Detailed list of CNC machining processes for marine propellers

The structure of marine propeller is relatively complicated. The difficulty of CNC machining lies in the processing of complex curved surfaces, including blade surface, blade back, blade root fillet and hub surface.

The blanks of marine propellers are generally machined castings with large machining allowances. The CNC machining technology of marine propeller mainly includes the following aspects:

(1) Processing of propeller hub

The parts processed by the hub are mainly two end faces. Since the end face of the hub is used as a positioning reference, the end face of the hub needs to be finished to meet the accuracy requirements. This finishing method is relatively simple and can be done with a common three-axis CNC machine tool.

(2) Blade processing

The main part of blade processing is the surface of the blade and the back of the blade. The surface is a free-form surface. It is difficult to process with three-axis CNC machine tools. A multi-axis CNC machine tool is required. Because the distance between the blades is relatively narrow, the cutter and the blade are prone to appear. For interference and collision, it is necessary to obtain a tool-free trajectory without collision interference through numerical control machining simulation. The surface of the blade is usually processed with a spherical end mill, but the processing efficiency is relatively low, and the use of an end mill can improve the processing efficiency.

(3) Leaf root processing

The blade root is the connecting part between the blade and the propeller hub. For large marine propellers, it is difficult to use the blade blades to machine the blade roots. The root of the blade is usually round, and a bulbous cutter is used to process the fillet.

(4) Leading and random processing

The shape of the front and rear sides of a marine propeller is determined by the surface of the blade. There are two main forms: curved and straight. Generally, a cylindrical milling cutter or a ball-end milling cutter is used to process the contour of the propeller along the contour of the propeller.