A molding module of a polyester bottle blow molding machine and a blow molding machine thereof

Abstract

The present invention relates to the field of plastic processing technology, specifically to a molding module of a polyester bottle blow molding machine and a blow molding machine thereof, comprising an upper mold, a bottom mold, an upper stretching module, a lower stretching module, and an air supply module, wherein the upper stretching module comprises a cylinder and an upper stretching rod, wherein the cylinder is above the upper mold, the upper stretching rod penetrates the cylinder, and a permanent magnet is provided at the lower end, and the lower stretching module is provided with a lower stretching rod, and a heating wire is provided at the upper end of the lower stretching rod, and the heating wire heats up and is magnetic after being energized; the upper stretching rod exhausts air in the parison and extends downward, and the parison is unfolded to increase the pressure of the closed mold cavity, and after the pressure of the cavity is increased, the gas inside is passed into the lower stretching module, and the lower stretching rod is driven upward by the gas, and does not contact the upper stretching rod due to the magnetic field. The present invention drives the lower stretching module by the high pressure generated on the mold cavity during the parison molding, and reduces the production cost while improving the product yield under the coordinated use of the lower stretching module and the upper stretching module.

Description

Technical Field

[0001] The invention relates to the technical field of plastic processing, in particular to a molding module of a polyester bottle blow molding machine and a blow molding machine thereof. Background Art

[0002] Polyester bottles are made of polyester terephthalate, or PET. As an ideal packaging container, it is highly transparent, pressure-resistant and environmentally friendly, so it is widely used, especially in the packaging of bottled beverages. The production of polyester bottles requires special blow molding equipment.

[0003] PET blow molding machines can be divided into extrusion type and injection type according to the molding method of polyester bottles. In the extrusion type molding, on the one hand, the parison is only stretched radially during the molding process, lacking axial stretching, and its own strength is insufficient; on the other hand, the bottle mouth texture of the polyester bottle is formed by fitting the mold under high pressure, and its own precision is not high, and it is difficult to ensure the seal when connected with the beverage bottle cap. Therefore, the present invention uses the injection type that can avoid the above problems.

[0004] The injection blow molding machine can stretch the parison axially and radially, which can ensure the strength of the formed polyester bottle to a certain extent. However, there are the following problems during the stretching process: Since the air outlet is arranged at the open end of the parison, when blowing inward, the pressure is the largest at the beginning, that is, the center of the parison opening, and then decays along the radial and axial directions. It can be seen that the axial stretching of the parison is much greater than the radial stretching, so the radial stretching will be completed first. After the radial stretching is completed, the parison part will exchange heat with the low-temperature mold after contacting it, so that its own temperature will be reduced. Once it is reduced to the temperature of the hard glass state, when the parison continues to be stretched axially, it will no longer be able to deform significantly. On the one hand, if the axial stretching is too large, it will cause the hard glass part of the parison to break; on the other hand, since the hard glass part of the parison cannot continue to deform, its own stretching ratio is insufficient, which leads to insufficient strength and cannot be used in negative pressure and high pressure environments, such as packaging carbonated beverages. In order to better package various beverages, the existing technology has been upgraded on the basis of injection blow molding, and a stretching device has been added. For example, in patent CN101758615A, a stretching rod is used to axially stretch and blow air inside the parison, thereby accelerating the axial stretching of the parison at the initial stage of blow molding, and preventing the parison from prematurely contacting the inner wall of the mold under radial stretching and entering a hard glass state. Although the existing technology can solve the above problems, it still has shortcomings.

[0005] The temperature of the preform is generally maintained at around 95° during blow molding, while the temperature of the stretching device is at room temperature. When the stretching device is against the bottom of the preform and drives it to stretch downward, the two will exchange heat. The junction between the preform and the stretching device enters the hard glass state first because the heat exchange temperature drops rapidly, and cannot be greatly deformed in the subsequent stretching. On the one hand, the PET material is accumulated here, causing waste, thereby increasing the production cost; on the other hand, the part of the preform that has been vitrified in advance cannot obtain sufficient stretching, and its own strength is insufficient, which makes the quality of the molded polyester bottle poor. After a certain period of stretching, the radial stretching of the preform is close to sufficient, and the gas in the preform will accelerate the axial stretching of the preform. When the stretching speed brought by the gas action is greater than the stretching device, the bottom of the preform will break away from the stretching device, and the subsequent molding of the preform will be completed by the gas action. Due to the uncertainty of the gas action, the preform will be skewed, and the initial contact between the preform and the stretching device will deviate from the center. However, accumulation has occurred here due to the early cooling, which is obviously different from other parts. If it appears in the non-bottom center position of the polyester bottle, it will seriously affect the aesthetics of the polyester bottle, making the polyester bottle a waste and seriously affecting the production yield.

[0006] Therefore, when producing beverage bottles, especially carbonated beverage bottles, the existing polyester bottle blow molding machines cannot avoid the waste of raw materials caused by the accumulation of PET materials on the bottom of the preform, which increases production costs. They cannot also ensure that the preform will not be skewed during the blow molding process, which easily produces waste products and thus affects the production yield.

