Papers by Keyword: Cutting Temperature

Abstract: This study aims to investigate the effects of Minimum Quantity Lubrication (MQL) independent pulse parameters, which are the intervals between two pulses (1, 2, and 3 seconds) and the duration of the lubricant application (1, 2, and 3 seconds), in the turning of AISI 1040 steel. MQL pulse parameters supplying the best lubrication in terms of cutting force, cutting temperature, and surface roughness were 1 second interval between pulses and 3 seconds duration of lubricant application. These parameters provided 10.7%, 43.6%, and 65.5% improvement in cutting force, cutting temperature and surface roughness values, respectively, compared to dry cutting conditions. When the MQL pulse parameters were compared among themselves, an improvement of 6.7%, 38.3% and 61.7% was achieved in the cutting force, cutting temperature, and surface roughness values, respectively, in the conditions that gave the worst and the best results. According to ANOVA (Analysis of variance) results, the duration of the lubricant application was determined as the most important parameter on the surface roughness and resultant force whereas the interval between two pulses was obtained the most important parameter on the cutting temperature.

Abstract: Adaptive feed-rate controlled (AFC) drilling has been proposed as a high-quality and highly efficient drilling method for thermoplastic resins. The feed rate of the drill tool is controlled by the load in the thrust direction during AFC drilling. In the early stages of AFC drilling, the drill feed rate is extremely low, followed by a sudden increase in the drill feed rate. Experimental investigations revealed that the temperature near the drilling point had a dominant effect on the position at which the drill feed rate transitioned from low to high. The feed-rate transition temperature was approximately 150 °C for PA6. Therefore, the feed-rate transition position accelerated as the spindle speed increased, which significantly affected the cutting temperature. After the feed rate transitioned to a higher speed, drilling progressed at a constant rate. Additionally, the temperature of the drilled hole was generally constant regardless of the hole depth. One of the applications in which AFC drilling is expected to be superior is the drilling of different stacked materials. The effectiveness of AFC drilling was examined and compared with general constant-feed drilling for a stacked material of PA6 and carbon-fiber-reinforced thermoplastics. When the drilling efficiency was aligned, the maximum thrust force during AFC drilling was suppressed to less than 50% of that during general constant-feed drilling. Furthermore, the finished inner surface of the drilled hole was better after AFC drilling.

Abstract: The utilization of hydrogen in the construction of a decarbonized society is expected to expand the application of austenitic stainless steels with high resistance to hydrogen embrittlement as structural materials. However, the residual stress generated during machining causes material deformation, leading to increased costs and decreased productivity. Therefore, cutting methods that can control residual stress are necessary, prompting numerous studies on residual stress. We proposed conditions to reduce deformation and clarify the relationship between the depth of cut and material deformation, as well as the relationship between residual stress and material thickness after machining. In this study, stainless steel (AISI 304) was face milled, and the relationship between the cutting temperature and material deformation after machining was evaluated, as in a previous study. In addition, electrolytic polishing was performed to measure the residual stress in the depth direction, and its relationship with material deformation was evaluated. The experimental results showed no correlation between the cutting temperature and deformation. However, the measurement of the residual stress in the depth direction suggests that the removal of the surface layer by electropolishing may affect material deformation and residual stress.

Abstract: Tool life is recognized as a critical factor in finishing a fine surface as well as high machining accuracy in cutting operation. The tool wear progress, therefore, should be evaluated in cutting simulation before the operation. This paper presents an analysis of tool wear rate during a rotation of tool in fly cutting as a manner of gear machining. The distribution of tool wear rate is analyzed with the stress and the temperature on the rake face based on a tool wear characteristic equation. The cutting force is estimated in a chip flow model, which piles up the orthogonal cuttings in the plane containing the cutting and the chip flow directions. The chip flow direction is determined to minimize the cutting energy. Then, the cutting temperature is analyzed numerically in the finite volume method, where the mechanical energy is converted to the heat generation in the shear zone and the rake face. In the fly cutting, the stress and temperature change with the uncut chip thickness and the tool-chip contact area during a rotation. Therefore, the instantaneous tool wear rates are analyzed for the rotation angles by the stress and the temperature distributions. This paper demonstrates an example of the tool wear analysis in cutting processes of a carbon steel. A cutting test was conducted to identify the force model with the orthogonal cutting data used in the analysis. Then, the temperature and tool wear distributions on the rake face are analyzed with the uncut chip thicknesses and the tool-chip contact areas.

