Solid End Mill Research Articles

Wheel path planning for flute grinding of non-cylindrical solid end-mills based on circular arc projection

Flute grinding is a crucial process in solid end-mill manufacturing, because the generated flute parameters, i.e. helix angle, rake angle, core radius, and flute width, have significant effects on the cutting performance of end-mills. However, the flute grinding of non-cylindrical solid end-mills is still challenging due to the variation of the flute parameters along the tool axis. This paper proposes an accurate and efficient method of wheel path planning for flute grinding of non-cylindrical solid end-mills based on circular arc projection. The wheel path determined by the new method can accurately generate the designed helix angle, rake angle, core radius, and flute width, even if all of these parameters vary along the tool axis. The helix angle and rake angle are ensured by the conjugate condition between the wheel surface and the cutting-edge curve. Based on circular arc projection, equivalent errors of the core radius and flute width are introduced to quantify the machining errors of the two parameters, without the need to predict the flute profile. Simulations and experiments are conducted to validate the proposed method. Three types of non-cylindrical end-mills i.e. tapered end-mill, tapered barrel end-mill, and barrel end-mill, are considered in the validation. The measured results indicate that the generated flute parameters coincide well with the designed ones at different axial positions of the end-mills.

Extendable machine tool wear monitoring process using image segmentation based deep learning model and automatic detection of depth of cut line

Automating the monitoring of machine tools poses a significant challenge, with previous studies relying on machine vision to address this issue, primarily focusing on measuring specific tool wear using custom algorithms. In this study, we introduce an automated tool wear monitoring process capable of assessing wear across various tools. Utilizing deep neural network models for image classification and segmentation, our proposed process effectively masks areas where tool wear occurs. The image classification model selects the best-performing backbone model based on the highest F1 score. To account for varying depths-of-cut lines among different tools in the masked area, we introduce an algorithm that utilizes the Hough transform to determine the horizontal angle with the cut line. By systematically measuring the maximum flank wear of diverse tools, including indexable, ball, and solid endmills, using this method, we can replace conventional manual processes. This approach can be extended and automated for various machine tools, offering substantial potential for enhancing manufacturing tool monitoring processes.

A grinding process method of solid end mills groove with segmented unequal helical angles by cutting edges offset and interference

Solid end mills with variable helical angles within a certain range can effectively mitigate cutting vibration and enhance the machining quality. However, the grinding process for these helical grooves is complex, and the existing disclosed process method cannot grind those helical grooves accurately. This study proposes a two-pass grinding method for the helical groove with variable helical angles. First, a cutting edge model with variable helical angles is established by edge offset to guide the grinding process. Second, to ensure the required cross-section parameters while avoiding overcutting and edge discontinuity, a novel optimization algorithm for determining the grinding wheel posture, and calculation rules of related process parameters for the two-pass grinding process are proposed. Finally, the verification is conducted and the results show that the maximum relative error of cross-section parameters is 1.254 % in simulation machining, which indicates the theoretical modeling of posture optimization and cutting edge are correct, and the two-pass grinding process is effective. Furthermore, this approach can be extended to grinding other complex structures with helical grooves.

Geometric Structures for Sialon Ceramic Solid End Mills and Its Performance in High-Speed Milling of Nickel-Based Superalloys

Sialon ceramic tool material has become one of the most ideal materials for the high-speed cutting of superalloy materials. However, studies on the geometric structure of sialon ceramic solid end mill is lacking at the present. In this work, the geometric structure of sialon ceramic end mills was designed for difficult-to-machine nickel-based superalloy materials. The cutting force and heat, flank wear and machined surface quality were analyzed to study the effect of the main parameters on tool performance. The results showed that the end mill experienced severe flank wear and chipping, which were the leading cause of its failure during high-speed cutting. The cutting force and temperature decreased gradually with the increase in the helix angle. With the increase in the rake angle, the flank wear and the quality of the machined surface of the specimen first decreased and then increased. With the increase in the relief angle, the cutting temperature of the ceramic end mill gradually decreased, and the cutting force and the machined surface roughness showed an initial decrease and then increased. When the helix angle, rake angle and relief angle were 35°, −15° and 12°, respectively, the sialon ceramic end mill exhibited the best cutting performance and obtained better machined surface quality in the nickel-based superalloys.

