Dissertations / Theses on the topic 'Cutting fluid High speed steel'

This thesis deals with technology design of stamping production made of CuSn4 bronzy band by using high-speed cutting. First part of the thesis is focused on description of cutting technology, second part analyses high-speed cutting technology. Thanks to both analysis a module sequential die was constructed. The die is connected to the BSTA machine via quick-clamp system. This BSTA 250 machine produced by Bruderer company was chosen based on technology calculations. All necessary calculations, selected parts of drawing documentation as well as technical-economical evaluation of the technology design are mentioned in the thesis.

The industrial development of metal cutting processes in gear manufacturing aims at continuously increasing productivity, including increased tool reliability. Basically, the parameters that have an influence on the cutting processes should be known and possible to control. Gear manufacturing is highly important for the automotive industry. The prevalent manufacturing method is gear hobbing with hobs consisting of solid Powder Metallurgical High Speed Steel (PM HSS) with Physical Vapor Deposited (PVD) coatings. The hob teeth have to be reconditioned before wear reaches such levels that the gear quality becomes impaired. Such wear often results in a total breakdown of the tool. One crucial reason for this is that hobbing processes for the present often lack reliability; which makes it difficult for the gear manufacturers to predict the tool wear on the hob teeth and decide when the tool should be replaced in order to avoid severe damages. A consequence of catastrophic tool wear is that it leads to an instantaneously changed geometry of the cutting edge, which in turn implies that the machined gears do not comply with the stipulated properties on the machined gear products. A single tooth milling test (STMT) with tools of PM-HSS in a conventional milling machine has been developed in this research project, aiming at characterizing the effect of tool preparation on the type of wear mechanism. The experience and conclusions from these tests may probably be transferred to real PM-HSS hob tooling (HT). The advantages of such a test, compared to a real gear hob test, are primarily the cost reductions and time saving aspects with respect to both the design and the manufacturing of the cutting teeth The research presented in this thesis is based on experimental investigations and theoretical studies of significant parameters, i.e. the surface roughness and edge rounding, contributing to the robust and reliable design of a PM-HSS cutting tool. The research work has in addition to, the development of the milling test method, also comprised development of measuring methods and a simulation model based on the Finite Element Model (FEM).<br><p>QC 20121105</p>

碩士<br>國立虎尾科技大學<br>創意工程與精密科技研究所在職專班<br>98<br>This study aims at producing an optimal cutting-parameter design for a finishing process for high-speed end milling using the grey relational analysis. The workpiece materials is SKD61 tool steel.The major performance indices chosen to evaluate the workpiece quality are surface roughness and surface waviness. The Taguchi method was used to produce parameter design for all experimental trials and the multiple performance characteristics(MPC)were evaluated using S/N ratio. The grey relational analysis was then used to convert the MPC into a single performance index. The Optimum design can be found by the analysis of variance and control factors response table on the single performance index. The confirmation results show that the surface roughness and surface waviness were significantly improved by the optimum design predicted by the grey relational analysis.

碩士<br>國立中央大學<br>機械工程研究所<br>100<br>This study was to improve the traditional free-abrasive wire saw machining,due to the abrasive doesn’t completely will immediately cutting debris andrefining discharged.High abrasive waste so that the required processing time of growth on the wire saw, the relative costs to be incurred higher shortcomings toimprove. In this study, the evelopment of composite plating nickel - diamond coated to the piano wire, the research study of piano wire itself cutting of the tool, hoping to effectively improve the traditional free-abrasive sawing, therebyreducing the cost of the process. The study divided into two parts, the first part of the preparation of piano wire: nickel - diamond composite lating solution to plating coated on the piano wire. Experimental results show that, with the increase of current density and plating time, the coating thickness increases. Current density of 7 A/dm2 and diamond concentration of 100 g/L, the parameters of the plating experiments, piano wire has a better coating thickness and diamond coated. The second part of the Taguchi experimental design for high-speed steel cutting, explore the impact of various parameters on the depth of cut. From the experimental results, better process parameters combination: Cutting load 500 g, workpiece rotation 3000 rpm, feed rate 3.5 mm/min, thread tension 1500 g, co-deposition time 10 min, current density 7 A/dm2 and diamond concentration 100 g/L for cutting, cutting depth up to 27.01 μm.

