Grinding Angles Research Articles

High-sensitivity biconical optical fiber SPR salinity sensor with a compact size by fiber grinding technique

For seawater salinity measurement, a high-sensitivity, ultra-compact, and corrosion-resistant biconical optical fiber surface plasmon resonance (SPR) sensor deposited with a 40 nm thick gold film based on fiber grinding technique was fabricated and demonstrated in this article. The ultra-compact biconical sensing structure with different grinding angles were fabricated by applying the optical fiber grinding machine, and the length of the sensing region was only hundreds of microns. The experimental results indicated that when the grinding angle was 14°, the sensor showed the highest sensitivity: a high refractive index sensitivity of 3965 nm/RIU and a high salinity sensitivity of 0.6898 nm/‰. Meanwhile, this biconical sensor had acceptable repeatability and stability. Therefore, this article demonstrated the feasibility of the biconical structure to improve the sensitivity of fiber-based SPR sensors, and provided a novel and practical solution for seawater salinity measurement.

МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ В ИССЛЕДОВАНИЯХ ШЕРОХОВАТОСТИ ПРИМЕНИТЕЛЬНО К ВНУТРЕННИМ ПОВЕРХНОСТЯМ

The article considers the problems of mathematical modeling roughness of surfaces obtained in the cutting process. Roughness is related with the technological parameters of the system “machine-fixture-tool-workpiece” and the problem of fine finish of internal threads. There have been analyzed the existing mathematical models of finished surface roughness and stated the need to develop a mathematical model of internal surface roughness. There has been worked out a mathematical model of threaded profile roughness of the internal thread made by the tap in the details made from high-strength corrosion-resistant DI-8 grade steel that is popular in ship equipment building, by using methods of planning experiments. Geometric parameters of the tap cutting part have been taken as independent: angle of the intake cone, face and rear grinding angles. There have been listed parameters for qualitative evaluating and rating sharpened surfaces that are given in GOST 2789-73: altitudinal, step, profile bearing surface parameters. A mean-square deviation of microroughness profile was suggested to use as a roughness parameter. Impression method was used to evaluate roughness, light section device МИС-11 of V.P. Linnik was used to measure mold surface roughness. The method of planning experiments of predicting the roughness of internal surfaces has been found efficient. Theoretical studies are based on metal cutting methods, as well on methods of experiment planning with application of regression analysis; experimental research was conducted under laboratory conditions by using a computation machine. The research results allow to greatly improve the surface finish technologies in shipbuilding.

Influence of environmental friendly multiphase lubricants on the friction and transfer layer formation during sliding against textured surfaces

Both surface texture and multiphase lubricants (additives in base oil) influence the friction and wear performance during sliding. However, the synergy of their interaction is still unknown. In the present investigation, an effort is made to understand the influence of environmental friendly multiphase lubricants on the friction and transfer layer formation during sliding against various surface textures. In this study, unidirectional surface textures were created and sliding tests were conducted against various grinding angles of the unidirectional texture. The sliding tests were conducted in multiphase lubricants consisting of canola oil (biolubricant) and nano-additives (graphene) at various concentrations. The results showed that the coefficient of friction (COF) and transfer layer formation was influenced by the grinding angle. However, it was found that this influence can be minimized by using an optimum concentration of graphene in canola oil. A minimum COF of 0.05 ± 0.01 could be achieved for various grinding angles by utilizing a specific concentration of graphene. It was found that a high concentration of Gr (3 wt%) was required when sliding at 0° and a low concentration of Gr (1 wt%) was required when sliding at 45° to achieve the minimum COF. This was attributed to the variations in asperity and Gr additive interaction when sliding at different grinding angles. The present study details the observed friction and transfer layer formation results and analyzes the mechanism of multiphase lubrication during sliding at various grinding angles. An asperity interaction model for sliding against various grinding angles and in a multiphase lubricant with varying additive concentrations has also been presented.

Numerical modelling of orthogonal cutting: application to woodworking with a bench plane.

A numerical model for orthogonal cutting using the material point method was applied to woodcutting using a bench plane. The cutting process was modelled by accounting for surface energy associated with wood fracture toughness for crack growth parallel to the grain. By using damping to deal with dynamic crack propagation and modelling all contact between wood and the plane, simulations could initiate chip formation and proceed into steady-state chip propagation including chip curling. Once steady-state conditions were achieved, the cutting forces became constant and could be determined as a function of various simulation variables. The modelling details included a cutting tool, the tool's rake and grinding angles, a chip breaker, a base plate and a mouth opening between the base plate and the tool. The wood was modelled as an anisotropic elastic-plastic material. The simulations were verified by comparison to an analytical model and then used to conduct virtual experiments on wood planing. The virtual experiments showed interactions between depth of cut, chip breaker location and mouth opening. Additional simulations investigated the role of tool grinding angle, tool sharpness and friction.

