PET bottle blowing machine FAQ

PET bottle blowing machine is a PET (full name: polyethylene terephthalate) material blowing equipment, mainly used for carbonated beverage bottles, mineral water bottles, cosmetic bottles, oil bottles, medicine bottles and other plastic hollow containers blowing Bottle making. At present, the PET bottle blowing machine on the market are mainly divided into two categories. One is the one-step blowing machine, which directly uses PET raw materials for drying, injection molding, temperature adjustment, stretching, and blowing. (Abbreviation: injection stretch blowing) At present, the one-step machine is mainly used in the cosmetics industry. It is compatible with various bottle diameters, thicknesses and shapes. The disadvantage is that it is limited by the injection time, its production efficiency is low, and the machine price expensive. The second type is a two-step blow molding machine. When using a two-step blow molding machine, PET raw materials must be made into preforms before blowing. The bottle production process is completed by preforming, heating, and stretching and blowing. Compared with the one-step blow molding machine, the two-step blow molding machine is not only more efficient and more energy-saving, but its price is more favorable than the one-step blow molding machine.

The two-step blow molding machine is divided into semi-automatic blow molding machine, automatic linear blow molding machine, rotary blow molding machine.

Semi-automatic bottle blowing machine: single-cavity and two-cavity blowing machines are common, and their efficiency is low. Fully automatic linear blowing machine: common models are 2 cavities, 4 cavities, 6 cavities, 8 cavities, 9 cavities, 10 cavities, etc. Most of the linear machines on the market are still flip-in embryo and flip-out bottle, and cannot be directly connected to the air duct. The handover of bottle blowing machine and filling machine requires the help of a bottle unscrambler to complete the handover. The output is generally not too high due to model restrictions, suitable for small and medium-sized enterprises.

Rotary bottle blowing machine: The bottle blowing workstation rotates, and the heating furnace still moves linearly. The internal structure and control mode of the machine are more complicated. Common models have 8 cavities, 10 cavities, and 16 cavities. 20 cavities, 24 cavities, 30 cavities, etc. Suitable for large factories, expensive, complex structure, and higher maintenance costs.

The two-step blow molding machine is divided into semi-automatic blow molding machine, automatic linear blow molding machine, rotary blow molding machine.

Semi-automatic bottle blowing machine: single-cavity and two-cavity blowing machines are common, and their efficiency is low. Fully automatic linear blowing machine: common models are 2 cavities, 4 cavities, 6 cavities, 8 cavities, 9 cavities, 10 cavities, etc. Most of the linear machines on the market are still flip-in embryo and flip-out bottle, and cannot be directly connected to the air duct. The handover of bottle blowing machine and filling machine requires the help of a bottle unscrambler to complete the handover. The output is generally not too high due to model restrictions, suitable for small and medium-sized enterprises.

Rotary bottle blowing machine: The bottle blowing workstation rotates, and the heating furnace still moves linearly. The internal structure and control mode of the machine are more complicated. Common models have 8 cavities, 10 cavities, and 16 cavities. 20 cavities, 24 cavities, 30 cavities, etc. Suitable for large factories, expensive, complex structure, and higher maintenance costs.

Faygo FG series linear blow molding machine combines the advantages of rotary blow molding machine and linear blow molding machine. It uses cam linkage to integrate mold clamping, mold clamping, sealing lowering and bottom mold raising. Driven by a servo electric cylinder, the blowing cycle is greatly shortened, which not only improves production efficiency, but also makes the movement of the entire clamping mechanism softer. The machine runs more stable and efficient. The whole machine adopts a modular design concept, and the part card slot installation does not require position adjustment, which is convenient for customers’ daily maintenance and mold replacement. The entire mold change time is basically about 25 minutes.

Heating method: The embryo feeding and heating method of FG series blow molding machine is the same as that of a rotary blow molding machine. The heating adopts a small pitch arrangement of 38mm to maximize the utilization rate of the heating furnace. So as to achieve a more energy-saving effect. Compared with the traditional linear blow molding machine, heating method, energy saving is about 40%. The inside of the light box is equipped with a bottle cooling system, a heating equalization fan and a residual temperature exhaust system. The constant temperature inside the light box makes the preform heating effect more stable. The heating furnaces of FG4 and FG6 models are heated by 9-layer infrared lamps, and bottles of 200ml~2000ml are compatible. The temperature of the light box can be controlled by adjusting the intensity of the output voltage through the display screen. Each layer of light tubes is individually adjustable, which can achieve more precise temperature control.

Variable pitch and preform take-up and bottle delivery: The heated preform is controlled by a servo motor to move the preform pitch to the blowing pitch through variable pitch control. The gripper for taking the embryo and the bottle is transferred to the mold for blowing. The gripper for taking the embryo and the bottle is a mechanical gripper. The cylinder is not used to control the opening and closing, and the operation is faster and more stable. The variable pitch and embryo fetching and bottle feeding mechanism are all servo controlled, which not only runs fast, but also runs very smoothly. The error per cycle will not exceed 0.01 second. Ensure the perfect transfer of the preform from the heating furnace to the mold.

