Grinding Wheel Specifications Research Articles

Grinding wheel specification cybernetic recommendation with multi-task multi-imbalanced learning in smart manufacturing system

Over the years, the grinding wheels industry has played a crucial role in mechanical engineering. Grinding wheel specification is composed of various factors such as abrasive type, wheel grade, bond type, and more, which are derived from customer workpiece operation information. Traditionally, the determination process of grinding wheel specifications is complicated. Experienced engineers need to check out the limitation and consider the interaction of each factor. When the new specification order comes, engineers have to spend a lot of time on historical data search and discussion. Recently, the application of artificial intelligence attracts more and more attention in the manufacturing industry. Through collecting historical data, the model has the ability to extract the domain knowledge, predict the specification that does not exist, and reduce the decision time. However, when training the model, this grinding wheel specification faced multiple imbalanced targets and multi-task issues. In the past, research efforts primarily focused on studying single-task learning (STL) algorithms. Seldom of them has a systematic way to discuss the model determination of multiple targets and correlation influence, especially on the tabular-type dataset. In this study, we proposed a multiple resampling chain multi-task learning framework to address the issue of data science. To tackle the multi-task imbalance resampling problem, we also proposed a resampling strategy called Multiple Resampling Chain. Moreover, we conducted a sensitivity analysis to examine the correlation effect on model improvement. Finally, we proposed a cyber-recommendation system that integrates the training model and interface to provide a more intuitive way of specification prediction. This system not only can help engineers to improve the time spent on making decisions, but also make the whole manufacturing process to be more intelligent.

Modeling the wetting behavior of grinding wheels

Helical flute grinding is an important process step in the manufacturing of cylindrical cemented carbide tools where the use of cooling lubricants is a defining factor determining process performance. Finding optimal parameters and cooling conditions for the efficient use of lubricant is essential in reducing energy consumption and in controlling properties of the boundary zone like residual stresses. Any mathematical model describing the interactions between grinding wheel, lubricant and workpiece during the process has to account for the complex microstructure of the wheel; however, this renders the identification of parameters like slip or heat exchange coefficients numerically prohibitively expensive. In this paper, results from grinding oil droplet experiments are compared with simulation results for the wetting behavior of grinding wheels. More specifically, finite element simulations of the thin-film equation are used to identify slip parameters for different grinding wheel specifications (grain size, bonding structure, wetting status). Our results show that both the bonding and the grain size have an influence on the wetting behavior. The slip parameters that we identified account for the fluid-microstructure interactions and will be used to effectively model those interactions in more complex 3D fluid-dynamic simulations via the Beavers-Joseph condition.

Prediction of the grinding wheel specification influence on thermal defects in dry grinding through a hierarchical FEM model

Prediction of the grinding wheel specification influence on thermal defects in dry grinding through a hierarchical FEM model

Feed based trajectory addition and elimination algorithm combined with stochastic meshless modelling to simulate roughness in surface grinding

Surface grinding is observed to be an inevitable machining event in many of the functional engineering surfaces after pre-processing stages such as milling. Prediction of roughness profile after grinding on such initial surfaces, for selected operating conditions and grinding wheel specification, is always an interesting topic of investigation. Though a number of models have been reported in prior art, value additions through hybrid modelling strategies have been always contributing positively to this field of research due to the stochastic nature of abrasive interactions. Since feed rate of work piece is identified as a key grinding variable influencing the surface roughness, present paper introduces grain trajectory addition and elimination algorithm driven by feed based time scale to predict the ground surface topography. A realistic initial surface modelling is considered using meshless moving least square approximation incorporating both roughness as well as geometric deviation, expected to be imparted during pre-grinding stages. The algorithm is configured to compute two dimensional roughness parameters from the simulated surface profiles and these results are compared with experimental outcomes at various depths of grinding to validate the proposed model.

