High Grinding Temperature Research Articles

Study of 3D grinding temperature field based on finite difference method: considering machining parameters and energy partition

Grinding temperature is an important parameter in affecting the quality of grinding. The higher grinding temperature would cause thermal damage to workpiece. But in the actual grinding processing, it is difficult to measure the grinding temperature in real time. This paper presents the finite difference method to calculate the grinding temperature. When calculating the grinding temperature, an important physical quantity cannot be avoided; it is the energy partition and it is the fraction of the grinding energy transported as heat to the workpiece at the grinding zone. At present, there are a lot of calculation models for the energy distribution, but no one is very exact, and most models are exclusive for alumina grinding wheel grinding. Based on measuring the grinding force and temperature, the heat flux toward the workpiece can be back-calculated by finite difference method that compared the difference between the thermal model and experimental results; thus, the energy partition can be obtained. The results show that it provides a 3D graphic image of the whole temperature field by using the fused deposition modeling (FDM). And the influences of feed rate on grinding temperature and of energy partition are significant compared with the grinding speed and depth of cut. The improvement of feed rate can effectively reduce the grinding temperature, but energy partition has a significant rise. After repeated research, an approximate value of energy partition was obtained by using vitrified bond cubic boron nitride (CBN) wheel grinding titanium alloy material TC4, and it was about 5 % under dry grinding.

Experimental study on grinding force and grinding temperature of Aermet 100 steel in surface grinding

This paper investigates grinding force and grinding temperature of ultra-high strength steel Aermet 100 in conventional surface grinding using a single alumina wheel, a white alumina wheel and a cubic boron nitride wheel. First, mathematical models of grinding force and grinding temperature for three wheels were established. Then, the role of chip formation force and friction force in grinding force was investigated and thermal distribution in contact zone between workpiece and wheel was analyzed based on the mathematical model. The experimental result indicated that the minimum grinding force and the maximum grinding force ratio under the same grinding parameters can be achieved when using a CBN wheel and a single alumina wheel, respectively. When the phenomenon of large grinding force and high grinding temperature appeared, the workpiece material would adhere locally to the single alumina wheel. Grinding temperature was in a high state under the effect of two main aspects: poor thermal properties of grinding wheel and low coolant efficiency. The predicted value of grinding force and grinding temperature were compared with those experimentally obtained and the results show a reasonable agreement.

Development of a Grinding Carriage for an Inner Cooling Grinding in a General Grinding Machine

As inner cooling grinding can break the closure of grinding area and solve practical engineering problems resulting from too high grinding temperature, it can be used to realize the grinding of difficult-to-machine materials, such as Titanium alloy, in a general machine such as M7130. An inner cooling grinding wheel, a grinding carriage and cutting fluid system are the key parts of a inner cooling grinding system, and an inner cooling grinding wheel must be fixed on a plain grinder by a grinding carriage, so this paper mainly studies how to design and manufacture a tooling for an inner cooling grinding wheel, which has simple construction and reliable performance. Grinding experiment shows it can dramatically reduce cutting temperature and effectively avoid grinding burn, thus grinding quality is improved.

Investigation of a heat pipe cooling system in high-efficiency grinding

The high grinding temperature is one of the problems restricting on the further development of high-efficiency grinding due to the workpiece burnout and excessive wheel wear. An original method about enhancing heat transfer in the contact zone based on heat pipe technology is put forward to reduce the grinding temperature in this paper. Drawing on the structure of rotation heat pipe, one heat pipe cooling system, heat pipe grinding wheel (HPGW) applied to high-efficiency grinding, is developed and its heat transfer principle is illustrated. Besides, the cooling effect in the contact zone using HPGW is simulated through a three-dimensional heat transfer model in grinding, and the influence of different parameters of the wheel speed, cooling condition, and heat flux input on the grinding temperature is analyzed. Eventually, preliminary grinding experiments with HPGW were carried out to verify the cooling effect by comparing with non-HPGW in grinding of 0.45 wt.% C steel and titanium alloy Ti-6A1-6V. Results show that using HPGW can significantly reduce the grinding temperature and prevent the burnout.

Research on Grinding Temperature of a New Diamond Grinding Wheel

It is aimed at developing a new diamond wheel in order to overcome the shortages of traditional grinding wheel, such as the abrasive easily fall off the grinding wheel prematurely, high grinding temperature, random grits distribution and the loading problems become more severe in grinding process. And further study on the grinding temperature of the new diamond wheel prepared in comparison with traditional resin-bonded diamond grinding wheel in machining Al2O3 ceramic. The prepared new diamond wheel has many diamond fibers involved in grinding process which are artificially ordered, diamond grits are not easily fall off, and it has big chip-pocket space and heat dissipating capability. The experimental results indicated that the grinding temperature of the new diamond wheel in comparison with the conventional diamond wheel under the same conditions was decreased by 80°C-120°C.

Exploring Grindability of Titanium Grade 1 Using Silicon Carbide Wheel

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

Optimalisasi Proses Gerinda Untuk Permukaan

Basically, surface grinding is mechanical process that result high temperature and chemical reaction on surface work piece. On this process, the heat energy has been released along of the surface. A part of the energy would be transferred to chip and the other would be continued to the environment by grinder and work piece. Use of coolant on the surface of the object will be function as lubricant, which can reduce friction between grinder and the object. Moreover, in grinding process, cooling can effect on temperature and surface roughness. This research used factorial design 2x3x3 to evaluate the effect some variables process such as table speed, depth of cut also cooling method on temperature and surface roughness. High pressure air and air in room temperature are kinds of cooling method in the process, the result of experiment would be analysis by ANAVA. The experiment shows that temperature in air cooling method it is lowerthan by air of room temperature cooling method. The surface roughness of the work piece in air cooling method is the lowest. The faster table speed of grinding machine caused that the lower of the grinding temperature and the work piece surface roughness. Moreover, the higher depth of cut would cause the higher grinding temperature and surface roughness.

