Grinding Performance Research Articles

Grinding performance investigation of multidirectional CF/PEEK composites—A comparative with unidirectional CF/PEEK

AbstractTo distinguish the grinding performance of the multidirectional (MD) and unidirectional (UD) carbon fiber‐reinforced thermoplastic (CFRTP) composites, MD and UD carbon fiber‐reinforced poly‐etherether‐ketone (CF/PEEK) composites were employed in this study. Different ply stacking sequences and process parameters were set for grinding experiments. Subsequently, the surface morphologies and roughness were observed and measured. Experimental results indicated that the variations of grinding forces with grinding parameters of MD‐CF/PEEK and UD‐CF/PEEK were consistent. However, the heat transfer mechanism and the effects of grinding parameters on the maximum grinding temperatures were different between the two composites. The grinding forces and temperatures of MD‐CF/PEEK were slightly lower than UD‐CF/PEEK, and MD‐CF/PEEK reached better surface quality under the same parameters, indicating that the grinding performance of MD‐CF/PEEK was not the simple superposition of UD‐CF/PEEK. In addition, the chip formation and material removal mechanism of CF/PEEK were investigated. The grinding performance of MD‐CF/PEEK was primarily dependent on the θ elements of laminate while the grinding performance of UD‐CF/PEEK was closely related to the fiber orientation angles during grinding. This study established a more in‐depth understanding into the grinding performance of MD‐CF/PEEK and provided technical guidance for high‐quality grinding of CFRTP.Highlights The grinding performance of the multidirectional (MD) and unidirectional (UD) carbon fiber‐reinforced poly‐etherether‐ketone (CF/PEEK) is compared. The grinding forces and temperatures of MD‐CF/PEEK are slightly lower than that of UD‐CF/PEEK, and the MD‐CF/PEEK reach a better surface quality under the same grinding parameters. The grinding performance of MD‐CF/PEEK is primarily dependent on the θ elements of laminate, and the change of layering order is not a critical factor. The grinding performance of UD‐CF/PEEK is closely related to the fiber orientation angles during the grinding process. The surface quality of MD‐CFRTP can be effectively improved by reducing the grinding depth and feed speed, and increasing the grinding wheel speed.

Some aspects on grindability of feldspar ore using ball mill

Egyptian feldspar ores are usually of low grade and need beneficiation to improve their grade for industrial applications. Therefore, feldspar should be ground to a reasonable liberation degree prior to beneficiation processes. Mineralogical studies showed that a good degree of liberation is below 0.25 mm. This work aims to optimize the grinding parameters for an Egyptian feldspar ore that ensures maximum production of size −250 + 45 µm and minimum % − 45 µm. Grinding was performed using a laboratory ball mill. The results displayed that the grinding performance was increased with decreasing the solid content with U between 0.5 and 1. A high milling rate was achieved at ball filling 20–30%. The ideal ball-filling ratio was determined to be 25%, with less production of fines. Hence, it was decided to crush the feed to less than 2 mm before grinding with 36.6 mm balls to reduce fines.

Study on structure-performance relationship and action mechanism of organic chemicals in cement grinding aids

Grinding aids (GAs) are an important addtive in the cement production process. However, the relationship between the molecular structure of GAs and its grinding efficiency has not been clearly revealed. In this study, the influence of GAs with different structures, including glycols and alkanolamines, on the grinding efficiency of pure clinker was systematically investigated. The working mechanism from their adsorption and dispersion configurations on tricalcium silicate (C3S) surface was investigated by first-principles method. As the structural parameters of GAs, number of polar groups is found to affect the grinding efficiency of cement clinker. The grinding performance of alkanolamines is better than that of glycols at the same dosage, when the number of hydroxyl groups is the same. The tertiary alkanolamines are adsorbed through the double-ended hydroxyl group to form larger molecular projection areas than the glycols with single-ended hydroxyl group, thus resulting in higher dispersion efficiency. Further, with the growth of the number of methyl groups in the molecular structure of the tertiary alkanolamines, the thickness of the adsorbed molecular layer grows from 9.25 Å to 9.87 Å, and the ability to shield the electrostatic forces between cement particles is enhanced and result in a better grinding aid performance.

