Tool Nose Radius Research Articles

Evaluation for tool flank wear and its influences on surface roughness in ultra-precision raster fly cutting

The occurrence of tool flank wear certainly affects the machined surface roughness in ultra-precision machining. The in-process evaluation of tool flank wear and its effects on machined surface roughness is significant, since it helps to find tool flank wear timely and reduce tool wear effect on surface roughness by further actions. However, little attention has been paid to the evaluation of tool flank wear and its effects on machined surface roughness in ultra-precision raster fly-cutting (UPRFC) process especially by using cutting chips. In the present research, evaluation of tool flank wear and its effects on surface roughness is conducted in UPRFC by examination of cutting chip morphologies. Based on the relations between chip morphologies and tool flank wear, a mathematical model was established to identify the width of flank wear land and the theoretical surface roughness under tool flank wear effects. Theoretical and experimental results show that: (1) Tool flank wear occurrence causes the formation of shutter-like structure rather than feather-like structure at the tool entry of cutting chips. (2) Cutting chips are truncated where chip thickness is comparable to the width of wear land. (3) The smooth tool flank wear increase the tool nose radius and therefore reduce the surface toughness theoretically.

An investigation of optimum cutting conditions in turning nodular cast iron using carbide inserts with different nose radius

Ductile iron can be produced to have different properties through proper control of heat treatments and additives that is directly related to the microstructure. The nodular form of the graphite imparts beneficial characteristics for this alloy. The purpose of this research is to investigate the effect of main process parameters, namely, feed rate, depth of cut, cutting speed and tool node radius on the surface roughness in nodular cast iron during turning operation. The concerned cutting tools used are turning tools with carbide inserts with tool nose radius of 0.4 and 0.8 mm. Three levels of cutting speed, feed rate and depth of cut are investigated. Surface roughness Ra was measured for each combination of machining conditions. Design of experiment tools were implemented to develop a model that relates the process variables to the resulting surface roughness. The model revealed the individual contribution of each parameter as well as the interaction among parameters to impart a change on the surface quality. The results showed that the feed rate and tool nose radius had the major contribution and to a lesser extent comes the role of cutting speed and depth of cut for controlling surface roughness. Minimum roughness was achieved at higher cutting speed, lower feed rate and lower depth of cut for the higher nose radius. Metal removal rate, as a measure for productivity, was also calculated and multi-objective optimization was conducted to minimize Ra and maximize metal removal rate simultaneously. Optical microscopy, on the effect of nose radius for the optimum process parameters for minimum Ra, revealed that for lower nose radius there are more occasions of graphite pullouts that affected the surface quality adversely.

Modeling and prediction for 3D surface topography in finish turning with conventional and wiper inserts

Wiper insert have the characteristics of achieving an excellent surface finish and improving the productivity in turning processes. Wiper insert can provide twice feed rate while maintaining the comparable surface roughness compared to that provided by the conventional insert. In the present study, surface topographies in finish turning with conventional and wiper inserts are investigated. The key element of this work is that the cutting edge path equation in the cutting tool coordinate system is transformed into the machine tool and workpiece coordinate system by the use of spatial coordinate transformation. Following that a surface topography simulation algorithm based on the cutting edge path equation and cutting parameters is put forward. The output of this work is that both the simulated surface topography and surface roughness profile are good agreement with the experimental results. Both the simulated and the actual machined surface results show that better surface topography is obtained in finish turning with the wiper insert than that with conventional insert. Burnishing effect of the wiper insert leads to half decrease of the Ra and Rz. The actual surface profiles are no longer regular wave shapes due to ploughing effect and side flow existing in the cutting zone. In addition, a surface roughness map has also been developed to optimize the selection of wiper radius and feed rate to satisfy the requirement of surface finishing with higher productivity. From the viewpoint of cutting tool design, the wiper radius with five times larger than tool nose radius can fully come into its role. This provides a novel insight into the design of wiper insert over conventional techniques. Above all, the proposed model gives a better prediction of surface roughness in finish turning process compared to the previous empirical and regression roughness models. The prediction of surface roughness in finish turning with wiper insert is also realized.

