creative dental

29

2022

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07

What are the factors affecting the process quality of the mineral water blow molding machine?

The factors that affect the quality of the bottle blowing machine of the mineral water blow molding machine include: preform and its heating, pre-blowing (position, excitation and flow), stretching rod, pressure blowing (pressure and excitation position), and molds, etc.


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The factors that affect the quality of the bottle blowing machine of the mineral water blow molding machine include: preform and its heating, pre-blowing (position, excitation and flow), stretching rod, pressure blowing (pressure and excitation position), and molds, etc.
1. Preform
The preform, also known as the parison, is made of PET pellets by injection molding. It requires that the proportion of recycled materials should not exceed 10%, and the number of recycling should not exceed two times. The preforms after injection molding or preforms used after heating need to be cooled for more than 48 hours, and the storage time of the preforms used should not exceed 6 months. The type of raw materials used in the preform, the proportion of secondary materials mixed in and the residual stress in the preform are different, and these factors have a significant impact on the molding process of the bottle, and should be treated according to the actual situation.
2. Heating
The heating of the preform is completed by the heating furnace, which is manually set and automatically adjusted. The height of the heating furnace is preferably about 25mm, and the distance from the conveying wheel is about 19.6mm. The preform runs continuously through the entire oven on the conveying wheel, so that the preform is heated more evenly.
It is uniform and can be formed well, which overcomes the shortcomings of uneven heating caused by static heating and manual rotation of the preform. However, if the heating furnace is improperly adjusted, it will cause uneven distribution of the wall thickness of the blown bottle (such as light on the top and heavy on the bottom), the bottle mouth becomes larger and exceeds the standard, the hard neck and other product defects, and even the torsion failure of the mechanical parts. The company mainly produces automatic blow molding machines.
The preform heating temperature is generally set at 85-120°C, the colorless preform is higher, and the colored preform is lower. If the temperature is set too high or too low, it will cause product defects, such as tearing, white fog, etc. The temperature of each area can be adjusted according to the molding situation of the product, and the opening of the oven lamp tube should be considered at the same time. In addition, the setting of the output power of the oven also has a great influence on the heating of the preform, which controls the heat output of the whole oven. When it is not turned on for a long time, when it is turned on again, the initial output power should be set higher accordingly, and then gradually reduced to the normal state during the normal production process. The output power is generally about 80%, especially when the ambient temperature is below 5°C , the effect is more pronounced.
The bottle blowing production process also has a definite relationship with the production ambient temperature, and the ambient temperature is generally room temperature (about 22°C). If the temperature is too high, the product is prone to condensation point agglomeration; if the temperature is too low, the product performance is unstable when the machine is started, and the specific operation should be adjusted according to the actual situation and experience.
3. Pre-blowing
The function of pre-blowing in the blowing process is to make the preform take shape, and at the same time, it is stretched longitudinally by the stretching rod to increase its longitudinal strength. The whole process is that the pre-blowing cam pushes the three-way valve to the pre-blowing position during the bottle blowing process, and is completed by the one-way valve. Pre-blow position, excitation and flow can all affect the quality of the bottle. If the pre-blowing position is in advance, the center point of the bottom of the bottle will be skewed and thinned, the wall thickness of the foot is uneven and white, the upper part is heavy and the lower part is light, the neck is hard, and even the bottom penetrates and other defects; Defects such as upper light and lower weight, thickening of the center point, and depression will appear.
Air flow The pre-blowing air flow is controlled by a one-way valve, and it is advisable to open 3-4 turns. The air flow is large, the bottom is heavy, the center point is thin and biased, the feet are white, and the wall thickness is uneven; the air flow is small, the center point is thick, and the weight of the segmented parts exceeds the standard.

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