Grinding Procedure Research Articles

Optimizing Cylindrical Grinding Proficiency and Surface Finish for EN24 Steel Alloy with the Use of Taguchi Analysis and Artificial Neural Network

Grinding is a material removal procedure used at the end of manufacturing to obtain high dimensional precision and a desirable surface polish. External cylindrical grinding is a type of grinding procedure that used to grind cylindrical things such as engine shafts, connecting rods, spindles, and axles. This study examines how control settings affect response parameters using EN24 alloy steel on a cylindrical grinding machine. Response parameters are material removal rate (MRR) and surface roughness (Ra), whereas control parameters are workpiece speed (v), feed rate (f), and depth of cut (d). Taguchi DOE is employed with L16 orthogonal array to optimize control parameter levels, followed by cylindrical grinding tests.An artificial neural network (ANN) model was created to validate and predict cylindrical grinding reaction parameters. To train the network, experimental data was used, and ANN predictions were compared to real data. Data collection has also completed.In the purposed work minimum Ra is 0.52 µm and maximum MRR is 0.6588 g/sec found and results indicate that feed rate and workpiece speed are the most dominating parameters of cylindrical grinding. The experimental results can be employed by various manufacturing and industrial firms and they can select suitable combinations of input parameters for desired Ra and MRR

Calcium Carbonate as Dephosphorization Agent in Direct Reduction Roasting of High-Phosphorus Oolitic Iron Ore: Reaction Behavior, Iron Recovery, and Dephosphorization Mechanism

Calcium carbonate, renowned for its affordability and potent dephosphorization capabilities, finds widespread use as a dephosphorization agent in the direct reduction roasting of high-phosphorus oolitic hematite (HPOIO). However, its precise impact on iron recovery and the dephosphorization of iron minerals with phosphorus within HPOIO, particularly the mineral transformation rule and dephosphorization mechanism, remains inadequately understood. This study delves into the nuanced effects of calcium carbonate on iron recovery and dephosphorization through direct reduction roasting and magnetic separation. A direct reduction iron (DRI) boasting 95.57% iron content, 93.94% iron recovery, 0.08% phosphorus content, and an impressive 92.08% dephosphorization is achieved. This study underscores how the addition of calcium carbonate facilitates the generation of apatite from phosphorus in iron minerals and catalyzes the formation of gehlenite by reacting with silicon dioxide and alumina, inhibiting apatite reduction. Furthermore, it increases the liquid phase, enhancing the dissociation of metallic iron monomers during the grinding procedure, thus facilitating efficient dephosphorization.

Simulation modeling of wafer grinding surface roughness considering grinding vibration

When using the workpiece rotation method to grind wafers, the grinding end vibration will deteriorate the surface roughness of the wafers. To study the impact law of vibration on the surface roughness of wafers during the grinding procedure, this paper presents a new approach to simulate and model the surface roughness of wafer grinding considering the grinding vibration. Firstly, the dynamics model under the consideration of grinding force was established for the grinding end of the grinding wheel and workpiece turntable. Secondly, using the iterative method to solve the dynamic equations that have been established, the vibration equation is obtained by fitting the displacement vibration curve of the end. Then, by reconstructing the surface grain of the gear teeth, a simulation model of wafer grinding surface roughness was established considering material removal, grain motion and grinding vibration. And then the grinding comparison test was conducted to compare the simulation and test surface roughness measurement results. The maximum deviation of the surface roughness Sz and Sa was 7.7 % and 5.4 %, respectively. The results indicate the accuracy of the modeling. Finally, based on the established wafer roughness model, explore the impact of vibration on wafer roughness during the grinding procedure. This model provides a reference for the research of wafer precision grinding technology.

Mechanical Grinding-Induced Intermolecular Charge Transfer for Near-Infrared Photothermal Conversion.

In this study, charge-transfer-type compounds comprising synthesized naphthalenediimide derivative (H4NDISA) or its Pb-based coordination polymer (Pb-NDISA) and suitable primary or secondary amine organic molecules were prepared by the solvent-free mechanical grinding method. The coloration phenomenon arising from charge transfer during grinding serves as a discriminative tool for distinguishing various organic guest molecules. The porous structure of Pb-NDISA crystals facilitates the infiltration of guest molecules and contributes to the preservation of the intermolecular charge transfer state. Moreover, the intermolecular charge transfer induced by grinding exhibits remarkable stability in an ambient atmosphere, underscoring the pivotal role of well-ordered molecules in the mechanical grinding procedure. This mechanochromic phenomenon holds promise for the detection and sensing of organic molecules, while the exceptional charge-transfer absorption characteristics offer the potential for efficient near-infrared photothermal conversion.