Tool path optimal design for slow tool servo turning of complex optical surface

In order to increase the machining accuracy of slow tool servo turning of complex optical surface, the optimal design for tool path was studied. A comprehensive tool path generation strategy was proposed to optimize the tool path for machining complex surfaces. A new algorithm was designed for tool nose radius compensation which had less calculation error. Hermite segment interpolation was analyzed based on integrated multi-axes controller, and a new interpolation method referred to as triangle rotary method was put forward and was compared with the area method and three-point method. The machining simulation indicated that the triangle rotary method was significant in error reduction. The interpolation error of toric surface was reduced to 0.0015 µm from 0.06 µm and sinusoidal array surface’s interpolation error decreases to 0.37 µm from 1.5 µm. Finally, a toric surface was machined using optimum tool path generation method to evaluate the proposed tool path generation method.

Optimization of Straight Cylindrical Turning Using Artificial Bee Colony (ABC) Algorithm

Artificial bee colony (ABC) algorithm, that mimics the intelligent foraging behavior of honey bees, is increasingly gaining acceptance in the field of process optimization, as it is capable of handling nonlinearity, complexity and uncertainty. Straight cylindrical turning is a complex and nonlinear machining process which involves the selection of appropriate cutting parameters that affect the quality of the workpiece. This paper presents the estimation of optimal cutting parameters of the straight cylindrical turning process using the ABC algorithm. The ABC algorithm is first tested on four benchmark problems of numerical optimization and its performance is compared with genetic algorithm (GA) and ant colony optimization (ACO) algorithm. Results indicate that, the rate of convergence of ABC algorithm is better than GA and ACO. Then, the ABC algorithm is used to predict optimal cutting parameters such as cutting speed, feed rate, depth of cut and tool nose radius to achieve good surface finish. Results indicate that, the ABC algorithm estimated a comparable surface finish when compared with real coded genetic algorithm and differential evolution algorithm.

An Investigation on Effect of Depth of Cut, Feed Rate and Tool Nose Radius on Induced Vibration and Surface Roughness during Hard Turning of 41Cr4 Alloy Steel Using Response Surface Methodology

This paper describes an aspect of a set of turning experiments performed in attempt to model, predict and optimize the machining induced vibration and surface roughness as functions of the machining, tool and work-piece variables during hard turning of 41Cr4 alloy special steel, with standard cutting tool, on a conventional lathe. Amongst others, the input variables of interest include the depth of cut, feed rate and tool nose radius. The response surface methodology, based on central composite design of experiment, was adopted, with analysis performed in Design Expert 9 software environment. Quadratic regression models were suggested, and proved significant by an analysis of variance, for the machining induced vibration of the cutting tool and surface roughness of the work-piece. They also have capability of being used for prediction within limits. Analysis of variance also showed the depth of cut, feed rate and tool nose radius have significant effect on the machining induced vibration and surface roughness. Whereas the depth of cut has dominant effect on the machining induced vibration, the tool nose radius has dominant effect on the surface roughness. The optimum setting of the depth of cut of 1.33095 mm, feed rate of 0.168695 mm/rev, and the tool nose radius of 1.71718 mm is required to minimize the machining induced vibration at 0.08 mm/s2 and surface roughness at 6.056 μmm with a desirability of 0.830.

An Investigation on Effect of Depth of Cut, Feed Rate and Tool Nose Radius on Induced Vibration and Surface Roughness during Hard Turning of 41Cr4 Alloy Steel Using Response Surface Methodology

This paper describes an aspect of a set of turning experiments performed in attempt to model, predict and optimize the machining induced vibration and surface roughness as functions of the machining, tool and work-piece variables during hard turning of 41Cr4 alloy special steel, with standard cutting tool, on a conventional lathe. Amongst others, the input variables of interest include the depth of cut, feed rate and tool nose radius. The response surface methodology, based on central composite design of experiment, was adopted, with analysis performed in Design Expert 9 software environment. Quadratic regression models were suggested, and proved significant by an analysis of variance, for the machining induced vibration of the cutting tool and surface roughness of the work-piece. They also have capability of being used for prediction within limits. Analysis of variance also showed the depth of cut, feed rate and tool nose radius have significant effect on the machining induced vibration and surface roughness. Whereas the depth of cut has dominant effect on the machining induced vibration, the tool nose radius has dominant effect on the surface roughness. The optimum setting of the depth of cut of 1.33095 mm, feed rate of 0.168695 mm/rev, and the tool nose radius of 1.71718 mm is required to minimize the machining induced vibration at 0.08 mm/s2 and surface roughness at 6.056 μmm with a desirability of 0.830.