High-pressure blowing system: FG series blow molding machine only requires the customer to provide 3.0MPa high-pressure gas, the internal pressure of the machine is reduced by a pressure reducing valve, and a precision filter is installed at the air inlet to ensure access The cleanliness of the machine air source. The machine is equipped with 3 stainless steel gas storage tanks to stabilize the pressure, respectively, the main gas tank, the pre-blowing gas tank and the second blowing gas tank to ensure the stability of the blowing pressure. The machine adopts the diaphragm valve of American Parker. This valve not only has a fast response speed, but also has a large flow rate. It can maximize the effect of blowing in the shortest time and greatly save the time of blowing. The high-pressure gas pipeline connection of the whole machine has been strictly measured and calculated to minimize the dead zone of high-pressure blowing, so as to achieve more energy-saving purposes.

Lifting mechanism embryo machine: The preforms are manually poured into the hopper, and the elevator detects whether there is a preform in the embryo falling track through the induction monitoring system, and then starts automatic feeding. During the feeding process, it can be adjusted according to the production speed of the machine. The lifting speed of the hoist is adjusted. If the embryo guide, signal shows that the embryo is full, the lifting machine will automatically stop the embryo. We use a preform recovery device for the unscrambler. If the elevator speed is too fast or there are excess preforms in the unscrambler, it will return to the hopper through the preform recovery device to ensure that the preforms can be safely and orderly Enter the embryo guide.

Bottle-out device: The bottle-out rail of the FG series bottle blowing machine can be directly connected with the air duct of the filling machine, and the bottle-out height is basically the same as that of a conventional filling machine. There is a set of bottle dropping cylinders on the bottle outlet guide. Its function is to detect a broken bottle and it will open to make the broken bottle fall down, so as to ensure that all the qualified bottles enter the air duct. It has another function: To prevent bottle blocking, if the air duct jams the bottle, it will open and close with the blowing rhythm of the machine, so that the blown bottle will fall into the bottling bucket below, and the machine will not stop because of the air duct jam. This makes the machine more automated.

Bottle mouth type: common bottle mouths are 28 (1810 and 1881), 30-25, 29-25, 38.

The 28mm screw thread with 28mm diameter is generally used for water, carbonated beverages, juice, tea, and carbonated beverages.

The outer diameter of the 30-25 mouth bottle thread and the inner diameter of the bottle thread are 30mm/25mm, respectively, and the height of the bottle mouth is 18.5mm, which is generally used for water bottles.

The outer diameter of the 29-25 mouth bottle thread and the inner diameter of the bottle thread are 29.4mm/25mm, and the height of the bottle mouth is about 12.5mm. It is a new lightweight bottle mouth that has appeared in recent years and is generally used for water bottles.

38 mouths are generally used for functional drinks, mixed juices, etc. The size of the bottle mouth varies greatly.

PET is divided into three forms: glass state, high elastic state, and molten state

The glass transition temperature of PET is about 80 degrees, and the crystallization temperature is about 150 degrees. The state between the two is generally called the high elastic state, and the preform can be blown within this temperature range. The blowing temperature of water bottles is generally between 90 and 120 degrees. Hot-filled bottles require a higher temperature, generally between 130 and 145 degrees.

The bottle is molded generally requires two blows to complete. The pre-blowing pressure is generally between 7 and 12 bars, and the pre-blowing and stretching are carried out simultaneously to stretch the preform in both directions to complete the bottle pre-forming effect. The effect of preforming determines the quality of the bottle.

High-pressure blowing is generally 25-40 bar, the higher the pressure, the faster the bottle forming speed. Low pressure will generally cause the bottle to be under-formed and insufficient in volume.

Bottle shaping: water bottles and gas-containing bottles need to be quickly cooled and shaped, so the chiller of the mold should be adjusted as low as possible without condensation. (6~12 degrees). The hot-filled bottle is completely different from the water bottle. It needs to hold pressure and heat setting, and the mold temperature is generally about 140 degrees. The purpose is to partially crystallize the surface of the bottle, and the crystallinity generally reaches about 30%, so that the heat resistance of the bottle will be better.

Axial stretch ratio: 2.4~2.6

Radial stretch ratio: 4~4.5

Total stretch ratio = axial x radial = 8~12 times

Generally, the water bottle is about 16 times, and the hot-filled bottle is about 10 times.

Therefore, the customer’s bottle shape for the customer allows them to provide suitable preforms. If the stretching ratio is not appropriate, the bottle process will be more difficult to adjust, and the process is not stable. It will be more sensitive, and it will change greatly as the ambient temperature changes.

Therefore, the preform is determined by the bottle shape, and the bottle shape must be determined first, and then the preform.