Chitosan-puerarin composite hydrogel with magnetic enhanced photothermal properties as sustained antimicrobial coatings for beef preservation

The bactericidal properties of traditional food coatings mostly depend on the amount of fungicides present, which reduces the sustainability of food packaging. Herein, we proposed a magnetic field to precisely modulate the near-infrared (NIR) absorption activity to enhance antimicrobial coatings sustainability. Inspired by the typical grinding procedure, the assembly of CP/Fe3O4@TA nanofiber hydrogel was proposed as the coating, applying mechanical force and encouraging the collision of effective molecules of puerarin (PUE), chitosan (CS), and Fe3O4@TA NFs. This hydrogel design offers precise control over the physical and chemical properties, including appearance, viscoelasticity, and rheology. Particularly, significant changes in photothermal performance were observed as a result of magnetic regulation of NIR absorption activity. As a result, the CP/Fe3O4@TA coatings achieve effective bacteria killing performance under NIR irradiation, magnetocaloric effect, boric acid adsorption, and aggregation interference. Finally, the hydrogel coating was applied to the beef surface and serves as an effective barrier against the growth of pathogenic bacteria, thereby preserving the freshness and tenderness of the beef. The finding from this work is expected to open up a new way in active nano hydrogel coating for food preservation.

Surface integrity improvement of the ground surface of Inconel 718 fabricated by forging and additive manufacturing using a robotic rotational burnishing method

Given that the surface acts as the primary interface with the surrounding environment, the surface integrity of a component significantly influences its operational effectiveness. In the aerospace industry, materials like Inconel 718 are often utilized for their high-temperature strength despite their poor thermal conductivity and machinability, resulting in inferior surface integrity during grinding procedures. This research proposes an innovative robotic rotational burnishing method that leverages self-generated heat to aid in the post-grinding burnishing process, eliminating the need for an external heat source. The surface integrity achieved through this method undergoes a comprehensive evaluation, encompassing surface topological features, microstructure, and mechanical properties, and is compared with surfaces treated by grinding and slide burnishing. The findings demonstrate that during the rotational burnishing process, the friction between the high-speed rotating burnishing tip and the workpiece surface induces circumferential flow of the surface material, thereby enhancing surface anisotropy. Additionally, this process generates significant heat, further encouraging plastic deformation of the material surface under high burnishing forces. As a result, the surface acquires a compressive residual stress exceeding 1000 MPa and develops a microhardness-strengthened layer with a thickness exceeding 500 μm. Both forging and additive manufacturing techniques for preparing Inconel 718 raw materials yield consistent outcomes. This study not only achieves a fusion of additive, subtractive, and equivalent manufacturing but also validates the applicability of the proposed robotic rotational burnishing method in enhancing surface integrity across materials manufactured by various techniques.

Investigation on the Micro-Grinding Induced Crystallographic Variations of Nine Different Clinkers

Although clinker has been used for many years, complicated mineralogical properties of clinker pose challenges for the precise quantification. In this study, the mineralogical and crystallographic properties of nine different clinkers according to grinding procedures were investigated. With the dry-grinding for 2 h, particle size reduction to 3 μm of median particle size with a substantial phase transition to an amorphous phase observed, to which alite (C3S) mainly contributed to the transition. Meanwhile, the crystallographic properties of the clinker phases were barely changed during the wet-grinding. In the wet-grinding program, the amount of ferrite solid solution (C4AF) with a high linear absorption coefficient was not underestimated. Furthermore, well-corrected preferred orientation effect on C3S was positively contributed to the analysis result of clinkers with the wet-grinding. Hence, it was suggested that the crystallographic effects observed in the wet-grinding program could produce more reliable results in phase analysis for the clinkers.

