D D A B C D A C C C A\C B B A B
二 √ × × √ × √ × × × √
三简答题
1根加工求规定刀面中间部分均磨损量 VB 允许达值作磨钝标准刀具刃磨开始切削直磨损量达磨钝标准止总切削时间T称刀具耐度影响刀具耐度素:(1)切削量(2)刀具参数(3)刀具材料(4)工件材料
2前角作选择原什?
前角作:① 影响切削区域变形程度② 影响切削刃刀头强度受力性质散热条件
③ 影响切屑形态断屑效果④ 影响已加工表面质量
合理前角选择原:
① 加工塑性材料取较前角加工脆性材料取较前角
② 工件材料强度硬度低取较前角工件材料强度硬度高应取较前角
③刀具材料抗弯强度击韧性较低时应取较前角④粗加工应取较前角甚负前角精加工应取较前角
⑤工艺系统刚性差机床功率时应选取较前角减切削力振动
⑥数控机床动线刀具刀具工作稳定性宜取较前角
3偏角作选择原什?
偏角作影响刀具耐度已加工表面粗糙度切削力
偏角选择原:
(1)粗加工半精加工硬质合金车刀般选较偏角利减少振动提高刀具耐度断屑
(2)加工硬材料冷硬铸铁淬硬钢减轻单位长度切削刃负荷改善刀头导热容热条件提高刀具耐度宜取较偏角(10°30°)
(3)工艺系统刚性低时应取偏角甚偏角κr≥90°减背力降低工艺系统弹性变形振动
(4)单件批生产希两刀具加工出工件表面选取通性较45°车刀90°车刀
(5)需工件中间切入车刀仿形加工车刀应适增偏角副偏角
4切削液作?
(1)冷作 (2)润滑作 (3)清洗作 (4)防锈作
5 什积屑瘤?抑制积屑瘤产生
切削塑性金属材料时常切削刃口附黏结硬度高楔状金属块包围着切削刃覆盖部分前面种楔状金属块称积屑瘤
积屑瘤防止(1)控制切削速度控制切削温度 (2)适降低进量减少刀屑接触长度
(3)增前角减前刀面摩擦 (4)采润滑性良切削液
(5)提高工件材料硬度降低塑性
四分析题
1外圆车刀:Kr90°Kr¢35°go8°aoao¢10°ls 5°求绘制刀具示意图标注述角度
书11页图19
2(1)45°端面车刀:KrKr¢45°go 5°aoao¢6°ls 3°
书11页图110
(2)孔镗刀:Kr75°Kr¢15°go10°aoao¢10°ls 10°
求绘制刀具示意图标注述角度
书12页图112
第2章数控机床刀具选择
D A C A A A B D A B A B C B D
二√ √ √ √√ × ×√√×
三简答题
1优点(1)刀具寿命长刀具避免焊接刃磨高温引起缺陷切削性稳定提高刀具寿命
(2)生产效率高减少停机换刀等辅助时间
(3)利推广新技术新工艺
2镗铣类工具系统结构形式分整体式结构模块式结构
整体式结构工具系统特点锥柄接杆连成体品种规格工作部分必须带机床相连柄部优点结构简单反方便更换迅速等缺点锥柄品种数量较
模块式工具系统克服整体式工具系统缺点工具柄部工作部分分割开制成种系列化模块然规格中间模块组成套套规格模块式工具优点方便制造保减少工具规格品种数量储备加工中心较企业高实价值
3优点(1)定位精度高
(2)静态动态刚度高
(3)适合高速加工
(4)质量轻尺寸结构紧凑
(5)清污垢方便
HSK刀柄适高速加工
第3章 数控加工中工件定位装夹
作业
单项选择题
B ADAC BDDDC BCBCA
二×√√√√ √√ ×√ ×
三简答题
1什欠定位?什采欠定位?什定位? |Un2p3JLK u0YQ 5 (5e*
加工求应该限制度没限制定位称欠定位
欠定位允许欠定位保证加工求
工件度定位元件重复限制定位称定位
2什定位误差?产生定位误差原什?
