Question: In an orthogonal cutting operation, the tool has a rake angle of 10°. The chip thickness before the cut is 0.5mm and the cut yields a deformed chip thickness of 1.125 mm. Calculate (i) shear plane angle, and (ii) shear strain for the operation. [IAS 2015] Solution: During machining, the excess material is gradually removed in the form of chip by shearing only. Although shearing takes place over a
Question: In a single point turning tool, the side rake angle and orthogonal rake angle are equal. φ is the principal cutting edge angle and its range is 0° ≤φ≤ 90°. The chip flows in the orthogonal plane. Determine the value of φ. [GATE 2008] Answer: Although in majority of the analysis for straight turning, it is assumed that the chip is flowing in orthogonal direction, but actually chip flow
Question: During orthogonal turning operation of a hollow cylindrical pipe, it is found that the thickness of the chip produced is 0.5mm. The feed given to the zero degree rake angle tool is 0.2mm/rev. Calculate the shear strain produced during the operation? [GATE 2014] Solution: Cutting stain indicates the shear strain developed during any conventional machining operation due to the shearing of one thin layer of workpiece material over another
Question: In a machining operation, the chip thickness ratio is 0.3 and the rake angle of the tool is 10°. What is the value of the shear strain? [ESE 2004] Solution: In any conventional machining process when sample material is ductile, material removal takes place due to shearing under the action of compressive force exerted by the cutting tool. The assumed 2-D plane along which shearing takes place is termed
Question: In an orthogonal machining with a tool of 9° orthogonal rake angle, the uncut chip thickness is 0.2mm. The chip thickness fluctuates between 0.25mm and 0.4mm. Determine the ratio between the maximum shear angle to the minimum shear angle in this case. [GATE 2017] Solution: Machining is one subtractive manufacturing process where material is gradually removed from the workpiece by shearing under the presence of compressive force exerted by
Question: Determine the theoretically minimum possible shear strain in orthogonal turning with a cutting tool of zero orthogonal rake angle. [ESE 2009] Solution: Metal cutting processes are employed to remove excess material from workpiece to impart desired shape and finish. This material removal takes place by shearing when a wedge shaped cutting tool compresses a layer of workpiece material. The cutting strain developed due to shearing is termed as shear
Question: A single point cutting tool with 12° orthogonal rake angle is used for orthogonal machining of a ductile material. Calculate the shear plane angle for the theoretically minimum possible shear strain. [GATE 1990] Solution: During machining, a layer of uncut workpiece material gets converted into chips by shearing. Chip thickness also increases substantially compared to the same before cut. The strain that is induced because of increment in dimension
Question: Following data correspond to an orthogonal turning of a 100mm diameter rod on a lathe. The orthogonal rake angle is +15°; the uncut chip thickness is 0.5mm, the nominal chip thickness after the cut 1.25mm. What is the shear angle for this? [GATE 2018] Solution: Shear angle (βo) indicates the direction of shear plane with respect to cutting velocity (Vc) vector. During any conventional machining process, the cutting tool
Question: A single point cutting tool with 12° orthogonal rake angle is used to machine a steel workpiece. The uncut chip thickness is 0.81mm. The chip thickness under orthogonal machining condition is 1.8mm. What is the shear angle? [GATE 2011] Solution: Machining is one subtractive manufacturing process where layers of material is gradually removed from workpiece by shearing in the form of chips. Shearing actually occurs throughout a 3-D region;
In orthogonal machining, cutting velocity (VC) , chip flow velocity (Vf) and shear velocity (VS) are interrelated. These three velocity vectors together form a triangle, which is called velocity triangle in machining. A typical velocity triangle is depicted below. Here length of the sides of the triangle indicates the magnitude of corresponding velocity. The triangle is based on the assumptions of orthogonal machining (chip is flowing in orthogonal direction) and
