Tutorial sheet

Module 1 Q1. Define

a) Single point cutting Tool b) Multipoint cutting Tool

Q2.Explain the various types of tool angles associated with the tool geometry with neat sketch. Q3. Explain ASA and ORS system of Tool signature. And also shows the relationship between them. Q4. Explain the different types of tool materials used for cutting tool. Q5. Explain the effects of various angles on the single point cutting tool. Q6. Differentiate between orthogonal and oblique system of cutting tool. Q7. Define nose radius and its effect on tool geometry. Q8. During turning process with 7-α-6-6-8-30-1 mm (ASA) tool the unreformed chip thickness of 0.2 mm and width of cut of 2.5 mm were used. The side rake angle of the tool was chosen such that the machining operation could be approximated to be orthogonal cutting. The tangential cutting force and thrust force were 1177 N and 560N respectively. Calculate:

1) The side rake angle 2) Coefficient of friction at the rake face 3) The dynamic shear strength of the work material.

Q9.

Module 2

Q1. Explain the mechanism of chip formation. Q2. Explain the different types of chips produced in metal cutting? Explain the continuous chip (BUE) with neat sketch. Q3.Explain the various factor involved in chip formation analysis. Q4.Explain

a) Shear plane b) Shear strain c) Shear angle d) Rate of shear strain e) Types of chips produced in milling and drilling

Q5.Define chip thickness ratio and derives an expression for chip thickness ratio in metal cutting. Q6. In orthogonal machining operation prove that

푡푎푛∅ =r cos α

l − r sinα

Where r=chip thickness ratio α=rake angle

∅=shear angle Q7. Show that the chip thickness ratio in metal cutting is give by the expression

푡푡

=푠푖푛∅

cos (∅−∝)

Where 푡 = chip thickness after cutting 푡 = uncut chip thickness ∅ = shear angle ∝ = rake angle

Module 3

Q1. Explain the various types of forces in metal cutting using Merchant circle diagram. Q2. Explain the velocity triangle in metal cutting with neat sketch. And also obtain the relationship between cutting velocity (V), shear velocity (Vs) and chip velocity (Vc). Q3. Derive an expression for specific cutting power in metal cutting. Q4. Explain

a) Ernst& merchant angle relationship, b) Lee-Shafer relationship

Q5. What do you mean by Dynamometer and explain mechanical and Strain gauge dynamometer. Q6. Explain the heat distribution zone in metal cutting. Q7. In an orthogonal cutting operation, the following data have been observed:

Uncut chip thickness =0.127mm Width of cut=6.35 mm Cutting speed =2 m/s Rake angle=10 degree Cutting force=567 N Thrust force=227 N Chip thickness=0.228mm

Determine shear angle, the friction angle, shear stress along the shear plane, and the power for the cutting operation. Also find the chip velocity, shear strain in chip and the strain rate. Q8. In an orthogonal cutting operation, the following data have been observed:

Rake angle=10 degree Chip thickness ratio=0.35, Uncut chip thickness=0.51 Width of cut=3mm Yield shear stress of work material=285N/mm2

Mean friction coefficient on rake face of tool face =0.65 Determine the (1) cutting force (2) Radial force (3) Normal force on tool (4) Shear force on the tool. Q9.During orthogonal machining with an HSS tool, the rake angle was 5 degree, the unreformed chip thickness was 0.25mm and width of cut was 4 mm. Assuming shear strength of work material to be 350 N/mm2 and coefficient of friction to be 0.5,estimate cutting and thrust force. Q10. Following data from the orthogonal cutting test is available rake angle = 10 degree, chip thickness ratio = 0.35, uncut chip thickness=0.51mm, width of cut =3 mm, yield shear stress of work material =285 N/mm2. Coefficient of friction at tool chip interface =0.65. Determine

1. Cutting force 2. Thrust force 3. Normal force on tool chip interface 4. Shear force on tool.

Module 4

Q1. Explain in details a) Crater wear b) Flank wear

Q2.What is the criteria for crater wear and flank wear. Q3. Define tool life and explain the Taylor tool life equation. Q4. Explain the various types of cutting fluids used in metal cutting process. Q5. Explain the cause and mechanism of tool failure. Q6.Explain the effects of cutting speed, feed and depth of cut on tool life. Q7. Following is the data available on cutting speed and tool life.

V=150 m/min T=60 min V=200 m/min T=23 min

Determine the Taylor constant and tool life exponent. Q8.A carbide tool with MS work piece was found to give tool life of 2hrs while cutting at 0.5 m/min. Compute the tool life if the same tool is used at speed of 25% higher than previous one. Also determine the value of cutting speed if the tool is required to have tool life of 3 hrs. Assume Taylor exponent ‘n’ to be 0.27. Q9.In a drilling operation under a given condition, the tool life found to decrease from 20 min to 5 min, due to increase in drilling speed from 200 rpm to 400 rpm. What will be the tool life of that drill under the same condition if the drill speed is 300 rpm? Q10.A generalised Taylor’s tool life equation was obtained for HSS tool.

푉 =C

T . f . d . A 60 min tool life was obtained using the following cutting parameters, V=40m/min, f=0.25 mm, d=2.00 mm. Compute the tool life if cutting speed, feed and depth of cut are increased by 25 % and also if they are increased individually by 25 % where V-cutting speed, f=feed, d=depth of cut.