How to improve the process quality of bottle blowing machine, Zhongsheng Machinery let you first recognize the blowing process quality of the factors affecting the quality of the bottle: preforms and their heating, pre-blowing (position, pressure and flow), stretching rod, high-pressure blowing (pressure, position), as well as molds, and so on, which are briefly introduced below:
1, bottle blank
Bottle blanks, also known as type blanks, is PET granules by injection molding, it requires the proportion of recycled material can not exceed 10%, the number of recycling can not be more than two times. After injection molding of preforms or heated reuse of preforms must be cooled for more than 48h, and the use of preforms can not be stored for more than 6 months, different production dates, especially the interval is too long preforms can not be mixed, the main reason is that the preforms used in raw material type, mixed into the proportion of the secondary material and the preforms within the residual stress caused by the different factors on the bottle blowing molding process have a significant impact on, should be based on the actual situation Specific treatment.
2、Heating
The heating of the preform is completed by the heating furnace, which is set manually and adjusted automatically. The height of the heating furnace is about 25mm, about 19.6mm from the conveyor wheel. Preforms in the conveyor wheel continuous operation through the entire oven, so that the preforms are heated more evenly, can be better molding, to overcome the previous preforms static heating, artificial rotation and uneven heating shortcomings. However, if the heating furnace is not properly adjusted, it will cause uneven distribution of the wall thickness of the blown bottles up and down (e.g. light on the top and heavy on the bottom), the bottle mouth becomes too large and over-sized, hard neck and other product defects, and even cause torsion failures of the mechanical parts. The company mainly produces automatic bottle blowing machine.
Preform heating temperature is generally set at 85-120 ℃, colorless preforms should be higher, colorful preforms should be lower. Temperature setting is too high or too low will cause product defects, such as pulling broken, white mist and so on. The temperature of each area can be specifically adjusted according to the molding of products, while taking into account the oven lamp on the situation. In addition, the oven output power setting also has a great impact on the heating of the bottle blank, which controls the entire oven heat output. When the long term does not start, start again, the initial output power should be set accordingly higher, the normal production process and then gradually reduced to the normal state, the output power is generally about 80% is appropriate, especially when the ambient temperature is below 5 ℃, the effect is more significant.
Blowing production process and production environment temperature also has a certain relationship, the ambient temperature is generally room temperature (22 ℃ or so) is appropriate. If the temperature is too high, the products are prone to agglomeration; temperature is too low, the product performance is not stable when the machine starts, the specific operation should be adjusted according to the actual situation and experience.
3, pre-blowing
The role of pre-blowing in the blowing process is to make the initial shape of the preform, and at the same time by the longitudinal stretching rod to increase its longitudinal strength. The whole process is pre-blowing cam in the bottle blowing process to push the three-way valve to the pre-blowing position, and by the check valve with the completion. The pre-blow position, pressure and flow rate can affect the quality of the bottle.
Position pre-blowing position in advance, there will be the bottom of the bottle center point skewed, thinning, uneven wall thickness at the foot and white, top-heavy bottom light, hard neck, and even the bottom penetration and other defects; pre-blowing position is wrong, there will be top-light bottom-heavy, the center point of the thickening, concave and other defects.
Gas flow pre-blowing gas flow controlled by the check valve, generally open 3-4 turns is appropriate. Air flow is large, the bottom heavy, the center point is thin, bias, foot white, uneven wall thickness; air flow is small, the center point becomes thicker, segmented pieces of heavy overload.
Pressure pre-blowing pressure at 0.8-1MPa is appropriate. When the pressure is high, it may cause the top to be heavy and the bottom to be light, the center point to be skewed, the wall thickness of the foot to be uneven, whitening, etc.; when the pressure is low, it can not be sufficiently stretched, the bottom is heavy and the center point is thick.
Bottle feet, the center point of the molding of the bottle quality has the greatest impact, improperly adjusted often cause bottle burst (under normal experimental conditions), leakage and other fatal defects.
4, stretching rod
Stretching rod is in the pre-blowing at the same time in the pre-blowing gas with the heated preform stretching device, it is in the high-pressure blowing, exhaust before reset. Stretching rod must be able to move up and down vertically and smoothly in the process of bottle blowing, the driving pressure is 0.55-0.8MPa, and the gap with the bottom of the mold is 2.3-2.5mm, that is, the thickness of the preforms 1/3-1/2. The gap is too large, it will result in the bottom of the bottle center point offset; gap is too small, the center of the point of thinning.
5, high pressure blowing
The role of high-pressure blowing is to make the melt fully extended, close to the mold wall, so that the bottle is fully formed, while the lateral stretching, improve its lateral strength. The main factors affecting its position and pressure.
High-pressure blowing pressure is generally 3.7-4MPa, which is determined by its molding characteristics and the nature of the filled beverage (carbon dioxide). There are two positions, namely, the location of high-pressure gas and the location of the exhaust, the time between the two for the molding in the holding pressure time, the length of this period of time on the stability of the bottle capacity has a great impact. Insufficient high-pressure gas, easy to make the bottle improperly molded, the foot blowing insufficient

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