[0007] Therefore, a forming module of a polyester bottle blow molding machine and a blow molding machine thereof are proposed. Summary of the invention

[0008] The purpose of the present invention is to provide a molding module of a polyester bottle blow molding machine and a blow molding machine thereof, which solves the problem that the use of a stretching device causes fixed-point accumulation of the parison during the molding process, and the stretching device does not stretch the parison sufficiently. The temperature of the accumulation location is raised by heat exchange so that the accumulation location exits the hard glass state, and the magnetic field generated during heat exchange prevents the accumulation location from being compressed to receive sufficient stretching. While improving the quality of the polyester bottle, the originally accumulated material is fully utilized, and the heat exchange process is driven by the high pressure formed on the inner wall of the mold during the parison molding process.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A forming module of a polyester bottle blow molding machine comprises an upper mold, a bottom mold, an upper stretching module, and a lower stretching module. The upper mold comprises a front mold and a rear mold. The front mold, the rear mold, and the bottom mold are respectively provided with a first cavity, a second cavity, and a third cavity. The rear mold is provided with a gas channel, and the gas channel leads from the second cavity to the inside of the bottom mold. The upper stretching module comprises a cylinder and an upper stretching rod. The cylinder is located above the upper mold. The upper stretching rod passes through the cylinder, and a permanent magnet is provided at the lower end of the upper stretching rod. A lower stretching rod is provided inside the lower stretching module, and a heating wire is provided at the upper end of the lower stretching rod. The heating wire has thermal energy and magnetic energy after being energized, and transfers the thermal energy to the upper end of the lower stretching rod.

[0011] The upper stretching rod exhausts air in the preform and extends downward, and the preform expands to increase the pressure of the cavity composed of the first cavity, the second cavity, and the third cavity. After the cavity is pressurized, the internal gas is squeezed along the gas channel through the bottom mold into the lower stretching module, and the lower stretching rod is driven upward by the gas, and the lower stretching rod does not contact the upper stretching rod under the action of the magnetic field of the heating wire and the permanent magnet.

[0012] During the blow molding process, the parison is stretched while squeezing the gas in the mold cavity. The squeezed gas is generally discharged into the outside along the mold's airway. From the perspective of energy circulation, this discharge is a continuous loss. In order to eliminate or reduce this loss, the discharged gas can be utilized through relevant designs, which will produce a beneficial effect on the parison molding.

[0013] Preferably, the gas channel includes a straight channel, an oblique channel, a first light hole, and a second light hole. The two straight channels are symmetrically distributed on both sides of the second cavity. One end of the oblique channel leads to the second cavity, and the other end is connected to the straight channel. The first light hole is opened at the corner of the lower end of the straight channel, and the second light hole is opened on the bottom surface of the rear mold, and the second light hole intersects with one side of the first light hole.

[0014] The inclined arrangement of the oblique channel is to guide the squeezed gas in the mold cavity to enter the straight channel better. The first light hole is arranged at the corner, which not only facilitates the gas in the horizontal section of the straight channel to be discharged into the first light hole, but also avoids the collision of the airflow in the vertical section of the straight channel. The above benefits make the gas discharge efficiency in the cavity higher, so as to drive the upper stretching rod to work faster and more stably, make the heat exchange process smoother, and thus use less PET material to produce higher quality polyester bottles.

[0015] The mold is composed of blocks and will open and close during the working process. Therefore, the connection of the gas passages between the molds cannot be affected by the opening and closing of the molds, nor can it affect the opening and closing of the molds.

[0016] Preferably, the bottom of the rear mold and the upper part of the bottom mold are respectively provided with a positioning pin and a positioning hole. The positioning pin is hollow inside, and the positioning pin is coaxially arranged with the second light hole, and the positioning hole wraps the positioning pin.

[0017] The original function of the positioning pin and the positioning hole is to ensure the accuracy of the combination of the bottom mold and the upper mold. This function is mainly achieved by the close fit of the circumferential surface, and the hollow design of the positioning pin will not affect this. In addition, the positioning pin is coaxially designed with the second light hole to allow the gas in the gas channel to pass into the positioning hole and pass into the shell along the channel below the positioning hole. In addition, in the process of the gas passing from the positioning pin to the positioning hole, the positioning pin and the circumferential surface of the positioning hole are closely matched, so that the gas transmission is more stable, thereby better realizing the heat exchange process and improving the production efficiency.

[0018] By clamping and driving between the upper stretching rod and the lower stretching rod, the parison can have a better molding effect. However, since the lower stretching rod is pushed down by the upper stretching rod, there is a certain force between the two rods. This force will squeeze the parison between the two rods, causing it to be excessively deformed or even damaged.

[0019] Preferably, a gap is formed between the upper stretching rod and the lower stretching rod by magnetic mutual repulsion. The upper stretching rod comprises a permanent magnet, a first rod body, and a first plug, wherein the first rod body is inserted into the cylinder, the first plug is connected to the lower end of the first rod body, and the permanent magnet is inserted into the first plug. The permanent magnet is in the shape of a strip or a column, which is not only convenient for arrangement in the plug, but also its own magnetic field can better interact with the magnetic field generated by the heating wire. In addition, the threaded connection between the first plug and the first rod body makes it more convenient to replace the permanent magnet. The intensity of the magnetic field effect can be adjusted by replacing the permanent magnet to adjust the spacing between the upper stretching rod and the lower stretching rod, so that the parison can accurately fall on the lower stretching rod when it is separated from the upper stretching rod, thereby the center position of the parison bottom surface does not change, thereby ensuring the aesthetics of the polyester bottle.

