Machining conditions such as cutting fluids exert a crucial function in micro-milling, which removes chips from the cutting area and lubricates the interface between the tool and workpiece. Therefore, it is necessary to identify suitable cutting fluids for processing different materials. In this article, the effects of cutting fluids (dry, flood cooling, minimum quantity lubrication, and jet cold air) on tool wear, surface roughness, and cutting force were studied. The Pugh matrix environmental approach was used to compare different cutting fluids in terms of sustainable production. In addition, a curved thin wall was processed to demonstrate the value of minimum quantity lubrication in industry. The experimental results illustrated that the minimum quantity lubrication can not only effectively reduce tool wear and cutting force but also improve the finished surface quality. According to the sustainability assessment results, minimum quantity lubrication was superior to other cutting fluids in terms of environmental impact and production quality. The curved thin wall size error was only 2.25% under minimum quantity lubrication condition. This indicated minimum quantity lubrication was particularly suitable for micro-milling of H59 brass and 6061 aluminum compared to other cutting fluids.

In the micro-end-milling of surfaces, thin walls, and micro channels, etc, both peripheral and end cutting edges of micro end mills are engaged in cutting. However, the microcutting fundamentals for end cutting edges have not been well studied, even though those for peripheral cutting edges have been studied widely. Key micromilling variable analyses show that the order of significance is the axial depth of cut ( a _p ), feed per tooth ( f _z ), and radial depth of cut ( a _e ). It means that the microcutting mechanisms of the end cutting edge need to be studied and compared with that of the peripheral cutting edge in order to understand micro-end-milling mechanisms more thoroughly. Simulations using the finite element method (FEM) show that the minimum undeformed chip thickness (MUCT) is different for peripheral and end cutting edges, even though the cutting edge radius remains unchanged. The results of those simulations have been experimentally validated. It shows that the MUCT of the end cutting edge is larger than that of the peripheral cutting edge. That means the MUCT is not only the size of a certain proportion of the cutting edge radius, as mentioned in previous studies, but also has a close relationship with the location of the cutting edge. Therefore, a _p could be several times larger than f _z according to the relationship between MUCT and the micromilling parameters. It creates a solid basis for the selection and quantization of micro-end-milling parameters in the fabrication of complicated geometries as thin walls and micro channels.

Machine vision has been studied for measurements of workpiece form deviations due to its ease of automation. However, the measurement accuracy limits its wide implementation in industrial applications. In this study, a method based on machine vision for measurement of straightness, roundness, and cylindricity of a workpiece is presented. A subsumed line search algorithm and an improved particle swarm optimization algorithm are proposed to evaluate the straightness and roundness deviations of the workpiece. Moreover, an image evaluation method of cylindricity deviation by the least-square fitting of the circle’s center coordinates is investigated. An image acquisition system incorporating image correction and sub-pixel edge positioning technology is developed. The performance of the developed system is evaluated against the measurement results of the standard cylindricity measuring instrument. The differences in the measurement of straightness, roundness, and cylindricity are −4.69 μm, 3.87 μm, and 8.51 μm, respectively. The proposed method would provide a viable industrial solution for the measurement of workpiece form deviations.