Saturday, August 3, 2019

Essay --

1. Introduction 1.1 Definition High speed machining (HSM) enables an increase in efficiency, accuracy, productivity and quality of work-pieces as well as a reduction in costs and completion time compared to conventional machining. [1, 2] HSM can trace back to early twenties of 20th century. However, the definitions of HSM are varied and complicated. The first definition is proposed by Carl Salomon in 1931. Salomon’s theory is that the chip-to-tool temperature will begin to decrease at a certain cutting speed which is 5 to10 times higher than conventional machining speed as shown in Figure 1. [1, 3] Figure 1 Salomon's theory Nowadays, one popular definition of HSM is based on the DN ratio, which means the bearing bore diameter (mm) multiplied by the maximum spindle speed (rev/min). For high-speed machining, the typical DN ratio is between 500,000 and 1,000,000. Moreover, HSM generally refers to end milling at high rotational speeds or surface speeds as shown in Figure 2. Figure 2 High Speed Machining HSM means utilizing cutting speed significantly higher than conventional machining speed. Generally, a specific range is used to quantitatively define machining speeds, which is shown as follows. [4] †¢ High speed machining : 600-1,800 m/min, †¢ Very high speed machining: 1,800-18,000 m/min, †¢ Ultra high speed machining : >18,000 m/min. The range of high speed milling is shown in Figure 3. Figure 3 Range of high speed milling There is a comparison between conventional machining and high speed machining shown in the table. Parameters Conventional HSM The tool/workpiece contact time Long Short Accuracy Low High Cutting force High Low Surface finish Low High Material removal rate Low High Cutting fluid Need No need normall... ...lusion Machining processes are fundamental and essential steps in manufacturing engineering. HSM as a modern technology can bring about a dramatic increase in efficiency, accuracy, productivity and quality of work-pieces as well as a reduction in costs and completion time. However, there are some disadvantages of HSM, which require to be overcome to realize scientific and economic benefits in a better way. Therefore, the potential improvement is proposed, such as the multi-purpose coatings as well as the combination with AR to become smart HSM. Additionally, it is of vital importance to hold and balance the tool properly to ensure the best performance. With the potential development in the future, HSM can find more applications in manufacturing engineering, and generate more perfect products in a more safe and effective method and finally contribute to the society.

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