In the fast-paced beverage packaging industry, achieving consistent bottle quality while reducing material costs is essential. This has led to the rapid development and adoption of advanced bottle blowing machines, particularly variable pitch blow molding machines. These machines are crucial in forming PET bottles used for carbonated drinks, juices, and cosmetics. Understanding how bottle blowing machines function, their technological evolution, and how to maintain them is vital for any production facility aiming to stay competitive.
1.Bottle blowing machine operating steps
Step 1. Place the preform in the preform container and automatically enter the preform positioning device through the conveyor device.
Step 2. Automatically load the preform mouth upward onto the preform holder, and then send it into the drying tunnel.
Step 3. After heating, the preform is sent to the blowing and drawing platform, and then the mold is clamped, followed by low-pressure blowing, high-pressure blowing, exhaust, and finally mold opening.
Step 4. The finished bottles are removed from the bottle blowing platform by the automatic demoulding system.
2.Development of bottle blowing machine technology
Beverage companies have two urgent needs for bottle blowing equipment. One is that because the price of plastic raw materials continues to rise, beverage companies are always thinking about how to reduce packaging costs to maximize profits, so they need to use advanced blow molding equipment to produce lighter bottles. The second is that due to the rapid changes in the market, beverage production companies must respond flexibly to the increasingly shorter life cycle of beverages. Correspondingly, there are increasingly frequent product updates in PET bottle production, and the time for changing molds needs to be minimized during the production process. These two urgent needs pose a big problem to bottle blowing equipment suppliers.
Closed Loop technology refers to integrating the process parameters of the online verification into the process control system of the stretch blow molding machine to form a closed production cycle process that combines automatic control and automatic adjustment. Intelligent machine control technology aims to improve the quality assurance system of bottle blowing machines. Through the use of the AgrPETWallplus monitoring system, various data of the preform, such as bottle wall thickness, can be monitored. During operation, data that deviates from the system’s rated value will be immediately identified, and this information will be promptly transmitted to the control system of the preform heating unit of the bottle blowing machine. The control system will quickly reflect and individually control the rated value of each heating lamp tube in the heating furnace. Therefore, even if the data of each bottle is different, the quality of the produced bottles will remain stable and reliable while the initially set process parameters remain unchanged.
3.Maintenance of bottle blowing machine
- No material is added to the feeding position: several conditions need to be checked
Is the hopper out of material? If so: need to add material quickly
No: Please check whether the control contactor of the elevator is in the powered state. If it is in the powered state, quickly check whether the motor is powered and loaded, because this situation is likely to be caused by the bottle preform (embryo) blocking the lifting belt. At this time, the easiest way is to manually help lift.
If the control contactor of the elevator is not in the energized state, please check whether the preform detection electric eye and the reflector are not in the same straight line. - The feed tray is stuck in the feed: This situation is a headache. From experience, if the length of the preform (embryo) is relatively long and the cutting weight is large, then this phenomenon is relatively rare.
- The bottle cannot be removed from the mold after it is blown.
First, you should open the mold and open and close it manually. If it is normal, run it in the dry running state. If it is also normal.
Please check your exhaust time setting. If the exhaust setting is normal and the problem occurs every time when the bottle is blown, then it can be judged to be a problem with the exhaust valve. Please open the exhaust valve and check the condition of its spring and seal (another symptom of this failure is that the exhaust sound is relatively loud or there is a sound of incomplete exhaust).
If you encounter a situation where the mold cannot be opened accidentally due to normal production of many molds, please check whether the clamping pin has a screw that is out of shape. Also, please check whether the clamping force is too strong. If it is too large, it should be readjusted according to the standard. - Bottles always get pinched
Is the position of the robot hand misaligned? - Two manipulators collide
This situation requires manual reset of the manipulator, which is caused by misalignment .
4.Bottle blowing machine operating specifications
Essential knowledge on safe operating specifications for fully automatic bottle blowing machines
(1) Before starting each shift, lubricating oil must be added to all moving parts. (Robot, robot guide rail, opening and closing mold guide rail)
(2) The arm swing can be added once every (3-4) days. The large chain and small chain of the heating machine can be used once a month. Always check whether the main engine reducer and heating machine reducer are short of oil. The main engine bearings can be added once every 3 months.
(3) Before production, check whether the moving parts are firm, whether the screws are loose and fall off, especially where the impact force is strong, and whether the belt transmission part is abnormal.
(4) Check whether the high-pressure air source, low-pressure air source, power supply, and water source are normal.
(5) Check whether each emergency stop switch, safety door switch, and protection device detection switch are normal.
(6) Check whether the embryo feeding and embryo removing parts of the heating head are working properly. If the embryo insertion is not in place, the nut of the embryo pressing device can be adjusted.
(7) Check whether the lamp tube is damaged or broken. Replace in time.
(8) Check whether each pneumatic component is leaking and whether the action is sensitive.
(9) Check whether the triplet is leaking abnormally, whether it is blocked, and whether the water cup is too full.
(10) When the solenoid valve of the fully automatic bottle blowing machine encounters an abnormality, it must be cleaned in time (cleaning once every 3.5 million bottles).
5.How the bottle blowing machine works
Blow molding machines are mainly divided into three categories: extrusion blow molding machines, injection blow molding machines and special structure blow molding machines. The processing technology is mainly divided into two types: one-step method and two-step method. One-step and two-step bottle blowing machine molding processes are mainly used for PET and BOPP hollow container molding. Both have their own characteristics and are widely used. In comparison, the two-step method is more suitable for centralized production of preforms and dispersed blowing of bottles; while the one-step method is more suitable for online production of beverage companies.
The blowing process of the bottle blowing machine mainly has 6 steps:
1) First put the heated plastic embryo into the mold;
2) Use the mold clamping cylinder to tighten the mold;
3) Then use high pressure or mechanical structure to lock the embryo mold;
4) Medium and high pressure pre-blowing, while stretching the cylinder action to expand the embryo mold; 5) High-pressure air blowing, the bottle embryo is shaped according to the mold, and the pressure is maintained for a certain period of time; 6) The high pressure in the formed bottle is released, the cylinder is reset – and the bottle is taken out. Pneumatic equipment is used in many places during the operation of the bottle blowing machine; from discharging – locking – stretching – high-pressure blowing/deflating – bottle removal, this series of actions are all assisted by pneumatic equipment. For example, if the high-pressure blowing and deflating circuit is stretched, the air circuit is divided into two parts, the normal pressure part and the high pressure part.
