Papers by Keyword: Dry Cutting

Abstract: This paper describes a temperature stabilization method in dry metal cutting. Using a hidden phase transfer heat allows to significantly reduce the wear rate. The tool holder design with porous evaporative cooling system is presented. Dependences of tool life of cutters on the cutting speed without cooling and with porous cooling are shown. This approach could be advantageous for the cutting of hard materials (titanium alloy).

Abstract: In this study, the transition of cutting force in the tangential and radial direction during one cut was investigated in milling of AISI-1045, AISI-304, and Ti-6Al-4V with a TiN coated carbide throw-away insert. In the case of 1045 and Ti-6Al-4V, there was not obvious difference in tangential forces between up-cut and down-cut. However, up-cut showed larger radial force than down-cut in any material. In down-cut, tangential force showed almost the same regardless of radial depth of cut. 304 and Ti-6Al-4V caused larger radial force with the increase of radial depth of cut at the same cut chip thickness.

Abstract: In this paper, there is an attempt to monitor and evaluate machining parameters when turning 34CrNiMo6 material under different cooling and lubrication conditions. The machining parameters concerned are temperature of the cutting tool and the workpiece, level of vibrations of the cutting tool, surface roughness of the workpiece, noise levels of the turning process and current drawn by the main spindle motor. Four different experimental machining scenarios were completed, specifically: conventional wet turning process, dry cutting and two additional modes employing cooling by cold air. Experimental data were acquired and recorded by an optimally designed network of sensors. Experimental data were statistically analyzed in order to reach conclusions. According to the research that has been done, although, overall, minimum cutting tool and workpiece temperatures were observed under wet machining, cold air cooling is capable of achieving comparable cooling results to wet machining. The lowest values of surface roughness were achieved by wet machining, whereas the lowest level of cutting tool vibrations were observed under cold air cooling.

Abstract: Turning is a utilized machining work. It is performed with a large types of tools adapted for required geometries. If starting from a full blank, a drilling operation is called in the beginning. In that case, the number of utilized tools increased. The use of a multifunctional tool for drilling followed by bore turning is an efficient solution. In this research, the case of single insert multifunctional tool is studied. The paper describes the quality of the surfaces obtained by using of this tool. The general idea is to verify the use of only one multifunctional tool for execution of all operations, from full drilling to finished surface. This was made by measuring the roughness Ra in three experiments with different materials: titanium, stainless steel and low carbon steel. Performed experiments lead to the idea of a recommended limit for feed speed to obtain a roughness Ra value below 0.8μm. This limit depends with the material type, but for some materials, it seems impossible to achieve this value!

Abstract: One of the problems of metal alloys machining in view of the environment protection is the use of cooling lubricants. From this viewpoint, it is preferred to limit the use or completely eliminate them from the cutting process. The solution may be the method of Minimum Quantity Cooling Lubrication (MQCL). The results of the machined surface roughness measurements of carbon steel C45 after turning when: machining for dry cutting, using cooling method MQCL and using MQCL with additives EP/AW have been presented. One used two anti-wear and antiseizure additives based on phosphate ester. Experimental studies have been planned according to the Parameter Space Investigation method. The application of EP/AW additives entered in the emulsion determined the ranges of cutting parameters at which lower values of selected roughness parameters were obtained in comparison with dry cutting. The lowest values of Ra and Rz parameter for variables of cutting parameters and creating emulsion mist within their whole range were obtained for cooling with pure emulsion mist based on boric acid and amine compound.

Abstract: An internal cooling system inside a toolholder was developed aiming to eliminate the need of using cutting fluid without compromising machining efficiency. A phase change coolant (R141-b), with boiling point of 32oC around 101.3 kPa (atmosphere pressure), was used to improve heat dissipation in the cutting tool. Turning tests on SAE XEV-F were carried out using coated cemented carbide inserts. The results showed that the cutting tools lives were greater with internally cooled method than in dry cutting conditions. Nevertheless, the results were limited due to the low thermal conductivity of the steel (14.5 W.m/K) that is similar to Inconel^®, its abrasivity, and absence of lubricant effect of the internal cooling method. On the other hand, the cutting tool geometry was not modified as was done in others solutions found in literature and the cooling system operated in a closed loop. It has a great possibility of use by the industry because is an environmentally friendly technology.

Abstract: The paper presents the results of research on the effect produced by various cooling methods on the chip thickness ratio, shear angle and shearing force. Dry cutting, cooling by compressed air and the MinimumQuantityCoolingLubrication (MQCL) method when finish turning of carbon steel with different speeds of cutting and feed rates were compared. The investigations were performed in accordance with the Parameter Space Investigation method. The advantage of the MQCL is confirmed by lower values of the chip thickening ratio, shearing force and higher values of the shear angle. Depending on the cutting conditions, the efficiency of the MQCL method is 6 to 30% higher compared to dry machining.

Abstract: The paper presents the results of research on the effect produced by modern cooling methods on the chip shapes and surface roughness when finish turning of ASTM A53 and AISI 1010 low carbon steels. Dry cutting, cooling by compressed air and the Minimum–Quantity–Cooling–Lubrication (MQCL) method were compared. The MQCL method is more effective for machining low carbon steel and ensures a usable chip shape and lesser surface roughness. Depending on the cutting conditions, the efficiency of the MQCL method is 10 to 30 % higher compared to dry machining. Examples of experimental investigations about reducing the use of cooling lubricant substances in turning process can be found in the open literature [1, 2].

Abstract: High speed cutting is an important means to improve the efficiency and the quality of machining mold steel, but the tool wear is one of the key factors restricting the increase of the cutting speed, leading to higher requirements for cutting tool materials. At present the researches of high-speed cutting of mold steel are mainly on the hardness mold steel, but less on P20 mold steel which hardness is 30-42HRC. This paper mainly studies the effect of cutting speed on wear property of TiAlN PVD coated tools when high-speed milling of P20 mold steels. The experiment was conducted using two different high cutting speeds under dry condition, 320m/min and 500m/min. Wear characterization of the rake and the flank surfaces as well as the collected chips were performed using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). It was found that at high speeds, the dominant wear mechanisms were oxidation wear and diffusion wear, followed by adhesive wear and melt wear; as the cutting speed increased, the wear surface area of rake face will be closer to the main cutting edge.

Abstract: The tool and workpiece surface layer states of the tribosystem uncoated WC-Co cutting tools vs. normalised SAE 1045 workpiece material are studied in detail for a dry metal cutting process. Within the system the cutting parameters (cutting speed, feed rate, cutting depth) determine the wear state of the cutting tool and the resulting surface layer state (residual stress) in the workpiece. As the built-up edge can be used as a possible wear protecting layer [1] the influence of built-up edge and wear behaviour of the cutting tool was examined with respect to the workpiece surface layer state for knowledge based metal cutting processing. Small compressive stresses (-60-80 MPa) are induced in the surface layer, that are nearly homogeneous for the highest built-up edge, which lead to the lowest tool wear in combination with lowest cutting temperature.