On machining dynamics of flexible parts

2001 ◽  
Vol 215 (1) ◽  
pp. 53-59 ◽  
Author(s):  
F Abrari ◽  
M A Elbestawi ◽  
A D Spence
Keyword(s):  
Cutting Forces ◽  
Computer Aided Design ◽  
Process Model ◽  
Tool Path ◽  
Cutting Tool ◽  
Machining Process ◽  
Research Progress ◽  
Element Analysis ◽  
Flexible Parts ◽  
Five Axis

Solid modellers are now well established for computer aided design of mechanical parts. Machining applications, however, remain limited to geometric tool path planning. The physical aspects of the process are largely ignored. Success in actual machining, however, depends on consideration of cutting forces, torques, part and tool deflection, chatter, tool breakage and wear. This paper reports research progress towards a comprehensive simulation of the physical machining process of thin flexible parts. The system is based on extensions to a commercially available solid modeller. Cutting tool location data (CL-DATA) files along with an initial solid model of the workpiece are inputs. Each tool motion is segmented into short steps along the path and angular increments of spindle rotation. At each simulation step, immersion of the cutting tool teeth with the part is calculated. This information is then used by a machining process model to calculate cutting forces and tool/workpiece deflection. Up to five-axis motion is supported using a sweep representation of the tool swept volume. Flexible tools are modelled as cantilevers; flexible parts are created as solid models, are meshed and are dynamically solved using finite element analysis. The mesh is updated as material is machined away from the part.

scholarly journals Experimental and simulation study on chatter stability region of integral impeller with non-uniform allowance

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042093341
Author(s):  
Yan Wu ◽  
Kaifa Wang ◽  
Gang Zheng ◽  
Boxin Lv ◽  
Yong He
Keyword(s):  
Natural Frequency ◽  
Stability Region ◽  
Tool Path ◽  
Surface Profile ◽  
Machining Process ◽  
Chatter Stability ◽  
Element Analysis ◽  
Impeller Blade ◽  
Five Axis ◽  
Milling Chatter

In order to accurately improve and predict chatter stability region of machining process, an optimization method of machining process with non-uniform allowance of integral impeller was proposed. The modal parameters of the workpiece process system were obtained using the finite element analysis. Based on the regenerative chatter analysis theory, a limit comparison diagram of the stability with uniform allowance and non-uniform allowance was established. The simulation results showed that the non-uniform allowance natural frequency is about 1.43 times as much as the uniform allowance natural frequency, and the machining system stiffness non-uniform allowance is twice as much as the uniform allowance, while the limit of chatter stability region is increased by 3 times. This article studied uniform allowance and non-uniform allowance of milling chatter stability with experimental method. Tool path for five-axis machining and machine tool simulation based on NX CAM were planned. The comparisons of cutting processing uniform allowance and non-uniform allowance were done, and the surface profile detection of the test part with the three-dimensional scanning was carried out. The experimental results showed that the average optimization rate for manufacturing precision of blade suction surface after optimization and pressure surface was 63.8% and 48.84%. The total experiment showed that this process optimization strategy could effectively improve the stiffness of the integral impeller blade and reduce the cutting chatter of the blade during the cutting process.

Tool Path Generation for Turbine Blades Machining With Twin Tool

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Dun Lu ◽  
Jun Liu ◽  
Wanhua Zhao ◽  
Bingheng Lu ◽  
Diaodiao Wu ◽  
...  
Keyword(s):  
Cutting Forces ◽  
Nuclear Power ◽  
Tool Path ◽  
Contact Point ◽  
Turbine Blades ◽  
Machining Process ◽  
Element Analysis ◽  
Machining Precision ◽  
Tool Paths ◽  
Geometric Precision

Blades are essential parts used in thermal and nuclear power generation. Its machining precision is a vital factor that influences the efficiency and life of those industries. Blades are thin-walled parts, which could easily deform under cutting forces, and hence deteriorate the machining precision. In our previous work, a milling process with twin tool for blade is proposed, in which two tools are assigned to machine the basin and dorsal surfaces simultaneously. It is expected that the cutting forces acted on the basin and dorsal surfaces can be counteracted to reduce the deformation of the blade. In this study, a method of twin-tool paths generation is developed. The tool center points and tool axis vectors are generated with consideration of the cutting forces balance, the machine tool kinematics, the surface geometric precision, and the same number of tool paths on basin and dorsal surfaces. Virtual machining, finite element analysis, and trial cutting are carried out and verified that the method which is used for generating the twin-tool paths is successful. The basin and dorsal surfaces have the same number of tool paths and tool contact point coordinates, which guarantees that the two surfaces can be completely machined and can be machined and finished simultaneously. Furthermore, the cutting forces acted on the basin and dorsal surfaces can achieve the balance along the twin-tool paths. Therefore, the deformation of a blade caused by cutting force is obviously reduced compared with a conventional machining process with a single tool.