Abstract: The present study describes the impact of cutting speed and various lubricant-cooling process agents on the temperature of alloy turning. The research was conducted for NiCr20TiAl and N07750 nickel alloys with the help of HG30 and HS123 carbide-tipped cutting tools. New lubricant-cooling process agents with nanodispersed diamond graphite additives are studied. The optimal composition of the diamond graphite additives is revealed when cutting these alloys. It is demonstrated on the basis of tests the positive effect of diamond graphite agents on the quantitative changes in measured cutting temperatures. In doing so, the cutting speed and the lubricant-cooling agents applied to the cutting zone have little impact on the nature of temperature patterns.

Abstract: This paper presents a prediction of cutting temperature in turning process, using a continuous cutting model of Johnson-Cook (J-C). An method to predict the temperature distribution in orthogonal cutting is based on the constituent model of various material and the mechanics of their cutting process. In this method, the average temperature at the primary shear zone (PSZ) and the secondary shear zone (SSZ) were determined for various materials, based on a constitutive model and a chip-formation model using measurements of cutting force and chip thicknes. The J-C model constants were taken from Hopkinson pressure bar tests. Cutting conditions, cutting forces and chip thickness were used to predict shear stress. Experimental cutting heat results with the same cutting parameters using the minimum lubrication method (MQL) were recorded through the Testo-871 thermal camera. The thermal distribution results between the two methods has a difference in value, as well as distribution. From the difference, we have analyzed some of the causes, finding the effect of the minimum quantity lubrication parameters on the difference.

Abstract: The subject of the research is the influence of contact interaction at the face surface on average cutting temperature at the face surface.

Abstract: Nickel-based alloys provide high corrosion resistance and high-temperature strength but these alloys possess poor machinability. Hastelloy-X is a nickel based alloy that has been used for high temperature use. There are many studies about finite element modeling of aerospace alloys but studies in literature with Hastelloy-X are limited. In the present work, machining characteristics of Hastelloy-X were investigated and a numerical model was developed for the turning operation of Hastelloy-X. Two input parameters (cutting speed and feed rate) were variated in the operations and the results were evaluated considering process outputs such as cutting forces, cutting temperature, effective stresses and chip morphology. Based on the verification of the numerical model using experimental results, presented material model is appropriate for the turning operation of Hastelloy-X at low and medium cutting speed machining conditions.

Abstract: In the article the model for forecasting of thermal processes arising during processing of bevel gears is presented. The kinematics of cutting is modeled due to the analytical model. Chipping is modeled using the finite element method. The experiment is based on the method of infrared photography of the cutting process. In the process of carrying out a numerical experiment, the graphs of the heat fields for the tool, the workpiece gear and chips were obtained, and an array of data on their change during the cutting process was achieved. The simulation results showed that the maximum temperatures and heat flows in the tool depend significantly on the choice of the rake and clearance angels of the cutting.

Abstract: In this article comparison of two methods of the cutting temperature calculation is made: according to the theory of A.N. Reznikov and the theory of S.S. Silin. The values of the cutting temperature calculated according to both methods are compared to the experimental data provided by various authors. It is determined that both methods can be used for cutting temperature calculation, however they have some limitations. In particular, when making the calculations according to S.S Silin’s theory the parameter, characterizing the degree of plastic deformation of the metal machined should be not less than 0.4. When calculating the cutting temperature by Reznikov’s theory it is necessary to take into account the nature of the physical processes of cutting.