Reflective-distributed SPR sensor based on twin-core fiber

We propose and demonstrate a reflective-distributed surface plasmon resonance (SPR) sensor based on the twin-core fiber. Firstly, we study the effects of the fiber dual tapered (DT) probe grinding angle on the SPR dynamic range. The results show that for larger grinding angles, the resonance wavelength increases, resulting in a higher testing sensitivity. By using this method, we can make the sensor operate in an optimal waveband. Secondly, on the basis of the results above, we grind the DT probe to be an asymmetric wedge shape to configure two grinding angles (6° and 17°) to realize the distributed sensing. Results show that, with the refractive index detecting a range of 1.333–1.385, we can get two separated sensing zones, 591–715nm and 729–966nm, the testing sensitivity are 2385nm/RIU and 4558nm/RIU respectively. By using this method, we can detect multiple analytes in the same sensing area simultaneously, besides that we can also effectively compensate for the errors caused by background index interference, and the refractive index change resulting from the non-specific binding, or physical absorption and others. It worth to say that by using this method, we can adjust and control the resonance wavelength by changing the fiber grinding angle, while keeping the testing sensitivity is not reduced. For practical applications, this reflective distributed fiber-based sensor is much suitable for biochemical sensing, it has small size and can enter a small testing spaces (μm scale). The diameter of the twin-core fiber is the only 125μm, which helps to be integrated into a micro-fluidic chip. In this paper, we integrate the fiber probe into an infusion needle to simulate blood vessels on-line monitoring.

Mechanistic force modeling of single point cutting tool in terms of grinding angles

The cutting tool angles have conventionally been presented using projective geometry in terms of the projections of cutting edges on respective planes, which makes the visualization of geometry difficult, particularly for complex tools. Modeling a cutting tool using the actual grinding angles can simplify the geometric definition of the tools and provide a comprehensive and simple definition of tools for downstream applications. The paper presents the 3D definition of the faces of a single point cutting tool (SPCT) in terms of 3D rotational grinding angles and maps the new tool nomenclature with the ASA, ORS and NRS nomenclatures. A mechanistic model is subsequently proposed to predict the forces in terms of the grinding angles, chip thickness and velocity using second degree polynomial function, unlike the conventionally used logarithmic ones. The model has been calibrated for HSS tool and Mild Steel workpiece combination for end turning of a tubular workpiece based on the regression analysis of a central composite design of the experiments. The results have been discussed and the model has been validated for a new set of experimental data. The model shows a good correlation to the observed results.

Experimental Research on Surface Integrity with Less or Non Fluid Grinding Process

The grinding fluid can realize its function of cooling and lubricating only when it breaks through the airflow barrier around the wheel and enter into the high pressure area between wheel and workiece. The grinding fluid with different jet angles and different flow quantity has the different effect of cooling and lubricating in the grinding process. The experimental research of grinding fluid jet flow is carried out in cylindrical grinding process and the affecting mechanism of the grinding fluid injection angles and quantity on the surface integrity are analyzed based on the cylindrical grinding under the less grinding fluid conditions in this paper. It is obtained that the surface integrity of the workpiece processed at 35° fluid jet angle is superior to that of the workpiece processed at 0° fluid injection angle. It is also obtained that the more the fluid quantity is, the better the surface quality is to some extent. It provides research foundation for designing the supplying parameters of the grinding fluid and realizing the grinding process with the less grinding fluid flow.

A generic mathematical model of single point cutting tools in terms of grinding parameters

The paper presents the analytical geometric details of the mathematical modeling of a single point cutting tool with a generic profile. The grinding angles and the ground depths on the tool are allowed to vary along the tool flanks and face, altering the cutting angles from point to point. The surface modeling begins with the creation of a tool blank model. Then unbounded surfaces are considered and transformed to get the cutting tool surfaces. The intersection of these surfaces gives the complete model of the tool. Starting from the basic model where the tool face and flank are planar, the generalization of the geometric design has been done in two steps to give free-form shapes to the tool surfaces, termed as the two generations of the generic profile. Then a forward and inverse mapping has been presented for the basic model and the two generations of the generic tool to relate the grinding angles with the prevalent nomenclatures (ASA, ORS and NRS). The model has been validated and the variation of tool angles with the grinding parameters has been illustrated with an example.

Experimental Study on Point Grinding Technical Parameters Affecting Coolant Jet Parameters

Point grinding is a new type of high and super-high speed grinding process with a point contact zone and less grinding force. Because of the lower grinding power, the grinding heat in point grinding process is much less than that of the conventional grinding process. Therefore, the less grinding coolant jet parameters can be used during point grinding process. That is very propitious to the environment and resource, as well as the green manufacturing. Based on the mathematic model of the edge contact area of point grinding, the simulations of the edge contact area with point grinding angles and depth of cut was performed to study the grinding power. In addition, the relations between the grinding power and the depth of cut and vertical grinding angle were investigated. The dynamic pressure and velocity distributions in the airflow layer around the wheel edge were analyzed more by means of experiment. The point grinding experiment for grinding coolant jet parameters was performed.

