12 common problems and cleaning methods of blow molding machine 1

Update:05 Feb 2021

 

Question 1

PET bottle transparency is not good

The reason:

1. The heating temperature is too high
2. The heating time is too long
3. Compressed air contains water
4. The injection embryo tube itself is opaque
5. The embryo tube planning is not suitable
6. The inflation ratio is too small

Cleaning method:

1. Cool down
2. Shorten the heating time
3. Use a dryer to remove water
4. Improve the quality of embryo tube, select materials and improve the dryness of raw materials
5. Improve embryo tube size planning
6. Reduce the diameter of embryo tube

Question 2

The PET bottle appears pearly and white

The reason:

1. The heating temperature is too low
2. Uneven wall thickness of embryo tube
3. The thickness of embryo tube is too thick and lack of penetration by heating

Cleaning method:

1. Heat up or slow down the revolution speed
2. Improve embryo tube quality
3. Reduce the thickness of the embryo tube, or try to increase the outer cover of the heating device to increase the surface temperature of the embryo tube

Question 3

Orientation deviation of PET bottle bottom nozzle

The reason:

1. It's too early to start blowing
2. The stretch rod is not down to the end
3. The extension rod is offset from the center line of the bottle axis
4. The embryo tube wall thickness is uneven or the injection density is uneven
5. Uneven heating

Cleaning method:

1. Delay the blowing time or add the descending speed of the stretching rod
2. Adjust the position of the magnetic pole switch
3. Adjust the position of the stretch rod
4. Improve embryo tube quality
5. Improve heating conditions, or check if there is any problem with the rotation of the embryo tube

Question 4

Uneven wall thickness of PET bottles

The reason:

1. The orientation of the stretching rod is not in the center of the embryo tube
2. The blowing holes are asymmetrical and the apertures are different
3. The stretching ratio is too low or the expansion ratio is too small
4. The embryo tube does not rotate in the heating furnace
5. Uneven embryo tube wall thickness or uneven injection density

Cleaning method:

1. Adjust the position of the stretch rod
2. Adjust the position and aperture of the blowing hole
3. Increase the stretching ratio or inflation ratio
4. Check the rotation device
5. Improve embryo tube quality

Question 5

The upper part of the bottle is too thick

The reason:

1. The upper temperature is too low
2. The position of the mold vent hole is too far from the upper part
3. The stretching ratio is too low
4. The inflation ratio of the upper part of the bottle is too low
5. The stretching rod speed is too slow

Cleaning method:

1. The upper part is heated
2. Adjust the vent position
3. Increase the stretching ratio
4. Change the shape of the bottle
5. Adjust the stretch rod speed

Question 6

The bottom of the bottle is too thin

The reason:

Cleaning method:

1. Delay the start blowing time
2. Lower the bottom temperature
3. Add the bottom thickness of the embryo tube

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