Research on Vibration and Surface Roughness in Hard Cutting Process of Hardened Steel

Vibration of cutting process is an important factor to influence the surface roughness. By Orthogonal design, take hard cutting surface roughness test for bearing steel GCr15 with 62~64HRC, analyzing the law of the variation of cutting parameters effect the amount of vibration and the surface roughness value. And it establishes the formula about vibration and surface roughness. The amount of vibration and the surface roughness increases first and then decreases while the cutting speed increases in a specific area, meanwhile its vibration will reduce and its surface roughness will enlarge while the feed increases. The cutting depth has a little influence to surface roughness and vibration, and the cutting depth is first decreased and then increased accompanied by the tool nose radius increases with the increase of vibration and the surface roughness. The research can provide reference for improving the surface quality.

Origins for the size effect of surface roughness in diamond turning

In this work, a novel surface roughness prediction model, in which the kinematics, plastic side flow, material spring back and random factors are considered, is theoretically formulated to reveal the underlying mechanisms for the observed size effect of surface roughness in diamond turning. In this newly developed model, the copy effect of tool edge waviness is successively integrated into the kinematic component, and a yield stress and minimum undeformed chip thickness related function is constructed for calculating the material spring back. For the component of plastic side flow, the effects of minimum undeformed chip thickness, tool nose radius, feed rate as well as cutting width are took into account. Moreover, the component of random factors is assumed to follow a Gaussian distribution. Theoretical predictions and experimental validations show that the feed rate dependent size effect of surface roughness as observed on the fine grain substrate is derived from the decrement of the kinematic component being less than the increment of the plastic side flow component. For the coarse grain substrate, the large and hard inclusion inevitably appears in the matrix. Therefore, the size effect of surface roughness can be attributed to the formation of pit defect and deep groove on the finished surface at large feed rate and the protrusion of hard inclusion from the finished surface at low feed rate.

Precision Deterministic Machining of Polymethyl Methacrylate by Single-Point Diamond Turning

Polymethyl methacrylate (PMMA) is widely used as substrate material for optical fabrication in infrared and visual applications. The single-point diamond turning (SPDT) being one of the deterministic precision machining technologies needs to be explored for the manufacturing of the optical components as it is capable of providing the required characteristics such as accuracy, quality, and repeatability. Therefore, it becomes imperative to study the role of influential factors in affecting the machining characteristics of PMMA. The present work is an experimental outcome of precision deterministic machining of PMMA with SPDT. The five input factors of depth of cut, tool overhang, tool nose radius, rotational speed of spindle, and cutting feed rate are considered for machining a flat profile. Surface roughness (Ra), waviness error (Wa), and profile error (Pt) are three output parameters. The process is optimized individually for Ra, Wa, and Pt by Taguchi method. Subsequently, Ra, Wa, and Pt are optimized simultaneously by grey relation to obtain an optimal solution which identifies rotational speed of the spindle, depth of cut, and cutting feed rate as significant parameters. Ra as 11.9 nm, Wa as 0.0289 µm, and Pt as 0.285 µm are obtained as minimum values. Effect of coolant on transmission of light is also studied.

Modeling and Optimization of Hard Turning Operation on 41Cr4 Alloy Steel Using Response Surface Methodology

Product quality, productivity and organizational goodwill are often the major concern of every production or manufacturing unit. These criteria, more especially product quality, cannot readily and effectively be met through dependence on the skills of an operator. Hence, the need for optimization in order to identify the best process condition, derived from parametric combinations of process variables, for the manufacturing process. The work presented concerns an aspect of a series of hard turning experiments on 41Cr4 alloy structural steel conducted to model, predict and optimize the machining induced vibration, and the surface roughness as functions of the cutting speed, feed rate, and the tool nose radius. The response surface methodology, based on the central composite design of experiment is employed in the study, and analysis of the generated data performed with the aid of Design expert 9 software. A quadratic regression model was suggested as best fits for both the machining induced vibration and surface roughness data. These were confirmed by analyses of variance, which also revealed the tool nose radius and cutting speed, as well as the feed rate and cutting speed to be important factors that determine changes in the machining induced vibration and surface roughness, respectively. The optimum setting of the tool nose radius at 1.72301 mm, feed rate at 0.15 mm/rev, and the cutting speed at 311.075 rev/min minimized the machining induced vibration to a value of 0.08 mm/min² and the surface roughness to a value of 4.74 µmm.