Finite Element Analysis of Incremental Sheet Forming for Metal Sheet

2018 ◽  
Vol 783 ◽  
pp. 148-153
Author(s):  
Muhammad Sajjad ◽  
Jithin Ambarayil Joy ◽  
Dong Won Jung
Keyword(s):  
Mechanical Properties ◽  
Sheet Metal ◽  
Tool Path ◽  
Incremental Forming ◽  
Single Point ◽  
Machining Process ◽  
Machining Parameters ◽  
Forming Process ◽  
Element Analysis ◽  
Tool Diameter

Incremental sheet metal forming, is a non-conventional machining process which offers higher formability, flexibility and low cost of production than the traditional conventional forming process. Punch or tool used in this forming process consecutively forces the sheet to deform locally and ultimately gives the target profile. Various machining parameters, such as type of tool, tool path, tool size, feed rate and mechanical properties of sheet metal, like strength co-efficient, strain hardening index and ultimate tensile strength, effects the forming process and the formability of final product. In this research paper, Single Point Incremental Forming was simulated using Dassault system’s Abaqus 6.12-1 and results are obtained. Results of sheet profile and there change in thickness is investigated. For this paper, we simulated the process in abaqus. The tool diameter and rotational speed is find out for the production of parts through incremental forming. The simulation is done for two type of material with different mechanical properties. Various research papers were used to understand the process of incremental forming and its simulation.

Some Theory and Algorithms Pertaining to Machinability and Visibility

Manufacturing ◽  
2002 ◽  
Author(s):  
Mahadevan Balasubramaniam ◽  
Taejung Kim ◽  
Sanjay Sarma
Keyword(s):  
Path Planning ◽  
Tool Path ◽  
Cutting Tool ◽  
Machining Process ◽  
Planning Problem ◽  
Topological Connectivity ◽  
Almost All ◽  
Feasible Space ◽  
Path Planning Problem ◽  
Theoretical Results

In previous work, we and others have developed visibility-based tool path generation schemes. Almost all previous research implicitly assumes that all visible parts are machinable. Though usually true practice, this assumption hides several subtleties inherent to the geometry of the machining process. Here, we define machinability in a stricter sense, as a generalization of the robotic path planning problem. Then, we define various “tight” necessary conditions for strict machinability, and show the connections between these conditions. After demonstrating the richness of the information contained in visibility, we show how to compute visibility effectively. Visible directions constitute an approximate feasible configuration space of a cutting tool. We also address questions pertaining to the topological connectivity of the feasible space. The theoretical results of this paper lay down a firmer foundation of machining path planning.

Geometric Modeling of Cutter/Workpiece Engagements in 3-Axis Milling Using Polyhedral Models

2007 ◽  
Author(s):  
Eyyup Aras ◽  
Derek Yip-Hoi
Keyword(s):  
Cutting Forces ◽  
Geometric Modeling ◽  
Tool Path ◽  
Cutting Tool ◽  
Milling Process ◽  
Mapping Technique ◽  
Depth Of Cut ◽  
Modeling Methodology ◽  
Machining System ◽  
Engagement Angle

Modeling the milling process requires cutter/workpiece engagement (CWE) geometry in order to predict cutting forces. The calculation of these engagements is challenging due to the complicated and changing intersection geometry that occurs between the cutter and the in-process workpiece. This geometry defines the instantaneous intersection boundary between the cutting tool and the in-process workpiece at each location along a tool path. This paper presents components of a robust and efficient geometric modeling methodology for finding CWEs generated during 3-axis machining of surfaces using a range of different types of cutting tool geometries. A mapping technique has been developed that transforms a polyhedral model of the removal volume from Euclidean space to a parametric space defined by location along the tool path, engagement angle and the depth-of-cut. As a result, intersection operations are reduced to first order plane-plane intersections. This approach reduces the complexity of the cutter/workpiece intersections and also eliminates robustness problems found in standard polyhedral modeling and improves accuracy over the Z-buffer technique. The CWEs extracted from this method are used as input to a force prediction model that determines the cutting forces experienced during the milling operation. The reported method has been implemented and tested using a combination of commercial applications. This paper highlights ongoing collaborative research into developing a Virtual Machining System.

Performance of Low Cost 3D Printed Minimum Quantity Lubrication Applicator Using Palm Oil in Milling Steel

2020 ◽  
Vol 997 ◽  
pp. 85-92
Author(s):  
Abang Mohammad Nizam Abang Kamaruddin ◽  
Abdullah Yassin ◽  
Shahrol Mohamaddan ◽  
Syaiful Anwar Rajaie ◽  
Muhammad Isyraf Mazlan ◽  
...  
Keyword(s):  
Tool Wear ◽  
Cutting Forces ◽  
Cutting Tool ◽  
Low Cost ◽  
Minimum Quantity Lubrication ◽  
Machining Process ◽  
Cutting Condition ◽  
Dry Cutting ◽  
Minimum Quantity ◽  
Tool Performance

One of the most significant factors in machining process or metal cutting is the cutting tool performance. The rapid wear rate of cutting tools and cutting forces expend due to high cutting temperature is a critical problem to be solved in high-speed machining process, milling. Near-dry machining such as minimum quantity lubrication (MQL) is regarded as one of the solutions to solve this problem. However, the function of MQL in milling process is still uncertain so far which prevents MQL from widely being utilized in this specific machining process. In this paper, the mechanism of cutting tool performance such as tool wear and cutting forces in MQL assisted milling is investigated more comprehensively and the results are compared in three different cutting conditions which is dry cutting, wet cutting (flooding) and MQL. The MQL applicator is constructed from a household grade low-cost 3D printing technique. The chips surface of chips formation in each cutting condition is also observed using Scanning Electron Microscopy (SEM) machine. It is found out that wet cutting (flooding) is the best cutting performance compare to MQL and dry cutting. However, it can also be said that wet cutting and MQL produced almost the same value of tool wear and cutting forces as there is negligible differences in average tool wear and cutting forces between them based on the experiment conducted.

