scholarly journals METHOD FOR CALCULATING CUTTING FORCES BY MODELING CAD WITH A SYSTEM OF GEOMETRIC CUTTING PARAMETERS WITH RADIAL MILLS

2021 ◽  
pp. 50-57
Author(s):  
Alexander Leshchenko
Keyword(s):  
Cutting Forces ◽  
Tool Path ◽  
Cutting Parameters ◽  
Cutting Edge ◽  
Software Module ◽  
Power Characteristics ◽  
Cad System ◽  
Shaping Process ◽  
End Mills ◽  
Processing Zone

The accuracy of processing surfaces of a complex profile largely depends on the selected processing strategy, which will allow creating the same, within certain limits, power characteristics of the shaping process at the intervals of the programmed tool path. In this case, it becomes possible to include tuning modules in programs for CNC machines that form vector values of corrections in certain areas, as reactors for elastic deformations of the cutting process. Therefore, it is especially important to know the modulus and direction of the resulting cutting force vector, which does not necessarily coincide with the feed direction. The purpose of this work is to build a method for calculating cutting forces by modeling the geometric parameters of a cut with a CAD system, a cutter with a nonlinear generatrix. Solid modeling of the process is based on the Boolean operations of "intersection" and "subtraction" of 3D objects: the teeth of a radius cutter with a helical cutting edge and a workpiece "moving" at a feed rate. The tool for the implementation of this method is a software module created on the basis of API functions, the input data for which are: a 3D tool and a workpiece, the equation of the trajectory of its movement and the parameters of the infeed movement. Targeting API properties, the application makes it possible to simulate various trajectories, helical or trochoidal, when machining complex surfaces. In the future, it is possible to take into account the plastic deformation processes in the chip formation zone in the model by connecting external modules. In the course of the conducted research on milling with radial end mills with a helical cutting edge, when two or more teeth are within the arc of contact, it was determined by 3D modeling how much thickness and width the layer cuts off each of the teeth during the feed per revolution. Consequently, in the process of shaping, normal and tangential cutting forces, which are different in direction and modulus, are present as a function of the angle of rotation of the cutter. Therefore, the concept of "circumferential force on the cutter", accepted in the theory of cutting, as a certain constant component of the process, can introduce an error when considering the causes of the excitation mechanism of vibrations of different nature that arise in the processing zone.

scholarly journals Mechanics and Dynamics of Serrated End Mills

Manufacturing ◽  
2002 ◽  
Author(s):  
S. Doruk Merdol ◽  
Yusuf Altintas
Keyword(s):  
Time Domain ◽  
Cutting Forces ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Chatter Stability ◽  
Edge Point ◽  
Oblique Cutting ◽  
Edge Geometry ◽  
End Mills ◽  
Chatter Stability Lobes

Mechanics and dynamics of serrated milling cutters are presented in the article. The serrated flute design knots are fitted to a cubic spline, which is then projected on helical flutes. Cutting edge geometry at any point along the serrated flute is represented by its immersion angle and tangent vectors in radial, tangential and helix directions. The chip thickness removed by each cutting edge point is determined by using previously proposed exact kinematics of dynamic milling. The cutting forces are evaluated by orthogonal to oblique cutting mechanics transformation. The experimentally proven model is able to predict the cutting forces and chatter stability lobes in time domain.

Cutting Forces in High Speed Milling of Hardened Steel by Coated Tool

2009 ◽  
Vol 69-70 ◽  
pp. 418-422
Author(s):  
L.D. Wu ◽  
Cheng Yong Wang ◽  
D.H. Yu ◽  
Yue Xian Song
Keyword(s):  
Cutting Forces ◽  
High Speed ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Hardened Steel ◽  
Depth Of Cut ◽  
Coated Tool ◽  
Radial Depth ◽  
Solid Carbide ◽  
End Mills

Hardened steel P20 at 50 HRC is milled at high speed by TiN coated and TiAlN coated solid carbide straight end mills, and the cutting forces and tool wear are measured. The result shows that TiAlN coated tool is more suitable for cutting hardened steel at high speed. Then the hardened steel is milled under different cutting parameters. It is indicated that the effect of cutting speed on cutting forces is small, but the effect of cutting speed on machine vibration should be considered. Increase feed per tooth or radial depth of cut will increase the cutting forces.

