Common quality defects in bottle blowing packaging materials and solutions (I)
1、 The bottom molding is not full (concave foot)
Symptoms: The bottom contour of petals is not ideal, especially the bottom corner is sunken. Although the bottom molding is not full, it has little impact on the filling, but it affects the stability of the bottle.
1. It is caused by insufficient high-pressure gas.
2. The temperature in the area where the bottom corner is located is not enough.
3. High pressure blowing time is too short (pre blowing time is too long).
4. The pre blowing air intake is too late.
5. The vent hole of bottom mold is blocked.
1. Check whether the high pressure air intake reaches above 28BAR.
2. Check whether the high-pressure filter on the side of the mold is unblocked.
3. Check the operation of each valve to ensure that the stretching is positioned accurately during pre blowing and high-pressure forming.
4. Check the pre blowing and high-pressure blowing control elements to ensure the correct setting value and smooth internal flow.
5. Ensure that the pre blowing is not too late and the time is not too long. Otherwise, the high-pressure blowing time is too short, and the effective cooling time of the bottle in the mold is not enough.
6. Ensure that the vent hole in the bottom mold is unblocked.
7. Increase the heating percentage of the area where the bottom corner is located or increase the number of lamps to increase the temperature of the area.
8. According to the actual situation of the bottle (bottle partition weight, thickness). Reduce the temperature of the thinner area, so that the material at the bottom corner is distributed to these areas.
2、 Bottle mouth expansion (thread expansion)
Symptom: The thread area expands, and it starts from the bottle mouth to the anti air groove, which is more serious in hot weather. Due to the high temperature, it will occur during bottle blowing, and the explosion sound of high-pressure air leakage can be heard.
1. The temperature of furnace cooling water is too high.
2. The flow of furnace cooling water is insufficient.
3. The position of the furnace cooling plate is incorrect.
4. The stove is poorly ventilated.
5. The height of the furnace lamp holder is not well adjusted.
6. The temperature in Zone 1 is too high.
1. Check the temperature and flow of furnace cooling water.
2. Adjust the position of the cooling plate to protect the threaded area of the bottle mouth. (Make the cooling plate 1.5mm away from the front and back of the bottle embryo, and 2mm higher than the plane of the bottle embryo support ring.
3. It can increase the blowing and exhaust of the furnace and reduce the ambient temperature. Or open the side door of the heating furnace to strengthen the air convection so that the heat dissipation of the heating furnace is good.
4. Lower the heating percentage of one zone or reduce the number of tubes.
5. The design of cooling plate is unreasonable.
3、 Curved neck (crooked neck)
Symptoms: Usually the neck is tilted and bent to one side. The convex ring under the thread of the bottle mouth is deformed and is not perpendicular to the center of the bottle body. This kind of bottle seriously affects filling and capping.
1. It is caused by mechanical reasons.
2. The mold body temperature is too high.
3. The mold body flow is insufficient.
4. The temperature on both sides of the mold body is inconsistent.
5. The material on the bottle neck is too thick.
1. The convex ring is clamped too tightly in the concave of the mold top plate, and the size of the bottle embryo must be fixed when it is still hot, and it needs to have a clearance of 0.25mm.
2. Check the mold body flow (insufficient flow leads to high temperature) and temperature (cooling water temperature or mold temperature machine temperature). The flow on both sides of the mold body is inconsistent, resulting in different temperatures on both sides. If the temperature is different or too high, when the bottle is shaped after being out of the mold, the neck will be skewed due to different shrinkage.
3. The blowing nozzle is not aligned with the mold.
4. If the accumulated material at the neck of the bottle is too thick, increase the temperature of the area (increase the heating percentage of the area or increase the number of tubes).
4、 Blue bottom line (hot bottle)
Symptoms: Pearlescent stripes appear along the cutting line at the bottom. The area with pearlescent stripes on the secondary bottle is thinner than that on the good bottle.
1. The pre blowing pressure is too high.
2. The extension is too slow.
3. The pre blowing air intake is too early.
1. In pre blowing, the bottle is blown up too fast (this is often the fault of the pre blowing solenoid valve, and high-pressure air leaks in during pre blowing).
2. The pre blowing pressure is too high.
3. The control pressure of the extension cylinder is insufficient, the solenoid valve is dirty, the seal ring of the control valve is worn or the coil reel is broken, causing air leakage.
4. There is resistance to the extension mechanical movement (the extension cylinder seal is worn or too dirty, the extension guide rail is improperly installed or the linear bearing is worn).
5. Exhaust of extension cylinder is blocked (exhaust muffler is blocked or air circuit is blocked).
6. Adjust the pre blowing inlet angle.
5、 Broken bottom
Symptoms: There is often a small section of tiny cracks at the place where the bottom accumulated material is too thick, and it always passes through or is close to the pouring point.
1. Mechanical causes.
2. The temperature at the bottom of the bottle embryo is not enough (especially the bottle shape with flat bottom of the mold).
1. Check the gap between the stretching rod and the die bottom (the gap is: 2/3 of the bottom thickness of the bottle embryo used)
2. Check the extension buffer.
3. Increase the heating percentage of the area where the bottom is located, and increase the number of tubes in the area where the bottom is located (the temperature at the bottom of the bottle embryo is low, when stretching, the stretching rod runs against it toward the bottom, and cracks will form at the bottom. However, the temperature at the bottom cannot be too high, and if it is too high, the bottom will bulge).