Question BankDuring shaping like single point machining/turning) a steel plate at feed, 0.20 mm/stroke and depth 4 mm by a tool of λ = γ = 0° and φ = 90° Fz and Fx were found (measured by dynamometer) to be 800 N and 400 N respectively, chip thickness, a2 is 0.4 mm. From the aforesaid conditions and using Merchant’s Circle Diagram determine the yield shear strength of the work material in the machining condition? Calculate the time taken to turn a brass component of 60 mm diameter by 84 mm long diameter if the cutting speed is 50 m/min and the feed is 0.4 mm/rev. Only one cut has to be considered. Neglect tool approach and tool travel We have set up a lathe and are doing an orthogonal cut. The feed rate of the lathe is 0.1mm, and the chip thickness after the cut is 0.2mm. The depth of the chip being cut is 5mm. The surface cutting speed of the tool is 2m/s. The tool has a rake angle of 10deg. The tangential force is measured as 200N, and the cutting force is 500N. a) Calculate the shear force and velocity. b) Calculate the total energy produced in the cut, c) Calculate the energy used to shear d) Explain the difference between the total and the shear energy. What type of chip is expected at higher cutting speeds? Sketch a single edge cutting tool and label the a) face, b) flank, c) nose, d) cutting edge, e) relief, f) shank. What factors will affect surface finish? Derive the ideal surface finish equation for a turning process 17. a) Define machinability. b) What determines the machinability of a metal? 17. a) Define machinability. b) What determines the machinability of a metal? We are going to estimate the effects of feedrate on tool life. Some simple calculations yield the Taylor tool life coefficients of n = 0.4 and a C = 400. Find the change in tool life (in %) when velocity drops by a) 20% and b) 40% c) the chasing dial is used for measuring fine cuts. Why are ceramic cutting tools generally designed with negative rake angles? .What happens to the cutting process as the temperature rises? What would happen if a drill without flutes was used? Which of the statements about lathes below is most correct? a) jawed chucks hold only standard sizes of pieces. b) mandrels hold work pieces from the outside. Explain the mechanism behind the Self-excited vibration. d) lead screws and feed rods are lathe parts What type of grinding is suited to the outside surfaces for the parts below? Explain about tool tuning in relation with chatter in machining process. Write short notes about criteria for Cutting Fluid Selection Explain the role of friction in power consumption in machining process. Write short notes about “Mitigation of Build edge formation”. Write a short note about the spindle design requirement for High speed machining Expalin the use chip breakers in machining What is lay pattern in a machined surface?. Shaping Taking a suitable example discuss how cutting tool wear can be mathematically modeled using different approaches? What benefits can be achieved from such modelling? (b) Write a note on 'tool life testing' and the success rate and reliability of the methods used for the same. Surface Grinding 2. End Milling 3. (ii) Crater wear . (c) Discuss the following: (i) Wear-Land wear.Explain the term carbon seeking and how it affects the PCD cutting tools Which conventional machining process consumes high specific cutting energy Explain about the design considerations for SPDT Explain the difference between the PVD and CVD coating process Compare hard turning with Grinding Write short notes about ductile regime grinding of ceramics Explain the relationship between the cutting force with cutting velocity for High speed machining. Indicate the lay pattern for 1. Explain any three of them along with the mechanism involved Taking the optimization variables as 'specific cost' and 'production rate'. (iii) Temperature measurement. Also describe the cutting action of the grit and the effect of grit force on wheel wear. (b) How grinding wheels are tested? (c) Mention the procedural steps required in simulating any grinding process. (b) Economics of metal machining and its importance.Write notes on the following: (a) Measurement of wear of cutting tools in machining. How does metallurgy of the work material and the cutting tool affect the machinability in any machining operation? Discuss what different types