technical analysis
According to different structures, automobile air-conditioning heat exchangers can be divided into: tube-sheet heat exchangers, tube-belt heat exchangers, parallel flow heat exchangers and stacked heat exchangers. According to various data, the parallel flow multihole aluminum flat tube as high technical content and is difficult to produce. The technical difficulty is mainly reflected in the following aspects:
1. Large extrusion ratio
Parallel flow multihole aluminum flat tube are currently one of the smallest aluminum alloy tubes with a cross-sectional area of about 0.16 cm2. They must be extruded at one time by hot extrusion, and the extrusion ratio should be more than 400 times. This brings the technical difficulties of extrusion ratio, and has very high technical requirements for process control, heating temperature difference, mold inlet, material channel, welding cavity, design of sizing belt, and cooling of the working process. .
2. Ultra-high dimensional accuracy
The dimensional accuracy of parallel flow multihole aluminum flat tube is much higher than conventional hot extrusion products. It is difficult for ordinary aluminum alloy profile manufacturers to meet this standard.
3. Air tightness
The parallel flow multihole aluminum flat tube produced by a casting rod have a length of nearly 500 meters. During the extrusion process, it is necessary to ensure that the production process is absolutely stable and reliable. A slight deviation in one link will cause defects in the product.
4. High quality casting rod requirements
The wall thickness of the parallel flow multihole aluminum flat tube is only 0.16-0.35mm. If the purity and hydrogen content of the casting rod cannot meet the requirements, as long as there are fine pores or impurities, the thin wall of the parallel flow multihole aluminum flat tube will leak.
5. Surface treatment requirements
Due to the very precise travel requirements of parallel flow multihole aluminum flat tube, the requirements for the bonding interface of the zinc sprayed layer on the surface are very high, resulting in only a few companies' zinc spraying equipment can be used for flat tube zinc spraying operations.
6 Product quality requirements
Due to the difficulty of production, high technical requirements, and strict precision requirements, it is inevitable that a small number of defects and defects will appear in the production line of flat tubes. To ensure the quality of the products, online inspection has become an important factor for controlling the quality of products. How to find defects on the production line, and detect defective products in time, plays a crucial role in the normal operation of the parallel flow aluminum flat tube production process.