Investigations on the micro-interactions of grit-workpiece and forces prediction in ultrasonic vibration side grinding of optical glass

The cutting force in ultrasonic vibration side grinding (UVSG) of brittle materials is of significance for the machined quality. However, the micro-interaction mechanism between abrasive grits and workpiece remains a significant issue in terms of the research on cutting forces in the brittle material grinding due to the stochastic distribution nature of the grits. Meanwhile, these micro-interactions are further affected by ultrasonic vibration in UVSG process. Considering these issues, this paper aims at modeling the cutting force affected by the stochastically distributed grits and ultrasonic vibration to reveal the multi-scale grinding mechanics in UVSG of optical glass. Through modeling the stochastic grinding wheel surface and analyzing the kinematics of multi-grits, the unified motion trajectory and the instantaneous chip thickness in UVSG were enabled to derived to determine the different grit-workpiece interaction stages. With consideration of the ultrasonic vibration effects on the micro-interactions, a novel theoretical cutting force model was developed based on the analysis of force generated at three interaction stages, i.e., rubbing, plowing, and cutting stages. The numerical simulations of this model could provide the time-domain variation features of cutting forces to evaluate the fluctuations and trends of the cutting forces from multi-scales. Experimental verifications indicated that the cutting force and its fluctuations are within the acceptable error margin. Furthermore, a thorough analysis of force fluctuating situations at different ultrasonic vibration amplitudes was conducted. The analytical results indicated that an increase in ultrasonic vibration amplitude was not only beneficial to restrain the force fluctuation, but helpful to reduce the brittle fracture damages of optical glass. The evolution trend of cutting force in different grinding conditions and wheel specifications were discussed in detail to reveal the influence mechanisms of machining parameters on the cutting forces. Afterwards, the detection results of ground workpieces demonstrate that the introduction of ultrasonic vibration would improve the machined quality of optical glass in UVSG process.

Optimization of the precision gear grinding operation based on integrated information system

In accordance with the principles of hierarchical management, a comprehensive two-level management system is presented for the development and manufacturing of products for the stages of pre-production (the upper level of the management hierarchy) and for the actual production stage (the lower level of the management hierarchy). At the stage of pre-production, the gear grinding oper-ation design on the “MAAG”type machines was carried out. For this purpose, a technique for optimizing the gear grinding parame-ters for a two dish-wheel rolling scheme has been developed, a mathematical optimization model containing an objective function with restrictions imposed on it has been created. The objective function is the gear grinding machine time, which depends on theoperation parameters (gear grinding stock allowance, cutting modes, grinding wheel specification, part material) and the design fea-tures of the gears beingground (module, diameter, number of teeth, radius of curvature of the involutes). The article showsthat at the stage of pre-production,the gear grinding optimizationis a method of operation design. At the stage of actual production, a closed-loop automatic control system with feedback on the deviation of the adjustable value (gear grinding power) automatically supports the numerical power values that were found at the operation design stage, taking into account ensuring defect-free high-performance gear grinding (minimum number of working strokes and maximum longitudinal feeds). At this stage, i.e. when a robust longitudinal feed automatic control system is operating, the optimization carried out at the previous stage (pre-production) sets the functioning algorithm for the adaptive systemwithcorresponding control algorithm. Thus, at the production stage (when the gear grinding ma-chine is running), the operation optimization is a control method. Therefore, it is shown that with two-level control, the gear grinding operation optimization performs a dual function. On the one hand, it is a design method (at the pre-production stage), and on the other –a management method (at the actual productionstage). With this approach, i.e. with the integration of production and its preparation based on a single two-level management, the efficiency of a single integrated design and production automation system is significantly higher due to general (unified)optimization, rather than partialone.

Parametric grinding wheel model for material removal simulation of tool grinding processes

Tool grinding is an essential process for the production of cemented carbide tools. In that context, the investigation of specific effects like the resulting surface profile and the fluid dynamic processes is of great interest, but requires microscopic modeling of the grinding wheel including its individual grains and bonding material. This paper introduces an approach for a parametric grinding wheel model, which provides a topography on microscopic scale depending on the grinding wheel specification and dressing conditions for subsequent use in material removal simulations. Scalable abrasive grains and variable distributions embedded in a shiftable bond layer are applied. Optical laser scans are used to derive surface parameters for an adaption and evaluation of the model. The prediction quality in terms of surface roughness is evaluated in surface grinding reference experiments.