Performance evaluation of high-pressure cooling by using external rotary liquid applicator in milling Ti–6Al–4V alloy

An effective cooling mode with appropriate process parameters can enhance the machinability as well as productivity. In this regard, this study focuses on evaluating the machinability of widely used Ti–6Al–4V alloy with the use of high-pressure coolant jets compared to dry milling. A novel rotary applicator was designed and developed to feed high-pressure coolant jets without any drastic change of solid end mill cutter. Four flutes solid HSS end mill cutter was selected for machining because of its some intensive properties. Biodegradable VG-68 cutting oil was chosen as cutting fluid due to its better thermo-physical properties with higher flash points. Machinability was assessed at 16–32 m/min cutting speeds and feed rates of 0.08–0.16 mm/tooth with a constant depth of cut of 1.0 mm, taking into account the average cutting temperature, resultant cutting force, mean surface roughness, and tool wear. Dry milling produced the worst results for all of the investigated responses, with excessive tool wear due to the lack of cooling and lubrication. Compared to dry milling, high-pressure cooling (HPC) lowered average cutting temperature, resultant cutting force, and mean surface roughness by 11.21–21.57%, 8.63–13.12%, and 6.09–29.6%, respectively, whereas rotary high-pressure cooling (RHPC) reduced these parameters by 15.39–27.27%, 14.05–21.18%, 16.48–41.04%. RHPC's efficient cooling and lubrication increased the machinability of the Ti–6Al–4V alloy. Dry milling showed severe flank wear with increased built-up edge (BUE) development, abrasion, and adhesion, whereas HPC and RHPC dramatically reduced the severity of tool wear. In HPC and RHPC, the tool life was consequently increased by 6.8 and 9 min, respectively.

Development and application of parametric design system for solid end mills based on Open CASCADE

Development and application of parametric design system for solid end mills based on Open CASCADE

An investigation of the effect of tool wear on cutting force coefficients for solid end mills

The traditional way to replace an end mill is based on empirical knowledge: a tool life criteria is defined according to the application, i.e. roughing or finishing, and the tool manufacturer provides tool life in different cutting conditions. The aim of this paper is to evaluate the possibility to use cutting force coefficients for identifying the tool wear of solid end mills with different number of flutes. Cutting forces have been measured with the new and worn tool, and they are used for estimating cutting force coefficients. Two different workpiece materials, DIN 42CrMo4 and AISI 304, have been used.

Examination of surface roughness values of 6061-T6 aluminum material after machining and after anodizing process

The use of aluminum material is very common, especially in parts that require precision mechanical processing, such as in the aerospace or defense industry. Since weight reduction in related vehicles or technologies in the fields of aviation and defense industry is one of the biggest goals, the use of aluminum as a metal material has become one of the first targets. The high weight/strength ratio of aluminum compared to steel is one of the main reasons why it is preferred. In addition to these advantages of aluminum materials, we have two expectations for 6061 aluminum parts in most of the projects we work on. The first is to minimize the frictional intensity of the aluminum parts working in contact with each other. The second is to provide the surface roughness of the gasket pressing surface on the surfaces where gaskets are used due to the need for sealing. For both requirements, our goal in this study will be to achieve the surface roughness value as maximum Ra 0.2 after machining and maximum Ra 0.3 after anodizing. The study was carried out with six different cutting tools. These tools, in order; end mill (with one insert) cutter, end mill (with two inserts) cutter, solid end mill, single insert diamond tool, monocrystalline diamond tool and superfinishing tool. Particular attention was paid to the cleanliness of the chemical baths used in the anodizing specific to this study. As a result, it has been observed that much more precise results can be achieved than the currently accepted surface roughness value when suitable machining parameters and optimum anodizing coating parameters are used. By using different cutting parameters with the same tool, by increasing the speed and feed values and decreasing the depth of cut, there is a slight improvement in the surface roughness values. The results of the experiments are presented in table and graphic and are suitable only for observed cutting conditions, used tools and material.

Investigation on the machinability of TiN nano particulate reinforced magnesium matrix composite

In the present work, the machinability of magnesium matrix nanocomposite was investigated. The nanocomposite consists of pure Mg as matrix and TiN Nano particulate as reinforcement. The composite was fabricated through powder metallurgy process for three different compositions such as 1.5, 2.5 and 5% by weight of TiN Nano particulates. Machinability behavior of the nanocomposite was studied through milling process with process parameters, feed rate of 5, 10 and 15 mm/min, depth of cut of 0.15, 0.3 and 0.45 mm and spindle speed of end mill remain constant of about 2000 rpm. The performance measures considered in this study are cutting forces, material removal rate, surface roughness and tool tip temperature. The milling process was carried out at room temperature for normal atmospheric conditions. Poly crystalline diamond (PCD) coated solid carbide flat type end mill was used in the study. L27 orthogonal array was used to conduct the experiments. The results from the study revealed the fact that the performance measures like cutting force, tool tip temperature and surface roughness are significantly influenced by TiN Nano particulate in the composite, whereas the material removal rate is greatly influenced by the machining parameter feed rate. High hardness, heat resistance and excellent wear resistance of TiN Nano particulate resulted in the influence of the performance measures. Main effect plots and interaction plots were generated for the performance measures which was further followed by ANOVA and second order polynomial regression equation to test the level of significance with least error.

