Virtual Five-Axis Flank Milling of Jet Engine Impellers: Part 1 — Mechanics of Five-Axis Flank Milling

2007 ◽  
Author(s):  
W. Ferry ◽  
Y. Altintas
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Friction Angle ◽  
Flank Milling ◽  
Cutting Force Prediction ◽  
Jet Engine ◽  
End Mills ◽  
Five Axis

Jet engine impeller blades are flank-milled with tapered, helical, ball-end mills on five-axis machining centers. The impellers are made from difficult-to-cut titanium or nickel alloys, and the blades must be machined within tight tolerances. As a consequence, deflections of the tool and flexible workpiece can jeopardize the precision of the impellers during milling. This work is the first of a two part paper on cutting force prediction and feed optimization for the five-axis flank milling of an impeller. In Part I, a mathematical model for predicting cutting forces is presented for five-axis machining with tapered, helical, ball-end mills with variable pitch and serrated flutes. The cutter is divided axially into a number of differential elements, each with its own feed coordinate system due to five-axis motion. At each element, the total velocity due to translation and rotation is split into horizontal and vertical feed components, which are used to calculate total chip thickness along the cutting edge. The cutting forces for each element are calculated by transforming friction angle, shear stress and shear angle from an orthogonal cutting database to the oblique cutting plane. The distributed cutting load is digitally summed to obtain the total forces acting on the cutter and blade. The model can be used for general five-axis flank milling processes, and supports a variety of cutting tools. Predicted cutting force measurements are shown to be in reasonable agreement with those collected during a roughing operation on a prototype integrally bladed rotor (IBR).

Virtual Five-Axis Flank Milling of Jet Engine Impellers—Part I: Mechanics of Five-Axis Flank Milling

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
W. B. Ferry ◽  
Y. Altintas
Keyword(s):  
Cutting Forces ◽  
Orthogonal Cutting ◽  
Cutting Tools ◽  
Chip Thickness ◽  
Friction Angle ◽  
Flank Milling ◽  
Cutting Force Prediction ◽  
Jet Engine ◽  
End Mills ◽  
Five Axis

This work is the first of a two part paper on cutting force prediction and feed optimization for the five-axis flank milling of jet engine impellers. In Part I, a mathematical model for predicting cutting forces is presented for five-axis machining with tapered, helical, ball-end mills with variable pitch and serrated flutes. The cutter is divided axially into a number of differential elements, each with its own feed-coordinate system due to five-axis motion. At each element, the total velocity due to translation and angular motion is split into horizontal and vertical feed components, which are used to calculate total chip thickness along the cutting edge. The cutting forces for each element are calculated by transforming friction angle, shear stress, and shear angle from an orthogonal cutting database to the oblique cutting plane. The distributed cutting load is digitally summed to obtain the total forces acting on the cutter and blade. The model can be used for general five-axis flank milling processes, and supports a variety of cutting tools. Predicted cutting forces are shown to be in reasonable agreement with those collected during a roughing operation on a prototype integrally bladed rotor.

Cutter-Workpiece Engagement Calculations by Parallel Slicing for Five-Axis Flank Milling of Jet Engine Impellers

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
W. Ferry ◽  
D. Yip-Hoi
Keyword(s):  
Cutting Forces ◽  
Solid Modeling ◽  
Boundary Representation ◽  
Flank Milling ◽  
Jet Engine ◽  
Current Configuration ◽  
End Mills ◽  
Machining Operations ◽  
Intersection Curves ◽  
Five Axis

Cutter-workpiece engagement maps, or cutting flute entry/exit locations as a function of height, are a requirement for prediction of cutting forces on the tool and workpiece in machining operations such as milling. This paper presents a new method of calculating tool-part intersection maps for the five-axis flank milling of jet engine impellers with tapered ball-end mills. The parallel slicing method (PSM) is a semi-discrete solid modeling technique written in C++ using the ACIS boundary representation solid modeling environment. The tool swept envelope is generated and intersected with the workpiece to obtain the removal volume. It is also subtracted from the workpiece to obtain the finished part. The removal volume is sliced into a number of parallel planes along a given axis, and the intersection curves between each tool move and plane are determined analytically. The swept area between successive tool positions is generated using the common tangent lines between intersection curves, and then removed from the workpiece. This deletes the material cut between tool moves, ensuring correct engagement conditions. Finally, the intersection curves are compared to the planar slices of the updated part, resulting in a series of arcs. The end points of these arcs are joined with linear segments to form the engagement polygon that is used to calculate the engagement maps. Using this method, cutter-workpiece engagement maps are generated for a five-axis flank milling toolpath on a prototype integrally bladed rotor with a tapered ball-end mill. These maps are compared to those obtained from a benchmark cutter-workpiece engagement extraction method, which employs a fast, z-buffer technique. Overall, the PSM appears to obtain more accurate engagement zones, which should result in more accurate prediction of cutting forces. With the method’s current configuration, however, the calculation time is longer.