5-Axis Control Dexterous Ultraprecision Micromilling of Ruled Surface with Side Cutting Edge

2012 ◽  
Vol 516 ◽  
pp. 176-180
Author(s):  
Ryo Nishiyama ◽  
Keiichi Nakamoto ◽  
Tohru Ishida ◽  
Yoshimi Takeuchi
Keyword(s):  
Tool Path ◽  
Tool Path Generation ◽  
Ruled Surface ◽  
Cutting Edge ◽  
Work Piece ◽  
End Mill ◽  
Ball End Mill ◽  
Tool Paths ◽  
End Mills ◽  
Quality Surface

This study deals with 5-axis control tool path generation to create microshapes dexterously and efficiently, while maintaining quality. Concerning 5-axis control machining, the use of ball end mills is generally employed. However, this method needs a lot of time to obtain high quality surface. To solve this problem, a side cutting edge of the ball end mill is positively utilized with its parallel to the ruled surface. Therefore, a new CAM system is developed to detect the surface to be machined with the side cutting edge, and to generate collision-free tool paths between the tool and the work piece. The effectiveness of the developed CAM system is experimentally confirmed by creating a tiny Möbius ring.

scholarly journals Influence of stiffness of the mechanical part of the drive and cutting parameters on the shaping elastic deformation control

2021 ◽  
Vol 21 (2) ◽  
pp. 154-162
Author(s):  
V. L. Zakovorotny ◽  
V. Е. Gvindjiliya ◽  
А. А. Zakalyuzhny
Keyword(s):  
Feed Rate ◽  
Cutting Forces ◽  
Tool Path ◽  
Cutting Parameters ◽  
Cutting Process ◽  
Return Flow ◽  
Elastic Deformations ◽  
Mechanical Part ◽  
Feed Drive ◽  
The Law

Introduction. One of the ways to improve the accuracy of manufacturing parts by cutting is related to the control of elastic deformations of the tool and the workpiece. This is particularly true for slender parts, whose stiffness law along the tool path is given. In this case, the control parameter, as a rule, is the return flow rate, which affects the cutting forces, whose change causes variations in elastic deformations. To provide the specified accuracy of the diameter, it is required to coordinate the controlled trajectory of the feed drive speed with the feed rate and a priori given law of change in the stiffness of the workpiece or the law of variation of the cutting process parameters. To do this, it is required to determine the law of converting the engine speed into the feed rate, and, ultimately, into elastic deformations. This law depends on the stiffness of the mechanical part of the feed drive and the changing parameters of the cutting process.Materials and Methods. The paper presents mathematical modeling and, on its basis, analysis of the conversion of the feed rate into cutting forces, taking into account the final stiffness value of the mechanical part of the drive and the evolutionary parameters of the cutting process.  Results. It is shown that, starting from a certain critical value, the law of converting the feed rate into cutting forces becomes fundamentally dependent on the stiffness of the mechanical part of the drive. At the same time, there is an increase in time for setting a new force value when the feed rate varies, which affects the accuracy of providing forces that are consistent with the stiffness law of the part. The paper presents algorithms for calculating elastic deformations for a given stiffness law, as well as algorithms for calculating the trajectory of the feed rate at which the deformations remain constant. It is shown that the law of conversion is also affected by variations in the cutting parameters. Discussion and Conclusion. The frequency and time characteristics of the conversion are discussed. A conclusion is made about the accuracy of the diameter formed through cutting, depending on the stiffness of the mechanical part of the feed drive and on some parameters of the cutting process. 

Generalized Modeling of Milling Mechanics and Dynamics: Part I — Helical End Mills

1999 ◽  
Author(s):  
Serafettin Engin ◽  
Yusuf Altintas
Keyword(s):  
Cutting Forces ◽  
Chip Thickness ◽  
Milling Process ◽  
Cutting Edge ◽  
End Mill ◽  
Edge Point ◽  
Stability Lobes ◽  
End Mills ◽  
Helical Flute ◽  
Cutting Point

Abstract Variety of helical end mill geometry is used in industry. Helical cylindrical, helical ball, taper helical ball, bull nosed and special purpose end mills are widely used in aerospace, automotive and die machining industry. While the geometry of each cutter may be different, the mechanics and dynamics of the milling process at each cutting edge point are common. This paper presents a generalized mathematical model of most helical end mills used in industry. The end mill geometry is modeled by helical flutes wrapped around a parametric envelope. The coordinates of a cutting edge point along the parametric helical flute are mathematically expressed. The chip thickness at each cutting point is evaluated by using the true kinematics of milling including the structural vibrations of both cutter and workpiece. By integrating the process along each cutting edge, which is in contact with the workpiece, the cutting forces, vibrations, dimensional surface finish and chatter stability lobes for an arbitrary end mill can be predicted. The predicted and measured cutting forces, surface roughness and stability lobes for ball, helical tapered ball, and bull nosed end mills are provided to illustrate the viability of the proposed generalized end mill analysis.

