Silicon Carbide Wheel Research Articles

Performance Evaluation of Conventional Abrasive Wheels for Grinding Ti-6Al-4V

The present experimental study represents comparative performances in between aluminium oxide and silicon carbide wheels for grinding Ti-6Al-4V, considering dry environment as well as using alkaline soap water, applied through a newly developed delivery technique, restricted quantity lubrication (RQL) in drop by drop (DBD) mode. Experiments have been performed on a surface grinding machine in up-grinding mode during which the wheels are passed 20 times over the workpiece substrate for each environmental condition with infeed, 10 μm per pass. The variations of tangential and normal force components have been accurately measured using strain gauge dynamometer for each set of experimentations. Grinding ratios have been evaluated after accurately estimating the volume of material removal of wheel and workpiece. The qualities of the ground surfaces are compared based on the surface roughness parameters, measured using contactile mechanical stylus and observations of the ground surface under high resolution microscope. The outcome of the present investigation indicates silicon carbide wheel is superior to alumina wheel for grinding Ti-6Al-4V in terms of grinding force, grinding ratio, surface quality and the form of chips, obtain herein.

Grinding of Ti2AlNb intermetallics using silicon carbide and alumina abrasive wheels: Tool surface topology effect on grinding force and ground surface quality

Ti2AlNb intermetallics have the potential to replace some of the nickel-based superalloys application in aero-engine components due to their outstanding high-temperature mechanical properties. As a result of high strength, they are difficult to grind and can induce rapid tool wear. The current study compares the grinding performance of Ti2AlNb intermetallics by using green silicon carbide (GC) and pink alumina (PA) wheels. The wheel wear and topology evolution have been assessed. The wear effect on the grinding force and ground surface quality has also been analyzed. It has been found that the adherent area on the abrasive grains of PA is 8 times larger than that of GC wheel, which dulls the PA wheel cutting tips. The plowing and chip formation power occupy about 40–60% of the total power for the PA wheel, and this value is above 80% for the GC wheel. In addition, the GC wheel shows less white etch layer issue which renders better surface finishing and it is preferred in the Ti2AlNb intermetallics grinding.

Performance of Diamond and Silicon Carbide Wheels on Grinding of Bioceramic Material Under Minimum Quantity Lubrication Condition

Advanced ceramic materials like sintered and presintered zirconia are frequently used in biomedical applications, where minimum quantity lubrication (MQL) assisted grinding is required to achieve a good surface finish instead of conventional flood coolant. However, insufficient cooling and wheel clogging are the major problems that exist in the MQL grinding process, which depends upon the type of work piece material and the grinding wheel being used. The present study is to determine the performance of the grinding wheels on presintered zirconia under MQL conditions in terms of grinding forces, specific energy, surface integrity, and wheel wear. Experiments are conducted with two different types of grinding wheels as silicon carbide (SiC) and diamond grinding wheels under the same condition. The results indicated that the diamond wheel provided a better surface finish and reduced tangential force under MQL condition, compared to the conventional SIC wheel. This was due to the reduction of wheel loading in the diamond grinding wheel. The specific energy of diamond grinding wheel was reduced with higher material removal rate compared to the conventional SiC wheel. The ground surfaces generated by the diamond grinding wheel showed fine grinding marks with better surface finish. The percentage of G-ratio calculated for the diamond wheel was higher than the SiC wheel by 77%. This was due to the sliding of the grains and less wheel loading in the diamond wheel. The cost difference between the corresponding wheels was discussed to improve the productivity of the grinding process.

Surface Grinding of Ti-6Al-4V Alloy with SiC Abrasive Wheel at Various Cutting Conditions

Ti-6Al-4V alloy is mostly used in biomedical and aerospace industries, as well as in automotive and cutting implements, like scissors and knives due to its high strength-to-weight ratio and excellent resistance to corrosion in many environments. However, Ti-6Al-4V alloy is referred as difficult-to-cut material due to its unique combination of low thermal conductivity and high chemical reactivity with most cutting tools, especially with ceramics, and rapid work hardening during machining,. This will accelerate tool wear and generally adversely affects surface quality of the component. This becomes more critical in grinding operation due to conventional abrasive wheels that have poor thermal conductivity and small dimension of chips, which in turn contributes to more heat to be concentrated in the cutting zone. Depending on the temperature gradient and workpiece, this heat can cause damage to the component surface. So, it is important to control the amount of heat entering the workpiece and prevent damages like burning, surface cracks and other metallurgical alterations in the workpiece. In this context, this work investigates the surface quality of the Ti-6Al-4V alloy in terms of surface roughness e microhardness, after surface grinding with silicon carbide wheel under various cutting conditions. The morphology of the machined was also analyzed in a Scanning Electron Microscope to understand the cutting mechanisms. Conventional and MQL coolant delivery techniques were tested. A specially designed nozzle was tested in the experiments with the MQL. Results showed that surface roughness is dependent on both radial depth of cut and coolant system; and the lowest results were recorded after machining with the combination of the lowest depth of cut and MQL technique. With respect to microhardness, little variation was observed after machining with the MQL technique, unlike when machining with conventional method, irrespective the depth of cut employed.