工件夹具定位准造成加工误差称定位误差
产生定位误差原定位基面定位元件工作表面身存定制造误差导致批工件夹具中实际位置完全样加工工件加工尺寸存误差 5| k~A2+
3 确定夹紧力作方作点应遵循原?
(1)夹紧力应定位基准
(2)夹紧力作点应落定位元件支承范围支承元件中心
(3)夹紧力方应利减夹紧力
(4)夹紧力方作点应施加工件刚性较方部位
(5)夹紧力作点应量工件加工表面
4粗基准选择原什?
(1)相互位置求原 (2)加工余量合理分配原 (3)重表面原
(4)重复原 (5)便工件装夹原
5精基准选择原什?
(1)基准重合原 (2)基准统原 (3)基准原
(4)互基准原 (5)便装夹原
6夹紧装置应具备基求什?
(1).夹紧程改变工件定位占正确位置
(2).夹紧力适保证工件加工程中位置稳定变振动工件会产生夹紧变形
(3).操作简单方便省力安全
(4).结构性夹紧装置结构力求简单紧凑便制造维修
四计算题
1轴套类零件铣槽时工序尺寸三种标注方法图1示定位销水放置试分计算工序尺寸H1H2H3定位误差
H3
图1
解图知 TD0021 Td(0007)(0028)0021
(1)工序尺寸H2时工序基准定位基准重合基准重合误差0
定位误差(TD +Td)2 (0021+0021)20021
(2) 工序尺寸H2时工序基准圆柱面母线定位基准重合工序基准相定位基准变动量基准重合误差 TD2工序基准定位基面定位误差两者变动方相反 00105
(3) 工序尺寸H3时 工序基准定位基面
00315
五分析题
1根六点定位原理分析图2定位方案定位元件限制度
图2
解图(a)限制
图(b)限制
图(c)限制
图(d)限制
2什定位?试分析图3中定位元件分限制度?否合理?改进?
图3
答工件度定位元件重复限制定位称定位
图(a)言圆锥销限制面限制合理时限制改进方法:圆锥销改圆柱销
图(b)言短销限制底面限制V型快限制合理改进方法:V型快变成加弹簧活V型快
图(c)言长销限制面限制轴合理改进方法:长销改短销侧面改成台阶
3试分析图4中夹紧力作点方否合理?什?改进?
图4
(a)合理夹紧力方作点应施加工件刚性较方部位薄壁箱体夹紧时应作刚性较凸边
(b)合理夹紧力作点应落定位元件支承范围支承元件中心图中夹紧力作支承面外导致工件倾斜移动破环工件定位
(c)合理 夹紧力方作点应施加工件刚性较方部位细杆长轴言 应作刚性较支承
(d)合理 夹紧力作点应落定位元件支承范围支承元件中心图中夹紧力作支承面外导致工件倾斜移动破环工件定位
单选择题
1D2A3A4B5D6B7D8A9D10C
判断题
1√2×3√4×5×67×8 ×9√10√
简答题
1 组工工作时工件连续完成部分工艺程称工序加工表面加工工具变情况连续完成部分工序称工步
划分工序工作否发生变化工作否连续划分工步加工表面工具否变化
2 数控机床加工零件般工序集中原划分工序划分方法:
①刀具划分:刀具完成部分工艺程道工序
②安装次数划分:次安装完成部分工艺程道工序
③粗精加工划分:粗加工道工序精加工道工序
④加工部位划分:完成相型面部分工艺程道工序
3 划分加工阶段目:① 保证加工质量② 合理设备③ 便时发现毛坯缺陷④ 便安排热处理工序
4 刀点数控加工时刀具相零件运动起点称起刀点程序运行起点
选择刀点原:
(1)选择刀点便数学处理简化程序编制
(2)刀点机床容易校准
(3)加工程中便检查
(4)引起加工误差
5 切削加工序安排应遵循原
①基面先行原
②先粗精原
③先次原
④先面孔原
6 确定加工余量时应该注意问题
①采加工余量原
②余量充分
③余量中应包含热处理引起变形
④零件取余量
⑤总加工余量(毛坯余量)工序余量分确定
7 加工精度指零件加工实际参数(尺寸形状相互位置)理想参数相符合程度
加工精度包括三方面:①尺寸精度②形状精度③相互位置精度
8 表面质量指零件加工表层状态衡量机械加工质量重方面表面质量包括方面
①表面粗糙度
②表面波纹度
③冷作硬化
④残余应力
⑤表层金相组织变化
9 产生加工误差原
① 加工原理误差
②工艺系统误差
③工艺系统受力变形引起误差
④工艺系统受热变形引起误差
⑤工件应力引起加工误差
⑥测量误差
10 ① 工件材料:
② 切削量
③刀具参数
④切削液
计算题答案
第1题答案:
方案:设计基准定位基准重合A1工序尺寸偏差12±01
方案二:设计基准定位基准重合确定A2设计尺寸12±01 间接封闭环图:
A2基尺寸:LA2=8+12=20
01=ESA2-(-005)ESA2=+005mm
-01=EIA2-0 EIA2=-01mm
mm
方案三:设计尺寸12±01 间接封闭环
A3 基尺寸:LA3=40-8-12=20mm
+01=0-EIA3-(-005)EIA3=-005mm
-01=-01-ESA3-0 ESA3=0mm
A3 基尺寸偏差:mm
第2题答案:
根题意知A3 封闭环A2 A4 增环A1 减环列出尺寸链图
A4 基尺寸
LA3=LA4+LA2-LA1LA4=LA3+LA1-LA2=20+70-60=30mm
ESA3=ESA2+ESA4-EIA1 ESA4=ESA3-ESA2+EIA1=019-0+(-007)=+012mm
EIA3=EIA2+EIA4-ESA1 EIA4=EIA3-EIA2+ESA1=0-(-004)+(-002)=+002mm
A4测量尺寸公差TA4=ESA4-EIA4=012-002=010mm
(种解法求公差计算)
第3题答案:
图尺寸链图设计尺寸L3工序加工中间接封闭环
t U0
箭头表示L2L4 增环L1 减环尺寸L4
计算:
基尺寸:L3=L2+L4-L1
L4=L3+L1-L2=100+280-80=300mm
偏差ESL3=ESL4+ESL2-EIL1
ESL4=ESL3-ESL2+EIL1
=015-0+0=+015mm
偏差ESI3=EIL4+EIL2-ESL1
EIL4=EIL3-EIL2+ESL1
=-015-(-006)+01=+001mm
L4工序尺寸偏差
第4题答案:
图(b)尺寸链图设计尺寸LA0工序加工中间接封闭环
箭头表示LA2LA3 增环LA1减环尺寸LA3
计算:
基尺寸:LA0=LA2+LA3-LA1
LA3=LA1+LA0-LA2=70+12-35=47mm
偏差ESL0=ESL2+ESL3-EIL1
ESL3=ESL1+ESL0EIL2
=007+015006=+016mm
偏差ESI0=EIL2+EIL3-ESL1
EIL3=EIL1+EIL0ESL2
=007+00=007mm
LA3工序尺寸偏差
数控加工工艺作业4
单项选择题
1 A 2A 3C 4B 5B 6B 7D 8A 9A 10 B 11B
二判断题
