ASSIGNMENT ON FORCE MEASUREMENT IN GRINDING USING

DYNAMOMETERSUBMITTED BY

ARJUN RAMESH(15002)ARUN KUMAR.G(15003)ILYAS HUSSAIN(15006)

oDynamometers are devices used to measure cutting forces in machining operation.o The Cutting force cannot be detected or quantified directly but their effect can be sensed using Transducer.oa force which can neither be seen nor be gripped but can be detected and also quantified respectively by its effect and the amount of those effects (on some material) like elastic deflection, deformation, pressure, strain etc.

DYNAMOMETER AND HOW ITS USED?

DYNAMOMETER CONSTRUCTIONoA rectangular stainless steel block is roughly made formaximum stock removal and then machined to get thedesired size.oIn making the octagonal rings, two holes are drilled by radial drilling machine followed by boring operation.oA stainless steel block is cut into an octagonal shape.oThe slit between the two horizontal members is made using a slitting saw.oTwo blind holes are made on the dynamometer to fit with the vice by nut bolt system.

FORCES-HOW THEY ACT?oGrinding dynamometers are used to measure radial and feed forces between grinding wheel and the work piece in a plunge surface grinding .oThe essential requirements of dynamometer are its mechanical rigidity and sensitivity.oTwo components of force namely radial and feed are measured with the help of a grinding dynamometer.oFeed forces are due to the cutting action of grinding wheel radial forces are due to the work piece motion.

Working principleThe principle of working may be understood from the

photo elastic pattern of a ring.

Under diametral compressive force stresses on the boundary between F and G are compressive while those between B and C are tensile. Point B and C are strain nodes that is stresses are absent. How ever the ring is fixed at the base and a horizontal force is applied at the top towards the right, it is observed that the points on a horizontal diameter are similarly stressed ; the stresses at B and D are tensile while those at A and C are compressive. Thus by fixing the strain guages at these point s in the adjacent arms of the wheat stone bridge it is possible to nullify the signals having vertical directions. The guages at B and C will not be affected by a vertical diametral load, while those fixed on a horizontal diameter will not be affected by a horizontal force i.e there will not be any cross sensitivity.

Signal conversion

Specification of dynamometer and grinding wheel

The materials used for experimental studies aretungsten carbide and stainless steel. The wheel used is adiamond - impregnated metal-bonded grinding wheel150 mm in diameter, 9 mm in width. The width of thelayer containing diamonds is 3 mm and abrasive gritsize is 80/100. A DC motor (3 Phase, 1.5/2 kW/hp,1400 rpm) was employed to rotate the grinding wheel.The total minimum load has been found to be 183.7N. Maximum value, the total load would be calculated as473.5 N.