Preparation and performance of high entropy alloy reinforced Cu-based bond diamond tool

The research on the influence of hot-press sintering on the properties of AlFeCrCoNi high-entropy alloy powders reinforced copper (HEA/Cu) alloys and the application of HEA/Cu alloys in diamond tools is still limited. Therefore, a new metal bond based on hot-press sintered HEA/Cu alloy for the diamond tool is proposed in this paper. The effect of adding HEA powder on the microstructure, mechanical, and tribological properties of the HEA/Cu alloy is investigated. A metal bond diamond tool based on the HEA/Cu alloy is prepared by hot-press sintering, and its grinding performance on alumina ceramic is examined. The results show that mutual element diffusion occurs between the HEA and Cu matrix during sintering, densifying the HEA/Cu alloys. The Cu alloy presents a higher hardness, yield strength, and wear resistance with a higher content of HEA powder. The hardness, yield strength, and wear resistance of Cu alloy are increased by 53.4%, 332%, and 200%, respectively, with the addition of 20 wt% HEA powders. The HEA/Cu bond diamond tool presents grinding forces and surface roughness equal to those of a commercial Cu-based alloy bond diamond tool.

Nanobiolubricant grinding: a comprehensive review

AbstractMinimum quantity lubrication (MQL), which considers the cost, sustainability, flexibility, and quality, has been actively explored by scholars. Nanoadditive phases have been widely investigated as atomizing media for MQL, aimed at enhancing the heat transfer and friction reduction performance of vegetable-oil-based biolubricants. However, the industrial application of nano-enhanced biolubricants (NEBL) in grinding wheels and workpiece interfaces as a cooling and lubricating medium still faces serious challenges, which are attributed to the knowledge gap in the current mapping between the properties and grindability of NEBL. This paper presents a comprehensive literature review of research developments in NEBL grinding, highlighting the key challenges, and clarifies the application of blind spots. Firstly, the physicochemical properties of the NEBL are elaborated from the perspective of the base fluid and nanoadditive phase. Secondly, the excellent grinding performance of the NEBL is clarified by its distinctive film formation, heat transfer, and multiple-field mobilization capacity. Nanoparticles with high thermal conductivity and excellent extreme-pressure film-forming properties significantly improved the high-temperature and extreme-friction conditions in the grinding zone. Furthermore, the sustainability of applying small amounts of NEBL to grinding is systematically evaluated, providing valuable insights for the industry. Finally, perspectives are proposed to address the engineering and scientific bottlenecks of NEBL. This review aims to contribute to the understanding of the effective mechanisms of NEBL and the development of green grinding technologies.

Enhancing the grinding performance of RB-SiC ceramic using abrasive water jet dressed diamond grinding wheels

Reaction-bonded silicon carbide (RB-SiC) is regarded as difficult-to-machine ceramic materials with extremely high strength and hardness. The work focuses on the grinding performance evaluation of RB-SiC ground by the dressing diamond grinding wheel with AWJ. Orthogonal experiments studied the influence of processing parameters on grinding force and 3D surface roughness, with the response surface method identifying optimal parameters. Explanation of the ground surface topography and 3D surface roughness in a comprehensive manner shows that an erosion of the bonding material by micro-cutting but diamond grains are being pulled out rather than cut. Results reflect a correlation between surface topography and diamond wheel dressing. The results are of great significance for future formulating an appropriate grinding process to machine RB-SiC ceramics.

Research on the Grinding Performance of an Electroplated Coarse-Grained Diamond Grinding Wheel by Dressing

The coarse-grained electroplated diamond grinding wheels is increasingly favored in precision grinding of hard and brittle materials owing to its high material removal efficiency, high wear resistance and steady surface contour accuracy. However, how to determine whether the dressed grinding wheel surface topography can achieve the desired precision ground surface quality is still a huge challenge to this day. In this paper, a novel numerical simulation model, which was established basing on the statistical features of actual electroplated coarse-grained diamond grinding wheel and the kinetics of the grinding process, was proposed for theoretically and thoroughly studying the influence of the surface dressing depth of coarse-grained electroplated diamond grinding wheel on ground workpiece surface morphology. At first, the statistical features of actual electroplated coarse-grained diamond grinding wheel was acquired and a novel numerical grinding wheel surface model was established. Subsequently, a numerical ground workpiece surface simulation model was also developed. And then, the evolving mechanism of the grinding wheel surface topography with the dressed wheel surface abrasive grain protrusion height was theoretically studied by numerical simulation. Moreover, the influence of the wheel surface abrasive grain protrusion height on the ground surface roughness was thoroughly researched by means of theoretical model and experiments. The simulation and experiments results in this paper indicated that precision ground workpiece surface with nano-scale surface roughness can be acquired by grinding with a dressed grinding wheel with a certain abrasive grain protrusion height of 25% of the typical abrasive size. Comparing with the undressed grinding wheel (grinding wheel with original surface topography and not be dressed), the surface roughness Sa and Sq of the surface ground with a well-dressed wheel can achieving a significant decrease of 97.75–99.77% and 97.57–99.73%, respectively. Therefore, carefully dressing the electroplated coarse-grained diamond grinding wheel is of great significance for obtaining a precision ground workpiece surface quality.

