Minimax Optimization Strategy for Process Parameters Planning: Toward Interference-Free Between Tool and Flexible Workpiece in Milling Process

2016 ◽  
Vol 139 (5) ◽  
Author(s):  
Xiao-Ming Zhang ◽  
Dong Zhang ◽  
Le Cao ◽  
Tao Huang ◽  
Jürgen Leopold ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Process Parameters ◽  
Tool Path ◽  
Milling Process ◽  
Tool Path Generation ◽  
Path Generation ◽  
Thin Wall ◽  
Minimax Optimization ◽  
Envelope Surface ◽  
Flexible Workpiece

In milling of flexible workpieces, like axial-flow compressor impellers with thin-wall blades and deep channels, interference occurrence between workpiece and tool shaft is a great adverse issue. Even though interference avoidance plays a mandatory role in tool path generation stage, the generated tool path remains just a nominally interference-free one. This challenge is attributed to the fact that workpiece flexibility and dynamic response cannot be considered in tool path generation stage. This paper presents a strategy in process parameters planning stage, aiming to avoid the interference between tool shaft and flexible workpiece with dynamic response in milling process. The interference problem is formulated as that to evaluate the approaching extent of two surfaces, i.e., the vibrating workpiece and the swept envelope surface generated by the tool undergoing spatial motions. A metric is defined to evaluate quantitatively the approaching extent. Then, a minimax optimization model is developed, in which the optimization objective is to maximize the metric, so as the interference-free can be guaranteed while constraints require the milling process to be stable and process parameters to fall into preferred intervals in which material removal rate is satisfactory. Finish milling of impeller using a conical cutter governed by a nominally interference-free tool path is numerically simulated to illustrate the dynamics responses of the spatially distributed nodal points on the thin-wall blade and approaching extent of the time-varying vibrating blades to the tool swept envelope surface. Furthermore, the present model results suggest to use an optimal process parameters set in finish milling, as a result improving machining efficiency in addition to ensuring the interference-free requirement. The model results are verified against milling experiments.

Tool Orientation Planning in Milling With Process Dynamic Constraints: A Minimax Optimization Approach

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Tao Huang ◽  
Xiao-Ming Zhang ◽  
Jürgen Leopold ◽  
Han Ding
Keyword(s):  
Tool Path ◽  
End Milling ◽  
Tool Path Generation ◽  
Optimization Approach ◽  
Path Generation ◽  
Tool Orientation ◽  
Minimax Optimization ◽  
Ball End Milling ◽  
Dynamic Constraints ◽  
Five Axis

In five-axis milling process, the tool path generated by a commercial software seldom takes the dynamics of the machining process into account. The neglect of process dynamics may lead to milling chatter, which causes overcut, quick tool wear, etc., and thus damages workpiece surface and shortens tool life. This motivates us to consider dynamic constraints in the tool path generation. Tool orientation variations in five-axis ball-end milling influence chatter stability and surface location error (SLE) due to the varying tool-workpiece immersion area and cutting force, which inversely provides us a feasible and flexible way to suppress chatter and SLE. However, tool orientations adjustment for suppression of chatter and SLE may cause drastic changes of the tool orientations and affects surface quality. The challenge is to strike a balance between the smooth tool orientations and suppression of chatter and SLE. To overcome the challenge, this paper presents a minimax optimization approach for planning tool orientations. The optimization objective is to obtain smooth tool orientations, by minimizing the maximum variation of the rotational angles between adjacent cutter locations, with constraints of chatter-free and SLE threshold. A dedicated designed ball-end milling experiment is conducted to validate the proposed approach. The work provides new insight into the tool path generation for ball-end milling of sculpture surface; also it would be helpful to decision-making for process parameters optimization in practical complex parts milling operations at shop floor.

High Efficiency Tool Path Generation for Freeform Surface Machining Based on NURBS Subdivision

2014 ◽  
Vol 625 ◽  
pp. 372-377 ◽  
Author(s):  
Jiang Zhu ◽  
Akimitsu Hozumi ◽  
Tomohisa Tanaka ◽  
Yoshio Saito
Keyword(s):  
Tool Path ◽  
High Efficiency ◽  
Rapid Development ◽  
Milling Process ◽  
Tool Path Generation ◽  
Freeform Surface ◽  
Path Generation ◽  
Nurbs Surface ◽  
Surface Machining ◽  
Freeform Surface Machining