1 X 2 V 3 V 4 X 5 V 6 V 7 V 8 V 9 X 10 X
三 简单题
1P P148149
2\
更正第题7 正确答案C 14 A
D二题 1 ∨
请您删容O(∩_∩)O谢谢2015年中央电期末复考试抄全电期末考试必备抄电考试必抄请您删容O(∩_∩)O谢谢2015年中央电期末复考试抄全电期末考试必备抄电考试必抄The battle for young viewers CCTV is embracing Internet culture and working with independent producers on TV shows to woo audiences under 35 Han Bing bin reports After charming audiences with his warm smile for 14 years China Central Television host Li Jiaming recently found himself targeted by a group of young netizens unhappy with his style The complaints came after Li hosted the premiere of Rising Star on Oct 31 It is a singing competition show that originated in Israel Many young netizens found his hosting style slow and boring and mocked it as CCTV evening gala style They even initiated an online campaign to replace him The 40yearold host's reaction to the criticism was surprising During the second episode he jokingly called himself the slow Jiaming and acted much younger talking faster and louder It's like selling a product When the customers file a complaint you must change says Li In the Internet age you get feedback very quickly These young people are so cute When you're willing to change for them they will quickly like you back In order to win more young viewers CCTV is relying on programs such as Rising Star to embrace Internet culture In Rising Star a studio audience and fans watching on television vote for their favorite singers in real time using the instantmessaging app WeChat Rising Star was designed to be a live broadcast but the Chinese version isn't because of policy reasons Still WeChat votes by viewers at home are still a major factor in determining which contestants advance to the next round In the show's latest episode more than 65 million votes were cast via WeChat Now the competition among entertainment shows is very fierce Audiences have more diverse needs CCTV needs to embrace an open attitude interact with young audiences and blend with the Internet says Lyu Yitao director of CCTV's entertainment channel The producer of Rising Star Enlight Media says the program will have a phenomenal effect given CCTV's audience base nationwide But it comes with a challenge says Zhang Hang chief producer of the program and CEO of Enlight Media's TV business Unlike topranking provincial satellite channels such as Hunan TV which have a large base of young fans thanks to a series of phenomenally popular entertainment and reality shows CCTV productions are usually more conservative and serious and thus have a much older audience base If we were to run this program on Hunan we may attract twice as many viewers says Zhang But since we didn't make it there we now have to make the best out of the given conditions And it means we have to make certain compromises When the current season of Rising Star ends Zhang says his company will