Grinding Characteristics Research Articles

Investigation on the grinding characteristics of binderless nanocrystalline cubic boron nitride (BNNC) as cutting material for the machining of hardened steels and superalloys

The direct synthesis of a binderless nanocrystalline cubic boron nitride (BNNC) from hexagonal boron nitride (hBN) has been developed by using a high-pressure / high-temperature process (HP/HT) with temperatures from 1400 °C - 2200 °C and pressures from 10 GPa - 20 GPa, the resulting BNNC compacts have a high hardness of more than 50 GPa as determined by Knoop-Indentation. A phase content of up to 97 % cBN could be determined by X-ray diffraction (XRD). The average crystallite size of the material is smaller than 100 nm and therefore significantly smaller than the crystallite size of conventional polycrystalline cubic boron nitride (PcBN) cutting materials. Compared to established PcBN cutting materials, the BNNC has an increased hardness and hot hardness and improved temperature stability. Utilization BNNC-based tools with defined cutting edge could provide an excellent alternative for the enhancement of the process limits for the machining of hardened steels and superalloys. This conference contribution will present the latest developments and challenges in the HP/HT direct synthesis of binderless nanocrystalline boron nitride (BNNC) as well as the investigation of its grinding characteristics for the application as cutting insert.

Research on Processing Efficiency and Contact Characteristics of M300 Steel Surface Grinding with Elastic Abrasives

Research on Processing Efficiency and Contact Characteristics of M300 Steel Surface Grinding with Elastic Abrasives

Experimental study on the characteristics of high speed cylindrical plunge grinding for annealed bearing steel 100Cr6

Experimental study on the characteristics of high speed cylindrical plunge grinding for annealed bearing steel 100Cr6

Investigation on grinding characteristics of metal additive manufactured maraging steel

Investigation on grinding characteristics of metal additive manufactured maraging steel

Optimal the Process Variables of Internal Grinding for Shrink Fit Tool Holder

The goal of this study was to investigate the optimal variables settings in internal grinding for shrink fit tool holder. The effects of the main grinding variables on finishing responses were comprehensively investigated based on Taguchi method. The main process variables such as abrasive grain size (AGS), grinding wheel speed (GWS), feed rate for rough (FRR), depth for rough (DR), feed rate for finishing (FRF), depth for finishing (DF), dressing speed (DS), and workpiece rotational speed (WRS) were chosen to determine their effects on grinding performances related to roundness and surface roughness in the internal grinding of the shrink fit tool holder. The experimental response values were transferred to signal-to-noise (S/N) ratios, and then the significant process variables associated with the grinding performance were examined by analysis of variance (ANOVA). In addition, the optimal combination levels of the grinding variables were also obtained from the response graphs of S/N ratios to improve the surface quality of internal grinding. The experimental results show that the significant grinding variable affecting the roundness was FRF. In addition, the significant variables with regard to surface roughness were AGS, GWS, FRR, DR, DF, and DS. The optimal grinding variable settings were achieved. Consequently, the finishing characteristics of internal grinding could be enhanced to meet the requirements of modern manufacturing applications.

Grinding characteristics of molybdenum tailings and properties of composite mortar containing molybdenum tailings

In order to promote the application of molybdenum (Mo) tailings in concrete industry, this paper studies the grinding characteristics of Mo tailings, the mechanical and hydration properties of mortars containing Mo tailings by X-ray diffraction (XRD), scanning electron microscope (SEM), laser particle size analysis, specific surface area analysis and strength test. The optimal grinding time is 80 mins to obtain the ground Mo tailings (-0.16 mm) with a specific surface area of 501 m2 kg-1 as mineral admixtures to the cementitious materials. With the coarse Mo tailings (+0.16 mm) as fine aggregate, composite mortars with a good workability were obtained with the compressive strength of 83.5 MPa and the flexural strength of 14.4 MPa after cured for 28 days. The comprehensive utilization rate of Mo tailings is 71 % in the composite mortars. The hydration of the cementitious composite containing Mo tailings at early age is primarily due to the hydration of the cement clinker (CC). While the large amount of quartz remains inert, the pozzolanic reaction of ground Mo tailings leads to the strength increases in long term. The main hydration phases in the cementitious composite are calcium silicate hydrates (C-S-H gels) and ettringite (AFt).