[0020] The lower stretching rod is driven by the pressure difference between the upper and lower parts of the piston in the shell. The air pressure below is the same as the air pressure in the mold cavity, and the upper gas is squeezed by the piston. As the piston moves upward, the pressure of the upper gas will continue to increase, but the volume of the cavity in the mold is limited, so the pressure increase of the lower gas is limited. When the upper and lower gases balance the piston, the piston will stop moving upward in advance, so that the parison cannot fall accurately on the lower stretching rod.

[0021] Preferably, the lower stretching module comprises a shell, an end cover, a clamp, and a lower stretching rod, wherein the shell is connected to the lower end of the bottom mold, the end cover is connected to the lower end of the shell, the two clamps are symmetrically inserted into the shell, and the lower stretching rod is inserted into the shell. The shell comprises a first vent and a second vent, wherein the first vent is arranged obliquely above the shell, and the upper and lower ends of the first vent are respectively on the inner and outer walls of the shell, and the second vent is below the shell.

[0022] The first vent hole is arranged to connect the housing with the outside world, so that the gas above the piston is close to the outside air pressure, and the gas pressure below the piston can always be greater than that above, thereby pushing the piston to continue to move upward. The inclined arrangement of the vent hole can not only allow the gas to be discharged downward along the outer wall of the housing to avoid interference with the working environment and ensure the safety and continuity of production, but also effectively reduce the blockage of the blank carried by the air when it is inhaled, so as to ensure the smooth upward movement of the piston, and then the upper stretching rod can run to the predetermined position to receive the fallen blank, so that the blank can be formed smoothly.

[0023] After the lower stretching rod moves upward to the specified position, it starts to move downward under the magnetic force of the upper stretching rod. At this time, the parison is still being stretched, and the gas pressure under the piston continues to increase with the pressure in the mold cavity, so a larger thrust is required when the piston moves downward. This increase in thrust will not only increase the output of energy, but also have higher requirements on the strength of the structure, thereby increasing the production cost.

[0024] Preferably, the card member includes a card body, a first stopper, and a second stopper, the card body is inserted into the shell, and the first stopper and the second stopper are respectively arranged at the upper end and the lower end of the card body. The card body, the first stopper, and the second stopper are all arranged as internal hollow structures, the length of the card body is 5 to 10 mm less than the height of the shell, and the lower edge of the second stopper is 3 to 5 mm away from the bottom surface of the card body.

[0025] When the piston moves upward, it will bring the first stopper upward and make the top of the card body contact the lower side of the bottom mold. At this time, because of the height difference of 5 to 10 mm between the shell and the outer shell, the lower end of the shell rises upward, leaking out of the second vent on the outer shell, so that the gas under the piston is discharged from the second vent and poured into the hollow card, so that the card remains floating under the internal and external pressure difference, so that the gas under the piston can be continuously discharged. When the piston moves downward to contact the second stopper, it drives the rod to move downward to cover the second vent again. The lower edge of the second stopper is 3 to 5 mm away from the bottom surface of the card body in order to leave a certain space at the bottom of the outer shell. On the one hand, the gas is fully in contact with the lower end surface of the piston, thereby providing sufficient power to make the piston move upward and ensure the normal operation of the molding module; on the other hand, the wire connected to the heating wire is inside the first stretching rod and fixed on the end cover. The wire will continuously stretch and retract as the piston moves upward and downward. This space can be used for the wire retraction, so that the wire will not be crushed by the piston, so that the heating process can proceed normally.

[0026] When the gas in the mold cavity drives the upper stretching module, the resistance in this process should be minimized to make the drive smoother, so as to ensure that the upper stretching rod can move up to the designated position in time to receive and heat the parison, so that the parison production can proceed normally.

[0027] Preferably, the lower stretching rod comprises a second rod body, a piston, a heating section, a connecting section, and a second top. The second rod body section is inserted into the bottom mold, the piston is connected to the lower end of the second rod body, the heating section is inserted into the upper end of the second rod body, the connecting section is connected to the heating section, and the second top is inserted into the connecting section. The second rod body and the connecting section are both configured as internal hollow structures. On the one hand, their own weight is reduced so that the gas can push the piston upward more quickly and the upper stretching rod can move up to the designated position in time. On the other hand, space is left for the connection wires of the heating wire to be placed. The heating wire will increase the surrounding temperature after working. In order to prevent the heated gas from diffusing downward and downward, causing heat loss and the risk of burning the wires, a solid section is provided inside the heating section to only allow the wires to pass through.

[0028] It can be seen that there are many ways to make the lower stretching rod move downward, for example, a linear cylinder is installed at the lower end of the bottom mold, and the cylinder push rod is controlled by PLC to move the lower stretching rod upward and downward respectively. Compared with this solution, although the above solution is simpler in structure, its cost is higher, and compared with the use of gas in this solution, the above solution not only cannot recycle gas, but also adds the use of cylinders, making the use cost higher.

[0029] Preferably, the heating wire is inserted into the heating section, the heating wire is spiral, and the central axis coincides with the heating section. After the heating section is powered on, it can not only provide heat, but also excite the magnetic field, so that the upper stretching rod pushes the lower stretching rod downward under the mutual repulsion of the magnetic field and the permanent magnet, so that there is a gap between the two rods, protecting the parison in the gap, thereby ensuring the production yield.