Cutter-Workpiece Engagement Calculations by Parallel Slicing for Five-Axis Flank Milling of Jet Engine Impellers

2007 ◽  
Author(s):  
W. Ferry ◽  
D. Yip-Hoi
Keyword(s):  
Application Programming Interface ◽  
Solid Modeling ◽  
Flank Milling ◽  
Workpiece Material ◽  
Jet Engine ◽  
End Mills ◽  
Slicing Method ◽  
Machining Operations ◽  
Intersection Curves ◽  
Five Axis

Cutter-workpiece engagement maps, or cutting flute entry/exit locations as a function of height, are a requirement for prediction of cutting-forces on the tool and workpiece in machining operations such as milling. This paper presents a new method of calculating tool-part intersection maps for five-axis flank milling of jet engine impellers with tapered ball-end mills. It is called the parallel slicing method (PSM) and is a semi-discrete solid modeling technique written in C++ using the ACIS B-rep solid modeling environment. Although it is tailored towards five-axis flank milling, it can also be applied to both planar and multi-axis milling processes. The tool swept envelope is generated and intersected with the workpiece to obtain the removal volume. The removal volume is then sliced into a number of parallel planes along a given axis and the intersection curves with the tool and each plane are determined analytically. The swept area between the intersection curves of successive tool moves is calculated by solving for the area enclosed by the tangent lines. This area is removed from the workpiece material, which deletes the material cut between tool moves. Finally, the intersection curves are compared with the planar slices of the updated part, which results in a series of arcs. The end points of these arcs are joined with linear segments to form the engagement polygon which is used to calculate the engagement maps. Using this method, cutter-workpiece engagement maps are generated for a five-axis flank milling toolpath on a prototype integrally bladed rotor (IBR) with a tapered ball-end mill. These maps are compared with those obtained from a benchmark cutter-workpiece engagement calculation method – the Manufacturing Automation Laboratory’s Virtual Machining Interface (MAL-VMI). The MAL-VMI uses an application programming interface (API) in a commercial NC verification software package to obtain cutter-part intersections through a fast, z-buffer technique. Overall, the parallel slicing method appears to obtain more accurate engagement zones than those given by the MAL-VMI, although the calculation time is longer.

Real-Time Cutting Force Prediction and Cutting Force Coefficient Determination during Machining Processes

2011 ◽  
Vol 223 ◽  
pp. 85-92 ◽  
Author(s):  
Balázs Tukora ◽  
Tibor Szalay
Keyword(s):  
Cutting Force ◽  
Real Time ◽  
Cutting Forces ◽  
End Milling ◽  
Orthogonal Cutting ◽  
Machining Process ◽  
Work Piece ◽  
Processing Unit ◽  
Cutting Force Prediction ◽  
Force Prediction

In this paper a new method for instantaneous cutting force prediction is presented, in case of sculptured surface milling. The method is executed in a highly parallel manner by the general purpose graphics processing unit (GPGPU). As opposed to the accustomed way, the geometric information of the work piece-cutter touching area is gained directly from the multi-dexel representation of the work-piece, which lets us compute the forces in real-time. Furthermore a new procedure is introduced for the determination of the cutting force coefficients on the basis of measured instantaneous or average orthogonal cutting forces. This method can determine the shear and ploughing coefficients even while the cutting geometry is continuously altering, e.g. in the course of multi-axis machining. In this way the cutting forces can be predicted during the machining process without a priori knowledge of the coefficients. The proposed methods are detailed and verified in case of ball-end milling, but the model also enables the applying of general-end cutters.

scholarly journals Adaptive Cutting Force Prediction in Milling Processes

2010 ◽  
Vol 4 (3) ◽  
pp. 221-228 ◽  
Author(s):  
Takashi Matsumura ◽  
◽  
Takahiro Shirakashi ◽  
Eiji Usui
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
Flow Model ◽  
Flow Direction ◽  
Orthogonal Cutting ◽  
Cutting Parameters ◽  
Milling Process ◽  
Force Model ◽  
Cutting Force Prediction ◽  
Chip Flow

An adaptive force model is presented to predict the cutting force and the chip flow direction in milling. The chip flow model in the milling process is made by piling up the orthogonal cuttings in the planes containing the cutting velocities and the chip flow velocities. The chip flow direction is determined to minimize the cutting energy. The cutting force is predicted using the determined chip flow model. The force model requires the orthogonal cutting data, which associate the orthogonal cutting models with the cutting parameters. Basically, the required data for simulation can be measured in the orthogonal cutting tests. However, it is difficult to perform the cutting tests with specialized setups in the machine shops. The paper presents the adaptive model to accumulate and update the orthogonal cutting data with referring the measured cutting forces in milling. The orthogonal cutting data are identified to minimize the error between the predicted and the measured cutting forces. Then, the cutting forces can be predicted well in many cutting operations using the identified orthogonal cutting data. The adaptive is effective not only in extending the database but also in improving the quality of the database for the accurate predictions.

Analytical Modeling and Experimental Validation of Cutting Forces Considering Edge Effects and Size Effects With Round Chamfered Ceramic Tools

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Kejia Zhuang ◽  
Jian Weng ◽  
Dahu Zhu ◽  
Han Ding
Keyword(s):  
Prediction Model ◽  
Cutting Force ◽  
Edge Effects ◽  
Size Effects ◽  
Cutting Forces ◽  
Chip Thickness ◽  
Cutting Parameters ◽  
Reference Plane ◽  
System Transformation ◽  
Cutting Force Prediction

The cutting force is one of the key factors for planning and optimizing the machining operation in material removal processes. An analytical cutting force prediction model that takes into consideration both edge effects and size effects based on the oblique cutting theory is developed and analyzed in this study. A detailed analysis of the cutting geometry is presented based on the coordinate system transformation and uncut chip thickness (UCT), which is evaluated on the rake plane instead of the reference plane. Then, the developed Johnson–Cook constitutive model of the workpiece that takes into consideration the size effects is then applied to the prediction of edge forces coefficients and cutting forces coefficients. The edge forces are predicted using the edge coefficients prediction model with the regularity found in the orthogonal simulations, which reflect the influences of chamfered length and chamfered angle. The developed model is validated using the turning operations of super alloys with round chamfered inserts. Finally, the effects of the cutter edge, cutting parameters, and UCT on the cutting forces are investigated using the developed model. The reasonableness and effectiveness of the proposed model is demonstrated through the comparison of the measured and predicted cutting forces for various chamfer characteristics.

Sign in / Sign up

Export Citation Format

Share Document