CN110065218B

CN110065218B - Extrusion, drawing and blowing processing method of plastic bent bottle

Info

Publication number: CN110065218B
Application number: CN201910475697.0A
Authority: CN
Inventors: 黄伟镜
Original assignee: Foshan Qianfeng Industrial Co ltd
Current assignee: Foshan Qianfeng Industrial Co ltd
Priority date: 2019-05-30
Filing date: 2019-05-30
Publication date: 2021-08-24
Anticipated expiration: 2039-05-30
Also published as: CN110065218A

Abstract

The invention relates to a blowing process for a plastic bottle extruding mold, and particularly discloses a method for extruding, drawing and blowing a plastic bent bottle. The invention can lead the bent special-shaped plastic bottle or plastic pipe to realize large-scale industrialized production through the extrusion and blowing process by the stretch bending process, saves a large amount of raw materials of which the edges need to be cut off compared with the traditional special-shaped bottle extrusion and blowing process by the processing method, and reduces the requirement on the shearing performance of the mould, thereby leading the precision of the mould to be higher, leading the blown bottle body to be more exquisite and beautiful, and leading the produced bottle body to be thinner and more uniform and leading the production yield to be higher because the thickness of the blank wall of the raw materials to be more easily controlled.

Description

Extrusion, drawing and blowing processing method of plastic bent bottle

Technical Field

The invention relates to a blowing processing technology of a plastic bottle extruding mold, and particularly discloses an extruding, drawing and blowing processing method of a plastic bent bottle.

Background

With the development of modern chemical industry, plastic products become the first choice for commodity packaging, and the production and life of people are greatly facilitated due to the characteristics of beating resistance, antibiosis, good sealing, chemical stability and recyclability.

The existing plastic bottles are generally used for packaging beverages, medicines and chemical preparations, the production amount is very large, and the industrial production degree is very high. The existing plastic bottle industrial production generally has two modes:

one is an extrusion blowing process, wherein plastic raw materials are extruded to drop from top to bottom through an extrusion port, clamped by a mold, cut and blown to form;

the other method is that after plastic material is first injection molded into bottle blank, the bottle blank is heated and drawn to certain height inside a drawing and blowing machine to close the mold, and high pressure air is then blown into the bottle blank for final formation.

The two methods are the most common industrial plastic bottle production processes, but both methods have a defect that the produced plastic bottles are generally straight bottles, namely, the produced plastic bottles always comprise an axis which penetrates through the whole bottle mouth, the whole bottle body and the whole bottle bottom.

Through the extrusion-blow technology, a large bending mould is opened, and a bent bottle or a bent pipe is blown by cutting off redundant raw materials of a vertical part, however, the mode has high requirements on a die assembly side edge of the mould, and the side surface of the produced plastic bottle has a heavy die assembly line, is not attractive and harsh to touch, and has low structural strength at the die assembly position and is fragile. The mold clamping line is difficult to control, a large amount of raw materials are wasted, the production efficiency is low, the quality is difficult to control, and the precision requirement on the mold and the processing equipment is higher.

However, in some applications, an integrally bent plastic bottle or a plastic elbow is required, such as a bent-mouth bottle which is convenient for a patient to open the bottle directly to take a medicine without raising his head. The existing large-scale production mode cannot meet the actual requirement, if the traditional extrusion blowing process is adopted for production, a large amount of plastic raw materials are wasted and cut at the turning position, the process requirement is more severe during realization, the finished product rate is low, and the product thickness is difficult to control.

Disclosure of Invention

The invention provides a method for extruding, drawing and blowing a plastic bent bottle, aiming at solving the problems of difficult realization and raw material waste of the existing extruding and blowing process of bent plastic bottles or pipes.

