Belt Grinding Mechanism Analysis And Experimental Study On Marine Propeller Material

In modern large marine equipment, propellers as a core component of ship propulsion system are usually made of copper. The accuracy of propeller have a significant impact on propulsive efficiency, noise and other factors. Propellers are often shape of helicoids and has been the difficulties in the field of machining. Currently, homemade propeller parts are mainly produced by CNC machine or by manual grinding. But due to technical limitations and other reasons, CNC equipments can’t meet the requirements of processing. There are still a considerable number of propellers made by manual, which made the propeller have a bad accuracy retentive and produced in bad environment as well. With the development of abrasive belt grinding technology, the accuracy of CNC belt grinding machine has greatly increased. Belt machining can already grinding most of complex surface parts. In this article, the rule of belt grinding was analyzed. The grinding process of propeller and its precision was studied. The main contents are as follows:The mechanism between the grit and workpiece during grinding process was analyzed. The max thickness of debris and contact zone length were studied. The wear form of the sanding belt was summed up and the principles of replacing a belt was proposed. The geometry characteristics of marine propeller was studied, the model was simplified by means of a section of a cylindrical. Considering the propeller manufacturing process, the impact of posture and belt type on the precision is discussed.Select paddle material as experimental materials, Feeding depth, Workpiece speed, belt speed and belt size were choosen as contributory factors. The tangential and normal force during the grinding were analyzed, the effect of different parameters on grinding force were studied. Belt thickness model was established through experiments, the effect of different parameters on belt thickness were studied. The relationship between factors and workpiece surface roughness was discussed by the Taguchi method. The contribution rate of different factors on surface roughness was calculated using ANOVA.While use a soft touch wheel, belt removal model can be simplified and obtained by experiment. The control method of speed of the workpiece under grinding allowance was discussed. The grinding depth was predicted by removal functions and validated by experiments. It shows that belt removal model can predict the trend of the surface contour. This paper studied the propeller belt grinding factors and the grinding effects under different conditions. It provides considerable theoretical reference value and guiding significance on the determination of machining parameters for grinding of marine propeller.