Analysis of the Surface Residual Stress in Grinding Aermet100

Grinding induces residual stresses, which can play an important role on the fatigue of the component. In general, residual stresses in a ground surface are primarily generated due to three effects: thermal expansion and contraction during grinding, plastic deformation caused by the abrasive grains of the wheel and phase transformations due to high grinding temperature. It was found that thermal expansion and plastic deformation in the grinding process were the major causes of residual stresses. In this paper, an analysis model for the calculation of residual stresses induced by a surface grinding process on an ultrahigh-strength steel (Aermet100) workpiece is presented. Firstly, the stress distribution induces by thermal expansion was obtained base on the transient heat conduction equation and the thermal properties of Aermet100. All the calculations were based on the moving heat source solution which was modeled as a uniformly distributed, 2D heat source moving across the surface of a half-space, found in Carslaw and Jaeger. The results show that the near surface residual stress is predominantly tensile and that the magnitude of this stress increases with increasing heat flux values. Secondly, the plastic deformation caused by the abrasive grains of the wheel was simulated base on the grain-workpiece interaction. The chip formation process and the material removal mechanisms can be examined using the micro-scale approach. The results show that the residual stress induced by the grinding force itself is generally compressive which is smaller than the residual tensile stress induced by thermal stress. Therefore, the residual stress brought about by grinding operation is generally a tensile stress. This paper offers an insight into the mechanism understanding of thermal and mechanical residual stresses induced by surface grinding. Key words: grinding, residual stress, grain

NUMERICAL SIMULATION AND EXPERIMENTAL VALIDATION OF THE TEMPERATURE FIELD IN SURFACE GRINDING

Three-dimensional numerical simulations are carried out to investigate the temperature field in the contact zone due to the thermal loading of the workpiece in surface grinding. This technique considers that the thermophysical properties of the workpiece material are non-linear according to temperature, the contact zone between the wheel and the workpiece is assumed as an arc surface, and the heat flux entering the workpiece is assumed as proportional to the local undeformed chip thickness. A good agreement is found between the simulated results and the experimental observations. The high grinding temperature leads to the thermal expansion of the workpiece material, which causes the thickness of the actual material removal layer to be larger than the cutting depth. The grinding temperature at the central portion is higher than that on the side of the workpiece during the wet grinding, thus the material removal layer in the central zone is thicker than that on the side zone, and the workpiece surface is concave across the grinding width.

Study on Performance and Mechanism of High Efficiency Organic Grinding Liquid for Ceramics with Silicon

This study selected three types of organic substance as the main components of high-efficient organic grinding liquid for grinding ceramics with silicon. The grinding efficiency test was conducted on the basis of self-developed grinding mechanism and the findings indicated that the grinding performance of all these three types of grinding liquid were better than average grinding liquid. With Si3N4 Ceramics as the representative test material, the grinding efficiency can be increased at least 1.37 times and more than twice with the grinding fluid prepared with oleic acid or oleic alcohol. The analysis of liquid-solid interface with the help of infrared spectrum showed that there existed abnormal vibration peaks in the liquid-solid interface between Si3N4 ceramics and grinding liquid with (organic substances)–OOH and －OH under normal temperature, which resulted from the adsorption effect of hydrogen bond generated between organic molecule and Si3N4 ceramics. Under high grinding temperature, the friction chemical reaction took place as the result of the absorption effect and the resultant could not only reduce the surface hardness, but also improve the lubricating effect, thus improving the grinding efficiency and surface quality.

Grinding of Nanostructured WC Coatings with Single Fibrous-Abrasive Wheel

The random nature of the abrasive geometries and their distribution in a grinding wheel results in high specific grinding energy and temperature rise, large grinding forces and large deflection in the grinding system. To overcome the shortcomings encountered in grinding, it is necessary to design a new grinding wheel that is structured in controlled abrasive geometries with preferred spatial positioning and orientation. This paper deals with an experimental research of single fibrous-abrasive grinding of a nanostructured WC/12Co Coating. Prepared by the laser cutting of polycrystalline diamond compact (PDC), the single fibrous-abrasive has the dimensions of 0.3×0.6×10mm. The paper reports the research findings on normal and tangential grinding forces in terms of depth of cut and feed rate and discusses the material removal mechanism of nanostructured WC/12Co Coating ground by fibrous abrasive.

Recent advances and future perspectives in grinding wheel structures

The random nature of the abrasive geometries and their distribution in a grinding wheel results in high specific grinding energy and temperature rise, large grinding forces and large deflection in the grinding system. It can also cause the abrasives to fall off the grinding wheel prematurely, leading to an inefficient use of the abrasives. Moreover, grinding wheel wear and loading problems become more severe when grinding hard and/or 'sticky' materials, which requires more frequent wheel truing and dressing, and thus reduces grinding efficiency. To overcome the problems encountered in grinding, it is necessary to design a new grinding wheel that is structured in predefined abrasive geometries with preferred spatial positioning and orientation. The new grinding wheel should be dressing-free due to its self-sharpening capability. The specific grinding energy in using the new wheel should be comparable to that of machining with predefined tools. This paper discusses the current state-of-the-art and future challenges in the grinding wheel structures, as well as the recent advances and future perspectives in grinding wheels through analysing and comparing grinding against machining processes with predefined tools.

Thermal Models of High Efficiency Deep Grinding and Grinding Temperature

Thermal Models of High Efficiency Deep Grinding and Grinding Temperature