Enhanced heat transfer in 3D printed ball-end grinding tool with blade-shaped structure

Complex curved components in aero-engines often require demand small-sized compliance ball-end (BE) grinding tools to achieve smooth machining in interference-prone-area. Nevertheless, heat accumulation during the grinding of difficult-to-process materials challenges the weak stability of flexible materials, thereby limited tool life and grinding performance. In this study, a novel rotary-enhanced heat transfer structure (REHT) based on aero-engine blades was introduced into the BE. The blade-shaped structure tools were fabricated using multi jet fusion (MJF). Numerical simulations were conducted to investigate the effects of blade type, rotating direction, rotating speed, and forced cold air velocity on the heat transfer mechanism of BE. The grinding performance of these tools, along with conventional structures, was comparatively investigated through robot-assisted grinding of titanium plates. The results indicated that the REHT improved the heat transfer capability of the tool by introducing high momentum fluids into the tool cavity and increasing the flow rate of the grinding interface. The REHT structure reduced the grinding temperature by over 19.84%, extending tool life by more than 40%. Furthermore, compliant grinding tools with REHT exhibited higher cumulative material removal alongside lower and more consistent surface roughness (Ra).

Research on the grinding performance of grinding wheel in the initial grinding stage after electric spark dressing of grinding wheel

Research on the grinding performance of grinding wheel in the initial grinding stage after electric spark dressing of grinding wheel

Evaluation of abrasive belt grinding performance in nickel-based superalloy robot grinding

ABSTRACT In order to evaluate the abrasive belt grinding performance, this paper proposes to conduct nickel-based superalloy robot abrasive belt grinding experiment based on different types of abrasive belts with multiple grit sizes. First, the single grinding performance evaluation is performed through five performance parameters: material removal rate, surface roughness, tangential force, specific grinding energy, and specific wear height. Then, based on the evaluation results of single grinding performance, a weighted evaluation function is established to comprehensively evaluate the grinding performance. It is found that the structured abrasive belt has relatively better grinding performance. The main factors affecting the abrasive belt grinding performance are identified through the evaluation results, with the effect of grit size being more significant. In addition, this paper analyzes the characteristics of material deformation based on the grinding subsurface microstructure, and discusses the effects of abrasive belts on material deformation.

Influence of bond thermal and mechanical properties on the additively manufactured grinding wheels performance: Mechanical, wear, surface integrity, and topography analysis

It is always a great challenge to fabricate customized grinding wheels using diverse bonding materials to determine their impacts on the cutting ability and grinding performance. Additive Manufacturing methods offer tremendous advantages for customized and prototype production to reduce the cost as well as increase speed to market. This work aims to extend the grinding operation knowledge by examining acrylate base resin bonds with different mechanical and thermal characteristics to print the grinding wheels. Extensive experiments are conducted to investigate their performance in metal grinding, with hardness ranging from soft to super hard. A remarkable improvement in grinding performance has been established by using high-temperature resistance bond material, which was more prominent in the case of aluminium and hardened steel. It was discovered that utilizing the bond material with a higher mechanical and thermal characteristic could provide high grain retention under elevated temperatures, which participated in less grinding force (up to 58 % and 18 % in the case of soft and hard metals, respectively). Employing bond material with improved mechanical and thermal properties to fabricate grinding wheels significantly prolonged the tool life, for example, by up to 80 % for hardened steel at maximum, along with promoting dimensional accuracy. Nevertheless, however, using high-temperature resistance resin brought slight improvement in tool life for the hard metals grinding due to the intensely aggressive grinding condition, which could not be largely compensated by using modified resin. The surface roughness of the ground part represented considerable improvements through using high-temperature resistance resin by representing 33 % and 30 % roughness values reduction for Al and hard metal, respectively, compared to those ground with lower temperature resistance resin. Moreover, the ground surface's microhardness examination indicated meaningful surface microstructure change by applying different grinding parameters and bond material types. Furthermore, the microtopography of the grinding wheels before and after the grinding operation revealed that employing the higher temperature resistance resin could bring about notably less chip loading and grain loss.

