機(jī)械制造技術(shù)基礎(chǔ)課件-chapter4-section3(new)

1、4.3 Hole making machine tool and cutting tool Drilling machine (鉆床鉆床) Boring machine (鏜床鏜床) Broaching machine (拉床拉床)Usually used hole making machine tools Usually used hole making cutting tools Twist drill (麻花鉆) and “masses drill” (群鉆) Core drill (擴(kuò)孔鉆) Reamer (鉸刀) Boring cutter (鏜刀) Broaching cutter

2、 (拉刀)4.3.1 Drilling machines Drilling machines and boring machines can both enlarge and finish cutting of holes from a small fraction of a millimetre to hundreds of millimetres in diameter. Drilling machines are used for rough drilling holes.Main types: Vertical(立式） 、Radial（搖臂）、Deep hole drills（深孔）.

3、The picture shows a typical Vertical Drilling machines.worktableBaseThe headstockcolumn主軸箱立柱工作臺(tái)底座Radial drill pressMethods of Machining operationsFig 3.29擴(kuò)孔鍃孔鉸孔深孔鉆4.3.1 Drilling machines 4.3.2 Boring machine Boring is the operation that enlarges a pre-existed internal hole. Several machines have bee

4、n developed that are specially adapted to boring work. .Main types of boring machines:Horizontal boring machine 、Jig boring machines and high accurate boring machine鞍形工作臺(tái)鏜鉆銑頭鏜桿支撐軸承Boring machine(鏜床)Performance: big size, high accurate, different surfaces, high accurate relative position.Main motion:

5、 rotation of the boring cutterfeed motion: cutter or workpieceJig boring machine (坐標(biāo)鏜床）: Very high accurate position.position accuracy is between 0.0020.01mmDiamond boring machine diamond boring cutters used. Jobs done by horizontal boring machine Method of Horizontal boring machine operations4.3.3

6、Drilling tools(1) Twist drillTip angleformed by two planes parallel with the two main cutting edges Chisel edgecenter edge linking the two main cutting edgesThe main geometry for twist drill are: the helical angle (2430)螺旋角, the tip angle 2(118130)鋒角, rake angle 前角, relief angle 后角 and Chisel edge a

7、ngle橫刃斜角 Lip relief angle 鉆緣后角Cutting performances affected by geometryHelical angle: it is the axial rake angle, f for standard twist drill =18 30。 drill bronze or soft copper： =10 17 light alloy, red copper： =35 40 high strength steel, cast iron =10 15 Axial force and momentCutting easyStrength an

8、d heat off Tool lifeTip angleCutting edge lengthUnit cutting edge force and axial forceTip strengthTwist momentHeat offTool life1 Ordinary Twist drills（麻花鉆）麻花鉆）The main geometry for twist drill are:the helical angle (2430), the tip angle 2(118130), rake angle , relief angle and wedge inclination ang

9、leDifferent types of twist drills adapted2 Adapted twist drills The quality of surface machined by twist drillThe accuracy: IT11-IT12The roughness: 5012.5mThe range of diameter machined: 0.180mmMaterial: 2 Adapted twist drillMasses DrillQuestion: what are the main disadvantages of traditional twist

10、drill ?What changes happened on “qun zuan”O(jiān)rdinary twist drill 三尖七刃銳當(dāng)先，月牙弧槽分兩邊，外刃再開(kāi)分屑槽，橫三尖七刃銳當(dāng)先，月牙弧槽分兩邊，外刃再開(kāi)分屑槽，橫刃磨低窄又尖。刃磨低窄又尖。 (2) Center drill (中心鉆） Center drill is used to machine the center hole of a workpiece. Fig 3.38 shows two kinds of center drilling .center drilling(3) Deep hole drilling (g

11、un drilling,深孔鉆深孔鉆)Definition of deep hole:When L/d is between 520Method :lengthen the twist drillWhen L/D is bigger than 20,Method:Specialized deep hole drilling machine Accuracy: usually reach IT8-IT10, sometimes IT6-IT9(Special design)Roughness: 3.20.8 mFluid inChip out(4) core drill(IT10-IT11,Ra

12、6.33.2)（擴(kuò)孔鉆）（擴(kuò)孔鉆）Accuracy: IT10-IT11Roughness:6.33.2 mSize: 10 80mmIntegral typeCarbide tipped typeRotational type(5) Counter boring drill (锪鉆）(6) Reamer(IT6IT11,Ra 1.6-0.2) 鉸刀鉸刀Fig structure and geometrical parameters of reamerWorking partneckshankCutting partGuide tapercalibrating partInclude Cyli

13、ndrical and cone partThe accuracy with reaming can reach IT6IT8, the roughness can be 1.60.4 m, suitable for finish or semi-finish machiningDiscussion: Why can the reaming method improve the machined qualities?various reamershandle fixed type(手動(dòng)式）handle adjustable type（可調(diào)整手動(dòng)式）shell type（套式）Carbide t

14、ipped type（鑲硬質(zhì)合金齒）various reamers(7) boring tool（a）（b）（c）single-blade boring toolAdvantage: simple, easy to make, general purpose, often usedCan you tell the disadvantage?Double blade boring tool Material:Floating type: why?Accuracy: IT6-IT7Roughness:can be 0.8 mQuestion: compared to single type, wh

15、at are the main advantages of double blade boring tool?Fig 3.46 examples for various broaching surface(8) Broaching cutterDiscussion: could you tell the advantage of broaching method? What is the disadvantage?structure of hole broaching cutterDiscussion: why can the broaching method achieve high accuracy ? 1head(頭部頭部)；2neck(頸部頸部)；3cone tra