scholarly journals Mesh-based tool path calculations for tubular joints

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402093338
Author(s):  
Morten Lind ◽  
Pål Ystgaard
Keyword(s):  
Tool Path ◽  
Cutting Tool ◽  
Angular Resolution ◽  
Software Tool ◽  
Steel Tube ◽  
Shop Floor ◽  
Interpolation Point ◽  
Reference Implementation ◽  
Normal Vectors ◽  
Construction Specification

Manufacturing of large steel tube structures is faced with excessive welding, fit-up and rework times in tube joints, due to various types of deviation from nominal shape of the tubes. This article presents a procedure and geometry calculus for generating cutting and welding paths based on measured geometries. The procedure poses the two measured meshes as per construction specification and invokes a mesh intersection procedure to get the mesh intersection path; performs an optional smoothing; interpolates the smoothed path to a specified angular resolution; estimates the two surface normal vectors and the two surface tangents in the plane spanned by the normals at each interpolation point; calculates the cutting tool and welding tool approach directions for obtaining the specified welding groove geometry at each interpolation point; and finally stores all the data parameterized by the interpolation angle. Illustrations of results with both synthetic, representative meshes and meshes obtained from scanning of actual tubes at the shop-floor at a manufacturer are presented. The reference implementation for the developed software tool is based on Python and uses the mesh modeller from the 3D creation suite Blender as platform.

A Generic, Geometric Approach to Accurate Machining-Error Predictions for 3-Axis CNC Milling of Sculptured Surface Parts: Part I — Modeling and Formulation

2006 ◽  
Author(s):  
Zezhong C. Chen ◽  
Wei Cai
Keyword(s):  
Tool Path ◽  
Cutting Tool ◽  
Geometric Model ◽  
Research Work ◽  
Geometric Approach ◽  
Cnc Machining ◽  
Sculptured Surface ◽  
Machining Error ◽  
Machining Errors ◽  
Tool Surface

In CNC machining, machining errors are usually caused by some of the sources such as cutting tool deflection, cutting tool wear, machine tool vibration, improper coolant/lubrication, and negative thermal effect. To increase product accuracy, much research has been carried out on the prediction of machining errors. However, in milling of sculptured surface parts, due to their curved shapes, the geometries of cutting tools do not match the parts’ surfaces well if the tools cut along the tool paths on the surfaces in a point-to-point way. As a consequence, machining error is inevitable, even if there is no other source of error in ideal machining conditions. To predict machining errors caused by this tool-surface mismatch, several methods have been proposed. Some of them are simple, and some represent the geometry of machined surfaces using cutter-swept surfaces. But none of these methods is accurate and practical. In this research work, a generic, geometric approach to predicting machining errors caused by the tool-surface mismatch is proposed for 3-axis sculptured surface milling. First, a new geometric model of the furrow formed by an APT tool moving between two neighboring cutter contact (CC) points is built. Second, the mathematical formula of cutting circle envelopes is derived. Then an algorithm for calculating machining errors in each tool motion is provided. Finally, this new approach is applied to two practical parts for the accurate machining-error predictions, and these predictions are then compared to the inaccurate predictions made by two established methods to demonstrate the advantages of this approach. This approach can be used in tool path planning for high precision machining of sculptured surface parts.

Development of Multi-Axis Laser-Assisted Milling Device

2017 ◽  
Author(s):  
Dong-Hyeon Kim ◽  
Wan-Sik Woo ◽  
Won-Shik Chu ◽  
Sung-Hoon Ahn ◽  
Choon-Man Lee
Keyword(s):  
Heat Source ◽  
Tool Path ◽  
Cutting Tool ◽  
Field Studies ◽  
Flat Surfaces ◽  
Laser Heat ◽  
Complex Shapes ◽  
Laser Heat Source ◽  
Removal Processes ◽  
Machining Productivity

Laser-assisted machining (LAM) process is an effective method to facilitate material removal processes for difficult-to-cut materials. In LAM process, the mechanical strength of various materials is reduced by a laser heat source focused in front of the cutting tool during machining. Since the laser heat source is located ahead of the cutting tool, the workpiece is preheated by the heat source. This enables difficult-to-cut materials to be machined more easily with low cutting energy, increasing the machining productivity and accuracy. It is difficult to apply laser-assisted milling (LAMilling) to workpieces having complex shapes, because it is not easy to control laser preheating and the cutting tool path for three-dimensionally shaped workpieces. LAMilling has only been used in limited fields such as single-direction machining of flat surfaces. To apply this process in the industrial field, studies on workpieces having various shapes are needed. This study aims to develop a laser-assisted milling device having multiple axes and to investigate the machining characteristics of several difficult-to-cut materials.

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.

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.

Tool Path Generation Method of Equal Approximation Error for Free-Form Surface in High Speed Machining

2010 ◽  
Vol 102-104 ◽  
pp. 544-549 ◽  
Author(s):  
Chun Jiang Zhou ◽  
Hong Chun Chen
Keyword(s):  
High Speed ◽  
Tool Path ◽  
Cutting Tool ◽  
End Milling ◽  
Approximation Error ◽  
Tool Path Generation ◽  
Free Form ◽  
Path Generation ◽  
High Speed Machining ◽  
Free Form Surface

The development of surface high-speed machining has put forward higher demands for uniform cutting load and smooth cutting tool path. Most current tool-path planning methods are based on constant scallop height, but they have the disadvantage of path point redundancy during the path discretization process. To overcome the problem, a tool path generation method of equal approximation error in each step for free-form surface is presented based on geodesic principle and curvature judgment. In this method, the NURBS curve is employed to realize smooth transition for adjacent two tool paths in high-speed machining. A certain angle of inclination of flat-end milling cutter during multi-axis machining improves the machining efficiency. Because of the advantage of this machining condition, the cutter location point generation algorithm during the machining condition is given by the method. The method is verified and simulated by C++. Experiment results proved that it can obtain uniform cutting load and continuous smooth cutting tool path during surface high-speed machining by the proposed method.

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.

Study on Path Planning of Involute Tooth Surface Milling With General Cutting Tool

2019 ◽  
Author(s):  
Zhaoyao Shi ◽  
Zhipeng Feng ◽  
Peng Wang
Keyword(s):  
Tool Path ◽  
Cutting Tool ◽  
Market Competition ◽  
Cutting Tools ◽  
Difficult Problem ◽  
Milling Process ◽  
Tooth Surface ◽  
Involute Gear ◽  
Accurate Position ◽  
Cutting Path

Abstract Milling involute tooth surface with universal cutting tool overcomes the difficult problem of customizing tool for nonstandard gear machining. It is difficult for gear manufacturers to gain an advantage in market competition because of the long cycle of customized cutting tools. In this paper, the milling path of involute tooth surface by a general cutting tool is studied, and how to obtain the uniform surface roughness of involute tooth surface and the cutting path scheme of cutting tool is discussed. The key point of this paper is to put forward the scheme of tool path in the milling process. The end profile of involute gear is modeled by an analytic method, and the equidistant contour of the profile of involute gear is established by using the principle of normal deviation, which provides an accurate position point for the cutting tool.

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