L 22.1 Factor Affecting the Temperature

L 22.1 Factor Affecting the Temperature

 

Effect of Work Material

·         Higher tensile strength of the material, greater the force is developed in the chip formation. Hence, more energy will be required for chip deformation and consequently more the heat generated followed by a higher cutting temperature.

 

·         The higher the thermal conductivity of the work material, the more heat is dissipated from the source into the chip formed and lower will be the temperature on the tool side.

 

·         When machining harder materials, the area of contact of the chip with the tool surface is smaller. Thus, the intensity of pressure is higher over a smaller area of contact and the area for passage of heat into the tool is also smaller. This raises the temperature on the tool surface over a smaller area with greater concentration.

 

Effect of Cutting Variables

 

·         Pm = Fc . Vc

From the above equation, that more heat will be generated with an increase in cutting speed.

 

·         Cutting force increases with an increase in the feed. Consequently, the amount of heat involved will also increase.

 

·         Work done increases with an increase in the depth,  the amount of heat generated will also increases.

T = K. Vcz . Fx . ay

K = Constant characterizing the cutting condition

Vc = Cutting speed

f = Feed

a = Depth of cut

 

Effect of Tool Geometry

 

·         Rake Angle

o   Reduction in rake angle increases the deformation and work done in chip formation leading to an increase in heat generation.

o   Chip contact area with tool face which improves heat removal into the tool thereby reducing the temperature at its contact surface.

o   A negative rake angle causes greater deformation than a positive angle leading to more heat generation.

 

·         Approach Angle

o   Larger the approach angles the higher will be the cutting temperature.

 

·         Nose Radius

o   The larger the nose radius the greater the deformation and tangential cutting force. More heat will be generated.

 

·         Cutting Fluid

o   Suitable cutting fluid reduces the heat in the matter cutting by reducing the friction.

o   it's also absorbed the heat and carries it away, thereby lowering the temperature.