining. This article proposes a feature-based five-axis additive manufacturing methodology to enhance and extend the additive manufacturing method. The additive manufacturing features are defined and categorized into two5D_AM_feature and freeform_AM_feature. A feature extraction method is proposed that can automatically recognize the additive manufacturing features from the input model. Specially for the freeform_AM_feature, a five-axis path planning method is proposed and split into three stages: (1) offset the reference surface, (2) spatially slice the freeform layers, and (3) generate the toolpaths for each freeform layer. Real additive manufacturing five-axis toolpaths can be obtained using the proposed algorithm that performs as a secondary developed plug-in in the CATIA® environment. A robotic additive manufacturing system is constructed for the implementation of the five-axis additive manufacturing tasks, which are generated by the proposed algorithms and post-processed after simulation and off-line programming. Some examples are printed to validate the feasibility and efficiency of the proposed method.

Path Planning for Motion Control of Hexapod Machines

2001 ◽  
Author(s):  
Zhiming Ji ◽  
Zhenqun Li
Keyword(s):  
Path Planning ◽  
Machine Tools ◽  
Tool Path ◽  
Local Planning ◽  
Tool Path Planning ◽  
Tool Paths ◽  
Condition Optimization ◽  
Planning Methods ◽  
Tool Motion ◽  
Five Axis

Abstract The dramatic departure in structure of the hexapod machine tools from the traditional five-axis machines leads to the question: can the planning and control methods for the traditional CNC machines be used for the hexapod machine tools? We studied several tool motion characteristics, such as Jocabian matrices, path tracking errors and the extra degree of freedom (e-DOF), and found that the traditional five-axis planning methods cannot take into consideration of the kinematics performance variation and the e-DOF in a hexapod. A kinematics-based tool path planning scheme for the hexapods is therefore proposed. It combines the traditional tool path planning with the kinematic condition optimization. The optimization is a two-step process. First a high accuracy zone of the workspace is identified globally for the placement of the part. Then a set of 5-DOF tool paths is generated and extended to a set of 6-DOF tool paths based on the local planning of e-DOF. Finally the relationship between the e-DOF and the stiffness of the Hexapods, another factor in the use of e-DOF, are discussed.

Curved-layered material extrusion modeling for thin-walled parts by a 5-axis machine

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xiaojing Feng ◽  
Bin Cui ◽  
Yaxiong Liu ◽  
Lianggang Li ◽  
Xiaojun Shi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Additive Manufacturing ◽  
Layered Material ◽  
Bottom Surface ◽  
Motion Mechanism ◽  
Content Type ◽  
Material Extrusion ◽  
Thin Walled ◽  
Five Axis

Purpose The purpose of this paper is to solve the problems of poor mechanical properties, high surface roughness and waste support materials of thin-walled parts fabricated by flat-layered additive manufacturing process. Design/methodology/approach This paper proposes a curved-layered material extrusion modeling process with a five-axis motion mechanism. This process has advantages of the platform rotating, non-support printing and three-dimensional printing path. First, the authors present a curved-layered algorithm by offsetting the bottom surface into a series of conformal surfaces and a toolpath generation algorithm based on the geodesic distance field in each conformal surface. Second, they introduce a parallel five-axis printing machine consisting of a printing head fixed on a delta-type manipulator and a rotary platform on a spherical parallel machine. Findings Mechanical experiments show the failure force of the five-axis printed samples is 153% higher than that of the three-axis printed samples. Forming experiments show that the surface roughness significantly decreases from 42.09 to 18.31 µm, and in addition, the material consumption reduces by 42.90%. These data indicate the curved-layered algorithm and five-axis motion mechanism in this paper could effectively improve mechanical properties and the surface roughness of thin-walled parts, and realize non-support printing. These methods also have reference value for other additive manufacturing processes. Originality/value Previous researchers mostly focus on printing simple shapes such as arch or “T”-like shape. In contrast, this study sets out to explore the algorithm and benefits of modeling thin-walled parts by a five-axis machine. Several validated models would allow comparability in five-axis printing.

Intelligent obstacle avoidance path planning method for picking manipulator combined with artificial potential field method

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zheng Fang ◽  
Xifeng Liang
Keyword(s):  
Genetic Algorithm ◽  
Reinforcement Learning ◽  
Path Planning ◽  
Obstacle Avoidance ◽  
Potential Field ◽  
Field Method ◽  
Planning Method ◽  
Artificial Potential Field ◽  
Content Type ◽  
Artificial Potential Field Method

