机械毕业设计134英文翻译外文文献翻译219
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机械毕业设计英文翻译
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机械毕业设计134英文翻译外文文献翻译219,机械毕业设计英文翻译
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1 附录 1 英 文原文 英文原文 CHAPTER III COST STUDY OF HIGH-SPEED CUTTING UNDER DRY AND WET CONDITIONS FOR MACHINING PROCESSES OPTIMIZATION 3.1 Introduction The aim of this study is to optimize the machining processes by investigating the relationship between the high speed machining (HSM) and the tool life for the cutting conditions under testing. Furthermore, studying the effect of cutting fluid on the selected wear criterion, and relationship between different wear criteria and machining cost for the cutting inserts under HSM. This investigation showed that wear rate is proportional to cutting speed supported with similar observations 12,18,19. Studying the correlation between high wear rates at high cutting speed and machining costs, provides better understanding on the performance of this policy and the benefit of its adoption. Currently, little or no data have been published relating the life -cycle costs, tool performance, work piece surface roughness and work piece dimensional accuracy when using solid and indexable cutters 10. However, studies have found that tool costs in metal cutting machines are a third of the cost of producing parts. Therefore reducing product cost is the first objective of a tool management system16. The benefits of adopting this research guideline will help determine the optimal machining cost and tool replacement policy based on different wear criterion values. Additionally this study provides insight in process control and helps the managers in the early process planning steps to associate factors such as preventive maintenance, levels of inventory, nts2 and machining cost. 3.2 Experimental Study The study developed a guideline of choosing the right cutting tool, cutting speed, and selecting the appropriate wear criteria of the cutting tool inserts for the work material under study. In this study variable wear criteria ranging from 0.lmm to 0.6mm (tool life limit) were taken into consideration. This experiment was conducted in accordance with the International Standard Organization ISO 3685 1993 46. The test was done on a (Clausing1300) variable spindle speed machine with a maximum power of 7.5Hp (see Figure 3-1). The tool wear measurements were performed using an optical microscope with a magnification of up to 300 times, and a Scanning Electron Microscope (SEM). The rotational speed of the work piece was measured before every cut by a (HT-5100) handheld digital Tachometer to insure that the work piece was accurately running at the exact cutting speed. On the other hand, the work piece material was replaced when the length/diameter ratio reaches 10, based on ISO 3685 1993 46, to ensure work piece stability and safety. Two precut were carried out with 1.2 mm depth, to clean up the thin layer of rust, and to ensure work piece straightness. nts3 Figure 3-1 The tuning machine used during the test. 3.2.1 Workpiece and Cutting Inserts In this study, hot rolled ASTM 4140 steel was selected as the workpiece material. The work piece properties are listed as follows: Description: Hot rolled alloy steel bars, SAE 4140H (UNS H4140) Dimensions: 15 cm Diameter x 62.25 cm length Heat Treatment: Vacuum degassed/processed, Cal-Al treated, annealed and special straightened, conforming to ASTM A322 and A304 Chemical compositions: The composition of the work piece material is listed in Table 3.1 according to the ASTM standards. The experiment was carried out in accordance with the international standard organization ISO3685-93 46, the experiment was stopped and the work piece was changed when the length /diameter ratio reached 10 to meet the requirements of ISO3685 46. The hardness