Grinding burn limits: Generation of surface layer modification charts for discontinuous profile grinding with analogy trials

By means of surface layer modification charts, the occurrence of thermal impact and thus the risk of grinding burn can be detected. With the present work it was shown that surface layer modification charts for discontinuous profile grinding can be generated using analogy trials carried out on a surface grinding machine for investigation of different grinding conditions and varied tilt angles in profile grinding. The experimental and the analysis effort for the analogy trials prove to be significantly more time and cost saving. The results also suggest that system parameters such as the grinding wheel specification or the cooling strategy are taken into account by the specific grinding power. Thus, the experimental results of this work allow the assumption that the determined process limit is not or just to a low extent depending on the system parameters. This assumption is supported by the thermal process limit determined by Malkin and converted in surface layer modification charts. Malkin's limit, identified for different ground steels with surface and cylindrical grinding processes and thus different system and process parameters, corresponds to the results generated in this work at workpieces ground with a kinematically more complex process. The results reveal that there is at least a group of steel materials which seems to share a similar thermal process limit.

Impact of grinding wheel specification on surface integrity and residual stress when grinding Inconel 718

The grinding process is often maligned by grinding burn; which refers to many unwanted effects, including residual stress formation. This paper presents an overview of the role of grinding wheel technologies in the surface response and residual stress formation of thin section Inconel 718. Using production standard equipment, conventional abrasive vitrified, and super abrasive electroplated wheel technologies were evaluated in initial comparative trials. Results revealed the dominant residual stress profiles, which manifested as measurable distortion and the thermo-mechanical impact of grinding, such as softening. Following this, a parametric study was carried out using cubic boron nitride super abrasive electroplated wheels to investigate the interaction of grinding parameters on the generated output. It was shown that at increased grinding aggressions, tensile stress regimes increased resulting in increased distortion magnitudes. The study highlights the importance of assessing residual stress formation when manipulating both wheel technologies and grinding parameters. It is envisaged that with additional assessment, a route to an engineered residual stress profile might be achieved.

Global strategy of grinding wheel performance evaluation applied to grinding of superalloys

For grinding of superalloys, Difficult to Grind (DTG) materials, superabrasive grinding wheels of cBN (cubic boron nitride) with vitrified bond are considered the first choice for light roughing and finishing due to their superior performance when compared to conventional grinding wheels. However, there are limitations on the use of cBN wheels due to the higher initial cost of the cutting tool and the need for dressing systems with rotary tools. Aiming at reducing operational costs, the use of conventional grinding wheels with ceramic grains and high retention binder and lower bond-abrasive ratio is becoming increasingly common. In this scenario of introduction of new abrasive tools, it is necessary to use tools to evaluate the comparative performance of grinding wheels, which can encompass different aspects of the grinding process under study and which includes technical requirements of the component to be ground, as well as indicators of sustainability of the process. Thus, the objective of this work is to propose an evaluate strategy of the performance of grinding wheels whose methodology of analysis encompasses, in a coordinated way, traditional evaluation parameters and sustainability criteria (economic, environmental, and social) and that can be applied, as a study of case, in the grinding of superalloys for engine components, with different degrees of grindability. A high-performance engineered conventional grinding wheel and a vitrified cBN wheel were comparatively evaluated. The proposed methodology included the determination of the characteristic curve of a grinding wheel, coordinated analysis of the output parameters of the grinding process and the introduction of sustainability indicators. The results show the proposed global strategy proved to be viable and effective in comparing different grinding wheel specifications by encompassing aspects of the economic, environmental, and social performance of the grinding process. As a conclusion, the feasibility of the high-performance conventional wheel in substitution of the cBN wheel was confirmed for the grinding of the tested superalloys.

IDENTIFIKASI BAHAYA DAN PENILAIAN RISIKO OPERATOR MESIN GERINDA

Research in the fabrication unit of PT. Bangun Sarana Baja Gresik to determine hazard identification and risk assessment in grinding machine operators. This research uses Systematic Human Error Reduction and Prediction Approach (SHERPA) to determine error in identify hazard consisting of task stage, error mode, error description, consequence analysis and recovery analysis. The AS/NZS 4360: 2004 standard is used to determine the severity, likelihood and risk matrix scales in assessing risks consisting of frequency analysis, severity analysis, and criticality analysis that results in the level of risk at each stage of the task. Population in this research is all grinding machine operator at PT. BangunSarana Baja Gresik which are 60 operators. The sample of this research is as much as 20 grinding machine operatorsfabrication unit of PT. Bangun Sarana Baja Gresik with purposive sampling technique.Hazard identification on the grinding process such as falling material, unstable material condition, cracked grinding wheel, grinding wheel specifications are incompatible with the grinding machine and vice versa, the cable is flaked, melted, even broken, cracked cable terminal, starter (switch on/off) is damaged, sparks, gram sparks, ergonomic body positions, high speed grinding wheels, welding rays, noise and tool hand vibration can result in scratches, abrasions, dislocations, fractures, scratches broken grinding stones, electric shock, pincers, burns, low back pain, sore eyes, hand arm vibration syndrome and carpal tunnel syndrome in the worker's body. Risk assessment for low risk task stage is 6 error descriptions which means acceptable risk and no action required, medium risk is 31 error descriptions which means more alert and corrective action is recommended if cost effective, and high risk is 12 error descriptions which means the risk to be aware and there are actions needed to control the risks. Keywords: grinding, hazard identification, risk assessment