碩士<br>國立虎尾科技大學<br>創意工程與精密科技研究所<br>97<br>In recent years, ours industries develop very rapidly, and cutting technology grows very well. Machining variety of mechanical parts needs high-precision, quality and promotion of production efficiency. Hence the cutting technology is with the trend of high-speed and high feed rate. By high-speed machining, reduction of manufacturing process time, enhancing machining accuracy and production cost-down can be achieved. Due to development of high-speed machining, cutting tool manufacturers use different cutting tool materials in different cutting conditions and materials to obtain maximum benefit. 　　In this study, finite element method is used to construct high-speed cutting mode basically, and then by commercial software DEFORM-2D to simulate the factors of maximum temperature of the cutting tool, the distance of the cutting tool tip and maximum temperature, and cutting force effected of cutting tool in different geometric angles and cutting conditions. By Taguchi method and Gray relational method the best results of simulation can be analyzed and designed. After the accomplishment of the best and the worst combination, using these two sets compare with the results of cutting tool steel SKD61 experiment. 　　Experimental results show that the best design combination of cutting time increased 5.71 and 4.95 minutes, the cutting length of the respective growth of 2.02 and 1.53m. Therefore, using finite element method to construct high-speed cutting mode is a cost-effective technology. This study is successful to design for tool steel SKD61, and identify the most suitable for high-speed machining tool steel SKD61 parameters

碩士<br>國立臺灣大學<br>機械工程學系<br>86<br>Inconel 718 alloy is well known as one of a difficult-to-cut material. In this research, high speed slot milling experiments under dry cutting and wet cutting conditions were conducted. Cutting forces, tool wear and chips produced were compared. It is found that tool geometry is retained, and tool wear is restrained effectively at low cutting speed with the application of sufficient cutting fluid. This results in lower cutting force. At extremely high cutting speed, progress of cutting process is strongly related to if the chip can be formed and flown out smoothly in dry cutting, whereas it depends on the red-hardness of the cutting tool in wet cutting. Specifically, a cutting tool will usually fracture in the form of crater wear or plastic deformation prior to the occurrence of chip welding on the tool and slot of the workpiece with cutting fluid applied. In addition, with the usage of cutting fluid, the appropriate range of cutting speed is widened, the surface finish is improved because the unstable BUE is prevented from scratching on the new machined surface. Incorporating with a thermal couple, it is also found that the g* phase softening phenomenon caused by high cutting temperature will take place at higher cutting speed as compared with that of dry cutting.

碩士<br>國立屏東科技大學<br>機械工程系所<br>95<br>The purpose of this research is to find optimum cutting parameters in order to achieve the same roughness level as well as polishing surface in high speed cutting (HSC) curved surface, such that it can reduce machining time for mold fabrication. The comparison between theoretical and experimental roughness on the curved surface is conducted. An orthogonal array of Taguchi method is used to find the two sets of optimum cutting parameters for the average and maximum roughness of curved surface by HSC, separately. Then the observation of surface roughness and tool flank wear is executed by adjusting each parameter as stepover, cutting angle, cutting speed or feed per tooth. It can be used to decide two set of optimum cutting parameters for minimizing curved surface roughness of average or maximum in HSC. The results indicate that the error between theoretical and experimental values is 1.25μm that means a overgreat error. Because milling cutting is a complex problem, it can not be easily expressed by a simple theoretical equation. In this research, experimental work is selected as the investigation method. Taguchi method combined with adjustment of each parameter steps have been conducted, and it has shown that 0.02mm for stepover, 45° cutting angle for tool path and 15000rpm for cutting speed can produce the best quality for surface roughnesses. As a result, an average surface roughness of 0.139μm and the maximum surface roughness of 0.854μm are found. Where the average surface roughness value is satisfied under polishing requirement and the tool life is 100 minutes. If the maximum surface roughness is selected as the objective, not only the roughness value is uncontrollable but also the tool life reduces to 70 minutes. Therefore, it can be concluded that choosing the average surface roughness as the objective can attain a better surface condition and to achieve polishing standard and longer tool life.

碩士<br>國立虎尾科技大學<br>機械與機電工程研究所<br>96<br>This study would use the Taguchi method on the optimal processing parameter design of end-mell for high speed cutting SKD61 mold steel. The tool life is the major performance indexes of cutting process. The cutting processing paramaters of end-mill for high speed cutting are spindle speed, feed per tooth, radial depth of cut, axial depth of cut, helix angle, radial rake angle, radial relief angle, axial rake angle and axial relief angle. The optimal processing parameters could be evaluated by the Taguchi method. The results of confirmation experiments show that the Taguchi method can effectively use to evaluate the optimal processing parameter, then the tool life of high speed cutting for SKD61 mold steel can be improved effectively.

碩士<br>國立高雄應用科技大學<br>模具工程系<br>97<br>The aims of this thesis are focused on the establishment of high speed cutting force model and the development of the cutting path planning of a thin plate of stainless steel. In the cutting process of a thin stainless plate, the finished part is of distortion due to the complex interaction of the cutting forces and the release of cold-rolled stresses. As a result, the flatness of the machined parts is poor and a cold sizing process is required. The proposed cutting force model was composed of the shearing and the plowing forces. The coefficients of the cutting force model are capable of considering the effect of different helical angle of cutting tools. The theories of cantilever beam and the proposed cutting force model were integrated to predict the deflection of cutting tools and the error of machining. The coefficients of the cutting force model were obtained for the aluminum alloy, the SKD die material, and the stainless steel, respectively. The developed cutting force model was applied to predict the deflection of cutters and compared with the results of FEM simulation. The cutting experiments were also carried out to measure the cutting forces and the tool deflection, a good agreement was obtained with the comparison of the experimental data and the theoretical prediction. In the cutting path planning of thin stainless steel plates, a square fixture with circular cavity was designed to clamp the plate with nuts. All nuts were screwed to a suitable constant torque to ensure minimum deformation of clamping. A better cutting path planning and combination of cutting condition was proposed via the Taguchi method to improve the tool life and surface roughness, and minimize the deformation of cutting. The spindle speed, feed rate, cutting depth, feed per tooth, and the cutting path were taken into consideration of the design factors. An alternative cutting path planning method was proposed to minimize the deformation of thin plate cutting and ensure the flatness of machined parts.