[0030] The intensity of the magnetic field excited by the heating wire is limited. In order to ensure that there is a sufficient distance between the upper stretching rod and the lower stretching rod to protect the preform, the intensity of the magnetic field excited by the heating wire should be increased.

[0031] Preferably, a heat-conducting rod is provided inside the second mandrel, and the heat-conducting rod is inserted into the heating wire coil, and the diameter of the heat-conducting rod is 2 / 3 to 3 / 4 of the inner diameter of the heating wire coil. On the one hand, the heat-conducting rod can quickly transfer the heat generated by the heating wire to the second mandrel, so that the second mandrel heats up the parison falling thereon, and the parison exits the hard glass state to continue to be stretched, thereby avoiding the accumulation of PET materials while giving the polyester bottle sufficient strength, thereby reducing costs while improving product quality; on the other hand, after the heat-conducting rod is inserted into the heating wire, the magnetic field intensity excited by the heating wire can be increased, so that there is a sufficient distance between the upper stretching rod and the lower stretching rod, thereby avoiding the squeezing of the parison while allowing the parison to be stretched in a stable state, and ensuring the product yield by ensuring the aesthetics of the polyester bottle. If the diameter of the heat-conducting rod is smaller than 2 / 3 of the inner diameter of the heating wire coil, the gain effect of the heat-conducting rod on the magnetic field strength will be affected; if the diameter of the heat-conducting rod is larger than 3 / 4 of the inner diameter of the heating wire coil, the heat exchange efficiency between the two will be reduced due to the increase in the volume of the heat-conducting rod, thereby affecting the heating of the second head to the preform, causing the PET material to accumulate, reducing the quality of the polyester bottle and being unfavorable for cost savings.

[0032] The blow molding process of polyester bottles is only one part of the entire polyester bottle production process, and this process should be continuous and linked with other processes.

[0033] A blow molding machine includes an air supply module and the molding module of the above-mentioned polyester bottle blow molding machine, wherein the air supply module includes a frame, an air pump, a guide rail, a slider, and a clamp. The frame is placed on a horizontal plane and connected to a cylinder. The air pump and the guide rail are respectively connected to the rear and front sides of the frame. The slider is nested and connected to the guide rail, and the clamp is connected to the slider. The continuous operation of blow molding can be completed by the movement of the slider on the guide rail. For example, while the clamp moves the blow-molded parison to the left and discharges it, the right clamp also moves the cavity to be blown to the left to the molding area. The air pump supplies air to the cylinder, the upper stretch rod, and the clamp respectively.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. In the present invention, by using the lower stretching module, on the one hand, the parison falling off from the upper stretching module can be received and heated, so that the strength and aesthetics of the parison are guaranteed, thereby improving the yield of the polyester bottle; on the other hand, the magnetic field generated by the heating of the lower stretching module and the interval between the lower stretching rod not only avoids the risk of the parison being squeezed and damaged, but also allows the parison to be stretched freely to avoid accumulation, so that the PET material can be fully utilized, thereby saving production costs.

[0036] 2. In the present invention, the lower stretching rod receives the parison that has fallen off and falls with it. The lower stretching rod is pushed down by the upper stretching rod, and the mutual repulsion of the magnetic field of the permanent magnet heating wire makes there always be a distance between the two rods. This distance can not only protect the parison and make the parison fully stretched, but also effectively reduce the absorption of heat on the second rod by the first rod body, thereby reducing the energy used for heating and reducing production costs. Moreover, through the effect of the magnetic field, there is a buffer between the upper stretching rod and the lower stretching rod, making the initial stage of the lower stretching rod's descent smoother, and because there is no contact, the two rods will not be damaged due to frequent collisions, thereby avoiding related maintenance and ensuring the normal production.

[0037] 3. In the present invention, the high pressure generated by the mold during the preform molding process is utilized to recycle the gas that should be discharged to the outside, so that the gas enters and drives the lower stretching module through the gas channel, which not only increases the functionality of the molding module, but also eliminates the risk of leaking gas. At the same time, the use of the clamp inside the lower stretching module and the first vent and the second vent makes the gas pressure below the piston tend to a certain value, and through the connection of the gas channel, the air pressure in the mold cavity also tends to this fixed value. The fixed air pressure can interact with the air pressure inside the cavity to relax the contact between the part of the preform that has completed radial stretching and the inner wall of the mold. On the one hand, the part of the preform that has completed radial stretching can continue to participate in axial stretching to obtain a better stretching effect, thereby improving its own strength and making the product quality higher; on the other hand, the heat exchange rate between the part of the preform that has completed radial stretching and the inner wall of the mold is reduced, so that the temperature of each part of the preform is uniform, and then the stretching is uniform, so as to ensure the overall strength and aesthetics of the polyester bottle and improve the product yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is an isometric structural schematic diagram of the forming module of the present invention;

[0039] Figure 2 It is a schematic diagram of an isometric cross-sectional structure of a molding module of the present invention;

[0040] Figure 3 It is a schematic diagram of the ventilation pipeline structure of the present invention;

[0041] Figure 4 It is a schematic diagram of the structure of the lower stretching module of the present invention;

[0042] Figure 5 It is a schematic diagram of the housing and the card structure of the present invention;

[0043] Figure 6 It is a schematic diagram of the heating section and heating wire structure of the present invention;

[0044] Figure 7 It is a schematic diagram of the overall isometric structure of the present invention;

[0045] Figure 8 It is a flow chart of the blank molding of the present invention.

