制冷时候出現弯折状况，缘故为：一般风冷式的标准下，铝卷的每个部位与气体触碰的传热指数均差不多，但由于厚度或样子不一样，各部位的热管散热速率不平衡，铝卷生产厂家导致薄壁部或中空管的热管散热速率比厚壁部慢，导致它在制冷时候出現向中空部位或壁厚偏厚的部位坎坷的状况。
Bending occurs during refrigeration because: under the general air-cooled standard, the heat transfer index of each part of the aluminum coil touching the gas is almost the same, but due to the different thickness or appearance, the heat pipe heat dissipation rate of each part is unbalanced, and the aluminum coil manufacturer causes the heat pipe heat dissipation rate of the thin-wall part or hollow pipe to be slower than that of the thick wall part, As a result, it is bumpy towards the hollow part or the part with thick wall thickness during refrigeration.
弯折缘故及全过程以下：
The bending reason and the whole process are as follows:
1、厚壁一部分温度降低快，先造成收缩力，薄壁一部分或中空管一部分温度降低慢，基本上沒有收缩力;
1. The temperature of part of the thick wall decreases rapidly, resulting in shrinkage force first. The temperature of part of the thin wall or part of the hollow pipe decreases slowly, and there is basically no shrinkage force;

2、厚壁一部分截面较小，造成的收缩力较小，或被光缆牵引机驱动力清除;
2. The section of part of the thick wall is small, resulting in small shrinkage force, or it is removed by the driving force of the optical cable tractor;
3、离去光缆牵引机，温度再次降低;
3. After leaving the optical cable tractor, the temperature decreases again;
4、薄壁一部分或中空管一部分截面很大，伴随着温度降低慢慢造成很大收缩力，厚壁一部分温度已大幅度降低，已不造成收缩力或收缩力较小;
4. A part of the thin wall or a part of the hollow pipe has a large section, which slowly causes a large shrinkage force with the decrease of temperature. The temperature of a part of the thick wall has been greatly reduced, which does not cause shrinkage force or small shrinkage force;
5、铝卷横截面上遭受的收缩力尺寸不匀，沿挤压成型方位往薄壁一部分或中空管一部分弯折。
5. The shrinkage force on the cross section of the aluminum coil is uneven, and it bends to a part of the thin wall or a part of the hollow tube along the extrusion direction.