Common problems of HDPE bottle blow molding

 HDPE bottles are commonly used packaging for capsules, oral liquids, tablets and other medicines. The quality of the bottle is of great significance to the efficacy of the medicine. In the process of blow molding, plastic bottles often encounter some quality problems. If these problems are controlled, the quality of the bottles will be more guaranteed.

HDPE pill bottle

1. Some parts of the HDPE bottle will appear whitish and excessively stretched. This is due to the fact that the central temperature is too low or the pre-blowing is formed too early. This can be solved by controlling the temperature and the timing of the pre-blowing. problem.

2. There are wrinkles in the bottom of the bottle. If the bottom temperature is too high, the pre-blowing is too late, the pre-blowing pressure is too low or the flow rate is too small.

3. The bottom of the bottle is thick and thin at the top. This phenomenon is mostly caused by uneven baking or insufficient temperature at the bottom of the bottle.

4. The eccentricity of the bottom of the plastic bottle is related to the temperature of the plastic preform, stretching, pre-blowing, high-pressure blowing, etc. Reduce the temperature of the plastic preform, accelerate the stretching speed of the plastic bottle, check the gap between the tie rod head and the bottom mold, extend the pre-blowing time, and reduce the pre-blowing pressure. Or postpone high-pressure blowing to check whether the preform is eccentric.

5. High-density polyethylene bottles are also particularly prone to deformation. If the wall thickness difference between the longitudinal wall thickness position and the radial wall thickness position is too large, it is easy to deform. The shrinkage formed by the position of the parting line of blow-molded container products is more serious than that of the adjacent position, which is that the cooling rate of the thicker area is much slower than that of the surrounding area. Different cooling rates cause different shrinkage and deformation. This defect is best dealt with by controlling the longitudinal wall thickness and the radial wall thickness at the same time.

The above are the common problems in the blow molding process of HDPE bottles. According to the specific problems that arise, the corresponding solutions can be selected to ensure the quality of the bottles and better protect the safety of medicines.