11. Wrinkles in the neck (commonly known as 'band rings')
Symptom:
The inner wrinkle is common at 5-8mm below the convex ring, which is in the shape of an obvious ring, and there are obvious creases on the outside by hand.
Factor:
It is related to the too easy stretching of the embryo from the thinner end of the tapered section. In severe cases, the stretching will start from the parallel section below the convex ring. When the preform is stretched, it gradually increases as the stretching rod goes down. It becomes cold, and the material at the second place is very thin, so it cools quickly. Natural wrinkles are created during the blowing process.
Solution:
1. Readjust the position of the hot spot so that it is close to the main body of the preform.
2. Adjust the pre-blowing air intake time to ensure that it is not too late. Check whether the pre-blowing solenoid valve is normal.
3. The mouthpiece is faulty. This is to check that the nozzle cylinder seals, diffusers, springs, solenoid valves, and retaining sleeves run smoothly up and down (these all cause the nozzle to run slowly).
4. The material in the area is very thin. Increase the material thickness in the zone (lower the temperature in the zone or raise the temperature in the zone where the bottle is thicker).
12. Bottleneck accumulation
Symptom:
Bottleneck accumulation is often seen in wavy stripes at 5-8mm below the convex ring, and the convex ring is irregular or oval.
Factor:
When the preform is sent to the mold cavity by the conveying arm, it encounters the cooled mold cavity and cools first or the pre-blowing air is too early when the preform is stretched. form.
Solution:
1. The pre-blowing pressure is too high.
2. The pre-blowing intake time is too early.
3. The temperature of one zone is not enough (increase the heating percentage of one zone or increase the number of lamps).
4. The light stand is too high, adjust the position of the light stand.
5. The temperature in the second area is too high or the temperature in other areas is too high (this requires adjusting the temperature of each area according to the actual weight and thickness of the bottle to reduce the bottleneck material).
13. Off Center
Symptom:
The bottom structure of the bottle is not concentric with the container, and the bottom corner will be whitened in severe cases. The bottom of the bottle has poor stress and is prone to cracks or bursts.
Factor:
This question has to do with two points. Recognizing which point requires looking at the position of the stretch point of the stretch rod. If the position of the stretch point is eccentric to the pour point at the bottom of the preform, it means that the stretch rod is not aligned with the mold. If the position of the stretch point is concentric with the pour point of the preform, it means that the stretch rod, although positioned correctly, has shifted during the blowing process.
Solution:
A. Mechanical reasons
1. The preform and the mold are not aligned.
2. The mouthpiece and the mold are not aligned.
3. The preform and the upper part of the mold are too tight.
4. The stretching rod is bow-shaped.
5. The sliding guide rail or linear bearing of the stretching rod is abnormal.
6. The adjustment of the buffer pad of the stretching rod is not suitable, which makes the stretching drop slower or cannot be completely lowered to the end.
B. Electrical failure
1. The pre-blowing pressure is too high.
2. The pre-blowing intake time is too early
3. The solenoid valve of the stretch rod is dirty, the seal of the control valve is worn or the coil reel is broken.
4. The exhaust of the stretching cylinder is blocked (the muffler is blocked).
5. The control pressure of the stretching cylinder is low (the turning loss of the air path).
14. Pearlescent - whitish bottom corners
Symptom:
Pearlescence can be found anywhere on the bottle, but is most common in the bottom corners of the bottle. A small amount of bluing at the bottom corners of the bottle is normal and indicates that the maximum bidirectional stretch was achieved during the blowing process.
Factor:
Pearlescent is a direct result of stretching beyond the natural stretch limit. In fact, the microstructure of the material is stretched and torn. The material in this area is noticeably thinner.
Solution:
Because the material in this area is thin, it is best to increase the material in this area. If the material in this area is sufficient, consider the reasons:
1. Make sure not to be eccentric.
2. Extend the pre-blowing time and the pre-blowing air intake time. Decrease the pre-blowing pressure.
3. Make sure that the extension gap is correct (2/3 of the bottom thickness of the blown preform). Too much clearance can cause blushing.
4. Ensure that the extension runs flexibly and smoothly (the extension runs slowly up and down, which will cause whitening).
5. The temperature of the preform is small or the overall temperature of the preform is small when it is heated.
15. Whitening (bottle body, bottle shoulder)
Symptom:
Whitening is common in blowing bottles, the most common being the whitening of the bottom corners (this has been mentioned in the previous section). For whitening, we must first be able to distinguish whether it is high temperature whitening or low temperature whitening, and low temperature whitening is foggy and opaque. High temperature whitening is reflected pearly color, transparent.
Factor:
A. Low temperature whitening - increase the temperature of the area or increase the overall heating percentage and preform temperature.
B. High temperature whitening - reduce the temperature in the area or the overall heating percentage and preform temperature.
C. Another situation is that if the bottles of other blowing stations are of good quality, and the bottles of individual blowing stations are whitened, two aspects must be considered.
1. The pre-blowing pressure is small.
2. The mouthpiece leaks. (The mouthpiece is higher or the height of the mold is different on both sides)
In this case, the whitening is generally on the waist of the bottle or the body of the bottle is whitening from top to bottom.
