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

Author(s):  
Hans-Henrik Westermann ◽  
Benjamin Thorenz ◽  
Robert Müller ◽  
Rolf Steinhilper

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.

Author(s):  
S. Doruk Merdol ◽  
Yusuf Altintas

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.


2011 ◽  
Vol 188 ◽  
pp. 423-428
Author(s):  
Xiao Hu Zheng ◽  
G.L. Zhang ◽  
Cai An Fu ◽  
Ming Chen ◽  
Cheng Yong Wang

A new grinding method for PCB drill-helical-conical grinding method which is combined helical method and conical method is introduced in this paper. Compared with conical grinding method, helical-conical grinding method avoids the tail rising problem and improves the clearance angle distribution along with the main cutting edge. The mathematical model of this method is given in this paper.


2018 ◽  
Vol 764 ◽  
pp. 383-390 ◽  
Author(s):  
Quan Qi Xin ◽  
Tai Yong Wang ◽  
Zhi Qiang Yu ◽  
Hong Yan Hu

In this paper, the mathematical model of "S" - shaped cutting-edge curve is optimized, and the position and orientation of the grinding wheel of the first and second flank of the ball end milling cutter are calculated, The correctness of the algorithm is verified by VERICUT simulation.


Author(s):  
Alexander Leshchenko

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.


2020 ◽  
Vol 10 (1) ◽  
pp. 185-192
Author(s):  
Maksim Gnusov ◽  
Mikhail Drapalyuk ◽  
P. Popikov ◽  
N. Sherstyukov

In this article, considerable attention is paid to the method of mathematical creation of a structurally complex soil environment with vegetation. Structural and technological parameters of the interaction of the working bodies of the fire-fighting soil thrower with soil have been determined using a simulation-physical-mathematical model of the spherical disk relationship with the soil environment. The disk is equipped with a cutting edge with semicircular cuts. The mathematical model presents complex geometry of all forms of active work planes, as well as the relationship of the working bodies with soil elements. Surfaces of complex construction in the process of applying the finite element method have been transformed into a large number of simplified planar figures. The soil in the simulation physical-mathematical model is described as a complex system of a large number of spherical elements, determinately connecting with each other, as well as with the working planes of the machine. It has been determined that the relationship between the soil particles during deformation is viscoelastic in its nature. The calculation of forces is presented in the form of an algorithm for the interaction of elements on each other in relation to the distance of their location. The equations of motion are used that describe the change in the dynamic state of the soil over time. The movement of the working bodies of the unit, including spherical disk working bodies with cutouts in the framework of the mathematical model, has been considered in the simulated space, described as a parallelepiped. The ability to simulate the interaction of the working bodies of a forest fire soil-throwing machine with a working medium, including plant roots, which are located next to each other in the form of spherical elements in the geometric region. The task of increasing the efficiency of the forest fire-fighting soil-throwing machine when laying fire strips has been solved by improving the quality of preparing the soil shaft with spherical hydraulic disks equipped with a cutting edge with semicircular cuts, which are subsequently taken by thrower-cutters and feed the soil flow in a given direction


2011 ◽  
Vol 121-126 ◽  
pp. 4753-4757
Author(s):  
Guo Chao Li ◽  
Jie Sun ◽  
Yong He

This paper describes a new approach to establish the helix flute model of solid carbide end mills. Based on the theory of differential geometry and coordinate transformation, a mathematical model of the end mill helix flute will be established.The main idea of the study is to envelop the helix flute by a one-parameter surface group which consists of the cross-sectional profiles of the wheel.Then, the mathematical model will be quickly verified by MATLAB.Thus the end mill design time will be saved and the new mathematical model will be checked effectively.


2012 ◽  
Vol 622-623 ◽  
pp. 1285-1289 ◽  
Author(s):  
T.N. Valarmathi ◽  
K. Palanikumar ◽  
S. Sekar

Medium density fiberboard (MDF) is an engineered wood generally used in wooden industries. Drilling is the most frequently used machining operation in the assembly of furniture working. During drilling cutting forces are developed. These cutting forces are affecting the surface qualities and also causes delamination damage. The cutting conditions and the process parameters play an important role in controlling the cutting forces. The objective of this work is to study the influence of cutting parameters such as spindle speed, feed rate and point angle to reduce the cutting forces developed during drilling. Drilling tests are conducted using Taguchi design of experiments. The mathematical model is developed using response surface methodology (RSM) to evaluate the influence of spindle speed, feed rate and point angle on thrust force. It is seen that high spindle speed with low feed rate combination gives better results in drilling of MDF panels.


2016 ◽  
pp. 1-20
Author(s):  
Ekaterina Vladimirovna Borovik ◽  
Mikhail Mikhailovich Krasnov ◽  
Yuri Germanovich Rykov ◽  
Dmitriy Konstantinovich Shalyga

Author(s):  
I. P. Deryabin ◽  
◽  
A. S. Tokarev ◽  
B. A. Lopatin ◽  
◽  
...  

This article discusses the developed mathematicalmodel that takes intoaccount the errors of sharpening and assembling the cutting blades of a countersink tool with carbide blades. This allows you to determine the actual area of the cut sections of the allowance for each blade and calculate the cutting forces acting on them. The resultant cutting forces leads to lateral displacements of the axis of the tool during machining of the hole. The mathematical model makes it possible to determine the errors of processing holes (axis retraction, split and shape accuracy) with a countersink with a carbideblades. To check the adequacy of the mathematical model, fullscale experiments were performed on blanks madeof various materials. The method of conducting a full-scale experiment was developed. Recommended cutting modes and a countersink with three blades are selected. Processing was performed at the MM800 Fanuc processing center. Using modern automation tools – the Renishaw system and additive technologies using the Range Vision Spectrum 3D scanner, the drift of the hole axis was measured after processing with a vertical drill with carbide blades. This device allows you to get the desired result in a very short time. A compact sensor was used to measure the deflection of the hole axis, allowing for very accurate results. Substituting the part processing data into the mathematical model, the calculated values (theoretical) of the hole axis withdrawal during processing for the prototypes are obtained. The theoretical results and the results of the field experiment are compared. Comparing the obtained theoretical results – the results of a mathematical model, and the results of a full-scale experiment, it was concluded that the developed mathematical model is adequate and can be used in production by technologists in the development and computer debugging of technological processes.


1999 ◽  
Author(s):  
Serafettin Engin ◽  
Yusuf Altintas

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.


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