[0046] In the figure: 1, upper mold; 11, front mold; 111, first cavity; 12, rear mold; 121, second cavity; 122, gas channel; 1221, straight channel; 1222, oblique channel; 1223, first light hole; 1224, second light hole; 123, positioning pin; 2, bottom mold; 21, third cavity; 22, positioning hole; 3, upper stretching module; 31, cylinder; 32, upper stretching rod; 321, permanent magnet; 322, first rod body; 323, first head; 4, lower stretching mold Block; 41, lower stretching rod; 411, heating wire; 412, second rod body; 413, piston; 414, heating section; 415, connecting section; 416, second head; 4161, heat conducting rod; 42, shell; 421, first vent hole; 422, second vent hole; 43, end cover; 44, clamp; 441, clamp body; 442, first stopper; 443, second stopper; 5, air supply module; 51, rack; 52, air pump; 53, guide rail; 54, slider; 55, clamp. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] A molding module of a polyester bottle blow molding machine comprises an upper mold 1, a bottom mold 2, an upper stretching module 3, and a lower stretching module 4. The upper mold 1 comprises a front mold 11 and a rear mold 12. The front mold 11, the rear mold 12, and the bottom mold 2 are respectively provided with a first cavity 111, a second cavity 121, and a third cavity 21. The rear mold 12 is provided with a gas channel 122, and the gas channel 122 leads from the second cavity 121 to the inside of the bottom mold 2. The upper stretching module 3 comprises a cylinder 31 and an upper stretching rod 32. The cylinder 31 is located above the upper mold 1. The upper stretching rod 32 runs through the cylinder 31, and a permanent magnet 321 is provided at the lower end of the upper stretching rod 32. A lower stretching rod 41 is provided inside the lower stretching module 4. A heating wire 411 is provided at the upper end of the lower stretching rod 41. The heating wire 411 has thermal energy and magnetic energy after being energized, and transfers the thermal energy to the upper end of the lower stretching rod 41.

[0049] The upper stretching rod 32 exhausts air in the preform and extends downward. The preform expands to increase the pressure of the cavity composed of the first cavity 111, the second cavity 121, and the third cavity 21. After the cavity is pressurized, the internal gas is squeezed along the gas channel 122 through the bottom mold 2 into the lower stretching module 4, and the lower stretching rod 41 is driven upward by the gas, and the lower stretching rod 41 does not contact the upper stretching rod 32 under the action of the magnetic field of the heating wire 411 and the permanent magnet 321.

[0050] As an embodiment of the present invention, refer to Figure 3 The gas channel 122 includes a straight channel 1221, an oblique channel 1222, a first light hole 1223, and a second light hole 1224. The two straight channels 1221 are symmetrically distributed on both sides of the second cavity 121. One end of the oblique channel 1222 leads to the second cavity 121, and the other end is connected to the straight channel 1221. The first light hole 1223 is opened at the corner of the lower end of the straight channel 1221. The second light hole 1224 is opened on the bottom surface of the rear mold 12, and the second light hole 1224 intersects with one side of the first light hole 1223. The front mold 11, the rear mold 12, and the bottom mold 2 are cast using P20 steel. The straight channel 1221, the oblique channel 1222, and the first light hole 1223 are all cast during casting, and the second light hole 1224 is obtained by drilling.

[0051] As an embodiment of the present invention, refer to Figure 3, a positioning pin 123 and a positioning hole 22 are respectively provided at the bottom of the rear mold 12 and the upper part of the bottom mold 2. The positioning pin 123 is hollow inside, and the positioning pin 123 is coaxially arranged with the second light hole 1224, and the positioning hole 22 wraps the positioning pin 123. The positioning pin 123 is welded to the lower end of the rear mold 12. When welding, the positioning pin 123 and the second light hole 1224 should be aligned as much as possible, and the weld should be continuous, so that the process of gas being discharged from the second light hole 1224 to the bottom mold 2 is sufficiently sealed. The positioning hole 22, the third cavity 21 and the internal channel on the bottom mold 2 are all obtained during casting, so a section of the channel in the bottom mold 2 leads to the side of the bottom mold 2, which is welded and sealed when in use to prevent gas from escaping therefrom.

[0052] As an embodiment of the present invention, refer to Figure 2 The upper stretching rod 32 includes a permanent magnet 321, a first rod body 322, and a first plug 323. The first rod body 322 is inserted into the cylinder 31, the first plug 323 is connected to the lower end of the first rod body 322, and the permanent magnet 321 is inserted into the first plug 323. The permanent magnet 321 is columnar and made of neodymium iron boron material, so as to avoid the permanent magnet losing its magnetism due to the temperature of the blank around 100°C.

[0053] The upper end of the first rod 322 is connected to the air pump 52 through a quick-change joint, an air pipe, and an electromagnetic two-position two-way valve, and the cylinder 31 is connected to the air pump 52 through a quick-change joint, an air pipe, and an electromagnetic two-position three-way valve. In the initial state, the electromagnetic two-position two-way valve blocks the gas in the air pipe, so that the gas cannot enter the first rod 322, and the electromagnetic two-position three-way valve is in the working position one, so that the first rod 322 retracts; during blow molding, the electromagnetic two-position three-way valve first changes to the working position two, so that the first rod 322 begins to extend, and after a certain period of time, the first rod 322 enters the parison, and at this time, the state of the electromagnetic two-position two-way valve is changed to discharge the gas into the first rod 322, and then discharged into the parison by the first rod 322. During installation, the permanent magnet 321 is first connected to the first head 323 by a pin, and the N pole of the permanent magnet 321 is facing downward, and then the first head 323 is inserted into the first rod 322 and tightened by threads.

