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Objective In engineering, the edge trimming method is often used to solve the problem of ship-machine-propeller mismatch caused by excessive load. In order to explore the effects of edge trimming on the vibration characteristics of the propeller, this paper studies the vibration of a propeller with edge trimming based on parametric modeling. MethodsDTMB4381, DTMB4382 and DTMB4383 propellers are selected as research examples, then Matlab programming technology and the ANSYS secondary development program are combined to obtain the influence laws of different unilateral edge trimming on the vibration characteristics of the propeller, and the different reasons behind the corresponding influence laws are analyzed. ResultsFor the DTMB4381 propeller without skew, the natural frequency increases slightly with the increase of the edge trimming amount, but the mode shape does not change much. For the DTMB4382 and DTMB4383 propellers with skew, with the increase of the edge trimming amount, the change law of the natural frequency remains basically the same as that of the DTMB4381 propeller without skew. ConclusionsSkew does not change the vibration characteristics of a propeller under different unilateral trimming amounts; with the increase of the trimming amount, the natural frequency change rate of the two types of propeller shapes after chamfering will be significantly improved, and the increase is more pronounced at higher levels. The corresponding secondary development program can help the relevant personnel to select the optimal trimming scheme from the perspective of vibration characteristics in practical engineering, providing a theoretical basis and guidance for the design and improvement of trimming schemes.

Cutting force plays an important role in the analysis of machining dynamics. In trimming of thin-walled structures, the stick-out length of the workpiece is very large when compared with the traditional milling process, which may result in a large vibration velocity along the tool axis. Since the amplitude of the vibration velocity of the workpiece is comparable to that of the tool velocity caused by the rotary motion of the spindle, it affects the relative velocity between the tool and the workpiece, making the trimming process an oblique cutting process with a time-varying inclination angle, instead of a constant value β , the helix angle of the tool. To this end, we developed a dynamic cutting force model to investigate this effect, and compared simulated and dynamometer-measured cutting forces to validate the established model. The results show that the vibration velocity of the workpiece in the trimming process has a modulating effect on cutting forces, which can significantly reduce the amplitude of the cutting force along the tool axis. [ABSTRACT FROM AUTHOR]

Carbon fiber-reinforced plastics (CFRP) composites are difficult-to-machine materials due to extensive tool wear. This article investigates the impact of carbon fiber types on tool wear in edge-trimming CFRPs, each with the ply angle of 0 deg, 45 deg, 90 deg, or 135 deg, using uncoated tungsten carbide endmills at the high spindle speed of 6000 rpm and the constant feed of 0.0508 mm/rev. Three distinct types of carbon fiber tows, including T300 as standard modulus (SM), IM-7 as intermediate modulus (IM), and K13312 as high modulus (HM), have been vacuum infused into CFRP laminates and edge trimmed to investigate wear characteristics. Three wear criteria measured are flank wear, edge rounding radii, and worn area. The results show that tool wear is influenced by carbon fiber properties, such as fiber tensile strength, tensile modulus, and fiber microstructure. Overall, IM carbon fibers with the highest tensile strength produced the most extensive tool wear due to the abrasive carbon fibers. Of four fiber directions, the largest tool wear was obtained from the 45 deg angle, while the lowest tool wear occurred in the 0 deg angle. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced polymer (CFRP) composites are widely used in the aerospace field because of their outstanding lightweight material characteristics, tensile strength, and stiffness properties. The tools used in composite machining exhibits different cutting performance and machining quality under different cutting conditions. The combination of tool material, tool geometry, and cutting conditions strongly influence the tool life and surface quality of the machined parts. Edge trimming of CFRP blanks with tungsten carbide two flute end mill cutter was conducted. The operation was carried out on a computer numerical control (CNC) router by varying cutting speed, feed speed, and depth of cut. Experimental results indicated that the wear of carbide tools is characterized by abrasive wear and rounding of the cutting edge. This occurred mainly by hard abrasion of the carbide grains. Tool life was observed to be inversely proportional to cutting speed, feed speed, and depth of cut. An expanded tool wear equation with power, average temperature, and resultant force as independent variables provided higher tool wear predictive capabilities. To check the adequacy of the regression model, validation runs were conducted. The experimental tool wear obtained from validation experiments were compared with the tool wear obtained using regression. An approximate average error of 5 % confirms that the experimental and regression tool wear values are very close. The equations and analysis permit trimming of CFRP to be designed such that tool wear is optimized and well forecasted. [ABSTRACT FROM AUTHOR]