An iterative optimization algorithm for posture and geometric parameters of grinding wheel based on cross-section sensitivity and matching constraints of solid end mills

Grinding wheel posture and geometric parameters are the key to optimizing the grinding process for helical grooves of solid end mills. However, the current envelope calculation models have not done enough research on the influence of the grinding wheel discretization method and grinding kinematics models mainly focus on helical grooves with constant core radius. Moreover, the matching error of the overall cross-section curve is ignored. These problems can reduce model generality, affect final calculation results, and cause inferior cutting performance. Therefore, a novel optimization algorithm for grinding wheel posture and geometric parameters is developed in this paper. Firstly, a parametric grinding wheel modeling method with adaptive adjustment of control variables is proposed, and a generalized grinding kinematics model for variable core radius is established. Then, by analyzing the sensitivity of cross-section parameters and the formation mechanism of the core radius, an iterative strategy based on parameter sets is established. Under the condition that the core radius is ensured in advance, the matching errors of rake angle, groove width, and overall cross-section curve are considered comprehensively to optimize the grinding wheel posture and geometric parameters. Finally, the proposed method is verified by simulation and machining. The results indicate that the proposed method can realize the envelope calculation of the helical groove with variable core radius, and optimize the grinding wheel posture and geometric parameters accurately and efficiently.

A study of machinability of Al7075-T6 with solid carbide end mills

The use of aluminium alloys in manufacturing industry has increased in recent years. Concomitant to this growth, the machining of aluminium alloys has enormously increased in volumetric proportions—the chip volume represents up to 80 % of the original volume of the machined material, like in aerospace. The focus is on roughing machining using solid end mills of Al7075-T6 in the general engineering application. The effect of cutting speed, feedrate, radial depth, lubricant and coating has been investigated.The machinability has been identified measuring cutting forces and workpiece wall deviation. Finally, the maximum productivity is calculated.

Tooling Innovations to Meet Precision Machining Demands

Sandvik Coromant launches new tools for precision; Seco Tools a new family of solid end mills; Guhring adds a new series of end mills; Walter’s new solid carbide end mills; ITC brings new innovations to the market; plus Horn introduces new modular system for reaming large diameter holes

Si-containing diamond-like carbon coatings to improve the wear resistance of solid ceramic end mills

The study’s purpose is to determine the rational Si content in the DLC-Si external layer of (CrAlSi)N/DLC-Si coatings deposited on α/β-SiAlON + TiN ceramics. The influence of Si content on physical and mechanical properties of coatings such as microhardness, modulus of elasticity, and friction coefficient, and wear resistance of solid ceramic end mills in machining nickel alloy NiCr20TiAl is determined.

An experimental investigation on Inconel 718 interrupted cutting with ceramic solid end mills

Solid ceramic end mills for machining heat resistant super alloys (HRSA) have the potential to generate higher material removal rates, up to one order of magnitude, with respect to standard carbide tools. The machining operations in aerospace industry, where large removals are required to obtain tiny and slender parts like turbine blades, is a cost-intensive task that can benefit of the adoption of ceramic solid end mills. However, these tools show a quite limited tool life, especially when used with interrupted tool engagement strategies. Moreover, they might induce heat-related problems in the workpiece material surface integrity. This paper investigates the cutting and the tool wear during milling Inconel 718 with solid ø12 mm cutting end tool made by SiAlON. The wear mechanisms are studied together with their effects on process signals as cutting forces and power, measured via external and CNC integrated sensors. The carried experimental campaign allowed to find out that tool clogging and edge chipping were the primary cutting phenomena leading the tool wear. Cutting strategy (downmilling or upmilling) produced different results in terms of tool wear sensitivity and process outputs whereas upmilling configuration showed the best results in terms of cutting signals stability and surface integrity. At the same time, cutting speed was found to increase the cutting power more in upmilling than downmilling cutting. The analysis of the forces and power demonstrated that the typical tool wear mechanisms can be traced by signal monitoring due to their high impact on cutting processes. This fact shows the good potential of signal monitoring for a better tool life evaluation.

Innovation in Ceramic End Milling

US tooling manufacturer Greenleaf has introduced a new product line in the shape of the XSYTIN-360 family of solid ceramic end mills that it says provide a range of benefits to users

Development of DLC-Coated Solid SiAlON/TiN Ceramic End Mills for Nickel Alloy Machining: Problems and Prospects

The study is devoted to the development and testing of technological principles for the manufacture of solid end mills from ceramics based on a powder composition of α-SiAlON, β-SiAlON, and TiN additives, including spark plasma sintering powder composition, diamond sharpening of sintered ceramic blanks for shaping the cutting part of mills and deposition of anti-friction Si-containing diamond-like carbon (DLC) coatings in the final stage. A rational relationship between the components of the powder composition at spark plasma sintering was established. The influence of optimum temperature, which is the most critical sintering parameter, on ceramic samples’ basic physical and mechanical properties was investigated. DLC coatings’ role in changing the surface properties of ceramics based on SiAlON, such as microrelief, friction coefficient, et cetera, was studied. A comparative analysis of the efficiency of two tool options, such as developed samples of experimental mills made of SiAlON/TiN and commercial samples ceramic mills based on SiAlON, doped with stabilizing additives containing Yb when processing nickel alloys (NiCr20TiAl alloy was used as an example). DLC coatings’ contribution to the quantitative indicators of the durability of ceramic mills and the surface quality of machined products made of nickel alloy is shown.

