Measurement in Machining and Tribology

This chapter reveals the modern objective of metal cutting processes as increased productivity of multiple machining operations. It is discussed that the only feasible option to increase productivity is increasing the cutting speed. The chapter further analyzed the known attempt to increase the cutting speed showing that the cutting temperature is the major constraint in such an endeavor. It is explained the notion of the optimal cutting temperature explaining that its wide acceptance is limited by lack of a physical explanation of its nature. The physical essence of the optimal cutting temperature is revealed. The place where the temperature in metal cutting should be measured is explained. The basic methods of measuring temperatures in metal cutting are discussed. Infrared measuring technology is explained in details including its physical principle, advantages and limitations, and use of very short-wave cameras.

This chapter presents an experimental investigation of the metal cutting tribology with the purpose of re-examining the role of oxygen in the process mechanics and obtaining a better understanding of the friction coefficient in terms of the major process parameters. Specially designed apparatus and tribological tools have been used to cut pure metals and metallic engineering materials under oxygen-rich surrounding medium. Friction coefficient has been evaluated, and the chip–tool interface has been observed in situ using optical microscopy. It has been shown that pressure-welded junctions occur near the point at which chip detaches from cutting tool, and it has been established that there is an intimate relation between the oxide films formation and the oxygen concentration in the surrounding medium. The chip curl, sticking and sliding zones were seen to change with oxygen concentration. It can be asserted that friction plays an important role in the free plastic flow of metal cutting due to the high friction coefficient values ranging from 0.3 to 1, or even higher. However, the main research contribution of this study is the remark of the friction coefficient as a function of the process parameters, rather than a constant numeric value representing complex phenomena at the contact interface between the chip and the cutting tool.

Geometric accuracy belongs to one of the main parameters of the machine tool. It serves not only for the purpose of machine delivery to the customer or for demonstration of proper service intervention but also for assessment of improvements compared to the current state. The information on geometric accuracy of the machine is also used as a feedback to the machine development. Therefore, increasing the geometric accuracy is a feature of the machine that needs to be constantly improved. This chapter presents geometric accuracy tests, instrumentation and examples of selected procedures to increase the geometric accuracy of CNC machine tools.

The demand in manufacturing industries productivity with high product quality is important. Nowadays, NC, CNC, and automated machine shops are playing vital role for higher productivity. Similarly, the quality inspection of the product also needed higher productivity. For the reason, there are lots of inspection methods such as direct and indirect measurement techniques which are used in measurement of products. In that machine vision is one of the newer techniques, which is used to measure the products with the aid of CCD camera and image processing techniques such as image acquisition, denoising with filters, comparison of real image and actual image, mapping of image, and image processing algorithm. In this chapter, the two important measurement techniques were discussed: firstly tool wear measurement and secondly surface finish measurement. Finally, this chapter proposes the machine vision technique that is best suitable to measure the tool wear and surface finish in automated manufacturing industries.

The tribological characteristics of electroless nickel coatings have been in focus since its inception. With the passage of time, electroless nickel coatings have proven to be a promising candidate as tribo-coatings. Electroless nickel coatings have now evolved into a large family of functional coatings due to the flexibility of the process. Depending upon the need and cater into the rising industrial demands, different varieties of electroless nickel coatings have been deposited and evaluated. In fact, simulation of test conditions and test environments as per industrial demands has led to the investigation of the coatings on a variety of test setups. Different tribological measurement techniques employed to evaluate the coatings and the response of the coatings to the same are summarized. The present chapter gives a comprehensive overview of tribological measurements and evaluation methods related to surface roughness and friction/wear characteristics of electroless nickel coatings.