薯類打漿制粉、干燥機的研究與設(shè)計,薯類打漿制粉、干燥機的研究與設(shè)計,薯類,打漿,制粉,干燥機,研究,鉆研,設(shè)計 附錄1英文原文 英文原文 COST STUDY OF HIGH-SPEED CUTTING UNDER DRY AND WET CONDITIONS FOR MACHINING PROCESSES OPTIMIZATION 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 system[16]. 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, and machining cost. 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. Figure 1 The tuning machine used during the test 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 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 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 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 Table3 Coatings properties Coating Thickness Number of layers TiALN 3.5 μ 1 TiN-TiCN-TiN 3 μ-3 t-1 t 3 (TiCN intermediate) 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 name`Novick'. It is mixed with water at a concentration of 10%. The coolant composition includes the listed chemicals in Table 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. Table 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' Table5 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% Angular tool Designation Back rake 0° Side rake 0° End relief 5 ° Side relief 5 ° End cutting edge 52° Side cutting edge 3° Nose radius 0.88mm Nose radius Cutting Back rake angle Side rake angle Figure 2 Assembled tool geometry Figure 3 Photogradph of the cutting insert fixed on the tool holder A B Figure 4 coolant stream direction 3 Cutting Conditions Based on I803685 [46] five cutting speeds were used throughout the testing as listed on Table 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. 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, VBnax =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 throughout the experiments. Figure (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 6 presents the flank wear as a function of cutting time for sandwich coated inserts ( KC732) under dry and wet conditions. Figure 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 5, and Figure 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 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 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. 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 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) Figure 5 Flank wear as a function of cutting time for KC313(dry and wet) TiN-TiCN-TiN(KC732) (wet & dry)  Figure 6 Flank wear as a function of cutting time for KC732(dry and wet) TiALN(KC5010) (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). 