Along with the rapid development of CAD/CAM system, the smooth surfaces are widely used in industry design. Especially NURBS surface attracts rising attentions because NURBS can describe flat surface, freeform surface and so on. Currently a lot of tool path generation patterns are proposed for milling process of freeform surface. Nevertheless there are still some problems on generating efficient tool path for freeform surface under the requested surface finish roughness. In this research, in order to resolve these problems, NURBS surface is divided into some patches and the tool path is generated on each patch. This paper proposes a surface divide method and makes a comparison between this method and undivided method. As a result, it is found that dividing the surface is helpful for the making shorter tool path and increase the machining efficiency.

scholarly journals A Multiaxis Tool Path Generation Approach for Thin Wall Structures Made with WAAM

2021 ◽  
Vol 5 (4) ◽  
pp. 128
Author(s):  
Matthieu Rauch ◽  
Jean-Yves Hascoet ◽  
Vincent Querard
Keyword(s):  
Additive Manufacturing ◽  
High Performance ◽  
Tool Path ◽  
Tool Path Generation ◽  
Path Generation ◽  
Thin Wall ◽  
Process Data ◽  
Technical Data ◽  
Wall Structures ◽  
Wire Arc Additive Manufacturing

Wire Arc Additive Manufacturing (WAAM) has emerged over the last decade and is dedicated to the realization of high-dimensional parts in various metallic materials. The usual process implementation consists in associating a high-performance welding generator as heat source, a NC controlled 6 or 8 degrees (for example) of freedom robotic arm as motion system and welding wire as feedstock. WAAM toolpath generation methods, although process specific, can be based on similar approaches developed for other processes, such as machining, to integrate the process data into a consistent technical data environment. This paper proposes a generic multiaxis tool path generation approach for thin wall structures made with WAAM. At first, the current technological and scientific challenges associated to CAD/CAM/CNC data chains for WAAM applications are introduced. The focus is on process planning aspects such as non-planar non-parallel slicing approaches and part orientation into the working space, and these are integrated in the proposed method. The interest of variable torch orientation control for complex shapes is proposed, and then, a new intersection crossing tool path method based on Design For Additive Manufacturing considerations is detailed. Eventually, two industrial use cases are introduced to highlight the interest of this approach for realizing large components.

scholarly journals Remarkable Characteristics of a Novel Path Interval Determination in Filleted End Milling

2021 ◽  
Vol 54 (3) ◽  
pp. 461-468
Author(s):  
Tsutomu Sekine ◽  
Kyoko Kameya
Keyword(s):  
Tool Path ◽  
End Milling ◽  
Milling Process ◽  
Tool Path Generation ◽  
Influential Factors ◽  
Path Generation ◽  
Technological Advancement ◽  
Cnc Milling ◽  
Machined Surface ◽  
Computer Aided

This study describes remarkable characteristics of a novel path interval determination in filleted end milling with a tool inclination. CNC milling machine is one of the core technologies in practical manufacturing. Computer-aided technologies have contributed to the technological advancement. Tool path generation in computer-aided manufacturing is really important for CNC milling process. Although there are a lot of parameters treated in tool path generation, path interval is one of the influential factors in considering the balance between manufacturing efficiency and machined surface feature. A path interval determination in filleted end milling commonly entails the intersection problems with mathematical complexities in essence. The related studies have been reported so far, while there has scarcely been a procedure to cope effectively with the complexities. Hence, this study focused on a novel path interval determination proposed in our previous study. After the analytical discussions were made with the computational and experimental results, it was acquired from the explicit evidences that the novel procedure possessed remarkable characteristics contributable for a path interval determination in multi-axis filleted end milling.

Tool Path Optimization of 2D Contour Considering Stock Boundary

2012 ◽  
Vol 251 ◽  
pp. 169-172
Author(s):  
Fu Zhong Wu
Keyword(s):  
Present Method ◽  
Tool Path ◽  
Three Dimensional ◽  
Boundary Curve ◽  
Tool Path Generation ◽  
Path Optimization ◽  
Path Generation ◽  
Offset Curves ◽  
Measuring Machine ◽  
Tool Diameter

Based on analyzing the existing algorithms, a novel tool path generation of 2D contour considering stock boundary is presented. Firstly the boundary points of stock are obtained by three-dimensional measuring machine. And the boundary curve is constructed by method of features identifying. The stock boundary is offset toward outside with tool diameter. An enclosed region is formed between the contour curves and the offset curves of stock boundary. The tool path is generated by form of parallel spiral by offsetting the stock boundary in the enclosed region. Finally the validity of present method is demonstrated by an example.

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