TOOL WEAR, TOOL LIFE, HAND TOOLS AND MACHINE TOOLS
TOOL WEAR, TOOL LIFE, HAND TOOLS AND MACHINE TOOLSemail: vkjain@iitk.ac.in1
PROCESS OF CUTTING TOOL FAILURECutting Tool Failure Mechanisms:1.2.3.4.By Plastic deformationBy chipping due to mechanical breakageBurning of the toolBy gradual wearFig: e) Create wear & flank wearTypical wear pattern in cutting toolFig: (f) small & Larger Flank wearA tool that no longer performs the desired function can be declared as “failed”
FLANK WEAR AND TIME RELATIONSHIPThree stages o flank wear:1. Rapid growth region (Break in region)2. Steady state region (Temperature Insensitiveregion)3. Catastrophe failure (Temperature sensitive region)Flank wear characterised by wear land (or Height) hf of wear bandFlank wear formation depends on* Cutting Conditions (f, d, V, tool angles)* Properties of work material and tool materialflcFlank Wear (mm), hf mmhfBreak tive area321lfel(a)lCf(c)Time (t) (min.)fTimec(b)Fig: (a) Three stage flank wear curve, (b) Various elements of flank wear and crater wear, (c) Variation of various craterwear with time
Tool wear Index, feed marks and surface finish Type of wear depends MAINLY on cutting speed If cutting speed increases, predominant wear may be “CRATER” wear else“FLANK” wear. Failure by crater takes place when index hk reaches 0.4 value, before flankwear limit of hf 1mm for carbide tools is attained.C(l / 2) fWhere, C Depthl Widthf Dis tan cefor HSS hk 0.6hk 8f 2RCLA R18 3Rmax 4 RCLAWhere, f FeedR Tool Nose Radius
Effect of tool wear on machined surfaceFLANK WEAR AFFECTS:* Dimensional accuracy* Process stability* Surface finishGenerated surfaceDesiredsurfaceAxisAmount offlank wearDepth of cutFlank WearToolMovementEffect of tool wear on machined component dimensions (Exaggerated view)
TOOL LIFE & MACHINABILITYTool no longer performs desired functionRe-sharpen and use it again.failedTOOL LIFE: Useful life of a tool expressed in terms of time from start of a cutto termination point (defined by failure criterion). Sometimes alsoexpressed in terms of no. Of the parts machined. Tool failure criterion depends on 1. The requirements of the component being produced. 2. Type of Operation: Roughing: force and power requirement. Finishing : Surface finish & dimensional accuracy.TAYLOR’S TOOL LIFE EQUATIONAfter 12 Years of ExperimentsVT n CWhere, V CuttingSpeedT Tool life ( Minutes )n Exponent for conditions testedCt Taylor’s constantCt represents cutting speed for 1 minute as tool life
TOOL LIFE & MACHINABILITYFeed (f)Depth of cut (d)Tool geometry (Rake Angle)(n 1), Ct is very largeTaking logarithm on both sidesCutting Speed (m/min.) LogDoes not account for:1 Unitn 1/2.52.5 UnitLogV nlogT LogCtThis becomes a straight line on the log-log scaleTool life (minutes) LogVTnfn1dn2 CN, n1, n2: Constants depending upon tool material ( 0.1 to 0.4).C: constant that depends on tool-work material combination and tool geometry ( 100)
VARIABLES AFFECTING TOOL LIFE Cutting Conditions (V, d, f) Tool Geometry (all six angles, and nose radius) Workpiece Material Cutting fluid Machine tool and Work piece region Tool MaterialMACHINABILITY. Mainly concerned with workpiece material properties not the tool properties.It depends on workpiece material properties and good machinability means:1. Low tool wear2. Good surface finish produced3. Low cutting forcesMachinability is defined as “THE EASE WITH WHICH A GIVEN WORKPIECCE MATERIALCAN BE MACHINED WIT A SPECIFIED CUTTING TOOL.