Influence of different grinding wheel and dressing roller specifications on grinding wheel wear

A targeted adjustment of the dressing results and the methodological influence of the dressing process on the non-stationary wear of a grinding wheel after dressing increases the productivity and the reproducibility of grinding processes. Despite the great economic importance of grinding processes with vitrified corundum grinding wheels and the great relevance of the dressing process for the application behavior of these grinding wheels, quantitative models are missing for the purposeful design of the dressing process. In previous studies, a dressing model was successfully developed which predicts the dressing force in the dressing process as well as the workpiece roughness and the grinding wheel wear behavior in a grinding process for a specific grinding wheel and form roller specification. However, a transferability of this model to other grinding wheel and form roller specifications is not possible because the influence of the grain size and the hardness of the grinding wheel as well as the dressing tool topography on the grinding wheel wear and thus on parameters of the dressing model are not known. The objective of this work was to extend the model to additional grinding wheel and form roller specifications to ensure a broad applicability of the model.

Detailed Analysis and Description of Grinding Wheel Topographies

In this paper, an innovative approach for the description of the functional properties of a grinding wheel surface is discussed. First, the state of the art in the description of grinding wheel topographies is summarized. Furthermore, the fundamentals for a new approach for the quantitative description of grinding wheel topographies are provided. In order to analyze the functional properties of a grinding wheel's topography depending on its specification, grinding experiments were carried out. For the experimental investigations vitrified, synthetic resin bonded and electroplated grinding wheels with varied compositions were analyzed. During the experiments, the topographies of the investigated grinding wheels have been analyzed by means of the topotool in detail. The developed software tool allows a detailed description of the kinematic cutting edges depending on the grinding process parameters and the grinding wheel specification. In addition to the calculation of the number of kinematic cutting edges and the area per cutting edge, a differentiation of the cutting edge areas in normal and tangential areas of the grinding wheel's circumferential direction is implemented. Furthermore, the topotool enables to analyze the kinematic cutting edges shape by calculating the angles of the grain in different directions. This enables a detailed analysis and a quantitative comparison of grinding wheel topographies related to different grinding wheel specifications. In addition, the influence of the dressing process and wear conditions to the grinding wheel topography can be evaluated. The new approach allows a better characterization of the contact conditions between grinding wheel and workpiece. Hence, the impact of a specific topography on the grinding process behavior, the generated grinding energy distribution, and the grinding result can be revealed.

Mathematical modeling of ceramic bond bridges in grinding wheels

Ceramic-bonded grinding wheels with cubic boron nitride (CBN) as grain material belong to the most efficient grinding tools available. They feature a high hardness combined with a high thermal stability and the applicability to grinding ferrous materials. However, the appropriate volumetric composition of grain and bonding material is an expensive and time-consuming process based on experience. Our objective is the mathematical modeling of grinding wheel structures for the prediction of compositions which fulfill given grinding requirements such that using trial and error methods can be avoided. For this purpose, we focus on a three-dimensional element of a grinding wheel which we call volumetric structure element. In this paper, we briefly describe our overall modeling approach and present in detail how we model the ceramic bond. For the latter, we combine analytical and discrete calculations, embedded into an iterative algorithm which ensures to meet bond volume fractions prescribed by grinding wheel specifications.

