How to Solve Common Problems in PET Stretch Blowing Machine

PET stretch blowing machine common problems solutions see as below:

No.	Forming situation	Reason	Solution
1	Roll up or buildup at the bottom or neck of bottle	Delay minor blowing time too long	Shorten the delay minor blowing time
1	Roll up or buildup at the bottom or neck of bottle	Temperature too low at the place where buildup	Raise the heating temperature at corresponding place in tube blank
2	Deformation at bottleneck	Blank head overheat	Check cooling water circulating
		Temperature of 1^st segment heating lamp too high	Reduce the voltage of 1^st segment heating lamp
		Air circulation not equal in heating case	Check the ventilator fan in heating case.
3	Bottom of the bottle too thick	Preheat of bottle bottom not finished	Raise temperature of heating case
		Blowing too late	Blowing in advance
		Advance blowing pressure too low	Increase advance blowing pressure
4	bottle bottom broken	Humidity not enough, permeation not enough	Increase humidity
		Delay stretching time too long	Shorten delay stretching time
		Extension ratio too large	Reduce extension ratio
		Bottom of tube blank too thin	Improve bottom design of tube blank
5	Buckling in bottle bottom	Temperature of bottom too high (poor cooling in sprue)	Reduce the temperature of bottle bottom properly
		Advance blowing too late	Advance blowing 0.1～0.2s ahead
		Blowing time too short	Longer blowing time 0.1～0.2s for 1 to 3 times
		Advance blowing pressure too low	Increase advance blowing pressure
6	Bottle bottom not full	Temperature of bottle bottom too low	Increase the temperature of bottom of heating area
		No enough air release hole or not equal at the bottle bottom of mold	Add air release hole and make them distribute equally.
		Design of stretching rod head not corresponding with the shape of bottom of tube blank	Replace stretching rod head
		Blowing pressure not enough	Increase blowing pressure
		rate of flow not enough at blowing valve	Wash blowing valve by gasoline
		Blowing time too short	Increase blowing time
7	Decentration on bottle bottom	Related to bottle blank temperature, advance blowing, high pressure blowing etc.	Reduce temperature of bottle blank; faster stretching speed; check the gap between stretching head and bottom mold; delay advance blowing, and reduce advance blowing pressure; delay high pressure blowing; check whether bottle blank decentration
		Stretching too short	Make sure the stretching rod leave bottle bottom for 0.1mm
		Delay minor blowing time too short	Increase delay minor blowing time
8	Bottom become white	Temperature too high	Reduce temperature
		Bottle blank too cold	Raise the temperature of bottle blank
		The weight of bottle blank is too light	Add weight of tube blank
		Stretching rod shifted from the centre line of bottle	Adjusting the position of stretching rod
		Advance blowing too late, advance blowing pressure too low	Increase advance blowing pressure
		Stretching rod didn’t reach the bottom	Adjusting the position of magnet ring switch
		Temperature too high	Reduce temperature
		Thickness of tube blank is not equal	Improve the quality of tube blank
		Injection density is not equal	Improve the heating
		Heating not equal	Check whether the rotation of tube blank has problem
9	Bottle bottom too thin	Blowing too earlier	Delay blowing time
		Temperature of bottom is too high	Reduce temperature of bottom
		Bottom of tube blank is too thin	Increase the thickness of bottom of tube blank
10	Bottle sticked on the base mold	The time of mold closing and base mold raising is not synchro	Faster the raising time for base mold
10	Bottle sticked on the base mold	Plastic blowing time is too short	Longer the plastic blowing time
11	Buckling at the middle of bottle	Blowing time is too short	Longer blowing time 0.1～0.2s for 1 to 3 times
11	Buckling at the middle of bottle	Temperature of middle of bottle is too low	Increase the temperature of middle of bottle properly
12	Crack at the middle of bottle just after blowing	Whole temperature of tube blank is too low	Increase the temperature of whole oven tunnel, increase properly the voltage of infrared lamp from 1^st segment to 7^th segment
		Delay minor blowing time is too long	Shorten delay minor blowing time
		Temperature difference of every part of bottle blank is too large	Heating equably
13	Bottle blank sticked on the stretching rod	No minor blowing or high pressure air source	Adjust minor blowing and high pressure air source
13	Bottle blank sticked on the stretching rod	Blowing valve not working	Check whether blowing valve connected power, whether industry blowing valve opened
14	Bottle blank stretched longer, but not expanded	No high pressure air source	Open high pressure air source
14	Bottle blank stretched longer, but not expanded	Blowing time is too short	Longer blowing time
15	Upper part of bottle is too thick	Temperature of upper part is too low	Increase temperature at upper part
		the position of air release hole of mold is far from upper part	Adjusting the position of air release hole
		Extension ratio is too low	Increase extension ratio
		Blowing ratio of upper part of bottle is too low	Change the shape of bottle
		The speed of stretching rod is too slow	Adjusting the speed of stretching rod
16	Obvious mold closing line	The pressure for mold closing is not enough	Increase the mold closing pressure, adjust the angle of support rod for mold closing (<5̊)
16	Obvious mold closing line	Sealing is too earlier	Move backward the position of position switch of mold closing
17	Mold closing line with different size	Mold closing is too loosing	Lock tightly the mold base
18	Whole bottle turbid and not transparent	Whole temperature of bottle blank is not enough	Increase whole temperature
19	The transparent of bottle is not good	Heating temperature is too high	Reduce the temperature
		Heating time is too long	Shorten the heating time
		moisture in the compressed air	Removing moisture by dryer
		The tube blank is not transparent itself	Improve the quality of tube blank, select to use material and improve the dryness of material
		Tube blank design not proper	Improve the size design of tube blank
		The blowing ratio is too small	Reduce the diameter of tube blank
20	pearly luster and whiten on the bottle	Heating temperature is too low	Raise temperature or slower the rotation speed
		The thickness of tube blank is unequal	Improve the quality of tube blank
		The thickness of tube blank is too thick, heating permeation not enough	Reduce the thickness of tube blank, or try to raise the cover of heating equipment, so as to increase the temperature distribution on the surface of tube blank
21	There is prints on the bottle	The quality of tube blank is not good	Check the quality of tube blank
21	There is prints on the bottle	Mold not clean	Cleaning the mold
22	Deformation just after leaving mold	Blowing time too short	Increase the blowing time
22	Deformation just after leaving mold	The temperature of cooling water is too high	Reduce the temperature of cooling water
23	Thickness distribution unequal at axial direction	Temperature of tube blank is unequal	Adjusting heating temperature
		Advance blowing pressure too low or too high	Increase or reduce advance blowing pressure
		Advance blowing too late or too earlier	Earlier or later advance blowing
24	Deformation after a longtime	Bottle blowing pressure too low	Increase bottle blowing pressure
24	Deformation after a longtime	Bottle blowing too short	Longer the bottle blowing time
25	Bending when heating bottle blank	Rotation wrongly when heating bottle blank	Make sure whether touch or hit aluminium baffle-board, etc.
		Overheat at partial of bottle blank	Adjusting the output of heater
		Pimple on the bottle blank	Check whether the bottle blank is qualified
26	Volume of produced bottle not enough	didn’t blowing to form shape	Check whether there is jam at the outlet
		Air pressure not enough for plastic blowing	Check the air circuit and supply source for plastic blowing

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