Experimental Investigation and Optimization of Machining Parameters in CNC Turning Operation of Duplex Stainless Steel

Turning is the one of the material removal process that finds vast application in manufacturing vital components such as axles, shafts, etc, in large numbers. In that, every manufacturing unit focuses on high quality with increased production rate, which decides the profit level of the firm. So, its important to determine the optimal machining parameters. This work deals with the selecting the optimal parameters that plays a critical role in increasing the productivity with desired product quality at minimum cost and reduced lead time. The problem is related to a single quality characteristic is called single objective optimization. It is difficult to select the optimal parameters, if more than one quality characteristics are considered. The experiments were conducted for both dry and wet conditions with Taguchi's L18 mixed orthogonal array. Cemented carbide tool was used to machine the Duplex alloy steel work pieces on Computer Numerical Controlled (CNC) lathe. The optimal parameters were found using Taguchi's approach individually for minimum surface roughness and maximum material removal rate (MRR) and were compared with the results obtained from Grey Relational Analysis by combing the objective functions into an equivalent objective. The influence of the machining parameters cutting speed, feed rate, depth of cut and tool nose radii were studied using Analysis of Variance technique (ANOVA).

Investigation and Prediction of Material Removal Rate and Surface Roughness in CNC Turning of En24 Alloy Steel

Every manufacturing or production unit should concern about the quality of the product. Apart from quality, there exists other criterion, called productivity which is directly proportional to the profit level. Every manufacturing industry aims at producing a large number of products in relatively lesser time. In any machining process, it is most important to determine the optimal settings of machining parameters aiming at reduction of production costs and achieving the desired product quality. If the problem is related to a single quality attribute then it is called single objective optimization. If more than one attribute comes into consideration it is very difficult to select the optimal setting which can achieve all quality requirements simultaneously. In this work, EN-24 alloy steel work pieces were turned on Computer Numerical Controlled (CNC) lathe by using Cemented carbide tool (coated). The influence of four cutting parameters, cutting speed, feed rate, depth of cut, and tool nose radius on minuscule surface roughness and material removal rate (MRR) were analyzed on the basis of Response Surface Methodology approach. The experimental results were collected by following the Taguchi's L16 mixed Orthogonal Array design.

Effect of high speed turning operation on surface roughness of hybrid metal matrix (Al-SiCp-fly ash) composite

This paper explains the effect of turning parameters such as cutting speed, feed rate, depth of cut and cutting tool nose radius on surface roughness of hybrid metal matrix (Al-SiCp-Fly ash) composite. Experiments have been conducted based on the orthogonal array L16(4)5 and surface roughness was tested on the composites turned by an high speed CNC centre lathe. Analysis of variance (ANOVA) was performed to predict the significant parameters and their contribution towards surface finish of the composite. A mathematical model was developed using non-linear regression analysis. Taguchi method and Genetic algorithm have been employed to optimize the turning parameters for optimum surface roughness of the composite. The optimum turning parametric conditions have been checked with the confirmation experiments. It has been noted that the optimum condition of genetic algorithm exhibited better results than the experimental results based on the orthogonal array and the optimum condition of Taguchi method.

Determining the Effect of Process Control Parameters on Tool - Chip Interface Temperature during Hard Turning of AISI D3 Tool Steel in Dry Condition

Hard turning is recent upcoming technology through which surface quality of machined components can be enhanced while comparing with the traditional grinding method. Since the absence of metal cutting fluids during this process, numerous harmful effects on shop floor operators and possible negative impacts on environment can be eliminated. Normally some of the vital machinability aspects such as surface integrity of machined parts has been influenced by magnitude of cutting temperature which evolved in metal cutting interface. Therefore in this experimental investigation, the influence of various process control parameters on tool-chip interface temperature was evaluated during hard turning of AISI D3 tool steel in dry condition. The machining trials were conducted as per the L9 Taguchi DOE approach and subsequent experimental data were analysed with the use of Design-Expert® V7 statistical software. This experiment results revealed that feed rate is having predominant influence in determining the magnitude of cutting temperature followed by depth of cut and cutting speed whereas the influence of cutting tool nose radius is insignificant.