Study of new solid end mill for side milling of Ti-6Al-4V with improved cooling efficiency

In the present work, machining performance of a new solid carbide end mill has been investigated during side milling of Ti-6Al-4V. It is observed that adding cooling grooves on the clearance side of the cutting tool improves the tool performance by decreasing tool wear. Tool temperature measurements by infrared camera showed that these grooves decreased the tool temperature during the machining process. In order to understand the mechanisms behind this improvement, simulations of the coolant flow around the tool with and without these grooves are performed. Modelling and simulation results showed that these cooling grooves lead to an increase in the velocity of fluid at the head of the tool, which results in more efficient cooling and consequently the temperature along the cutting edge is decreased.

Effect of Geometrical Parameter Cutting Edge on the Toroidal Forming Surface of a Solid End Mill

Solid end mill with a toroidal forming section are the most productive solutions in the field of processing difficult-to-process materials. The process of forming the cutting geometry of such cutters is performed on grinding machines with CNC with the use of abrasive grinding wheels. The formation of the cutting edge on the toroidal section is carried out by discrete movements of the working bodies of the machine in accordance with the control program. The disadvantage of the stepper drive used in CNC machines is the limited discreteness of the described trajectory resulted in the loss of accuracy when forming radius, arc, spherical and toroidal sections. Loss of accuracy in the formation of elements of the working geometry of a solid end mill can negatively affect the tool life, and the structural strength of the joints of the transition of working surfaces. The study is aimed at identifying the necessary and sufficient number of points that describe the spatial shape of the cutting edge with acceptable loss of accuracy.

Investigation of Technological Parameters for Machining Toroidal Section of Solid Ceramic End Mills

Solid ceramic mills are a promising technological solution for cutting heat-resistant materials. Although nanostructured cutting ceramics has a number of valuable physical and mechanical properties providing high operational performance of mills, it has low strength. The design of a solid ceramic mills is formed by smooth surfaces without stress concentrators to ensure operability and to reduce the probability of failure. The most important structural element of solid ceramic end mill is a helical groove with a negative rake angle needed to increase surface strength. This groove can be machined with standard grinding wheels of type 1A1 or 1V1. However, the application of grinding wheels of a standard shape requires the use of reduced cutting parameters to prevent chipping on the forming sections of the cutter. Chipping can be caused by too short length of the contact line and the stress concentration at the end point of the profile of the grinding wheel, which is typically fully responsible for shaping the front surface and its transition to the tooth back. In this paper, in order to increase the contact line, we develop a new approach to designing grinding wheels for machining helical grooves of solid mills and determining rational technological and operational parameters for there use. A new approach is developed based on the fundamental principles of analytical geometry and linear algebra, numerical methods and basic axioms of the shaping theory. In this study, we have identified the key relationships between parameters determining the position of the grinding wheel relative to the workpiece and the geometrical parameters of a solid ceramic mills. The developed approach allowing to determine the specific design of the grinding wheel, depending on the initial parameters of the mill and the trajectory of the axis of the wheel relative to the mill, was implemented in the MathCAD environment.

An iteration-based algorithm for two-pass flute grinding of slide round milling tools

Solid end mill cutting tools are widely used in machining of curved surface parts in many industrial sectors, e.g., aerospace, automotive, and energy. Grinding is one of the most important processes in the manufacturing of the tools, and the movement of the grinding wheel closely influences the key parameters of helical groove cross-section, i.e., rake angle γo, inner core radius Rc, outer core radius Rcb, and edge width Ew, as well as chip removal capacity. However, a “closed” flute of a tool, which is one style of flute, may cause many problems if grinding it by one-pass, e.g., grinding wheel dressing to adapt to the change of flute parameters. To solve the problem in “closed” flute grinding, this paper proposes a two-pass flute grinding based on the iteration method. Within the context, some parameters and rules are identified in modeling of the two-pass grinding to control grinding wheel width and to smoothen grinding marks between the two passes of grinding. Finally, the method is implemented and validated by a set of numeric simulations and experiments. The results show that the errors of core radius, rake angle, edge width, and big core radius of the two ground tools are 1.1%, 2.0%, 3.4%, and 2.2%, respectively, which are within the designed tolerances.