Investigation on Grindability of Medical Implant Material Using a Silicon Carbide Wheel with Different Cooling Conditions

Zirconia is the preferred material used in many applications including biomedical implant. The zirconia in its sintered form is the most preferred one to manufacture a near net shaped implant material with minimal work. But it is very difficult to shape as the material chip away during the machining or grinding process. Hence zirconia in a pre-sintered form is used to achieve the required shape and size for a specific application. Then it is sintered and used. In this work, the grindability of the presintered zirconia was evaluated using a dense vitreous bond silicon carbide wheel. The grinding parameters such as wheel speed, radial depth of cut and feed rate are varied to investigate its grindability in terms of force ratio, specific energy, surface finish, G-ratio and ground surface under both wet and MQL cooling conditions. The forces produced during the grinding of pre-sintered zirconia was observed lower in the MQL (Minimum Quantity Lubrication) technique due to the reduction of friction, when compared to the wet cooling condition. The calculated specific energy was less in MQL cooling condition, due to the reduction in heat generation and friction. The surface finish of the workpiece obtained from the wet cooling condition was better due to the reduction in wheel loading. The percentage difference of the G-ratio between both the wet and MQL cooling conditions was observed to be 24 percent. This was due to the active participation of grains and less wheel loading in wet grinding condition. The ground surfaces obtained from the wet cooling condition were smooth and regular, compared to the MQL grinding condition.

The Condition of Machined Surface of Titanium Alloy in Dry Grinding

The Versa 3D twin-beam electron microscope was used to study the relief and chemical composition of the VT3-1 titanium alloy surface after grinding with the ceramic bonded silicon-carbide wheel without grinding fluid. The results show that the process of infeed grinding of titanium alloy is associated with adhesive and cohesive processes which lead to the formation of a multi-layer structure of the machined surface. The thickness of the multi-layer structure without adhered material amounts to 2-4 µm. The X-ray spectral microanalysis elicited the modification of the chemical composition. The experimental result indicated that the mass concentration of oxygen, nitrogen, and carbon atoms increases by more than 20 times. The concentration of carbon, nitrogen and silicon becomes lower as the analyzed layer thickness increases.

The grinding performance of a laser-dressed bronze-bonded diamond grinding wheel

Coarse-grained bronze-bonded diamond grinding wheels dressed using lasers and silicon carbide dressing wheels were used to grind YG8-cemented carbide workpieces. The wear patterns and grinding ratios of the laser-dressed grinding wheels were investigated after different grinding stages. After grinding, the laser-dressed grinding wheel displayed superior surface topography compared to the silicon carbide wheel, and the surface quality of the workpiece also improved. The minimum surface roughness of the workpiece was 0.425 μm. In the initial wear regime, the primary mechanisms included abrasive wear and grain removal. The grinding ratio was approximately 205.4, and the surface roughness of the workpiece after grinding was 0.314 μm. In the steady-state wear regime, abrasive wear was the primary mechanism of wearing, while minor amounts of grain removal and bond wear were observed. The grinding ratio was approximately 405.1, and the surface roughness was 0.337 μm. In the accelerated wear regime, the primary mechanisms were grain removal, abrasive wear, and bond wear. The grinding ratio was approximately 96.0, and the surface roughness was 0.454 μm.

Concentration gradients in the surface layer of titanium alloy ground by a silicon-carbide wheel

The concentration gradients of alloying elements and impurities in surface nanolayers of BEZ-1 titanium alloy after grinding by a silicon-carbide wheel are determined. The concentrations are determined by local X-ray spectral microanalysis.

An investigation on surface burn during grinding of Inconel 718

Grinding nowadays is extensively used for machining of superalloys. Inconel 718 is a Ni-based superalloy which is known as difficult to grind material (DTG) due to its inherent properties like high hardness, high hot strength, severe strain hardening and low thermal conductivity. In the present work, grindability of Inconel 718 using conventional abrasive grinding wheels has been experimentally explored. Ground surfaces have been characterized after grinding with silicon carbide (SiC) and alumina (Al2O3) wheels under dry condition. Surface integrity of the ground product has been studied using surface characterization techniques like Energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Further, the surface behavior of the ground surface has been investigated using microscopic images, micro-hardness tests, and surface roughness measurements. The major conclusion of the present work is that Inconel 718 can be ground more efficiently using alumina grinding wheels compared to the SiC grinding wheel. In the case of SiC wheel, it has been found that the severe attritious wear of the wheel took place primarily due to the chemical reaction between SiC grits and workpiece material at a higher grinding temperature. The mechanism for such attritious wear has been studied, and it appears to be a dissociation of SiC at higher temperature.