附錄2外文翻譯 在干燥和潮濕的條件下研究高速切削的費用以及便于機械制造過程的優(yōu)化 1介紹 這項研究的目的是在已知試驗的切削條件下通過對高速加工與刀具間的壽命之間的關(guān)系的調(diào)查，來優(yōu)化選擇機械加工過程。此外，在具有可選擇的磨損標(biāo)準(zhǔn)下研究切削液的影響，以及研究不同的磨損標(biāo)準(zhǔn)與處于高速加工過程中切削用具的加工費用之間的關(guān)系。 這項調(diào)查研究顯示：磨損率與切削速度成比例，觀察到的[12，18，19]證明了這一結(jié)論。通過研究在高速切削條件下的高磨損率和加工費用之間的彼此關(guān)系，可以更好得了解這項方案的執(zhí)行過程以及采用這種方案所帶來的效益。目前，幾乎沒有或者說沒有數(shù)據(jù)來解釋當(dāng)使用堅固以及帶分度的切削機[10]時，所需的生命周期的費用，刀具性能，工件的表面粗糙度和尺寸精度。但是，這項研究發(fā)現(xiàn)金屬切削機床中的刀具費用是加工零件所需費用的三分之一。因此降低制造費用是刀具經(jīng)營系統(tǒng)[16]的首要目標(biāo)。采用這項研究的指導(dǎo)方針的好處有：在不同的磨損標(biāo)準(zhǔn)價值的基礎(chǔ)上，它將幫助決定最合理的加工費用以及刀具的更換方案。這項研究另外還提供了程序控制的可視性以及幫助經(jīng)理在早期的處理計劃中與某些因素進一步聯(lián)系起來。比如，這些因素指的是定期檢修，存貨水平和加工費用。 2實驗性研究 研究形成了選擇正確的切削刀具，切削速度以及選擇處于研究過程中用來加工工件材料的切削工具的合理磨損標(biāo)準(zhǔn)的指導(dǎo)方針。這項研究還考慮了各種不同的磨損標(biāo)準(zhǔn)范圍為0.1mm到0.6mm(刀具壽命的限制)。本實驗是根據(jù)國際標(biāo)準(zhǔn)ISO3685 1993[46]而進行的。 試驗是在多主軸高速機床上進行的，該機床型號為Clausing1300，最大動力為7.5HP（圖1）刀具磨損量的測量采用放大倍數(shù)為300的光學(xué)顯微鏡，并且該顯微鏡裝有電子顯微掃描儀（SEM）。為了確保工件是在極其精確的切削速度下進行，工件的旋轉(zhuǎn)速度是在每一次切削之前由數(shù)字轉(zhuǎn)速表（HT—5100）測量所得。另一方面，根據(jù)ISO3685 1993[46]當(dāng)工件材料的長度與直徑比達到10時，該工件材料就的被替換，這是為了確保工件的穩(wěn)定性與安全性。為了清除灰塵薄膜以及確保工件的直線度，兩次試切的深度應(yīng)為1.2mm。  圖1 實驗所用的車床 2.1工件與切削刀具 在這次實驗中，熱軋鋼ASTM4140被選擇作為工件材料。以下列出了工件屬性： 描述： 熱扎合金鋼條，SAE 4140H(UNS H4140)。 尺寸： 直徑15cm，軸線方向長62.25cm。 熱處理： 真空處理，Cal—Al處理，退火和調(diào)制處理，形成ASTM A322和A304。 化學(xué)成分： 依據(jù)ASTM標(biāo)準(zhǔn)，工件的化學(xué)成分在表1中已給出。實驗的執(zhí)行是符合國際標(biāo)準(zhǔn)組織ISO 3685—93[46]的，當(dāng)工件的長度與直徑比為10時，該實驗就停止進行并且替換工件，目的是為了符合ISO3685[46]的規(guī)定。每根鋼條的硬度通過直徑比被測量的，以及平均硬度的測量值為29HRC。依據(jù)ISO規(guī)定，表1列出了實驗期間所用的各種切削刀具。表2列出了實驗中所用的三種切削工具，表3—3給出了涂層種類，表3—4列出了被檢測的三種切削刀具的結(jié)構(gòu)。圖2給出了普通切削刀具的幾何角度。根據(jù)ISO標(biāo)準(zhǔn)SUJBR 2525 M16所規(guī)定，圖3描繪出了刀具牢固地安裝在刀夾上的情況。 表1 實驗所用的ASTM 4140鋼的化學(xué)成分 切削刀具 ISO 標(biāo)準(zhǔn) 基 材 級 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2：實驗所用的各種切削刀具 碳 0.4 錳 0.91 磷 0.017 硫 0.02 硅 0.24 鎳 0.10 鉻 1.01 錫 0.008 鋁 0.030 釩 0.002 鈣 0.0064 鉬 0.2 銅 0.12 表3 ：涂層物 涂 層 厚 度 層 數(shù) TiALN 3.5u 1 Ti—TiCN—TiN 3u-3 t-1 t 3 (TiCN 中間體) 2.2 冷卻物 普遍認(rèn)為冷卻乳化液能幫助降低磨損率和切削溫度。實驗所用冷卻液是以乳化液為基礎(chǔ)的水溶液，商業(yè)上稱作′Novick‵。其中含水量為10%。冷卻液的化學(xué)成分在表5已列出。以前的研究人員就更好的冷卻液的流向有著不同的意見。Taylor[17]表明為了減少刀具磨損率切削液的流向應(yīng)在切屑的背后（A向）。Pigott和Colwell[47]發(fā)現(xiàn)通過使用高噴射流的冷卻液對準(zhǔn)B向就能減少刀具磨損率。Smart和Trent[48]調(diào)查了降低刀具磨損的冷卻液方向并且發(fā)現(xiàn)在所有的建議中最有效的方向是B向。因此，圖4所用的冷卻液以直徑為1.3cm的噴嘴流出，流速為7.1L/min方向是B向。