of each bar was checked across the diameter, and the average hardness measurement was 29HRC. The types of tested cutting tool inserts are listed on Table 3.1 according to the ISO designation. Three types of cutting inserts were used in the experiment as illustrated in Table 3-2; and the coating properties are also listed in Table3-3. The configuration of the investigated three cutting inserts was the same as listed in Table 3.4. The general cutting insert assembled geometry is nts4 shown in Figure3-2. The inserts were mounted rigidly on a tool holder are depicted in Figure3-3 with an ISO designation of SVJBR 2525 M16. Table 3-1 Chemical composition of ASTM4140 steel used in the test Cutting inserts ISO Designation Substrate Grade Company Uncoated cemented Carbide VBMT 160408 . KC 313 Kennametal TiAlN VBMT 160408 KC313 KC5010 Kennametal TiN-TiCN-TiN VBMT 160408 KC313 KC732 Kennametal Table 3-2 Types of the tested cutting inserts Carbon Manganese Phosphorus Sulfur Silicon Nickel Chromium 0.4 0.91 0.017 0.02 0.24 0.10 1.01 Tin 0.008 Aluminum 0.030 Vanadium 0.002 Calcium 0.0064 Molly 0.2 Copper 0.12 Table 3-3 Coatings properties Coating Thickness Number of layers nts5 TiALN 3.5 1 TiN-TiCN-TiN 3 -3 t-1 t 3 (TiCN intermediate) 3.2.2 Coolant Properties It is a common belief that coolant emulsion helps in reducing wear rate and cutting temperature. The coolant used in the test was water based emulsion has commercial nameNovick. It is mixed with water at a concentration of 10%. The coolant composition includes the listed chemicals in Table 3.5. Previous researchers on the better coolant stream directions made different suggestions. Taylor 17 indicated that to reduce tool wear the cutting fluid is to be directed at the back of the chip (direction A). Pigott and Colwell 47 found that by using high stream jet of coolant aimed in direction B it was able to reduce tool wear. Smart and Trent 48 investigated the direction of coolant in reducing the tool wear and found that the most effective direction between all other suggested options was direction B. Therefore, coolant was applied in direction B as listed in Figure 3.4 from a nozzle with diameter of 1.3 cm and a flow rate of 7.1 liters/minute. However, the current study showed that this is not necessarily true in all cases as coolant extends the tool life. It was found that coolant emulsion helped reduce tool life by activating certain wear mechanism at high speed machining (HSM). Detailed explanations of this type of coolant effect will be discussed in Chapter 5. Further more, a brief summary and explanation of types and usage of coolant will be covered in Chapter 5. nts6 Table 3-4 Assembled cutting tool geometry Tool geometry Dimension Nose radius 0.8 (mm) Bake rake angle 0 End relief angle 5 End cutting-edge angle 52 Side cutting-edge angle 30 Side rake angle 0 Side relief angle 5 Table 3-5 Coolant chemical compositions Sulfate 20-30% Aromatic alcohol 3-5% Propylene glycol ether 3-5% Petroleum oil 30-35% Nonionic surfactant 3-5% Chlorinated alkene polymer 20-30% nts7 Angular tool Designation Back rake0 Side rake _ 0 End relief 5 Side relief 5 End cutting edge _ 52 nts8 Side cutting edge _ 3 Nose radius 0.88mm Nose radius Cutting Back rake angle Side rake angle Figure 3-2 Assembled tool geometry nts9 Figure 3-3 Photograph of the cutting insert fixed on the tool holder A B nts10 Figure 3-4 coolant stream direction. 3.3 Cutting Conditions Based on I803685 46 five cutting speeds were used throughout the testing as listed on Table 3-6. Cutting speeds corresponding to 410 m/min for the coated carbide tools and180 m/min for the uncoated carbide tools were approximately the upper limit of the application range. Since any further increment resulted in very short cutting tool life or premature tool damage soon after the test was started. The turning experiments were carried out under dry and wet cutting conditions at different cutting speeds, while fixing both feed rate at 0.14 mm/rev and depth of cut at(1mm). Five cutting speeds were selected for the three types of cutting inserts, as listed in Table3-6. 