[0054] As an embodiment of the present invention, refer to Figure 4 and Figure 5The lower stretching module 4 includes a shell 42, an end cover 43, a clamp 44, and a lower stretching rod 41. The shell 42 is connected to the lower end of the bottom mold 2, the end cover 43 is connected to the lower end of the shell 42, the two clamps 44 are symmetrically inserted into the shell 42, and the lower stretching rod 41 is inserted into the shell 42. The shell 42 includes a first vent 421 and a second vent 422. The first vent 421 is arranged obliquely above the shell 42, and the upper and lower ends of the first vent 421 are respectively on the inner wall and the outer wall of the shell 42, and the second vent 422 is below the shell 42. The clamp 44 includes a card body 441, a first stopper 442, and a second stopper 443. The card body 441 is inserted into the shell 42, and the first stopper 442 and the second stopper 443 are respectively arranged at the upper end and the lower end of the card body 441. The card body 441 , the first stopper 442 , and the second stopper 443 are all configured as internal hollow structures. The length of the card body 441 is 5.8 mm less than the height of the shell 42 , and the lowest edge of the second stopper 443 is 3.5 mm away from the bottom surface of the card body 441 .

[0055] The shell 42 and the end cover 43 are made of 3003 aluminum alloy material and are obtained by turning and milling. The clamp 44 is made of 1100 pure aluminum material and is obtained by stretching with a press. During installation, the upper end of the clamp body 441 is first inserted along the clamping groove at the lower end of the shell 42 for a distance, then the upper stretching rod 32 is inserted from the lower end of the shell 42 and the piston 413 is fully inserted into the shell 42, then the clamp body 441 is fully inserted into the shell 42, and then the end cover 43 is connected to the lower end of the shell 42 by bolts, and finally the shell 42 is connected to the lower end of the bottom mold 2 by bolts. When connecting, pay attention to the position of the channel opening at the upper end of the shell 42, so that the two openings are aligned with the openings on the bottom mold 2.

[0056] When in use, the gas in the first cavity 111, the second cavity 121, and the third cavity 21 is discharged into the housing 42 after being pressurized, and gathers under the piston 413, and pushes the piston 413 upward. During the upward movement, the gas above the piston 413 is discharged from the first vent hole 421. When the piston 413 ascends to a certain height, it presses against the first stopper 442 and drives the clamp 44 to move upward, so that the second vent is exposed, and then the gas below the piston 413 is discharged from the second vent hole 422. While being discharged, the gas below the piston 413 also flows into the clamp 44, so that the clamp 44 remains floating. When the lower stretching rod 41 moves downward due to the force of the upper stretching rod 32, the air pressure above the piston 413 decreases and the air pressure below the piston 413 increases, which is more conducive to the floating of the clamping member 44. When the piston 413 descends to a certain height, it supports the second stopper 443 and drives the clamping member 44 to move downward, so that the second vent hole 422 is covered again to stop the discharge of gas below the piston 413.

[0057] As an embodiment of the present invention, refer to Figure 4 and Figure 6 The lower stretching rod 41 includes a heating wire 411, a second rod body 412, a piston 413, a heating section 414, a connecting section 415, and a second head 416. The second rod body 412 is inserted into the bottom mold 2, the piston 413 is connected to the lower end of the second rod body 412, the heating section 414 is inserted into the upper end of the second rod body 412, the connecting section 415 is connected to the heating section 414, and the second head 416 is inserted into the connecting section 415. The second rod body 412 and the connecting section 415 are both configured as internal hollow structures, and the heating section 414 has a solid section inside. The heating wire 411 is inserted into the heating section 414, and the heating wire 411 is spirally shaped, and the central axis coincides with the heating section 414. A heat conducting rod 4161 is provided in the second head 416, and the heat conducting rod 4161 is inserted into the coil of the heating wire 411, and the diameter of the heat conducting rod 4161 is 4 mm.

[0058] The second rod body 412, the connecting section 415, and the second plug 416 are made of 1100 pure aluminum material, the piston 413 is made of NBR material, the heating section 414 is made of bakelite material, and the heating wire 411 is made of iron-chromium-aluminum alloy material. During installation, the heating wire 411 is first inserted into the slot at the upper end of the heating section 414, and then the connecting section 415 is connected to the upper end of the heating section 414 by screws, and then the heating section 414 is screwed to the second rod body 412 by threads, and finally the heat conducting rod 4161 is connected to the second plug 416 by a pin, and the second plug 416 is screwed to the connecting section 415 by threads. When installing the heating wire 411, it is rotated right, and the bottom of the heating wire 411 is connected to the live wire, and the top is connected to the neutral wire. According to Ampere's law, the N pole of the magnetic field excited by the heating wire 411 is at the top, and it is mutually repelled with the N pole of the permanent magnet 321 facing downward.