Energy consumption characterization in precision hard machining using CBN cutting tools

In this paper, the contribution of tool wear to the energy balance was determined for precision hard turning using chamfered CBN cutting tools. The tool nose wear VBC and the corresponding changes of component forces F c, F f and F p resulting from tool wear evolution were continuously measured during wear tests. Based on the cutting mechanics, specific cutting and ploughing energies were calculated for a number of tool wear states. In particular, changes of energy balance due to tool wear under variable feed rate, depth of cut and tool nose radius were discussed. A distinction between material removal conditions resulting from precision cutting and grinding at a very low uncut chip thickness is considered.

Considerations Regarding Some Surface State Parameters Characterized by a more Restricted Use

Frequently, on the drawings of mechanical parts, only indications concerning the surface roughness parameter Ra and, relatively rarely, the surface roughness parameter Rz are included. However, the study of the machined surface roughness highlights the necessity to use yet other surface roughness parameters, in order to have a clearer image on the state of the machined surface. Some other surface roughness parameters possible to be used and presenting importance, without the parameters Ra and Rz, were highlighted. One took into consideration the possibility of measuring parameters Rsk and Rmr by means of the available surface roughness testers. Experimental researches of turning by applying the method of full factorial experiment were developed. As input factors in turning process, the cutting speed, the feed rate and the tool nose radius were used. The experimental results were mathematically processed, being determined empirical mathematical models that highlight the influence of certain input factors of turning process on the values of some surface roughness parameters characterized by a more restricted use

A Study of Relation between Roundness and Cutting Force in CNC Turning Process

The roundness is one of the most important criteria to accept the mechanical parts in the CNC turning process. The relations of the roundness, the cutting conditions and the cutting forces in CNC turning is hence studied in this research. The dynamometer is installed on the turret of the CNC turning machine to measure the in-process cutting force signals. The cutting parameters are investigated to analyze the effects of them on the roundness which are the cutting speed, the feed rate, the depth of cut, the tool nose radius and the rake angle. The experimentally obtained results showed that the better roundness is obtained with an increase in cutting speed, tool nose radius and rake angle. The relation between the cutting parameters and the roundness can be explained by the in-process cutting forces. It is understood that the roundness can be monitored by using the in-process cutting forces.

Correlation Between Friction and Wear of Cubic Borone Nitride Cutting Tools in Precision Hard Machining

In this paper, the contribution of tool wear to friction was determined for precision hard turning using Cubic Borone Nitride (CBN) cutting tools. The tool nose wear VBC and the corresponding changes of component forces Fc, Ff, and Fp resulting from tool wear evolution were continuously measured during wear tests. Based on the mechanics of nonorthogonal cutting, the normal and friction forces acting on rake and flank faces were calculated for all measuring points, and as a result, relevant changes of the friction coefficient were determined. Additionally, friction changes resulting from tool wear under different feed rate, depth of cut, and tool nose radius were discussed in terms of the plowing energy produced by the tool nose.

Material Plastic Side Flow and White Layer in Hardened Steel GCr15 Precision Turning

Turning instead of grinding of the hardened steel is an environmentally cleaner production technology and green fabrication technique. Using the negative rake angle basic shape blades of Mountain of Sweden Sandvik Coromant PCBN7015 cut hardened bearing steel GCr15 and observe fine surface under microscopic condition.. Microscopic observation showed that there was side stream between hard turning two knife marks forming carinata. Side stream level aggravate on the fine surface with the enlargement of Tool Nose radius. The White layer of hard turning fine surface is divided into three areas. White-bright zone is made up of Cryptocrystalline martensite, Dark gray zone is made up of tempered martensite, Grayish zone is made up of the original martensite. This research will enrich theory of hard turning.