Changes of surface properties of sucrose particles during grinding in a cocoa butter-based suspension and their influence on the macroscopic behavior of the suspension

Chocolate mass is a cocoa butter-based suspension, which mainly consists of sugar and cocoa particles dispersed in a continuous lipid phase. During chocolate manufacturing, sugar particles have to be ground to sizes below 25–30 µm. Such a fine grinding is carried out either by five roll refiners or by ball mills. Despite obtaining similar particle size distributions at the end, the grinding procedures result in different chocolate mass properties. The reasons for that are not fully understood, so far. Therefore, changes in particle sizes and surface properties of sucrose particles as well as their interactions with surrounding cocoa butter during the different grinding processes were investigated including atomic force microscopy techniques to characterize local surface states. It was found that especially the alteration of surfaces during continued grinding differed. In the case of roller grinding, surface states became more inhomogeneous and different surfaces states at microscopic level existed in parallel. More homogenous surfaces but with a higher degree of amorphous states were formed during grinding in the ball mill. Variations in macroscopic behavior of the suspension can be explained by the differences in interaction of particles with each other and with the surrounding lipid phase.

Evaluation of particle morphology and size of mineral filler and their effects on mastic rheological and creep behavior: Experimental and numerical characterizations

The primary objective was to evaluate the effects of particle morphology and size of mineral fillers on mastic rheological and creep properties. Experimentally, eight fillers prepared using the same grinding procedure were characterized. Dynamic shear rheometer and bending beam rheometer tests were employed to evaluate mastic rheological and creep behavior, respectively. Numerically, a dynamic viscoelastic model and Burgers creep damage model based on fractional derivatives were established. Results demonstrate that the datasets agree well using fewer model parameters, which can illustrate the availability of the proposed numerical method for the response of all analyzed mastic specimens. As the particle size decreases, material parameter and fractional order are increased by 10.31%, 23.45%, 24.72% and 0.68%, 1.46%, 1.48% for mastics containing limestone filler; and that are increased by 7.07%, 15.38%, 38.06% and 0.76%, 0.85%, 1.18% for mastics with granite filler at 45 °C, respectively. Apart from 150 to 200 mesh size range, the mastic with granite filler is less prone to creep damage accumulation inside the specimen than that containing limestone filler during the loading process. As the particle size increases, relaxation time is rapidly increased by 5.41%, 26.35%, 27.99% and 5.55%, 20.98%, −1.33% for limestone filler-asphalt mastics and granite filler-asphalt mastics, respectively. Moreover, form factor is the determining influential factor for mastic anti-rutting performance, temperature susceptibility and creep damage, while fractal dimension is the most relational factor affecting mastic dissipation capacity, regardless of filler lithology. All the results are conducive to designing mineral filler that fabricates mastic with the desired property.

Mechanochemical Encapsulation of Caffeine in UiO-66 and UiO-66-NH2 to Obtain Polymeric Composites by Extrusion with Recycled Polyamide 6 or Polylactic Acid Biopolymer.

The development of capsules with additives that can be added to polymers during extrusion processing can lead to advances in the manufacturing of textile fabrics with improved and durable properties. In this work, caffeine (CAF), which has anti-cellulite properties, has been encapsulated by liquid-assisted milling in zirconium-based metal-organic frameworks (MOFs) with different textural properties and chemical functionalization: commercial UiO-66, UiO-66 synthesized without solvents, and UiO-66-NH2 synthesized in ethanol. The CAF@MOF capsules obtained through the grinding procedure have been added during the extrusion process to recycled polyamide 6 (PA6) and to a biopolymer based on polylactic acid (PLA) to obtain a load of approximately 2.5 wt% of caffeine. The materials have been characterized by various techniques (XRD, NMR, TGA, FTIR, nitrogen sorption, UV-vis, SEM, and TEM) that confirm the caffeine encapsulation, the preservation of caffeine during the extrusion process, and the good contact between the polymer and the MOF. Studies of the capsules and PA6 polymer+capsules composites have shown that release is slower when caffeine is encapsulated than when it is free, and the textural properties of UiO-66 influence the release more prominently than the NH2 group. However, an interaction is established between the biopolymer PLA and caffeine that delays the release of the additive.