of wear can take place in cutting tool. What advantages are associated with it? Using the concept of dynamometry and theoretical considerations. explain how the following can be measured during metal cutting (i) Force measurement. . Discuss the mechanism of grinding in detail. (ii) Heat measurement. describe the procedural steps that are involved in optimizing any machining operation? Support your answer with a suitable example. . How does it differ from orthogonal cutting? . (c) Mechanics of lapping. Discuss in detail the force system in oblique cutting. How brittle fracture is analyzed in tools using the fracture mechanics approach. (d) Force system in milling operation A HSS tool requires regrinding after 2 hours and 45 minutes when machining steel at a cutting speed of 35m/min: Calculate the tool Iife if the speed is increased to 70m/min. The wheel grade is medium hard 4. Continuous chips with built up edge d. 1. The tool life equations are: Carbide tool: VT1. Shear plane and the vertical direction d.0 VT6 = 200 . (ii) Rate of strain. Discontinuous chips d) c. using the standard alphanumeric codification: i) 1. 20 degree to 40 degree b. shear angle is the angle between o) a. 40 degree to 60 degree g) c. (iii) Total energy consumed per unit volume A cutting tool must posses the following property to enable high speed machining a) Hardness 2) red hardness c) wear resiatnce d) hardness and toughness b) Cast iron during machining process produces c) a. 80 degree to 90 degree h) Consider the following statements in respect of a grinding wheel of specifications. Shear plane and the cutting velocity b. 4 and 5 n) In orthogonal cutting. 3 and 5 d. The grain size of abrasive is medium j) 3. Shear plane and the direction of elongation of crystals in the chip. Two cutting tools are being compared for a machining operation. 3 and 4 c. 1. It has resinoid as bonding agent l) Which of these statements are correct? m) a. Continuous chips b. Abrasive used in the wheel is aluminium oxide 2. 1. Shear plane and the rake plane p) c. 60 degree to 80 degree d. Segmented chips e) The lip angle of a single point tool is usually f) a. 2.Describe the following in relation to orthogonal cutting (i) Shear strain.6 = 3000 HSS tool: 6. It has an open structure k) 5. 2 and 3 b. 51A-36-L-7-R-23. m-3.2 mm/rev. determine the percentage of the total energy that goes into overcoming friction at the tool-chip interface and the percentage that is required for cutting along the shear plane.36 g of steel chips with a total length of 500 mm are obtained. The carbide tool will provide higher tool life if the cutting speed in m/min exceeds (A) 15. 7°. (Density ρ = 7830 kg. what is the slip plane angle? density = 7830 kg. If 13.0 Expalian the role of regulating wheel in centerless grinding process. Determine the values of cutting ratio and shear angle in the above case. A TAP is a cutting tool used to create which one of the following geometries a) External threads b) Flat planar surfaces c) holes d) internal thread Write a short note about a) Reaming b) Boring c) Broaching In an orthogonal cutting process v = 2.4 (C) 49. The value of chip reduction coefficient. 0°.) .s-1.0 (B) 39. 0 (mm) at s0= 0.5 m.3 (D) 60. If a toolpost dynamometer gives cutting and thrust forces of Fh = 1100 N and Fv = 440 N. 15°. 0°. 8°. The underformed chip thickness is 200 µm.5 mm.m-3. and the width of cut is b = 10 mm. α = 6°.where V is the cutting speed in m/min and T is the tool life in min. ζ does not depend upon (a) cutting velocity (b) depth of cut (c) cutting tool material (d) tool rake angle During plain turning mild steel by a tool of geometry. the chip thickness was found to be 0. 90°. Select the process which corrects the following Errors in the cylinder bore a) Curvature b) conicity c) barrel form d) lack of roundness e) taper f) waviness Explain its operating principles.05 mm. Writes a short notes about a) Burn b) Residual stress in a grinding process . What is flow stress in machining operation explain its importance for modeling of machining process.A horizontal spindle surface grinder is cutting with t = 5 mm and U = 40 GPa.2 mm. the work speed is 0.s-1. the cross-feed per stroke is 1.3 m. and the wheel depth of cut is 0. Estimate the tangential force on the wheel if the wheel speed is 30 m.s-1.
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