Purpose The results of obstacle avoidance path planning for the manipulator using artificial potential field (APF) method contain a large number of path nodes, which reduce the efficiency of manipulators. This paper aims to propose a new intelligent obstacle avoidance path planning method for picking robot to improve the efficiency of manipulators. Design/methodology/approach To improve the efficiency of the robot, this paper proposes a new intelligent obstacle avoidance path planning method for picking robot. In this method, we present a snake-tongue algorithm based on slope-type potential field and combine the snake-tongue algorithm with genetic algorithm (GA) and reinforcement learning (RL) to reduce the path length and the number of path nodes in the path planning results. Findings Simulation experiments were conducted with tomato string picking manipulator. The results showed that the path length is reduced from 4.1 to 2.979 m, the number of nodes is reduced from 31 to 3 and the working time of the robot is reduced from 87.35 to 37.12 s, after APF method combined with GA and RL. Originality/value This paper proposes a new improved method of APF, and combines it with GA and RL. The experimental results show that the new intelligent obstacle avoidance path planning method proposed in this paper is beneficial to improve the efficiency of the robotic arm. Graphical abstract Figure 1 According to principles of bionics, we propose a new path search method, snake-tongue algorithm, based on a slope-type potential field. At the same time, we use genetic algorithm to strengthen the ability of the artificial potential field method for path searching, so that it can complete the path searching in a variety of complex obstacle distribution situations with shorter path searching results. Reinforcement learning is used to reduce the number of path nodes, which is good for improving the efficiency of robot work. The use of genetic algorithm and reinforcement learning lays the foundation for intelligent control.

Toolpaths for additive manufacturing of functionally graded materials (FGM) parts

2014 ◽  
Vol 20 (6) ◽  
pp. 511-522 ◽  
Author(s):  
Pierre Muller ◽  
Jean-Yves Hascoet ◽  
Pascal Mognol
Keyword(s):  
Additive Manufacturing ◽  
Path Planning ◽  
Functionally Graded Materials ◽  
Process Modeling ◽  
Functionally Graded ◽  
System Control ◽  
Graded Materials ◽  
Content Type ◽  
Manufacturing Procedure ◽  
Selection Of

Purpose – The purpose of this paper is to propose an evaluation of toolpaths for additive manufacturing of functionally graded materials (FGM) parts to ensure the manufacturing of parts in compliance with the desired material distribution. The selection of an appropriate path strategy is critical when manufacturing FGM parts. Design/methodology/approach – The selection of a path strategy is based on a process modeling and an additive laser melting (ALM) system control. To do that, some path strategies are selected, simulated and compared. Findings – The comparison of some paths strategies was applied on a study case from the biomedical field. Test-parts were manufactured and analyzed. Results show a good correlation between the simulated and the deposited material distributions. The evaluation of toolpaths based on the process modeling and the system control was validated. Originality/value – Nowadays, FGM parts manufactured with ALM processes are not functional. To move from these samples to functional parts, it is necessary to have a global approach of the manufacturing procedure centered on the path planning. Few methodologies of path planning are adapted to FGM parts but are still limited.

Direct fabrication of inclined thin-walled parts by exploiting inherent overhanging capability of CMT process

2019 ◽  
Vol 26 (3) ◽  
pp. 499-508
Author(s):  
Yun Zhao ◽  
Fang Li ◽  
Shujun Chen ◽  
Zhenyang Lu
Keyword(s):  
Additive Manufacturing ◽  
Welding Process ◽  
Travel Speed ◽  
Statistical Prediction ◽  
Feed Speed ◽  
Auxiliary Equipment ◽  
Content Type ◽  
Geometrical Features ◽  
Thin Walled ◽  
Wire Arc Additive Manufacturing

Purpose The purpose of this paper is to develop a build strategy for inclined thin-walled parts by exploiting the inherent overhanging capability of the cold metal transfer (CMT) process, which release wire-arc additive manufacturing from tedious programming work and restriction of producible size of parts. Design/methodology/approach Inclined thin-walled parts were fabricated with vertically placed welding torch free from any auxiliary equipment. The inclined features were defined and analyzed based on the geometrical model of inclined parts. A statistical prediction model was developed to describe the dependence of inclined geometrical features on process variables. Based on these models, a build strategy was proposed to plan tool path and output process parameters. After that, the flow work was illustrated by fabricating a vase part. Findings The formation mechanism and regulation of inclined geometrical features were revealed by conducting experimental trials. The inclined angle can be significantly increased along with the travel speed and offset distance, whereas the wall width is mainly dependent on the ratio of wire feed speed to travel speed. In contrast to other welding process, CMT has a stronger overhanging capability, which provides the possibility to fabricate parts with large overhanging features directly with high forming accuracy. Originality/value This paper describes a novel build strategy for inclined thin-walled parts free from any auxiliary equipment. With the proposed strategy, a complex structural component can be deposited directly in the rectangular coordinates additive manufacturing system, indicating infinite possibilities on the producible size of the parts. Moreover, equipment requirements and tedious program work can also be significantly reduced.

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