The most suitable system to grind the whole tooth to use it as graft material

Aim: In regenerative dentistry, the success is influenced by the graft material, which should act as an osteoconductive scaffold. It provides a mineral substrate during resorption and induces the activity of osteoinductive cells capable of producing new bone, platelet growth factors, and cell differentiation factors that guide the differentiation of undifferentiated mesenchymal cells. Given that dentin shares many biochemical characteristics with bone tissue, it has recently attracted considerable interest as a biomaterial for bone repair. The aim of this study is to compare two grinder types to determine the optimal method for producing dentinal particles using a mechanical grinder. Methods: A sample of 40 natural human teeth without restorations, prostheses, or root canal treatments was used and divided into two groups subjected to two different grinder speeds (high-speed and low-speed). Results: The high-speed showed a greater dispersion (53.5% ± 9.89% of the tooth) due to the pulverisation (highly thin granules) of part of the tooth. The low-speed grinder did not pulverize the dentin and the percentage of tooth loss is 9.16% ± 2.34%. Conclusions: The low-speed grinder allows to save a major part of the tooth and has a maximum quantity of graft material but requires more time. Further studies must be promoted to optimise the grinding procedures.

Medical Imaging and Analysis of Thermal Necrosis During Bone Grinding: Implementation of Non-dominated Sorting Genetic Algorithm (NSGA-III) in Healthcare.

Medical imaging plays a key role in neurosurgery; thereby, imaging and analysis of the soft and hard tissues during bone grinding is of paramount importance for neurosurgeons. Bone grinding, a minimally invasive operation in the field of neurosurgery amid osteotomy, has been used during brain cancer surgery. With increasing attention to neural tissue damage in machining operations, imaging of these neural tissues becomes vital and reducing temperature is imperative. In the present study, a novel attempt has been made to perform the imaging of bone tissues during the bone grinding procedure and further investigate the relationship between rotational speed, feed rate, depth of cut with cutting forces, and temperature. The role of cutting forces and temperature has been addressed as per the requirements of neurosurgeons. Firstly, a three-factor, three-level design was constructed with a full factorial design. Regression models were employed to construct the models between input parameters and response characteristics. Medical imaging techniques were used to perform a thorough analysis of thermal necrosis and damage to the bone. Subsequently, the non-dominated sorting genetic algorithm (NSGA-III) was used to optimize the parameters for reduction in the cutting forces and temperature during bone grinding while reducing neural tissue damage. The results revealed that the maximum value of tangential force was 21.32 N, thrust force was 9.25 N, grinding force ratio was 0.453, torque was 4.55 N-mm, and temperature was 59.3°C. It has been observed that maximum temperature was generated at a rotational speed of 55000 rpm, feed rate of 60 mm/min, and depth of cut of 1.0 mm. Histopathological imaging analysis revealed the presence of viable lacunas, empty lacunas, haversian canals, and osteocytes in the bone samples. Furthermore, the elemental composition of the bone highlights the presence of carbon (c) 59.49%, oxygen (O) 35.82%, sodium (Na) 0.11%, phosphorous 1.50%, sulphur 0.33%, chlorine 0.98%, and calcium 1.77%. The study revealed that compared to the initial scenario, NSGA-III can produce better results without compromising the trial results. According to a statistical study, the rise in temperature during bone grinding was significantly influenced by rotating speed. The density of osteocytes in the lacunas was higher at lower temperatures. Furthermore, the results of surface electron microscopy and energy dispersive spectroscopy revealed the presence of bone over the surface of the grinding burr, which resulted in the loading of the grinding burr. The results of the present investigation will be beneficial for researchers and clinical practitioners worldwide.

Study on Plastic Deformation Removal Mechanism and Dislocation Change in Nanogrinding of Single Crystal Silicon Carbide with Random Rough Surface

This investigation centers on exploring the plastic deformation removal mechanism and dislocation dynamics in the nanogrinding of single‐crystal silicon carbide featuring a randomly rough surface. To simulate this, an approach combining the Weierstrass–Mandelbrot fractal surface function with molecular dynamics is employed. Randomly rough surface contours are generated using the Weierstrass–Mandelbrot fractal surface function. By adjusting the fractal dimension, an ideal representation of single‐crystal silicon carbide with randomly rough surfaces is obtained. By combining plastic deformation detection methods, the process of workpiece sliding, plowing, and chip removal is studied, and the plastic deformation removal mechanism of random rough surface grinding is explored. Combining postprocessing methods such as sheer strain and dislocation trajectory, the morphological changes and transformation mechanisms of dislocations are analyzed. Notably, at grinding depth of 33.18 nm, the activation of slip systems induces dislocation formation, enabling plastic deformation. Furthermore, at depths exceeding 144.00‐nm, the emergence of stacking faults on the random rough surface is observed. Throughout the grinding procedure, plastic deformation of debris occurs, leading to the formation of plastic bulges on both sides of the tool, and the debris generated during processing does not impact the defects encountered during secondary grinding of the rough surface.

