"Closing and closing the bottom" refers to the hot spinning forming process in which one end of the cylinder blank is heated to about 1200℃ according to the production process requirements to make it a soft and plastic body. In the process of high speed rotation, one end of the cylinder blank is fused and pressed into the bottom of the cylinder, or it is shaped into the mouth of the cylinder, and finally the blank of the cylinder is formed.

1. The appearance of the bottom of the bottle should be smooth, and folding, steps and grooves are not allowed; The inner surface of the bottom of the bottle should not have visible concave holes, folds, bumps and oxide skin; Cylinder quality traceability from the source, each cylinder is stamped at the bottom of the transplant number, to ensure the traceability of cylinder products.

2. The outer diameter and height of the bottle mouth should meet relevant standards

(such as iso9809-3 /ISO9809-1/GB/T5099.3/TUV/TPED);

3. The cylinder shoulder, the cylinder bottom and the cylinder body must be smooth and smooth, without gouging, folding, steps, tilt head and other defects.

4. If there are defects, grinding is allowed. The grinding area should be smooth, and the actual wall thickness at the cleaning area should not be less than the minimum allowable wall thickness.

5. There shall be no black spots, star cracks or steps at the bottom of the cylinder.

6. The straightness of the cylinder shall not exceed 3‰ of the length of the cylinder.

7. The perpendicularity of the cylinder should not exceed 10‰ of the length of the cylinder.

8. The bottom transplant number of each cylinder must be complete, clear and consistent with the tube's marked transplant number.