conduct an overall evaluation of the program and make adjustments for future seasons Although audience ratings haven't lived up to Zhang's expectations he says the program has already helped CCTV attract more young people According to Enlight Media the number of people ages 15 to 35 who watched the first episode of Rising Star was 76 percent higher than the usual audience for CCTV entertainment productions In order to attract young audiences CCTV has been working with independent production companies As one of CCTV's closest partners Enlight Media has produced several entertainment and reality shows for the company's channels including the Chinese version of The Biggest Loser on CCTV's business channel and an original teenager talent show Shaonian Zhongguo-qiang (Strong Young Chinese) on CCTV1 This year CCTV also licensed EEMedia the producer of the popular Super Girl talent shows to produce the talk show Hi 2014 hosted by Taiwan pop star Harlem Yu and one of China's most popular TV stars Xie Na The show is geared toward younger audiences Canxing Productions which rose to fame with the success of its Voice of China series on Zhejiang TV also produced two talent shows for CCTV One is an original production called Songs of China which ended up as one of CCTV's most watched programs of 2014 The State Administration of Press Publication Radio Film and Television announced earlier this year that starting in 2015 only one music talent show can be aired nationwide during prime time each season and there can be only one program based on foreign formats each year However domestic media report that such policies don't apply to CCTV meaning it will become a highly desired platform by production companies Wang Changtian CEO of Enlight Media confirmed to the Shanghai Securities News that its programs scheduled to air on CCTV next year which include at least two reality shows won't be affected A kung futhemed reality show produced by Canxing is also reportedly scheduled to run on CCTV next year CCTV is very active The level of its acceptance of new ideas is even beyond my imagination says Zhang Hang Our cooperation with CCTV will surely continue When winter comes nothing is more relaxing than a hot spring bath For thousands of years natural mineralrich hot spring baths have also been used to relieve health ailments The water found in natural hot springs contains a variety of different minerals and the most common one is sulfur It has a rotten egg smell but is excellent for skin The sulfurcontaining water might be just what the doctor ordered when it comes to relieving pain stress itchy skin arthritis and more Hot springs resorts are thriving as biting cold winter arrives Here we take a look at some of the best natural hot springs China has to offer
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