Study on Edge Contact Area and Surface Integrity of Workpiece in Point Grinding Process

During cylindrical grinding process, the geometric configuration and size of the edge contact area between the grinding wheel and workpiece have the heavy effects on the workpiece surface integrity. In consideration of the differences between the point grinding and the conventional high speed cylindrical grinding, the geometric and mathematic models of the edge contact area in point grinding were established. Based on the models, the numerical simulation for the edge contact area was performed. By means of the point grinding experiment, the effect mechanism of the edge contact area on the ground surface integrity was investigated. These will offer the applied theoretic foundations for optimizing the point grinding angles, depth of cut, wheel and workpiece speed, geometrical configuration and size of CBN wheel and some other grinding parameters in point grinding process.

Study on Edge Contact Area and Surface Integrity of Workpiece in Point Grinding Process

During cylindrical grinding process, the geometric configuration and size of the edge contact area between the grinding wheel and workpiece have the heavy effects on the workpiece surface integrity. In consideration of the differences between the point grinding and the conventional high speed cylindrical grinding, the geometric and mathematic models of the edge contact area in point grinding were established. Based on the models, the numerical simulation for the edge contact area was performed. By means of the point grinding experiment, the effect mechanism of the edge contact area on the ground surface integrity was investigated. These will offer the applied theoretic foundations for optimizing the point grinding angles, depth of cut, wheel and workpiece speed, geometrical configuration and size of CBN wheel and some other grinding parameters in point grinding process.

Experimental Investigation on Effects of Depth of Cut on Micro-Geometric Properties in Quick-Point Grinding

Quick-point grinding is used to machine the round surface with super abrasive wheel at high grinding speed. Because it is point contact between the grinding wheel and the workpiece due to the point grinding angles in the process, the grinding model is different from the conventional cylindrical grinding in theory. Especially, the edge contact width between the wheel and the workpiece is not always equal to the thickness of the wheel, but rests with the depth of cut and the grinding angles greatly. The depth of cut has the effects on the micro-geometric properties especially the ground surface roughness by means of the variations of the edge contact width, the grinding force and heat in the process. Based on the theoretical studies on the surface roughness, the quick-point grinding experiments and the measures for the surface roughness were performed at different depth of cut. The effective mechanism of the depth of cut on the ground surface roughness was analyzed deeply. Some conclusions to influence surface roughness were also gained.

Experimental Study on Surface Finishing Performances in Quick-Point Grinding

There are lower grinding force and temperature in quick-point grinding process because of the higher grinding speed and the less depth of cut, especially the point contact between the grinding wheel and the workpiece due to the point grinding angles. Thus it can achieve better surface finishing process in grinding cylindrical surface. Since the point grinding model is different from the conventional cylindrical grinding in theory, the surface roughness is in relation to the point-grinding angles greatly besides the grain granularity, depth of cut, grinding speed and axial feeding rate like the conventional cylindrical grinding process. Based on the theoretical studies on the surface roughness in the process, the surface finishing experiments and measures at the various grinding parameters were performed. The experimental results show that the process parameters, such as point-grinding angles, depth of cut, grinding speed and axial feeding rate, must be controlled reasonably for the higher surface finishing demand in quick-point grinding process.

Geometric modeling of single point cutting tool surfaces

In this paper we have established a new three-dimensional standard to specify single point cutting tool geometry. The paper models a single point cutting tool in terms of biparametric surface patches. Six new angles, called grinding angles, are proposed to define the orientation of these surface patches. Forward and inverse mappings among grinding angles (α i , β i , γ i ), conventional tool nomenclature (γ y, γ x, α y, α x , ..... ), and setting or swivel angles for grinding (θ A , θ B , θ C ) are established. The benefits of the new paradigm include ease of finite element based engineering analysis, simulation, and programming of the CNC tool cutter and grinder for tool sharpening. The proposed methodology is illustrated with a few numerical examples.

An Analysis of Conical Drill Point Grinding — the Generation Process and Effects of Setting Errors

The final drill point geometry generation process for general purpose twist drills using the popular conical grinding method is described and modelled. Based on the “ideal” case analysis previously reported, the fundamental elements of this process are identified and analysed. For this “ideal” (design) case, the grinder described can produce all the recommended specified drill point feature values for a range of grinding cone angles. The introduction of grinder setting deviations from the “ideal” case (setting errors) severely complicates the analysis and the generated curved lip drill point shape. New definitions for the geometrical features and the “acceptable grinder criteria” had to be established. The effects of deviations in six grinder settings and two drill flute-features have been studied for 80 general purpose combinations of drill point feature values. It is shown that even with small deviations, unacceptable drill shapes occur for 26 combinations. For the remaining 54 combinations essentially straight drill lips are obtained although the ranges between the design and generated features can differ substantially. The dominant setting errors and the susceptible generated features are identified. This study highlights the difficulties in achieving and controlling the specified geometry in practice.