Machining Of Fiber-reinforced Composites Research Articles

A review on research progress of machining technologies of carbon fiber-reinforced polymer and aramid fiber-reinforced polymer

Since the application of fiber-reinforced polymer continues to expand, the demands of product quality for secondary cutting process are becoming increasingly higher to ensure the accurate coordination, connection, and assembly. There are some defects such as tearing, burr, delamination, and thermal damage after secondary cutting process, which limit the further applications of the materials. It is urgent to carry out comprehensive research on the secondary processing technology. In this paper, the fiber-reinforced composites' category, characteristics, and their applications were first described. Then the cutting performances, the causes of machining defects, and machining mechanisms have been analyzed. Finally, different compound processing methods, their characteristics, and applications have been elaborated. The most common forms of compound processing method including combined machining of cutting and grinding, ultrasonic vibration–assisted machining, and low-temperature–assisted machining have been covered in this paper. Results show that the compound processing method is the most effective way for improving the second processing quality of fiber-reinforced polymer. More machining mechanisms and applications of compound processing method need further experimental research. The barriers and future in the fields of research on machining of fiber-reinforced composites have been analyzed in this paper.

An optical method for measuring surface roughness of machined carbon fibre-reinforced plastic composites

Characterization of the damage induced by machining of fibre-reinforced composites is usually performed by measuring surface roughness. Contact-based surface profilometers are the most used equipment in industry; however, it has been found that there are performance limitations which may result when used to measure machined heterogeneous composite surfaces. In this research, surface roughness is characterised using a commercial non-contact optical method, and compared with a conventional stylus profilometer. Unidirectional and multidirectional carbon fibre laminates were edge trimmed and slot milled. The variation in surface roughness was compared using different tool types, fibre orientations and cutting parameters. Surface damage and cutting mechanisms were assessed by using scanning electron microscope images, and the suitability of roughness parameters were also analysed including: Sa, Skewness and Kurtosis. Using the optical system allowed accurate roughness calculation of individual plies on a multidirectional laminate with different fibre orientations. The research has also shown that the optical system, including the use of areal roughness parameters, can increase the accuracy of roughness measurement for machined fibrous composite surfaces and is less sensitive to measurement position than the stylus.

Hydrodynamic Machining of Fiber-Reinforced Composites

This paper presents the results of an experimental investigation aimed at studying the applicability of waterjet machining to reinforced plastics. Representative samples of plastics over a wide range of matrices and fibers of various thicknesses were chosen. The machined samples were studied under a scanning electron microscope (SEM) for surface characteristics. Some samples were measured for roughness using a stylus profilometer and later non-contact laser holography for confirmation. The SEM study revealed that under conditions of excessive cutting speed, high stand-off distance, low water pressure, small nozzle diameter, which are considered nonoptimum, the surfaces displayed signs of fiber debonding, pull-out, matrix chipping, and delamination. Roughness readings revealed that surface quality improves with larger-diameter nozzles and at low machining speeds.