The technical scheme adopted by the invention is as follows: a method for extruding, drawing and blowing a plastic bent bottle comprises the following steps: extruding, die assembling, shearing, blowing and cutting a bottle mouth; the mold closing step is realized by the following steps:

s1, fixing a billet tube, fixing the upper end of the billet tube when the extrusion of the billet tube reaches a specified length, and fixing the lower end of the billet tube at the same time;

s2, stretch bending, namely bending the blank pipe to enable the blank pipe to be bent at a bending point by a specified angle;

and S3, closing the mold, namely closing a mold closing device containing a plastic bent bottle bending cavity, cutting off the billet tube by the lower end of the mold closing device corresponding to the lower knife opening at the tail end of the bent billet tube, and closing and bonding the lower end of the billet tube in the mold closing device.

Preferably, in step S2, the motion trajectory of the bending mechanism at the position where the blank tube is fixed is an arc trajectory with the bending point of the blank tube as the center.

Preferably, after step S3, the bending mechanism removes the billet tail cut by the lower blade from the clamping device and releases the tail in the recovery area of the tail.

The invention has the beneficial effects that: through the stretch bending process, large-scale industrial production of bent special-shaped plastic bottles or plastic pipes can be realized through the extrusion blowing process, compared with the traditional special-shaped bottle extrusion blowing process, the processing method saves a large amount of raw materials of which the edges need to be cut off, and reduces the requirements on the shearing performance of the die, so that the precision of the die is higher, the blown bottle body is more exquisite and attractive, and the thickness of the blank wall of the raw materials is easier to control, so that the produced bottle body is thinner and more uniform, and the production yield is higher.

Drawings

FIG. 1 is a schematic view of the internal structure of the extrusion of the present invention.

Fig. 2 is a front view of the upper mold of the present invention.

FIG. 3 is a schematic view of the internal structure of the lower mold half of the present invention.

Fig. 4 is a schematic view of a plastic curved bottle produced by the present invention.

Fig. 5 is a schematic view of another plastic curved bottle produced by the present invention.

In the figure: 101. a blank tube 102, a bottle opening 103, an upper positioning tube 104, a tailing 201, an extrusion opening 202, an upper knife edge 501 and an air blowing tube; 601. a lower die set, 602, an upper die set, 603, a lower die cavity, 604, an upper die cavity, 605, a lower die closing driving part, 606, an upper die closing driving part, 607, a side wall vertical plate, 608 and a lower knife edge; 701. mechanical claw, 702, transmission rod, 703, power piece.

Detailed Description

Referring to fig. 1 to 5, the invention is a method for extruding, drawing and blowing plastic curved bottles.

Referring to fig. 1 to 3, in order to implement the processing method, the processing equipment needs to be improved, and one embodiment is as follows:

an extrusion, bending and blowing processing device for plastic bent bottles comprises an extrusion device, a mold closing device, a blowing device and a cutting device.

Referring to fig. 1 and 2, the extruding device is the same as the conventional extruding and blowing apparatus, and includes an extruding opening 201 for extruding the heated and melted plastic material downward into the blank tube 101, and an upper knife edge 202 for cutting off the upper end of the blank tube 101 is provided on the lower side surface of the extruding opening 201. The extrusion opening 201 can be movably adjusted in shape to achieve adjustment of the shape and wall thickness of the blank pipe 101. The blank size of the blank 101 of the present application is cut in accordance with the shape of the blank when the unbent straight bottle is blown.

Referring to fig. 3, the blowing device includes an air blowing pipe 501, an air pipe and a movable mechanism for moving the air blowing pipe 501 up and down are disposed above the air blowing pipe 501, the other end of the air pipe is connected to an air pump, and an electromagnetic valve for controlling the air output of the air blowing pipe 501 is further disposed on the air pipe. The air blowing pipe 501 moves downwards to extend into the upper positioning pipe 103 during air blowing, after the blowing is completed, the upper positioning pipe 103 fixes the plastic bent bottle outside the air blowing pipe 501 after the mold closing device is opened, and when the air blowing pipe 501 retracts upwards, the upper positioning pipe 103 falls off.