Mechanics and Dynamics of Serrated Cylindrical and Tapered End Mills

2004 ◽  
Vol 126 (2) ◽  
pp. 317-326 ◽  
Author(s):  
S. D. Merdol ◽  
Y. Altintas
Keyword(s):  
Cutting Forces ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Chatter Stability ◽  
Edge Point ◽  
Edge Geometry ◽  
Proposed Model ◽  
Chatter Vibrations ◽  
End Mills ◽  
Chatter Stability Lobes

Serrated end mills are effectively used in suppressing chatter vibrations in roughing operations. Mechanics and dynamics of serrated cylindrical and tapered helical end mills are presented in the article. The serrated flute design knots are fitted to a cubic spline, which is then projected on helical flutes. Cutting edge geometry at any point along the serrated flute is represented by its immersion angle and tangent vectors in radial, tangential and helical directions. The chip thickness removed by each cutting edge point is determined by using exact kinematics of dynamic milling. The cutting forces are evaluated by orthogonal to oblique cutting mechanics transformation. The experimentally proven model is able to predict the cutting forces and chatter stability lobes in time domain. It is shown that the proposed model can be used in evaluating the performance of serrated end mills during their stage.

Prediction of Cutting Forces of Solid End Mills With Differential Helix Angles: A Numerical Approach

2016 ◽  
Author(s):  
Hans-Henrik Westermann ◽  
Benjamin Thorenz ◽  
Robert Müller ◽  
Rolf Steinhilper
Keyword(s):  
Mathematical Model ◽  
Cutting Forces ◽  
Numerical Approach ◽  
Edge Length ◽  
Cutting Edge ◽  
Milling Operations ◽  
Variable Helix ◽  
Constant State ◽  
End Mills ◽  
The Mathematical Model

Solid end mills with multi-section cutting edges and variable helix angles are available for application. New types of solid end mills for low energy consumption have recently been developed. These so-called Low Power Cutting (LPC)-Tools are characterized by differential helix angles. Compared to solid end mills with variable helix angles, the new differential helix angles change their pitch continuously over the cutting edge length. Due to this fact the cutting conditions are not in a constant state during the revolution of the cutting tool. Existing mathematical approaches for the calculation of cutting forces only consider constant helix angles in milling operations. This paper describes an approach for the prediction of cutting forces for differential helix angles. The developed mathematical model is based on geometrical considerations. Due to a continuously changing pitch over the cutting edge length a numerical approach for the mathematical model is chosen.

A New Method for the Preparation of Cutting Edges via Grinding

2013 ◽  
Vol 769 ◽  
pp. 85-92 ◽  
Author(s):  
Christian Effgen ◽  
Bejamin Kirsch
Keyword(s):  
Tool Path ◽  
Cutting Edge ◽  
New Method ◽  
Grinding Wheel ◽  
Outer Diameter ◽  
Processing Times ◽  
Elastic Bond ◽  
End Mills ◽  
Grinding Machine ◽  
Milling Tools

In this paper, a new method for the preparation of cutting edges via grinding is presented. This method enables the manufacturing of the tool macro and micro geometry in one setup without reclamping, allowing improved flexibility, repeatability and accuracy at reduced processing times. This new method is path controlled using a special elastic bond for the grinding wheels. By using elastic bond, a rounded cutting edge instead of undesired chamfers can be achieved, as the bond nestles around the cutting edge and elastically deforms. The elastic bond is specified by the grain concentration and its basic hardness. Besides the specifications of the bond, the process kinematics highly influences the properties of the cutting edge. The kinematics is a combination of the tool path (machining strategy) and the grinding wheel geometry. The presented experiments include the examination of three different kinematics using three different grinding wheel geometries, FEPA 1A1, 1V1 and 4A2. For each kinematics, three different grain concentrations and three degrees of basic bond hardness were tested, resulting in a complete amount of 27 parameter combinations. The outer diameter cutting edges of cemented carbide milling tools (end mills) were prepared in a 5-axis tool grinding machine. The shape and quality of the achieved cutting edge rounding was qualitatively evaluated by means of scanning electron microscopy (SEM).

PREDICTION OF CUTTING FORCES IN BROACHING OPERATION

2013 ◽  
Vol 12 (01) ◽  
pp. 1-14 ◽  
Author(s):  
A. HOSSEINI ◽  
H. A. KISHAWY
Keyword(s):  
Cutting Forces ◽  
Cutting Parameters ◽  
Cutting Edge ◽  
Force Model ◽  
Machining Processes ◽  
Parametric Curve ◽  
Virtual Simulations ◽  
Machining Operations ◽  
Chip Load ◽  
Made In

Prediction of cutting forces is one of the fundamental stages in the modeling of machining processes. The costly machining tests can be replaced by virtual simulations where cutting parameters and material properties can be altered repeatedly with no cost. Broaching is one of the machining operations which is extensively used in the industry. The geometry of broaching tool varies according to the desired profile of the workpiece which can be a simple line or complicated curves. This broad range of geometries imposes complexity on the distribution of the chip load along the cutting edge. Therefore, introducing a practical force model for broaching operation can be challenging. An attempt is made in this paper to present a force model for broaching. The newly proposed force model expresses the cutting edge as a B-spline parametric curve and uses its flexibility to calculate the chip load as well as cutting forces for orthogonal and oblique broaching. Verified by previously published experimental results, the presented model has a great capability to simulate broaching cutter geometry along with cutting forces.

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