Grinding Fluid Jet Characteristics and Their Effect on a Gear Profile Grinding Process

Profile gear grinding is characterized by a high level of achievable process performance and workpiece quality. However, the wide contact length between the workpiece and the grinding wheel is disadvantageous for the fluid supply to the contact zone and leads to the risk of locally burning the workpiece surface. For the reduction of both the thermal load and the risk of thermo-mechanical damage, the usage of a grinding fluid needs to be investigated and optimized. For this purpose, different kinds of grinding fluid nozzles were tested, which provide different grinding fluid jet characteristics. Through a specific design of the nozzles, it is possible to control the fluid flow inside the nozzle. It was found that this internal fluid flow directly influences the breakup of the coolant fluid jet. There are three groups of jet breakup (“droplet”, “wave & droplet”, and “atomization”). The first experimental results show that the influence of the jet breakup on the process performance is significant. The “wave & droplet” jet breakup can achieve a high process performance, in contrast to the “atomization” jet breakup. It can therefore be assumed that the wetting of the grinding wheel by the grinding fluid jet is significantly influenced by the jet breakup.

Grinding characteristics of cBN-WC-10Co composites

In order to explore the grinding characteristics of cBN-WC-10Co composites, the grinding experiment with a resin bond diamond grinding wheel was carried out. The grinding forces, surface roughness, surface morphology and residual stress were investigated. It was found that the material removal mechanism of cBN-WC-10Co was the combination of the brittle fracture of cBN particles, ductile removal of Co phase, plastic deformation, grain dislodgement and grain crush of WC grains. The brittle removal model resulted in a lower specific grinding energy. The main contributor to the surface roughness was cBN particles. Some cBN particles over the surface of cBN-WC-10Co composites were fractured or pulled out and then formed cavities with different depths, this led to a rougher surface. The surface roughness was increased but the specific grinding energy decreased with an increase of the maximum undeformed chip thickness. A high-level residual compressive stress was induced at WC phase and it was increased with an increase of the depth of cut. The depth of cut has more significant influence on the grinding forces than the table speed or the wheel speed.

Effect of drying and grinding characteristics of colored potato (Solanum tuberosum L.) on tribology of mashed colored potato paste

ABSTRACTThe mouthfeel of mashed potato prepared with steamed purple flesh potato (SPFP) was investigated by measuring tribological and rheological characteristics. Mathematical models describing pre-processes such as drying and grinding associated with physical properties of mashed potato were also explored. The effect of drying temperature (60, 70, 80, and 90°C) on quality changes (moisture and anthocyanin content) of SPFP was successfully described (R2 > 0.9583). The sigmoid model was suitably applied to estimate particle sizes of dried SPFP during grinding (R2 > 0.9864). As the particle size of mashed SPFP increased, friction coefficient increased, and storage and loss modulus decreased. Taste, smoothness, and after-feel sensation were increased as particle sizes decreased, while appearance and odor showed no significant differences. To predict the sensory property using tribology and rheology, the specific conditions were successfully determined (R2 > 0.9926).