TOOL SPECIFICATION Apart from tool material, one has to give tool angles and tool noseradius in the following sequence while going to purchase or askingsome one to make a tool : Tool specifications (all six angles, and nose radius) :7-8-5-6-9-4-1mm. Back rake angle (70 ), Side rake angle (80), End clearance (relief) angle (50 ), Side clearance (relief) angle (60), End cutting edge angle (90), Side cutting edge angle (40), Nose radius (1 mm)
FITTING SHOP EQUIPMENTFileBENCH VICEHAND VICEPIPE VICEHand FileFlat FileFile CardHammerHalf-round FileRound FileSquare FileHack SawPitches of Hack SawThree Square File
Fitting Shop EquipmentHand ReamerMachine ReamerTwist DrillCounter bore DrillCountersink DrillAdjustable ReamerDieTapsChiselsDie NutTap Wrench
Measuring EquipmentRuler ScaleVernier CaliperOutside MicrometerInside MicrometerOutside CaliperDepth MicrometerDial GaugeInside CaliperVernier Height Gauge
Measuring & Marking EquipmentScriberDividerSurface PlateBevel ProtectorEngineer’s try SquareCombination SetWire GaugeV-BlockStriking Tools/HammersAngle PlateCenter SquareUniversal Marking Surface GaugeCenter PunchDot Punch
Measuring, Marking Equipment, tools and cuttersDog CarrierUniversal Marking Surface GaugeDrill Chuck & KeyThreading ToolParting ToolRevolving CentreBoring ToolDog PlateCylindrical CutterTurning ToolKnurling ToolSlitting Saw CutterScrew Driver
Power Hack Saw
lingMachineLathe Machine
THANK YOU18
SUPPLEMENTARY MATERIAL19
Tool wear Index, feed marks and surface finish Type of wear depends MAINLY on cutting speed If cutting speed increases, predominant wear may be “CRATER”wear else “FLANK”wear. Failure by crater takes place when inde
Tool wear is gradual and depends on tool and workpiece materials, tool shape, cutting fluids, process parameters, and machine tools Two basic types of wear: Flank wear and Crater wear Tool Wear (d) (e) (a) (b) (c) Figure 20.15 (a) Flank and crater wear in a cutting tool. Tool
Lower Wear Pad L 204mm Doosan 9 - Lower wear pads. LOWER WEAR PADS CODE PART DESCRIPTION BRAND F11B01 Upper Wear Pad L 156mm Doosan Daewoo 8508376 Lower WearPad Class II L 160mm Hyster Yale 10 - Lower wear pads. MAST WEAR PADS AND HOOKS CODE PART DESCRIPTION BRAND 61356-23600-71 Mast Wear Pad
wear of insignia, wear of the shoulder sleeve insignia (current organization and former wartime service), and wear of the dress uniform insignia; adds wear of insignia on the old and new versions of the female blue and white coats, wear of the full-color U.S. flag cloth replica, and a new paragraph on the wear .
tool wear mechanisms were observed using the tool maker’s microscope and scanning electron microscope. The tool wear was found to be more rapid at larger radial depth of cuts at all three cutting speeds. It was also found that the main wear mechanisms presen
Rare earth alloy wear-resistant pipe The wear and tear of rare earth alloy is a phenomenon of material loss caused by relative motion between objects. Rare earth wear-resistant alloy steel tube wear-resistant materials can resist wear and prolong the life of the product. Main Material: ZG40CrNiMoMnSiRe Heat treatment hardness: HRC 40
A hand hygiene action is defined as hand-rubbing with an alcohol-based product or by hand washing with soap and water i 4.7 Hand hygiene indication The WHO 'Five Moments for Hand Hygiene' are used to define a hand hygiene indication or indications i 4.8 Hand hygiene opportunity A hand hygiene opportunity is defined as the requirement
1/4/2013 6 Tool life cont. 21 Example AA steelsteel barbar ofof 40mm diameter is to be turned over a length of 200mm with a depth of cut 1.2mm and feed of .2mm/rev at 200rpm.If the tool life equation is given by VT 2d 13 f0. 31 40 Tool life and Tool Wear 1/4/2013 Determine the number of components that may be turned before
adventure tourism (ISO 21101 and TR 21102)2 addresses adventure travel specifically, and none of these standards or quality assurance systems cover all the aspects necessary for excellent adventure travel guiding. In the absence of a global qualification and performance standard, a variety of approaches to managing adventure travel guiding can be