但是，目前的研究表明在所有作為冷卻液而增加刀具壽命的事例中，這種方案并不是十分正確的。研究發(fā)現(xiàn)通過某中磨損機制的作用如高速機床（HSM），冷卻乳化液幫助減少了刀具磨損率。這種冷卻液的效果的詳細(xì)解釋將在第5章介紹。另外，第5章還覆蓋了冷卻液的簡歷種類解釋以及使用方法。 表4：切削刀具的幾何數(shù)據(jù) 刀具幾何 Tool geometry 尺寸 刀尖圓弧半徑 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5：冷卻劑的化學(xué)成分 硫 20—30% 芳香酒精 3—5% 丙烯甘醇以太 3—5% 石油潤滑油 30—35% 非離子表面活化劑 3—5% 氯化烯烴聚合物 20—30% Designation Back rake 0° Side rake 0° End relief 5 ° Side relief 5 ° End cutting edge 52° Side cutting edge 3° Nose radius 0.88mm Nose radius Cutting Back rake angle Side rake angle 圖2 刀具幾何  圖3 安裝在刀夾上的切削刀具照片 A B 圖4 冷卻液的流向 3.切削條件 根據(jù)ISO 3685[46]規(guī)定，表6列出了整個實驗過程所用的五種切削速度。切削速度為410m/min對應(yīng)的刀具涂層含碳，180m/min對應(yīng)的刀具涂層不含碳，這兩種速度大約達到了應(yīng)用范圍的最高極限。如果速度再增加的話將會導(dǎo)致刀具的壽命再實驗開始時很短時間內(nèi)就耗盡或很快損壞。 車削實驗是在干燥，潮濕以及不同切削速度的條件下進行的，然而兩種實驗所需的進給量和切削深度各自為0.14mm/rev，1mm。表6給出了三種切削刀具所用的五種速度。 4.刀具壽命過程的實驗測試 最大動力為7.5HP的車床（Clausing 1300）用于車削熱軋鋼SAE4140H，并且車削過程是在前面所描述的條件下進行的。為了保證切削是在非常正確的速度下執(zhí)行的，該實驗采用了轉(zhuǎn)速表來測量每次單獨切削工件前的旋轉(zhuǎn)速度。 光學(xué)顯微鏡用來測量切削刀具的后刀面磨損。如果以下兩種條件中有一種發(fā)生的話，該實驗就停止進行。 1. 最大的后刀面磨損為0.7mm 2. 平均后刀面磨損為0.6mm 起初實驗的目的是為了確定磨損極限。然而，實驗發(fā)現(xiàn)在常規(guī)條件下切削刀具也存在磨損破壞。因此，VB=0.7mm就作為刀具壽命的極限。在整個實驗過程的不同間隔時期觀察并測量到刀具后刀面磨損。圖5是在干燥，潮濕條件下，不含碳（KC313）刀具的后刀面磨損量與時間的函數(shù)圖象，并且只包含了三種切削速度。 圖6是含有夾層刀具（KC732）的后刀面磨損與切削時間函數(shù)圖象。圖3—7是含TiALN刀具（KC5010）后刀面磨損與切削時間的函數(shù)圖象，前面所提到的三張圖包含了三種切削速度。附件上的切削速度曲線清晰地表示出機器的兩種條件下的磨損狀況。以上所提到的圖象表現(xiàn)出：乳化液可提高KC313，KC732切削刀具的壽命；尤其是在切削時（KC313）3分鐘后使用切削液，(KC732)7分鐘后更明顯。但是，KC5010使用乳化液則產(chǎn)生負(fù)面影響。 圖5， 6說明了任何所闡述的車削條件下，刀具在正常磨損階段干燥切削條件下，后刀面磨損率會增高，圖7說明了任何所闡述的車削條件下，在正常磨損階段潮濕切削條件下刀具后刀面磨損率也會增高。這種材料性能行為的原因?qū)⒃诘谖逭拢ㄔ诔睗駰l件下KC5010的磨損機理）進行詳細(xì)全面的介紹。 在正常磨損階段之后，曲線看起來彼此互相平行。這就說明了在干燥和潮濕切削條件下刀具后刀面的磨損率是相同的。前面的圖表說明了后刀面磨損曲線經(jīng)歷了三個階段：初期磨損階段，正常磨損階段或穩(wěn)定磨損階段以及急劇磨損階段。相似的觀察結(jié)果也記錄在Chubb和Billingham[11]，Haron[12]。以下介紹這三個階段的概況： 初期磨損階段：產(chǎn)生的原因是為了快速磨平切削刃，而該時期磨損率較高，它隨著時間的增長而減少。圖6的曲線1，2，3隨著切削速度的增高而下降。 正常磨損階段：圖片中的三種切削工具，經(jīng)過初期磨損階段之后，就意味著進入正常磨損階段。但是，該時期的磨損率沒有初期階段那么劇烈，而是比較緩慢均勻。 急劇磨損階段：這個時期是磨損的最后階段，它將導(dǎo)致刀具的損壞?？焖倌p揭示了裂紋的形成，它們將削減切削刃并且持續(xù)抵抗高切削力，因此導(dǎo)致刀具出現(xiàn)裂紋。該實驗揭示了快速破壞發(fā)生在切削過程中；將導(dǎo)致工件表面的損壞。因此，可以想象，到最后切削階段通過工件時刀具損壞產(chǎn)生，也就使工件產(chǎn)生刮痕的幾率增高。 表6：實驗中特殊刀具的切削速度 切削工具 切削速度（m/min） KC313 90 120 150 180 KC5010 260 310 360 410 KC732 260 310 360 410 含碳（KC313） (潮濕&干燥) 圖5 KC313(干燥和潮濕)后刀面磨損與切削 TiN-TiCN-TiN(KC732) (潮濕&干燥) 圖6 KC732(干燥和潮濕)后刀面磨損與切削時間函數(shù) TiALN(KC5010)(干燥&潮濕) (wet & dry) 0.0 o t t 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Time (min) 圖7 ：KC5010(干燥和潮濕)后刀面磨損與切削時間函數(shù)