Flexural Strength of Monolithic Zirconia After Zirconia-specific Grinding Procedures and Hydrothermal Aging

Flexural Strength of Monolithic Zirconia After Zirconia-specific Grinding Procedures and Hydrothermal Aging

Quantification of surface grinding during the sample preparation of cementitious materials by optical profilometry.

Sample preparation is of utmost importance for any microscopy and microstructural analysis. Correct preparation will allow accurate interpretation of microstructural features. A well-polished section is essential when scanning electron microscopy (SEM) is used in backscattering electron (BSE) mode and characteristic X-rays are to be quantified using an energy-dispersive spectroscopy (EDS) detector. However, obtaining a well-polished section, especially for cementitious materials containing aggregates, is considered to be challenging and requires experience. A sample preparation procedure consists of cutting, grinding and polishing. Undercutting of soft and brittle paste between harder aggregates can be overcome by vacuum epoxy impregnation offering mechanical support in the matrix. Furthermore, most of the attention during the sample preparation is given to the polishing of the sample. There is a wide range of suggestions on polishing steps, ranging from grain sizes, time and applied force; however, the final assessment of a polish surface is often subjective and qualitative. Therefore, a quantitative, reproducible guidance on the grinding steps, effect of experimental parameters and the influence of different grinding steps on the surface quality are required. In this paper, the influence of grinding was quantitatively evaluated by a digital microscope equipped with optical profilometry tools, through a step-wise procedure, including sample orientation, grinding time and the difference between cement paste and concrete. Throughout the grinding procedure, the surface profiles were determined after each grinding step. This showed the step-wise change in surface roughness and quality during the grinding procedure. Finally, the surface qualities were evaluated using optical and electron microscopy, which show the importance of the grinding/prepolishing steps during sample preparation.

Shear bond strength of the ceramic veneer to additively manufactured titanium.

The objective of this in vitro study was to evaluate the shear bond strength between the ceramic veneer and additively manufactured titanium with different surface treatments, and to compare with milled titanium. Also, to characterize the surface and the presence of an α-case layer of additively manufactured and milled titanium. Sixty additively manufactured titanium grade 23, and 20 milled titanium grade 4 cylindrical specimens were divided into four groups based on surface treatments, air-particle abrasion and grinding. After ceramic veneering half of each group were thermocycled. The bond strength was analyzed using a shear bond strength test. The surfaces were analyzed using interferometry and scanning electron microscopy. The grinding procedure and air-particle abrading pressure had no significant effect on the shear bond strength (p = .264 and p = .344). Thermocycling showed a tendency towards an effect but not significant (p = .052). The group with the highest air-abrading pressure showed the highest surface roughness. No presence of an α-case layer was detected in any of the groups. Additively manufactured titanium grade 23 may be veneered with ceramics without prior grinding of the surfaces.

Industrial Robots in Mechanical Machining: Perspectives and Limitations

Recently, the need to produce from soft materials or components in extra-large sizes has appeared, requiring special solutions that are affordable using industrial robots. Industrial robots are suitable for such tasks due to their flexibility, accuracy, and consistency in machining operations. However, robot implementation faces some limitations, such as a huge variety of materials and tools, low adaptability to environmental changes, flexibility issues, a complicated tool path preparation process, and challenges in quality control. Industrial robotics applications include cutting, milling, drilling, and grinding procedures on various materials, including metal, plastics, and wood. Advanced robotics technologies involve the latest advances in robotics, including integrating sophisticated control systems, sensors, data fusion techniques, and machine learning algorithms. These innovations enable robots to adapt better and interact with their environment, ultimately increasing their accuracy. The main focus of this study is to cover the most common industrial robotic machining processes and to identify how specific advanced technologies can improve their performance. In most of the studied literature, the primary research objective across all operations is to enhance the stiffness of the robotic arm’s structure. Some publications propose approaches for planning the robot’s posture or tool orientation. In contrast, others focus on optimizing machining parameters through the utilization of advanced control and computation, including machine learning methods with the integration of collected sensor data.