Surface-layer composition of titanium alloy after dry grinding by a silicon-carbide wheel

The concentration of ten chemical elements in the surface of a titanium alloy after grinding by a silicon-carbide wheel is determined by means of a Versa 3D twin-beam electron microscope. The content of C, N, O, and Si in a surface layer of up to 200 nm much exceeds the values permitted by the corresponding GOST State Standard. Silicon-carbide crystals are found in the ground surface.

Factors affecting the surface roughness in the deep grinding of titanium alloys

The influence of dressing of the abrasive tool and the table’s direction on the final surface roughness Ra in deep grinding of titanium alloys by a silicon-carbide wheel is investigated. Formulas are derived by dispersional analysis of Ra measurements over the length of the blank.

Acoustic emission testing of surface roughness and wear caused by grinding of ceramic materials

The current manufacturing trend mainly involves automation precisely to offer better productivity and improved quality. In this context, on-line monitoring of tools becomes essential. Acoustic emission is the most recognized technique used for condition monitoring of machine tools. Grinding is a material removal and surface generation process employed to shape and finish components made of metals and other materials. The research work deals with machining of CUMITUFF WR-90 alumina ceramics by employing two different grinding wheels made of aluminum oxide and silicon carbide under varying depth of cut. Surface roughness of the machined component and wear of both grinding wheels were analyzed using acoustic emission technique. For a constant depth, the quality of machining has been improved for the material grinded using silicon carbide wheel, which is inferred from low surface roughness value compared to material grinded using aluminum oxide wheel.

Research on Grinding of Silicon Particles Reinforced Aluminum Matrix Composites with High Volume Fraction

With silicon particles reinforced aluminum matrix composites with high volume fraction becoming a new hotspot on research and application in the aerospace materials and electronic packaging materials, the machinability of this material needs to be explored. This paper reports research results obtained from the surface grinding experiment of silicon particles reinforced aluminum matrix composites using black silicon carbide wheel, green silicon carbide wheel, white fused alumina wheel and chromium alumina wheel. The issues discussed are grinding force, surface roughness, the comparison of different grinding wheels, the micro-morphology of the work piece. The results showed that the grinding force was related with the grinding depth and the grinding wheel material, the grinding force was increasing as the grinding depth growing. The surface roughness was between 0.29μm and 0.48μm using the silicon carbide wheel. The surface of the work piece had concaves caused by silicon particles shedding and grooves caused by the grains observed by the SEM and CLSM.

Effect of parameters on grinding forces and energy while grinding Al (A356)/SiC composites

Grinding processes require a high energy input per unit volume of material removed, which is converted to heat at the grinding zone, resulting in increased force and wear. In the present study, the influence of grinding parameters like work speed and depth of cut on grinding forces and energy was studied. An attempt has been made to study the forces and energy involved while grinding aluminium alloy (A356)/silicon carbide (SiC) composite material with different grinding wheels. Experiments were carried out on a surface grinding machine. Three different types of wheels like SiC, cubic boron nitride (CBN) and diamond wheels were used. The grinding forces increased with increase in depth of cut and work speed. SiC exhibited high grinding force compared to the CBN wheel. In the case of the diamond wheel, it was even less. The specific grinding energy was highest for the diamond wheel followed by CBN and SiC wheels. The specific grinding energy decreased with increase in depth of cut and work speed.

Grinding Characteristics and Mechanism of Ceramic Alumina Wheels on Aeronautical Alloys

The present investigation was dedicated to elucidate grinding characteristics during surface grinding of titanium alloy(TC6) and high temperature alloy (GH2132) by using silicon carbide(SiC) and sol-gel (SG) wheel respectively. The grinding characteristic of SG wheel on aeronautical alloys was studied on the base of systematical measurement of the grinding force, grinding temperature, surface roughness and grinding ratio. The results indicated that the SG grinding wheel possesses excellent grinding properties and is more suitable for grinding these aeronautical alloys compared with conventional abrasive tools. Finally, the grinding mechanism of new-typed SG wheel was unveiled on the base of the microcrystalline structure analysis of SG grains.