3.4 Experimental Procedure of Tool Life Testing A Clausing 1300 lathe with maximum 7.5HP was used f alloy steel SAE4140H work piece, and the turning process was carried out in the way or the turning of the Hot rolled previously described. A Tachometer was used to measure the rotational speed before each single cut occurred on the work piece in order to ensure that the cutting was performed at the exact speed. An optical microscope was used to measure the flank wear of the cutting inserts. The experiment was terminated if either of the two following conditions occurred 1- The maximum flank wear 0.7 mm and/or; 2- The average flank wear 0.6 mm. Preliminary experiments were carried out in order to determine the wear limit. It was found that the cutting inserts were worn out regularly on the flank side. Therfore, VB,nax =0.7 mm, is chosen to be the wear limit for the tool life. The flank wear was observed and measured at various cutting intervals nts11 throughout the experiments. Figure (3-5) shows flank wear as a function of cutting time for the cemented carbide (KC313) under dry and wet conditions, and includes only three cutting speeds for clarity. Figure 3-6 presents the flank wear as a function of cutting time for sandwich coated inserts ( KC732) under dry and wet conditions. Figure 3-7 shows the flank wear as a function of cutting time for TiALN coated cutting inserts (KC5010). Previous figures included three cutting speeds. Clarity of cutting speed curves are presented at the attached appendix for both conditions of machining. The aforementioned figures, present the effect of coolant emulsion in extending the tool life for the KC313, and KC732 cutting inserts; especially after 3 minutes for KC313, and after 7 minutes for KC732 of cutting. However, the usage of coolant emulsion on KC5010 showed negative influence. Figure 3-5, and Figure 3-6 show that at any set of turning conditions, the flank wear increased at a higher rate at dry cutting during the gradual wear stage. Figure 3-7 shows that at any set of turning conditions, the flmk wear increased at a higher rate at wet cutting during the gradual wear stage. The explanation of this material behavior will be covered in detail though-out chapter 5 (wear mechanisms of (KC5010) under wet condition). After gradual wear stage the curves look parallel to each other. This shows that flank wear occurs at the same rate under dry and wet cutting conditions. The previous figures show that flank wear curves went through three stages of wear: running in wear stage, gradual wear stage or steady state wear, and followed by rapid, fatal wear. Similar observations were documented by Chubb and Billingham 11, Haron 12. The following terminologies are used: Initial or running in wear stage: takes place due to the rapid breakdown of the edge, which is shown by the initial high wear rate in the graph of wear against time. Curves 1, 2, and 3 in Figure 3-6 this stage is decreased as the cutting speed increased Gradual wear stage: the figures of the three types of cutting inserts, after the initial wear has taken place, indicating a steady gradual stage on the insert wear will form. However, it will increase with less dramatic pattern than the initial stage. nts12 Rapid, fatal wear: the final stage of wear, which leads to a catastrophic failure of the cutting inserts. Rapid fatal wear revealed both flank and large crater formation that weakened the tool edge and under sustained resistance to the high cutting forces, caused it to fracture. Testing methods indicated rapid breakdown took place during cutting; causing severe damage to take place on the