Numerical Analysis of Stress Force on Vessel Walls in Atherosclerotic Plaque Removal through Coronary Rotational Atherectomy.

Coronary rotational atherectomy is an effective technique for treating cardiovascular disease by removing calcified tissue using small rotary grinding tools. However, it is difficult to analyze the stress force on vessel walls using experiments directly. Using computational fluid dynamics is a better way to study the stress force characteristics of the burr grinding procedure from a fluid dynamics perspective. For this purpose, physical and simulation models of atherosclerotic plaque removal were constructed in this study. The simulation results show that smaller ratios between the burr and arterial diameter (B/A = 0.5) result in a more stable flow field domain. Additionally, the pressure and stress force generated by the 4.5 mm diameter grinding tool reach 92.77 kPa and 10.36 kPa, surpassing those of the 2.5 mm and 3.5 mm grinding tools. The study has demonstrated the use of computational fluid dynamics to investigate wall shear stress characteristics in medical procedures, providing valuable guidance for optimizing the procedure and minimizing complications.

Shot peening simulation oriented to residual stress interaction with gear grinding

The current study proposes a shot peening model which enables the residual stress interaction with grinding, a typical combination for gear finishing. The effect of the interaction on the stress state development was addressed by comparing the residual stress state from a standalone shot peening procedure, against the residual stress state arising from a manufacturing route where the interaction of shot peening and grinding takes place. In the interaction model, the grinding procedure generates a pre-loaded condition on the material, modifying the internal strain system of the gear tooth. This pre-loaded system, when disturbed by shot peening, reaches a new internal strain equilibrium. In the interaction model, a 24% less compressive stress state was attained when compared with the standalone shot peening process. A significant shift in the depth and magnitude of the peak compressive stress was also observed. On account of the numerical study of the processes’ interaction, the developed model substantially contributed to understanding the residual stress formation during manufacturing chains.

Residual stress associated with crystalline phase transformation of 3–6 mol% yttria-stabilized zirconia ceramics induced by mechanical surface treatments

Monolithic dental prostheses made of 3–6 mol% yttria-stabilized zirconia (3–6YSZ) have gained popularity owing to their improved material properties and semi-automated fabrication processes. In this study, we aimed to evaluate the influence of mechanical surface treatments, such as polishing, grinding, and sandblasting, on the residual stress of 3–6YSZ used for monolithic prostheses in association with crystalline phase transformation. Plate specimens were prepared from five dental zirconia blocks: Aadva Zirconia ST (3YSZ), Aadva Zirconia NT (6YSZ), Katana HT (4YSZ), Katana STML (5YSZ), and Katana UTML (6YSZ). The specimens were either polished using 1, 3, or 9 μm diamond suspensions, ground using 15, 35, or 55 μm diamond discs, or sandblasted at 0.2, 0.3, or 0.4 MPa. The residual stress, crystalline phase, and hardness were analyzed using the cosα method, X-ray diffraction (XRD), and Vickers hardness test, respectively. Additionally, we analyzed the residual stress on the surfaces of monolithic zirconia crowns (MZCs) made of 4YSZ, 5YSZ, and 6YSZ, which were processed using clinically relevant procedures, including manual grinding, followed by polishing using a dental electric motor on the external surface, and sandblasting on the internal surface. Residual stress analysis demonstrated that grinding and sandblasting, particularly the latter, resulted in the generation of compressive residual stress on the surfaces of the plate specimens. XRD revealed that the ground and sandblasted specimens contained a larger amount of the rhombohedral phase than that of the polished specimens, which may be a cause of the residual stress. Sandblasting significantly increased the Vickers hardness compared to polishing, which may possibly be due to the generation of compressive residual stress. In the case of MZCs, compressive residual stress was detected not only on the sandblasted surface, but also on the polished surface. The difference in the residual stress between the plate and crown specimens may be related to the force applied during the automated and manual grinding and polishing procedures. Further studies are required to elucidate the effects of the compressive residual stress on the clinical performance of MZCs.