Investigation into on-line optimization of cutting tool geometry.

Abstract

Metal cutting is an important process used to manufacture components with machined surfaces or holes. Due to the wide usage o f this manufacturing process, research with the aim to optimize the cutting processes is important. Improving cutting techniques even mild)s can result in major cost savings in high volume

production. Better machining practices will result in products of better precision and of greater useful life . Benefits can also be had from increasing the rate of production and producing a bigger variety of .. products with the tools available. The area of metal cutting has been researched widely by people like Tourrett, Taylor, Cohen, Davis and many others to find improved techniques and methods. This project was conducted to improve cutting conditions by ensuring that the tool geometry is always optimal . The effect of tool geometry on cutting performance has been discussed in detail by many researchers, but the practical application of these theories is an area that needs further attention. For this project a device was developed to vary the tool geometry with stepper motors on command from the controller. This device was used for research into the viability of varying tool geometry during machining to obtain different cutting conditions. Stepper motors ensure high accuracy in the control of tool geometries. The ease of controlling stepper motors, also simplified the controlling program and communication devices a lot. Rotating the stepper motors results in rotation o f the tool holder around the tool tip. Tool angles are varied without affecting the other cutting parameters like the depth o f cut, metal removal rate and cutting speed. With these cutting parameters staying the same, the change in tool geometry should result in a change in the power consumed during cutting and the force required for cutting . Other measurements for cutting performance like temperature of the tool and workpiece and the acoustic print of the tool will also change. Results prove that cutting force measurement can be used effectively to measure the optimal cutting conditions . The back rake angles and side rake angles have the biggest influence of all the tool angles on metal cutting . This is demonstrated by a number of researchers [28] as discussed in section 2 . 2. This thesis proves how the on-line changing of tool geometry, ensures the optimal cutting conditions.