碩士<br>國立屏東科技大學<br>機械工程系所<br>96<br>In this paper a manufacturing process is investigated for the machined surface roughness to meet polishing effect of a saddle-type curved surface in high speed milling SKD61 mould steel in order to reduce the machining time for mould fabrication. Firstly, a comparison for the diversity of the curved surface roughness between the theoretical derived and experimental results is conducted. The smaller-the-better characteristic of Taguchi method is used to arrange experiments for high speed machining the curved surface, such that the optimum parameters combination can be obtained to find a minimum surface roughness (Ra) and a minimum tool flank wear (VB), separately. Then the optimum parameters combination for the minimum surface roughness is chosen as the basis, the influence on surface roughness and tool flank wear is observed as any of those parameters to be changed. Finally, the influence on surface roughness and tool flank wear is studied with the comparison between a green cutting and a traditional cutting in a different providing cutting fluid method. It can be shown that a large error is found by comparing the theoretical derived results with the experimental results. This is because that the complexity of a milling process and the theoretical derived formula is not suit for this investigation. Insteadly, the experimental method is selected in this research. After conducting arranged experiments, an objective for a minimum surface roughness can be achieved with the milling parameters combination as stepover is A3 (0.02mm), feed per tooth is B2 (0.07mm/tooth), cutting speed is C1 (600m/min), and depth of cut is D2 (0.15mm) that causes the surface roughness Ra as 0.188μm, Rmax as 0.758μm and the tool flank wear VB as 0.022mm. The corresponding surface quality met the polishing standard. If the other objective for a minimum tool flank wear is achieved with the milling parameters combination as stepover is A1 (0.18mm), feed per tooth is B1 (0.1mm/tooth), cutting speed is C2 (500m/min), and depth of cut is D1 (0.2mm) that causes the tool flank wear VB as 0.010mm, however, the surface roughness Ra as 0.509μm and Rmax as 2.184μm. The corresponding surface quality does not meet the polishing standard therefore this parameters combination is not suit for the requirement. The comparison of experimental results for green cutting and traditional cutting showed that the formed chip type is the most important affecting factor on the machining quality. Although the surface quality produced is not as good as the traditional mode, the high pressure gas processing mode produced highly chip expelling effect and still met the polishing standard. Hence it can be used for replacing huge cutting fluid implemented method. The investigated results in this research showed that high speed cutting can meet the polishing standard requirement, and the green cutting mode introduced properly, could provide a similar effect as the traditional mode. The contribution in this research can help the related industry reduce the subsequent processing time and cost furthermore increase its compatibility.

碩士<br>南開科技大學<br>車輛與機電產業研究所<br>100<br>The high cutting temperature generated in the high-speed milling of mold steel would lead to the rapid wear of cutting tool and poor surface roughness. The technique of minimum quantity lubrication (MQL) is regarded as an alternative to solve the above-mentioned problems. The objective of this work is to study the influence of cutting environments of MQL on the tool wear and wear mechanism in the high-speed milling of mold steel used with coated carbide tool. Cutting force, tool wear and machined surface roughness under various cutting environments such as direction of fluid application, type of lubricant supplication will be evaluated. SEM micrograph and EDAX analysis will be used to investigate the wear mechanism and the formation of oxide layer in cutting tools as well. Consequently, the appropriate cutting environment will be proposed to get the best tool performance. Firstly, the influences of direction of lubricant application on tool wear is investigated. Secondly, various types of lubricant, such as oil-based MQL, water-based MQL, high-pressure air, cooling air and dry cutting, were taken into account to find the optimal type of lubricant. It is shown that the smallest tool wear, in comparison with other directions of lubricant application, was induced by the external lubricant which was supplied to the cutting area as cutting tool was engaged in cutting. As regards the influences of various types of lubricant, the oil-based MQL would lead to the lowest tool wear under lower cutting speed as 300 m/min. While the water-based MQL performed the best when the cutting speed increased to 400 m/min and 500 m/min. It was attributed to the appropriate cooling effect of water mist and the formation of oxidation layer on the cutting tool. While the excessive cooling effect of cooling air would reduce the strength of cutting edge; hence in tern to cause a deteriorated tool wear such as breakage. It is concluded that the tool wear can be significantly reduced when the appropriate direction of lubricant application and type of lubricant were supplied.