Study on the Fabrication and Grinding Performance of the Self-sharpening Cr2O3 Gel Abrasive Tool

Study on the Fabrication and Grinding Performance of the Self-sharpening Cr2O3 Gel Abrasive Tool

Comprehensive analysis of the effects of different parameters on the grinding performance for surfaces

Comprehensive analysis of the effects of different parameters on the grinding performance for surfaces

Modelling and simulation of tool passivation by magnetic elastic abrasive particles

Magnetic elastic abrasive particles possess magnetism, low elasticity, and excellent grinding performance. Utilizing a double magnetic disk magnetic force tool for passivation can significantly enhance the efficiency and quality of passivation. Firstly, a mathematical model for the impact depth and volume on the tool is established. Secondly, using the simulation software ABAQUS, a simulation model is constructed to investigate the influence of grit size, quantity of abrasives, impact angle, disk rotation speed, and tool rotation speed on stress, energy, impact depth, and impact volume. Furthermore, the feasibility of the simulation and the reliability of the mathematical model are verified.

Nickel-based super alloy grinding optimisation using a hybrid multi attribute decision making method based on entropy, AHP and TOPSIS

ABSTRACT Nickel-based superalloy grinding, as well as selecting the appropriate operational parameters, is one of the major challenges in machining engineering. The conducted research consists of two sections. The first section presents a systematic experimentation, which has been carried out to qualitatively and quantitatively investigate nickel-based superalloy grinding. Vitrified CBN grinding wheels, along with a rotary diamond cup dresser, were utilised to conduct the experiments with the workpiece of Inconel 738. Specific grinding energy, G-ratio and surface roughness were indicated as three major machining outputs, while the inputs were the dressing conditioning and grinding parameters. In the following, the effects of different operational parameters were relatively ranked according to their weighted impact on the grinding performance using hybrid multi-attribute decision-making (MADM) methods. For this purpose, a combination of three techniques: Analytic Hierarchy Process (AHP), Entropy and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was utilised to select the most appropriate grinding conditions, while considering the conflicting effect of the different dressing and grinding parameters. The results indicate that specific energy can be an important criterion for evaluating the process efficiency. The changes in G-ratio and surface roughness have the same trends, as opposed to specific grinding energy mutation. The grinding parameters are summarised in equivalent chip thickness. Our findings show that dresser cross feed rate, along with equivalent chip thickness, has the greatest impact on the grinding process efficiency.

Self-lubricating performance of a grinding wheel filled with CNTs@T304 nano-capsules

This paper introduces a new grinding wheel which lubricates the grinding area directly. This is achieved by filling a resin grinding wheel with nano-capsules comprised of carbon nanotubes (CNTs) and di-n-butyl phosphite (T304) (CNTs@T304). The CNTs@T304 nano-capsules filled grinding wheel reduces the grinding force, lowers the grinding temperature, and improves the workpiece surface quality. The T304 lubricant is first filled into the CNT cavity to prepare nano-capsules, which exhibit better friction and wear quality than CNTs. Then the paper analyzes the configuration of the nano-capsules in the grinding wheel, together with the investigation of how the filling content impacts the mechanical properties. Additionally, the effects of nano-capsule filling content and grinding parameters on grinding force, grinding temperature, grinding ratio, as well as workpiece surface roughness are studied and the self-lubricating mechanism of the nano-capsules is assessed. According to the experimental results, nano-capsules maintain stable under thermal condition and resist the curing temperature. Moreover, the tensile strength and hardness exhibited by the grinding wheel still meet the application requirements at a filling content <16 wt%. Compared with the grinding wheel without fillers, the nano-capsule filled wheel exhibits superior grinding performance, with a 33 % reduction in the grinding force. Also, the grinding temperature is 28 % lower, there is a 30 % improvement in the grinding ratio, and the workpiece surface quality increases by 35 % under the same conditions. The T304 in the nano-capsules is continually released onto the grinding interface with the wear of the wheel in the grinding process, which forms a self-lubricating layer along with the friction products of the CNTs. This exerts an outstanding anti-friction and anti-wear effect, thereby improving the grinding performance.

Evaluating the grinding performance of cutter-type disk mills using DEM-CFD simulations with a breakage model

In the recycling process of plastics, grinding is commonly employed as a pre-treatment method to facilitate molding by increasing the specific surface area. A cutter-type disk mill that mainly causes shear forces is expected to be the most efficient for grinding plastics. However, it is necessary to optimize the geometry and operating conditions of the mill. This study aimed to evaluate the grinding performance of different blade geometries in the cutter-type disk mill. To optimize the blade geometry, the discrete element method (DEM) coupled with the computational fluid dynamics (CFD) and a breakage model was employed to simulate plastic particle breakage. The simulations showed that the highest grinding performance was achieved with a grinding blade angle of 45°. Depending on the angle of the grinding blade, the effects of the power acting on the grinding blade and the force acting on the particles varied. According to these results, an appropriate blade geometry in the cutter-type disk mill can be proposed for grinding plastic. This study demonstrated that the DEM-CFD simulations are effective for evaluating the grinding performance and optimizing the blade geometry of the cutter-type disk mill.