Grinding of magnesium /Y2O3 metal matrix composites

The advanced metal matrix composites are finding high technology applications in aerospace and automotive industries because of their light weight coupled with high specific strength. Although advances have been made in near-net-shape technology, a finishing operation is needed to achieve the required dimensional tolerance and good surface finish. Magnesium especially experiences problems during grinding owing to its ductility and fire hazardous nature. Though grinding is not preferred for a pure magnesium matrix composite, owing to their increased hardness necessitate grinding, an attempt was made to perform grinding on the magnesium yttria composites with commercially available alumina and silicon carbide wheels. Grinding of magnesium composite was carried out by varying process parameters, such as wheel peripheral speed, workpiece velocity, and depth of cut. During the process the forces were monitored by a piezoelectric dynamometer. The performance of the grinding was studied by analyzing and comparing the grinding forces, specific grinding energy, and the average surface roughness. The ground surface was analyzed using optical and scanning electron microscopy. The grinding forces were observed to be decreasing with the increase in hardness, which in turn resulted in smooth surfaces. The obtained surface roughness (Ra) values were in the range of 0.6–1.3 µm.

Exploring Grindability of Titanium Grade 1 Using Silicon Carbide Wheel

Titanium and its alloys are being increasingly used in aerospace engineering, corrosive fluid pumps, heat exchangers, sea vehicles, etc. However, it is quite difficult to grind for its high chemical reactivity, high strength, high hardenability and low thermal conductivity causing high grinding temperature, wheel loading, wheel material removal, grit wear, etc. Therefore, selection of wheel, wheel speed and fluid for grinding of titanium is important to achieve desirable surface quality. Formation of a stiff air layer is a major constrain restricting the fluid enter the grinding zone. Optimization of a method of grinding fluid application is essential to control thermal problems from interaction of the wheel grains with the work surface. Adopting an appropriate fluid delivery system may enhance grindability of titanium alloy and can reduce environmental pollution. In the present experimental work, surface roughness, grinding forces and grinding chips are observed under the condition of dry, and wet using a compound nozzle. Surface grinding of titanium Grade 1 alloy is done with the use of silicon carbide wheel. It is found out that grinding under wet with compound nozzle fluid delivery system exhibits fairly good grindability.

Grinding the sharp tip in thin NiTi and stainless steel wires

This paper investigates the grinding process to generate the sharp tip of thin nickel titanium (NiTi) and stainless steel (SS) wires, which are commonly used in medical device applications. The large deflection of thin wires and variation of forces during grinding a 15° bevel angle tip are studied experimentally using the cubic boron nitride (CBN) and silicon carbide (SiC) wheels, respectively. During grinding, as the wire length gradually decreases and the stiffness increases, the wire deflection generally reaches a peak value and then gradually decreases. The results show that CBN grinding has a lower (about 1/3−1/2) grinding force and smaller (about 1/4−1/3) wire deflection than that of the SiC. Compared to SS wire, the NiTi exhibits a larger grinding force and wire deflection, lower surface roughness, and the breakage of wire at the collet chucking location using the SiC wheel due to the high stress induced phase transformation and brittle fracture. The grinding forces and wire tip deflection have large effects on the contact length and grinding time. A model based on the measured grinding forces as the input is developed to estimate the wire deflection and grinding time. This model is validated with experimental measurements and the effects of burr formation and NiTi phase transformation on grinding time are discussed.

Relevance of laser touch-dressed diamond tools for the dressing performance of vitrified-bonded silicon carbide wheels

Touch dressing of electroplated diamond grinding and dressing tools enable the generation of well-defined profile modifications and grain protrusions. This paper contributes to the utilisation of ultra-short pulse laser in touch dressing technology and outlines the cutting performance of laser touch-dressed diamond tools in dressing operations of vitrified-bonded silicon carbide. Surfaces of abrasive diamond tools are cut using a picoseconds laser beam to generate a well-defined grain protrusion without thermal damage of either the nickel matrix or the diamond structure. Irradiation parameters were systematically varied in order to determine a process window. Dressing operations were carried out using conventional and laser touch-dressed dressing tools. Lower dressing forces and higher dressing force ratios outline the advantage of the laser touch-dressed diamond tools in terms of material removal efficiency. Additionally, no remarkable differences in wear progression of conventional and laser touch-dressed diamond tools were observed. Furthermore, the laser touch-dressing model is presented using stochastically-distributed grain morphologies.

Experimental Research of Grinding TC4 Titanium Alloy Using Green Silicon Carbide Wheel

Titanium alloy is widely used in aerospace and aircraft industries but it is a kind of difficult-to-cut material. In this paper, wet grinding and dry grinding of titanium alloy Ti-6Al-4V using green silicon carbide wheel were investigated. The specific tangential force and force ratio were calculated and surface roughness of machined surfaces was measured. The morphology of machined surface were observed by SEM. The experimental results showed that the specific tangential forces were big. The depth of cutting has greater influence on surface roughness than workpiece speed. The surface roughness of wet grinding was better than dry grinding. Micro cracks were observed on wet grinding. The main reason is the high temperature and quenching cracking.