[0059] A blow molding machine comprises an air supply module 5 and the above-mentioned molding module of the polyester bottle blow molding machine, wherein the air supply module 5 comprises a frame 51, an air pump 52, a guide rail 53, a slide block 54, and a clamping claw 55.

[0060] As an embodiment of the present invention, refer to Figure 7, the frame 51 is placed on a horizontal plane, the cylinder 31 is connected to the front of the frame 51 by bolts, the air pump 52 is connected to the rear of the frame 51 by bolts, the guide rail 53 is connected to the front side of the frame 51 and below the cylinder 31 by bolts, the clamp 55 is first connected to the slider 54 by bolts, and then the slider 54 is inserted from a section of the guide rail 53, and the guide rail 53 is capped after the insertion. The frame 51 is built with aluminum profiles, and the cylinder 31, the upper stretch rod 32, the clamp 55 and the air pump 52 are connected respectively by the above-mentioned electromagnetic two-position three-way valve, electromagnetic two-position two-way valve, air pipe, and quick-change joint. In addition, the driving mode of the front mold 11, the rear mold 12, and the bottom mold 2 is pneumatic, and the driving devices of the three are also connected to the air pump 52.

[0061] Working principle: The upper stretching rod 32 performs double stretching on the parison by exhausting and stretching downward in the parison. The volume of the stretched parison increases, and the gas in the mold is squeezed to the lower stretching module 4. The lower stretching module 4 is driven by the squeezed gas to make the upper stretching rod 32 ascend to the specified position. At the beginning of the upward movement, the heating wire 411 is energized and has magnetism while heating. The lower end of the upper stretching rod 32 has a permanent magnet 321. After the upper stretching rod 32 descends a certain distance, it begins to push the lower stretching rod 41 downward, but because of the mutual repulsion of magnetism, there is always a gap between the two rods. At the same time, the radial stretching of the parison is completed first, and the axial stretching is accelerated under the action of the gas, so that the bottom of the parison is separated from the upper stretching rod 32 and falls on the lower stretching rod 41. When the stroke of the upper stretching rod 32 reaches the maximum, the lower stretching rod 41 is pushed to the bottom, and this state is maintained for a certain time to make the parison completely formed. Afterwards, the upper stretching rod 32 moves upward, the heating wire 411 is powered off, and then the cooling system is started to cool and solidify the preform. Then, the front mold 11, the rear mold 12, and the bottom mold 2 are opened, and the slider 54 moves left to move the molded polyester bottle out while moving the preform to be blown into the molding area.

[0062] Specifically, the air pump 52 supplies air to the air cylinder 31, the upper stretching rod 32 and the clamping claw 55 in the upper stretching module 3, and the electromagnetic two-position three-way valve connected to the air cylinder 31 changes state first, so that the upper stretching rod 32 extends downward, and when the lower stretching rod 41 extends into the parison, the electromagnetic two-position two-way valve connected to the upper stretching rod 32 changes state to allow the gas in the air pump 52 to enter the upper stretching rod 32. In this way, the upper stretching rod 32 continues to exhaust gas while extending downward in the parison.

[0063] At the same time as the above process, the parison is continuously stretched, so that the gas in the first cavity 111, the second cavity 121, and the third cavity 21 are continuously squeezed, and then these gases pass into the interior of the shell 42 through the gas channel 122, and gather under the piston 413 to push the piston 413 upward. During the upward movement of the piston 413, the gas above is squeezed out from the first exhaust hole. When the piston 413 moves up to a certain position, it contacts the first stopper 442, and then drives the clamp 44 to continue to move up 5.8 mm, so that the second exhaust hole leaks.

[0064] At the beginning of the above process, the heating wire 411 is energized.

[0065] The lower stretching rod 41 first moves up to the designated position, and when the first plug 323 moves down to a certain distance from the second plug 416, the magnetic mutual repulsion between the permanent magnet 321 and the heat-conducting rod 4161 pushes the lower stretching rod 41 to move down and keep a distance from it. At this time, the gas below the piston 413 is not only discharged from the second vent 422, but also flows into the interior of the card 44, so that the card 44 remains in a floating state due to the internal and external pressure difference, thereby keeping the second vent 422 leaking. The piston 413 moves down to a certain position and contacts the second stopper 443, and then drives the card 44 to move down 5.8 mm, covering the second exhaust hole again, so that the gas below the piston 413 stops being discharged.

[0066] Keep this state for a certain time to complete the blow molding of the parison. Afterwards, the state of the electromagnetic two-position three-way valve is changed to make the upper stretch rod 32 ascend, and when the first head 323 stretches out the parison, the state of the electromagnetic two-position two-way valve is changed to cut off the air supply to the upper stretch rod 32.

[0067] After the upper stretching rod 32 begins to retract, the power supply to the heating wire 411 is stopped, and the cooling system is started to cool and solidify the parison. After that, the bottom mold 2 is first driven downward to separate from the upper mold 1, and then the front mold 11 is separated from the rear mold 12, and then the slider 54 is moved to the left to move the molded polyester bottle out while moving the parison to be blown into the molding area.