A novel 3D printed compliant ball-end grinding tool with crystal structure: Feasibility and performance analysis

During grinding complex components with difficult-to-machine materials, compliance grinding tools often experience shortened life and weakened performance due to intense temperature rise. This paper presents a novel solution strategy of preparing crystal-structured compliance tools using multi jet fusion (MJF), and five structures were selected to evaluates its feasibility and grinding performance. The macro and micro elastic deformation of the tools were analyzed by combining finite element and experiment. The results show that the crystal structure provides similar macroscopic stiffness of the tools and introduces microscopic compliance anisotropy. The crystal structure resulted in a reduction of the grit pull-out ratio by more than 82.60 %, while also alleviating the adhesion of flexible substrates adhesion and the prevention of abrasive layer fall-off, leading to prolonged tool life. Furthermore, compliant grinding tools with a crystal structure achieved comparable material removal capacity, lower surface roughness, and higher energy efficiency. In addition, they used only 29.06 % to 36.22 % of the material consumed in manufacturing. Notably, the material removal rate (MMR) of the star-structure tool can reached 94.72 % of the solid-structure tool. The diamond-structure tool exhibited the lowest ground Ra, accompanied by a reduction in grinding temperature of 19.4 °C.

Fabrication of Vitrified Bond Diamond Grinding Wheel via LCD Photopolymerization

In this paper, a liquid crystal display (LCD) photopolymerization method is proposed, and a vitrified bond diamond grinding wheel is successfully prepared. A high-performance vitrified bond was obtained by melting SiO2-B2O3-Al2O3-Na2O ceramic raw materials and used for grinding wheel preparation. LCD photopolymerization technology is characterized by high precision in shaping, fast processing speed, and superior quality, making it a promising technology for fabricating vitrified bond diamond grinding wheels. The preparation of vitrified bond slurry with high solid content and low viscosity was extensively investigated to meet the fabrication requirements. The effects of dispersant, the particle size of the vitrified bond, and solid content on the viscosity of the slurry were systematically analyzed. The vitrified bond slurry with solid content up to 65 wt.% (approximately 45.5 vol.%) was successfully prepared and met the requirements for printing. Furthermore, we explored the optimal formulation of the grinding wheel, debinding and sintering conditions, sintering temperature, grit-to-bond ratio, and the evaluation of the grinding performance of the wheel on hard and brittle materials, such as silicon carbide ceramic. Vitrified bond and abrasive slurry systems with a solid content of 65 wt.% (approximately 42.8 vol.%) were prepared. The results show that the vitrified bond diamond grinding wheel exhibits optimal comprehensive performance, with a sintering temperature of 680 °C and a grit-to-bond ratio of 4:6. The minimum surface roughness of the workpiece after grinding was 1.767 μm, the material removal rate was 5.08 mg/s, the grinding ratio was 9.78, and the friction coefficient was stabilized at about 0.5 during grinding. This paper guides the manufacturing of vitrified bond diamond grinding wheels via LCD photopolymerization.

Comparative study on induction brazing of diamond with rare earth Nd-doped crystalline and amorphous Ni-based filler alloy

This essay aims to comparatively study the microscopic morphology and grinding properties of brazed diamonds with amorphous and crystalline filler alloy in the case of rare-earth Nd-doped modified Ni-based filler alloy. The results show that at the same content of Nd, Cr7C3 is mainly generated at the brazing interface of crystalline samples. In contrast, Cr27C6 is mainly generated at the brazing interface of amorphous samples. Amorphous solder material achieves a robust chemical metallurgical union, producing a dense and homogeneous carbide layer. The bonding strength between amorphous solder material and diamond is further enhanced. The addition of rare earth element Nd contributes greatly to the forming ability of amorphous filler alloy. Nd atoms in the amorphous solder material readily bond with Ni atoms, reducing the chemical corrosion of Ni atoms on diamonds and resulting in a lower degree of graphitization. When the amount of Nd added is 1.0 wt%, the morphology of amorphous filler alloy brazing diamond is more complete than the effect of the crystalline state, the degree of thermal damage is lower, and the surface of amorphous filler alloy brazing is smoother. Frictional wear experiments show that the amorphous filler alloy holds diamond better than the crystalline filler alloy, and the diamond specimens prepared with the amorphous filler alloy demonstrate a significantly superior grinding performance in comparison to the diamond specimens prepared with the crystalline filler alloy.