砥石内研削液供給機構における砥石要目が砥石表面温度と仕上げ面粗さに及ぼす影響

砥石内研削液供給機構における砥石要目が砥石表面温度と仕上げ面粗さに及ぼす影響

Grinding of Austempered Ductile Iron Grade 3 as Function of the Microcrystalline Al<sub>2</sub>O<sub>3</sub> Grinding Wheels Composition

The conventional grinding wheels employment is an economically viable alternative on Austempered ductile iron (ADI) grinding. The machining of this iron is in most cases performed with superabrasive grinding wheels, requiring machine tools with higher costs. The ADI grinding with conventional grinding wheels can produce work results comparable to the superabrasive grinding wheels, followed by lower costs and flexibility in profile grinding, since these wheels can be easily re-profiled. The aim of this work is to verify the work results of grinding ADI Grade 3 employing conventional grinding wheels. The approach is based on the influence evaluation of different abrasive microcrystalline Al2O3 percentage in these tools on the force results and roughness values in the ADI grinding. The findings show a correlation between the grinding forces and the microcrystalline abrasive percentage of microcrystalline Al2O3, since lower forces were demanded for wheels with higher percentages. Regarding the surface parameters, there was a decrease in roughness values by employing less percentages. The originality of this research is reflected in the fact that it is the first time that the influence of the composition of conventional grinding wheels is investigated on ADI Grade 3 grinding. The results present in this research will contribute to the most appropriate conventional grinding wheel specification for the ADI Grade 3 grinding.

Advances in Tool Grinding and Development of End Mills for Machining of Fibre Reinforced Plastics

The extensive use of lightweight construction materials in the aerospace industry poses a great challenge for tool manufacturers. Materials like carbon fibre reinforced plastics (CFRP) are difficult to machine and therefore put high demands on cutting tools in terms of the cutting material as well as the macro- and microscopic design. In this paper two approaches for the improvement of CFRP milling processes are presented. One approach involves the optimization of the flute grinding process for cemented carbide milling tools by the use of innovative grinding wheel specifications and their influence on cutting-relevant tool features. The other approach deals with the development of ceramic end mills for CFRP machining. Investigations about the influence of different process- and tool-related parameters on the work result and process parameters are presented.

Wafer Grinding of Using Fixed Abrasive Diamond Wheel - Evaluation of Cutting Edge Distribution in Diamond Wheels

The wafer grinding by use of fixed abrasive diamond wheels is required to create a high-quality wafer surface in a short time. In general, it is known that the grinding performance of diamond wheel is mainly dependent on grinding wheel specifications and grinding conditions. The cutting edge distribution or abrasive protrusion height in depth-wise of a specified wheel is one of the most important factors to determine the finishing surface roughness and the grinding force, which in turn determine the surface and subsurface quality of ground wafers. The overall purpose of this study is to understand the dynamic behavior of each diamond abrasive via modeling an actual diamond wheel and simulating of wafer grinding. In previous report [1], we have theoretically analyzed three-dimensional cutting edge distribution on the working surface of diamond wheels. This paper reports our recent achievements in the evaluation of 3-D cutting edge distribution in depth-wise of a specified wheel via the bearing ratio of its topography.

Study on Hydrodynamic Pressure in Grinding Contact Zone Considering Grinding Parameters and Grinding Wheel Specifications

In the grinding process, coolant lubricant is used to lubricate and mainly to transmit the heat generated in the contact zone. Grinding wheel accelerates a portion of the coolant lubricant into the contact zone. As e resault of the wedge effect between grinding wheel and workpiece in the contact zone a hydrodynamic pressure is generated, which influences the grinding results. In this paper, a new model for the hydrodynamic pressure of the coolant in the contact zone is presented. The simulation results show that the hydrodynamic pressure is proportion to grinding wheel velocity, and in inverse proportion to the minimum gap between wheel and workpiece. Furthermore, it could be investigated that the specification of the grinding wheel can affect the value of this pressure. The experimental results correspond to the simulation results, which show the validity of the simulation.

Fine finishing of gears with high shape accuracy

Besides high demands on surface integrity machining of gears aims on very low surface roughness and high shape accuracy. These properties will have positive impacts on the lifetime of gears. In this context the challenges of profile grinding of cylindrical gears by using elastic bonded grinding wheels are addressed. For this new gear fine finishing approach, the very high potential of the process is revealed by analyzing the influence of the grinding wheel specification and the machining parameters on surface finish. Results show that gears with high shape accuracy and very good surface finish with almost optical quality can be achieved.