work-piece surface. Therefore, imagining that the catastrophic failure took place during the final cutting pass at the work piece surface, it is highly likely that the work piece has to be scrapped. Table 3-6 Cutting speeds used in the test for the specific type of inserts Cutting Insert Cutting Speed (m/min) KC313 60 90 120 150 180 KC5010 210 260 310 360 410 KC732 210 260 310 360 410 Cemented Carbide (KC313) (wet & dry) nts13 Time (min) Figure 3-5 Flank wear as a function of cutting time for KC313 (dry and wet). TiN-TiCN-TiN(KC732) (wet & dry) nts14 Figure 3-6 Flank wear as a function of cutting time for KC732 (dry and wet). TiALN(KC5010) nts15 (wet & dry) 0.0 o t t 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Time (min) Figure 3-7 Flank wear as a function of cutting time for KC5010 (dry and wet). 附录 2 外文翻译 nts16 第三章 在干燥和潮湿的条件下研究高速切削的费用以及便于机械制造过程的优化 3 1 介绍 这项研究的目的是在已知试验的切削条件下通过对高速加工与刀具间的寿命之间的关系的调查，来优化选择机械加工过程。此外，在具有可选择的磨损标准下研究切削液的影响，以及研究不同的磨损标准与处于高速加工过程中切削用具的加工费用之间的关系。 这项调查研究显示：磨损率与切削速度成比例，观察到的 12， 18， 19证明了这一结论。通过研究在高速切削条件下的高磨损率和加工费用之间的彼此关系，可以更好得了解这项方案的执行过程以及采用这种方案所带来的效益。目前，几乎没有或者说没有数据来解释当使用坚固以及带分度的切削机 10时，所需的生命周期的费用，刀具性能，工件的表面粗糙度和尺寸精度。但是，这项研究发现金属切削机床中的刀具费用是加工零件所需费用的三分之一。因此降低制造费用是刀具经营系统 16的首要目标。采用这项研究的指导方针的好处有：在不同的磨损标准价值的基础上，它将帮助决定最合理的加工费用以及刀具的更换方案。这项研究 另外还提供了程序控制的可视性以及帮助经理在早期的处理计划中与某些因素进一步联系起来。比如，这些因素指的是定期检修，存货水平和加工费用。 3 2 实验性研究 研究形成了选择正确的切削刀具，切削速度以及选择处于研究过程中用来加工工件材料的切削工具的合理磨损标准的指导方针。这项研究还考虑了各种不同的磨损标准范围为 0.1mm 到 0.6mm(刀具寿命的限制 )。本实验是根据国际标准 ISO3685 199346而进行的。 试验是在多主轴高速机床上进行的，该机床型号为 Clausing1300，最大动力为 7.5HP（图 3 1）刀具磨损量的测量采用放大倍数为 300 的光学显微镜，并且该显微镜装有电子显微扫描仪（ SEM）。为了确保工件是在极其精确的切削速度下进行，工件的旋转速度是在每一次切削之前由数字转速表nts17 （ HT 5100）测量所得。另一方面，根据 ISO3685 199346当工件材料的长度与直径比达到 10 时，该工件材料就的被替换，这是为了确保工件的稳定性与安全性。为了清除灰尘薄膜以及确保工件的直线度，两次试切的深度应为 1.2mm。 图 3 1：实验所用的车床 3.2.1 工件与切削刀具 在这 次实验中，热轧钢 ASTM4140 被选择作为工件材料。以下列出了工件属性： 描述： 热扎合金钢条， SAE 4140H(UNS H4140)。 尺寸： 直径 15cm，轴线方向长 62.25cm。 热处理： 真空处理， Cal Al 处理，退火和调制处理，形成 ASTM A322 和 A304。 化学成分： 依据 ASTM 标准，工件的化学成分在表 3.1 中已给出。实验的执行是符nts18 合国际标准组织 ISO 3685 9346的，当工件的长度与直径比为 10 时，该实验就停止进行并且替换工件，目的是为了符合 ISO368546的规定。 每根钢条的硬度通过直径比被测量的，以及平均硬度的测量值为 29HRC。依据 ISO规定，表 3.1 列出了实验期间所用的各种切削刀具。表 3 2 列出了实验中所用的三种切削工具，表 3 3 给出了涂层种类，表 3 4 列出了被检测的三种切削刀具的结构。图 3 2 给出了普通切削刀具的几何角度。根据 ISO标准 SUJBR 2525 M16 所规定，图 3 3 描绘出了刀具牢固地安装在刀夹上的情况。 表 3 1 实验所用的 ASTM 4140 钢的化学成分 切削刀具 ISO 标准 基 材 级 配 公 司 未涂碳 VBMT 160408 KC 313 Kennametal TiAlN VBMT 160408 KC 313 KC 5010 Kennametal TiN_TiCN_TiN VBMT 160408 KC 313 KC 732 Kennametal 表 3 2：实验所用的各种切削刀具 碳 0.4 锰 0.91 磷 0.017 硫 0.02 硅 0.24 镍 0.10 铬 1.01 锡 0.008 铝 0.030 钒 0.002 钙 0.0064 钼 0.2 铜 0.12 表 3 3 ：涂层物 涂 层 厚 度 层 数 TiALN 3.5u 1 Ti TiCN TiN 3u-3 t-1 t 3 (TiCN 中间体 ) 3.2.2 冷却物 普遍认为冷却乳化液能帮助降低磨损率和切削温度。实验所用冷却液是nts19 以乳化液为基础的水溶液，商业上称作 Novick。其中含水量为 10%。冷却液的化学成分在表 3 5 已列出。以前的研究人员就更好的冷却液的流向有着不同的意见。 Taylor17表明为了减少刀具磨损率切削液的流向应在切屑的背后（ A 向）。 Pigott 和 Colwell47发现通过使用高喷射流的冷却液对准 B 向就能减少刀具磨损率。 Smart 和 Trent48调查了降低刀具磨损的冷却液方向并且发现在所有的建议中最有效的方向是 B 向。因此，图 3.4所用的冷却液以直径为 1.3cm 的喷嘴流出，流速为 7.1L/min 方向是 B 向。但是，目前的研究表明在所有作为冷却液而增 加刀具寿命的事例中，这种方案并不是十分正确的。研究发现通过某中磨损机制的作用如高速机床（ HSM），冷却乳化液帮助减少了刀具磨损率。这种冷却液的效果的详细解释将在第 5章介绍。另外，第 5 章还覆盖了冷却液的简历种类解释以及使用方法。 表 3 4：切削刀具的几何数据 刀具几何 Tool geometry 尺寸 刀尖圆弧半径 Nose radius 0.8mm 前角 Bake rake angle 0 后角 End cutting-edge angle 5 副偏角 End cutting-edge angle 52 余偏角 Side cutting-edge angle 30 副前角 Side rake angle 0 副后角 Side relief angle 5 表 3 5：冷却剂的化学成分 硫 芳香酒精 丙烯甘醇以太 nts20 20 30% 3 5% 3 5% 石油润滑油 30 35% 非离子表面活化剂 3 5% 氯化烯烃聚合物 20 30% Angular tool Designation Back rake0 Side rake _ 0 End relief 5 Side relief 5 End cutting edge _ 52 Side cutting edge _ 3 Nose radius 0.88mm nts21 Nose radius Cutting Back rake angle Side rake angle 图 3 2：刀具几何 nts22 图 3 3：安装在刀夹上的切削刀具照片 A B nts23 图 3 4：冷却液的流向 3.3 切削条件 根据 ISO 368546规定，表 3 6 列出了整个实验过程所用的五种切削速度。切削速度为 410m/min 对应的刀具涂层含碳， 180m/min 对应的刀具涂层不含碳，这两种速度大约达到了应用范围的最高极限。如果速度再增加的话将会导致刀具的寿命再实验开始时很短时间内就耗尽或很
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