Effect of Pre-treatment at Subzero Temperature on the Grinding Characteristics of Grains

Effect of Pre-treatment at Subzero Temperature on the Grinding Characteristics of Grains

Experimental investigations on grinding characteristics and removal mechanisms of 2D–Cf/C-SiC composites based on reinforced fiber orientations

The effects of fiber orientations on the grinding force and ground surface roughness in grinding 2D–Cf/C–SiC composites were investigated in this work. The characteristics of surface microstructure and the mechanism of the grinding phenomena are also discussed. The results show that the prominent removal mechanism for grinding the 2D-Cf/C-SiC composites is the brittle fracture, and the destruction of the composites is mainly via breaking of interfacial bonds, fiber fracture, and matrix cracking. The grinding force of different grinding surfaces follows the order: Surface B > Surface A > Surface C, and the surface roughness follows: Surface C > Surface A > Surface B. Grinding parameters, such as feeding speed, depth of cut, and wheel speed, have a great influence on the grinding force and surface roughness. This result suggests that this body of work offers a useful guideline for improving the design and processing of 2D–Cf/C–SiC composites.

IM (Indentation Method) Based Impact Fracture Characteristics of cBN Crystal and Their Influence on High Speed Wheel Performance

Cubic Boron Nitride (cBN) is considered a superabrasive due to its excellent material behavior, and is commonly used in the manufacturing of high end grinding tools, in particular for machining hard-to-machine materials, in order to achieve high productivity in combination with high precision. During the actual grinding process, the performance of grinding tools is significantly affected by the fracture response of employed cBN crystals to the external impact load related to the grinding speed. Therefore, two types of cBN crystals are selected in this paper and their fracture resisting behaviors are measured under various impact loading rates through the Indentation Method (IM). In order to establish the fracture behavior of cBN crystals and the overall grinding performance of cBN wheels, high speed surface grinding experiments are conducted and grinding performances are evaluated regarding the evolution of grinding force and power consumption, wheel wear and grinding efficiency, as well as the chemical stability of cBN materials on affinity. The experimental results show a good agreement of cBN crystal’s impact fracture properties on the cBN grinding wheel performance, which helps to understand cBN crystal’s high speed grinding characteristics.

Grinding characteristics, physical, and flow specific properties of roasted maize and soybean flour

Grinding characteristics (one and two stage grinding) of roasted maize (RM) and soybean (RS) were conducted in attrition mill to find the effect of feed rate and peripheral speed on average particle size (APS), specific energy consumption (SEC), size reduction ratio (SRR), and grinding constants. Carr Index (CI), Housner ratio (HR), density, water, and oil absorption capacity of flour were also studied as a function of particle size. The higher SRR, APS, and grinding recovery were recorded in the first stage grinding as compared with second one. SEC was decreasing significantly (p < .05) from 0.0039 ± 0.0011 to 0.0013 ± 0.0019 kwh/kg as, feed rate increased from 9 to 15 kg/hr. The grinding constants were significantly increased in the second stage grinding. The flowability of flour such as CI and HR was poor at lower particle size. SEC and APS analysis revealed that a two-stage segregated grinding would be suitable for RM and RS grinding. Practical applications Roasted maize and soybean flour are highly nutritive food and prepared by roasting, grinding and sieving. Flour particle sizes and flow specific properties play an important role in addressing malnutrition and ready-to-eat food formulations. The digestibility and release of bioactive components also depend upon particle size and granular morphology of the food. Though, the present study is also acquainted with energy consumption during processing operation and product quality and which are key parameters for scaling-up and designing the grinding equipment. The information generated regarding the energy consumption and health benefits may be useful for food processors and consumers as well.

A comparative study of conventional and high speed grinding characteristics of a thin film multilayer structure

High speed and conventional speed grinding characteristics of a thin film multilayer solar panel were investigated. The grinding force and surface roughness were measured and the interface integrity of the ground workpieces was examined. The results indicated that when applying a high wheel speed of up to 120m/s, the ground surfaces predominantly exhibited ductile flow and the interface integrity was significantly improved. The maximum undeformed chip thickness was found to be an important parameter to measure grinding performance and interfacial failure. Delamination was observed at interfaces when the maximum undeformed chip thickness exceeded a threshold value and the finite element method (FEM) analysis revealed that the interfacial failure was mainly induced by shear stress.

