# Research on the Technologies of the Compressor Remanufacturing Process
## 3 Materials and Methods
### Disassembly  
Disassembly is the process of breaking down a product into structurally complete or functionally independent parts. The remanufacturing disassembly follows certain technical rules and requirements. According to the value of the parts and the connection method, suitable methods and equipment should be used to preserve the core value parts or main components from damage as much as possible [15].  
The structure of the refrigerator compressor is shown in Figure 2. The shell consists of upper and lower parts. They are usually made of 2.5-4.0 mm mild steel, and the movement assembly is sealed inside the shell by welding. The movement assembly consists of a motor and pump body, where the motor rotor and pump body crankshaft are assembled by interference fit, and the other parts are assembled by bolt connection or clearance fit. Therefore, cover disassembly and rotor disassembly are important for compressor disassembly.  
For compressor cover disassembly, the commonly used methods are lathe turning, manual sawing, flame cutting, plasma cutting, cryogenic crushing and profile milling [16]. The profile milling method involves a simple structure, high disassembly efficiency and little damage to parts. It is the most suitable method for compressor remanufacturing cover disassembly. Its basic structure is shown in Figure 3. The cryogenic crushing method is a completely destructive dismantling technique and is inapplicable to remanufacturing dismantling. The manual sawing method is extremely inefficient for dismantling and is only suitable for very small amounts of dismantling. Flame cutting and plasma cutting produce poor section quality, which may damage the internal parts of the compressor. The lathe turning can only be used for round compressor processing.  
Figure 3: Compressor profile of open shell disassembly equipment: (a) tool holders, (b) compressor, (c) clamp, (d) rotary workbench, (e) spring and push rod, and (f) guide rail.  
Figure 2: Structure of refrigerator compressor products: (a) upper shell, (b) weld seam, (c) lower shell, (d) pedestal, (e) cranksae, (f) hook spring, (g) motor stator, and (h) crankshaft.  
The common methods for the rotor disassembly include the heating or pressure dismantling method. The pressure dismantling method is used to remove the crankshaft from the rotor via pressure and a push bar. It involves high efficiency, little damage to the parts and the good reusability of the parts. However, the design of the fixture has demanding requirements. The heating method uses high-frequency heating to expand the rotor bore for separation. Its energy consumption is high, and it is prone to aluminium leakage and the deformation of silicon steel or vortex loss increase phenomenon, which is not conducive to the use of rotor remanufacturing.  
Compressor disassembly removes parts with low value or that are evidently damaged and cannot be remanufactured or processed, such as valves, gaskets, broken shells and seriously worn pistons. Moreover, waste oil and residual refrigerant should be collected. After the disassembly is completed, the disassembled parts should be classified and stored and should undergo antirust and antiscratch treatment.