[0068] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A molding module for a polyester bottle blow molding machine, comprising an upper mold (1), a bottom mold (2), and an upper stretching module (3), characterized in that: The upper mold (1) further comprises a lower stretching module (4), wherein the upper mold (1) comprises a front mold (11) and a rear mold (12), wherein the front mold (11), the rear mold (12) and the bottom mold (2) are respectively provided with a first cavity (111), a second cavity (121) and a third cavity (21), wherein the rear mold (12) is provided with a gas passage (122), wherein the gas passage (122) leads from the second cavity (121) to the inside of the bottom mold (2), and wherein the upper stretching module (3) comprises a cylinder ( 31), an upper stretching rod (32), the cylinder (31) being located above the upper die (1), the upper stretching rod (32) penetrating the cylinder (31), and a permanent magnet (321) being provided at the lower end of the upper stretching rod (32), a lower stretching rod (41) being provided inside the lower stretching module (4), and a heating wire (411) being provided at the upper end of the lower stretching rod (41), the heating wire (411) having thermal energy and magnetic energy when energized, and transferring the thermal energy to the upper end of the lower stretching rod (41); The lower stretching rod (41) further comprises a second rod body (412), a piston (413), a heating section (414), a connecting section (415), and a second plug (416); the second rod body (412) is inserted into the bottom mold (2); the piston (413) is connected to the lower end of the second rod body (412); the heating section (414) is inserted into the upper end of the second rod body (412); the connecting section (415) is connected to the heating section (414); and the second plug (416) is inserted into the connecting section (415); The second rod body (412) and the connecting section (415) are both configured as internal hollow structures, and a solid section is provided inside the heating section (414); The upper stretching rod (32) exhausts air in the preform and extends downward, and the preform expands to increase the pressure of the cavity formed by the first cavity (111), the second cavity (121), and the third cavity (21). After the cavity is pressurized, the internal gas is squeezed along the gas channel (122) through the bottom mold (2) into the lower stretching module (4), and the lower stretching rod (41) is driven upward by the gas. Under the action of the magnetic field of the heating wire (411) and the permanent magnet (321), the lower stretching rod (41) does not contact the upper stretching rod (32).

2. A molding module for a polyester bottle blow molding machine according to claim 1, characterized in that: The gas channel (122) comprises a straight channel (1221), an oblique channel (1222), a first light hole (1223), and a second light hole (1224); the two straight channels (1221) are symmetrically distributed on both sides of the second cavity (121); one end of the oblique channel (1222) leads into the second cavity (121), and the other end is connected to the straight channel (1221); the first light hole (1223) is provided at the lower end of the straight channel (1221); the second light hole (1224) is provided on the bottom surface of the rear mold (12), and the second light hole (1224) intersects with one side of the first light hole (1223).

3. A molding module for a polyester bottle blow molding machine according to claim 2, characterized in that: A positioning pin (123) and a positioning hole (22) are respectively provided at the bottom of the rear mold (12) and the upper part of the bottom mold (2); the interior of the positioning pin (123) is hollow, and the positioning pin (123) and the second light hole (1224) are coaxially arranged; the positioning hole (22) wraps around the positioning pin (123).

4. The molding module of a polyester bottle blow molding machine according to claim 1, characterized in that: The upper stretching rod (32) further comprises a first rod body (322) and a first plug (323); the first rod body (322) is inserted into the cylinder (31); the first plug (323) is connected to the lower end of the first rod body (322); and the permanent magnet (321) is inserted into the first plug (323); The permanent magnet (321) is in the shape of a long strip or a column.

5. The molding module of a polyester bottle blow molding machine according to claim 1, characterized in that: The lower stretching module (4) further comprises a shell (42), an end cover (43), and a clamp (44); the shell (42) is connected to the lower end of the bottom mold (2); the end cover (43) is connected to the lower end of the shell (42); and the two clamps (44) are symmetrically inserted into the shell (42); The housing (42) comprises a first vent hole (421) and a second vent hole (422); the first vent hole (421) is arranged obliquely above the housing (42), and the second vent hole (422) is arranged below the housing (42).

6. A molding module for a polyester bottle blow molding machine according to claim 5, characterized in that: The card member (44) comprises a card body (441), a first stopper (442), and a second stopper (443); the card body (441) is inserted into the housing (42); the first stopper (442) and the second stopper (443) are respectively arranged at the upper end and the lower end of the card body (441); The card body (441), the first stopper (442) and the second stopper (443) are all configured as internal hollow structures.

7. The molding module of a polyester bottle blow molding machine according to claim 1, characterized in that: The heating wire (411) is inserted into the heating section (414); the heating wire (411) is in a spiral shape, and the central axis of the heating wire (411) coincides with the heating section (414).

8. The molding module of a polyester bottle blow molding machine according to claim 1, characterized in that: A heat conducting rod (4161) is provided inside the second top head (416), and the heat conducting rod (4161) is inserted into the coil of the heating wire (411), and the diameter of the heat conducting rod (4161) is 2 / 3 to 3 / 4 of the inner diameter of the coil of the heating wire (411).

9. A blow molding machine, characterized in that: The invention comprises an air supply module (5) and a molding module of a polyester bottle blow molding machine according to any one of claims 1 to 8, wherein the air supply module (5) comprises a frame (51), an air pump (52), a guide rail (53), a slider (54), and a clamp (55); the frame (51) is placed on a horizontal plane and connected to a cylinder (31); the air pump (52) and the guide rail (53) are respectively connected to the rear side and the front side of the frame (51); the slider (54) is nested and connected to the guide rail (53); and the clamp (55) is connected to the slider (54).

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