A novel approach to machining process fault detection using unsupervised learning

2020 ◽  
pp. 095440542093755
Author(s):  
Thomas McLeay ◽  
Michael S Turner ◽  
Keith Worden
Keyword(s):  
Fault Detection ◽  
Unsupervised Learning ◽  
Tool Path ◽  
Cutting Tool ◽  
Novelty Detection ◽  
Cutting Parameters ◽  
Machining Process ◽  
Machining Processes ◽  
Workpiece Material ◽  
Data Set

The most common machining processes of turning, drilling, milling and grinding concern the removal of material from a workpiece using a cutting tool. The performance of machining processes depends on a number of key method parameters, including cutting tool, workpiece material, machine configuration, fixturing, cutting parameters and tool path trajectory. The large number of possible configurations can make it difficult to implement fault detection systems without having to train the system to a particular method or fault type. The research of this article applies a novel method to detect the changing state of a process over time in order to detect faulty machining conditions such as worn tools and cutting depth changes. Unlike studies in the previous literature in this domain, an unsupervised learning method is used, so that the method can be applied in production to unfamiliar processes or fault conditions. In the case presented, novelty detection is applied to a multivariate sensor feature data set obtained from a milling process. Sensor modalities include acoustic emission, vibration and spindle power and time and frequency domain features are employed. The Mahalanobis squared-distance is used to measure discordancy of each new data point, and values that exceed a principled novelty threshold are categorised as fault conditions.

Synthesis of Cutting Tool Placement, Orientation and Motion Based on Surface Analysis

2000 ◽  
Author(s):  
C. G. Jensen ◽  
J. K. Hill ◽  
K. A. White
Keyword(s):  
Tool Path ◽  
Cutting Tool ◽  
A Priori ◽  
Cutting Tools ◽  
Detection Algorithm ◽  
Detection Methods ◽  
Machined Surface ◽  
Mathematical Basis ◽  
Five Axis ◽  
Verification Techniques

Abstract Engineers and designers use a wide variety of curve and surface formulations to describe products. The process of producing the physical shape of these products has remained essentially unchanged for many years. Traditionally, the process of finish surface machining has been error prone and inefficient due in large part to the mathematical basis used to control the positioning, orientation and movement of cutting tools in five-axis machining centers. This paper presents swept silhouette curvature matching algorithms for positioning and orienting a cutter such that tool and surface curvatures match. Formulations are given for both flat and filleted end mill cutters. The benefits of curvature matching are: reduction of local machining errors, reduction or elimination of grinding of the finished machined surface, and the improvement of machine tool efficiency. Examples are given that compare curvature matching to traditional machining methods. The paper concludes by discussing current research into a priori gouge detection methods based on intersection contact between the cutting tool and the design surface or the lower tolerance-bound offset surface to the design surface. An a priori gouge detection algorithm is necessary for the development of optimal tool motion and the reduction of time spent in tool path editing and verification. Techniques involving collinear normals, Bézier clipping, triangulation, normal intersection and swept volumes are suggested as techniques for examining the positional and translational tool gouge problem.

Synchronous Adjustment of Milling Tool Path Based on the Relative Deviation

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Xiao-Jin Wan ◽  
Cai-Hua Xiong ◽  
Lin Hua
Keyword(s):  
Tool Path ◽  
Cutting Tool ◽  
Cnc Machining ◽  
Numerical Control ◽  
Machining Process ◽  
Machining Accuracy ◽  
Source File ◽  
Modern Computer ◽  
Adjustment Strategy ◽  
Machining System

In machining process, machining accuracy of part mainly depends on the position and orientation of the cutting tool with respect to the workpiece which is influenced by errors of machine tools and cutter-workpiece-fixture system. A systematic modeling method is presented to integrate the two types of error sources into the deviation of the cutting tool relative to the workpiece which determines the accuracy of the machining system. For the purpose of minimizing the machining error, an adjustment strategy of tool path is proposed on the basis of the generation principle of the cutter location source file (CLSF) in modern computer aided manufacturing (CAM) system by means of the prediction deviation, namely, the deviation of the cutting tool relative to the workpiece in computer numerical control (CNC) machining operation. The resulting errors are introduced as adjustment values to adjust the nominal tool path points from cutter location source file from commercial CAM system prior to machining. Finally, this paper demonstrates the effectiveness of the prediction model and the adjustment technique by two study cases.

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