Cnc Machining And Manual Machining Of Marine Propellers
|What is the difference and definition between CNC-Machining and manual machining propellers? This article tells you, follow PTJ Shop, a factory focused on precision-machining of ship propeller parts|
1.Machining Of Marine Propellers
- (1) Remove the risers, gates and other excess parts at both ends of the hub, resulting in two reference planes with a smoothness of 5 and a non-parallelism of less than 0.1mm.
- (2) Boring or turning shaft holes in the center of the propeller hub, the smoothness is 25, and the non-verticality does not exceed 0.15mm / M.
- (3) Insert the plating slot along the inside of the shaft hole. The two sides of the key slot should be parallel to the axis of the tapered hole. The contact surface with the key after assembly is not less than 75%.
- (4) The connection between the cone and the keyhole can also be divided into two cases: bonding and seamless bonding. With and without keys, the requirements for the hub and shaft are different. Bonded epoxy bonding requires a mating surface with a length of 30 ~ 70mm at each end of the tapered hole. The others are 0.2 ~ 0.3mm lower for research and fitting. There is no cavity in the cone on the shaft. When epoxy bonding is used, the processing requirements and bonding requirements of keys and keyways can be reduced, reducing the workload of research and development.
- (5) Formula of epoxy adhesive
2.Manual Machining Of Marine Propellers
The contents of manual processing include: blade hub, blade, surface treatment of the hub and scraping of shaft holes, eliminating static imbalance, using wind shovel, grinding wheel and several files.
The steps are: according to the measurement results, draw a processing line, chisel the blade profile in batches, remove excess metal from the blank, and make the propeller have the required finish.
(1) Leaf surface machining
When making a foliar template, generally the entire machining allowance is placed on the back of the leaf. It is believed that the surface of the leaf is facing down, and the casting quality is easy to ensure the smooth surface. In this case, the geometry of the blade surface always deviates. The task of foliar machining is to correct deviations caused during machining castings. During processing, according to the measurement results of the casting, mark several points on each radius section of the blade where the thickness of the metal layer must be removed, and then drill holes at each point just to remove the thickness of the metal layer. The blade surface can be finished by removing the excess metal along the blade radius cut plane to obtain a number of smooth propeller lines. Based on these propeller lines, the excess metal can be removed along the blade radial direction.
(2) Leaf back machining
The blade back is processed with the blade surface as the reference surface. After the blade surface is cnc machined, the blade thickness is re-measured. According to the requirements of the drawing, the thickness of the metal to be removed from the blade back is determined. As with the blade surface processing, the hole is drilled first and the cut surfaces are removed Shape curve, and then remove excess metal radially along the blade.
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