Predictive Modelling and Analysis of Process Parameters on Material Removal Characteristics in Abrasive Belt Grinding Process

The surface finishing and stock removal of complicated geometries is the principal objective for grinding with compliant abrasive tools. To understand and achieve optimum material removal in a tertiary finishing process such as Abrasive Belt Grinding, it is essential to look in more detail at the process parameters/variables that affect the stock removal rate. The process variables involved in a belt grinding process include the grit and abrasive type of grinding belt, belt speed, contact wheel hardness, serration, and grinding force. Changing these process variables will affect the performance of the process. The literature survey on belt grinding shows certain limited understanding of material removal on the process variables. Experimental trials were conducted based on the Taguchi Method to evaluate the influence of individual and interactive process variables. Analysis of variance (ANOVA) was employed to investigate the belt grinding characteristics on material removal. This research work describes a systematic approach to optimise process parameters to achieve the desired stock removal in a compliant Abrasive Belt Grinding process. Experimental study showed that the removed material from a surface due to the belt grinding process has a non-linear relationship with the process variables. In this paper, the Adaptive Neuro-Fuzzy Inference System (ANFIS) model is used to determine material removal. Compared with the experimental results, the model accurately predicts the stock removal. With further verification of the empirical model, a better understanding of the grinding parameters involved in material removal, particularly the influence of the individual process variables and their interaction, can be obtained.

Comparison of grinding characteristics in high-pressure grinding roller (HPGR) and cone crusher (CC)

Comparison of grinding characteristics in high-pressure grinding roller (HPGR) and cone crusher (CC)

No.24 木質炭化燃料の高混焼率利用時における粉砕・燃焼特性(重質油・バイオマス・コプロセッシング(4)、灰・微量元素(2))

No.24 木質炭化燃料の高混焼率利用時における粉砕・燃焼特性(重質油・バイオマス・コプロセッシング(4)、灰・微量元素(2))

Mechanism underlying the effect of conventional drying on the grinding characteristics of Ximeng lignite

Same amounts of moisture were removed from Ximeng lignite (XL) with different particle size ranges pretreated at different drying temperatures. The effect of conventional drying on the grindability of the XLs was investigated. Increasing the drying temperature improved the grindability of all the samples. The results of scanning electron microscopy and mercury intrusion porosimetry revealed that the dominant mechanism enhancing the grindability of XL with high moisture was the pore structure destruction induced by the steam jet flow generated with the removal of moisture. Especially, the development of large fractures had a strong connection with the change in the grindability. According to the pore size distribution, the internal structure of the 2.5-4.0mm coal samples did not develop well under high drying temperature because of the exceedingly short heating time. Therefore, coal particle size, drying temperature, and heating time must be coordinated well to achieve the enhanced drying effect. The grindability of XL had a negative linear correlation with the pore volume fractal dimension, revealing the possibility of fractal dimension for the analysis of lignite grindability.

Investigation on temperature distribution in form grinding of 9Mn2V thread gauge

Accurate simulation about the grinding temperature distribution helps to decrease the thermal damage and microcracks during the grinding process. In this article, the grinding heat transfer process of form grinding was analyzed and a temperature distribution model was derived in form grinding of 9Mn2V thread gauge. Considering the characteristics of form grinding, the temperature rise of the intersection region can be affected by two kinds of heat sources, and the impact between the two heat sources has been investigated. Also, the influence of the grinding depth on the temperature rise was analyzed. Depending on the analysis, an improved heat partition model has been derived, which is based on single-grain energy partition model. A series of experiments were carried out to investigate the grinding performance of 9Mn2V. The grinding force was obtained, the specific grinding energy was discussed, and the experimental temperature was measured by infrared imager. It is shown that the experiment results correspond well to the theoretical temperature calculated by the prediction model. This temperature model can be used to optimize the grinding conditions and the critical depth in form grinding of 9Mn2V thread gauge.

蓝宝石不同晶面磨削特性比较

蓝宝石不同晶面磨削特性比较