Nine problems that easily occur when making PET plastic blow-molded bottles


The following problems are often encountered when makin […]

The following problems are often encountered when making blow-molded bottles with PET plastic raw materials, so today I will summarize the situations and solutions that are easy to occur in the production process.

Problem 1: The upper part is thick and the lower part is thin. Solution: It is necessary to delay the pre-blowing time or reduce the pre-blowing pressure to reduce the air flow.

Problem 2: There is a situation where the bottom is thick and the top is thin, and the solution: the opposite of the first solution.

Problem 3: There will be wrinkles under the bottleneck. Solution: Pre-blowing is too late or pre-blowing pressure is too low, or the billet is not cooled well.

Problem 4: The bottom is white. Solution: The main cause is that the preform is too cold; at the same time it is too stretched; the pre-blowing time is too early or the pre-blowing pressure is too high.

Problem 5: There is a magnifying glass at the bottom of the bottle and too much material at the bottom of the bottle. Solution: the pre-blowing is too late and the pre-blowing pressure is too low.

Problem 6: There are wrinkles in the bottom of the bottle, and the bottom temperature is too high (the cooling at the gate is not good). Solution: The pre-blowing is too late and the pre-blowing pressure is too low and the flow is too small.

Problem 7: The whole bottle looks turbid and has lower transparency. Solution: insufficient cooling.

Problem 8: Partial whitening: Excessive stretching. Solution: The temperature here is too low, or the pre-blowing is too early, or the stretch rod is encountered.

Question 9: The eccentricity of the PET plastic bottle bottom may be related to the preform temperature, stretching, pre-blowing, and high-pressure blowing. Solution: First, reduce the temperature of the preform; at the same time, speed up the drawing speed; check the gap between the tie rod head and the bottom mold; postpone the pre-blowing and reduce the pre-blowing pressure; postpone the high-pressure blowing; check it after processing Will the preform still appear eccentric?