The same equipment can comprise a plurality of sets of extrusion ports 201, a mold closing device and an air blow pipe 501, and the extrusion ports, the mold closing device and the air blow pipe are arranged in parallel and work simultaneously to improve the production efficiency.

Referring to fig. 1 to 3, the mold closing device is divided into a lower mold set 601 including a corresponding bending cavity for a plastic bent bottle and an upper mold set 602 for fixing the upper end of the parison 101, a lower knife edge 608 for shearing and clamping the lower end of the parison 101 is arranged in the lower mold set 601, the lower mold set 601 and the upper mold set 602 are respectively a left half mold and a right half mold which are arranged in parallel along the vertical direction, a lower cavity 603 is arranged in the lower mold set 601, an upper cavity 604 is arranged in the upper mold set 602, the upper cavity 604 and the lower cavity 603 are combined into a cavity corresponding to the shape of the produced plastic bent bottle, the cavity sequentially comprises an upper positioning tube 103, a bottle mouth 102, a bent bottle body and a bottle bottom from top to bottom, the lower knife edge 608 is located at the middle position of the bottom of the plastic bent bottle, and the parison 101 cut out of the outer side of the cavity after the lower knife edge 608 is cut is the tail material 104.

The dividing line between the lower die set 601 and the upper die set 602 is located in the middle region of the lower end of the upper positioning tube 103 above the bending point of the blank 101.

The lower die set 601 has lower die driving members 605 on both sides thereof, and the upper die set 602 has upper die driving members 606 on both sides thereof. Side wall vertical plates 607 for fixing the whole mold clamping device are arranged on two sides of the lower mold clamping driving part 605 and the upper mold clamping driving part 606.

Referring to fig. 2, the lower mold clamping driving member 605 and the upper mold clamping driving member 606 have two design concepts, one of which is to separately provide 2 sets of mold clamping driving members which independently operate, and to provide power by using a push rod motor or a cylinder. The other is that the upper mold clamping driving member 606 is a set of elastic mechanisms, such as springs or pneumatic rods, as shown in the figure, the other end of the elastic mechanism is connected to the pushing surface of the lower mold clamping driving member 605, the extension length difference of the elastic mechanism is larger than the width of half of the parison 101, two sides of the upper mold set 602 respectively protrude from the lower mold set 601 by the extension length difference of one elastic mechanism, at this time, when the lower mold clamping driving member 605 starts to close, the upper mold set 602 protrudes from the lower mold set 601, so the upper mold set 602 is closed first, and then, when the lower mold clamping driving member 605 continues to push in the box, the elastic mechanism of the upper mold clamping driving member 606 compresses and shortens, and finally, the lower mold set 601 also completes to close.

The outside of the mold closing device is provided with a sliding mechanism, so that the mold closing device reciprocates below the extrusion port 201 and below the blow pipe 501. Of course, the roller mode or the rotation mode is used, so that the reciprocating motion of a plurality of mold closing devices below the extrusion opening 201 and the blowing pipe 501 is also feasible, and the utilization rate of the extrusion opening 201 and the blowing pipe 501 is increased.

A bending mechanism is arranged below the lower die set 601, the bending mechanism comprises a mechanical claw 701 for fixing the tail 104 of the embryonic tube 101, the mechanical claw 701 comprises a pair of symmetrical clamping plates, a groove for fixing the embryonic tube 101 is formed in the middle of each clamping plate, a pair of power parts 703 for controlling the mechanical claw 701 to open and close is arranged on the outer side of each clamping plate, and each power part 703 can be an air cylinder or a push rod motor.

A power mechanism for driving the gripper 701 to move along an arc track with a bending point of the blank tube 101 as a center is arranged below or behind the gripper 701. The gripper 701 is connected to a power mechanism via a transmission rod 702. The driving rod 702 has a structure for assisting the gripper 701 to determine a motion trajectory, such as a connecting rod, a positioning swing arm, and the like, so as to ensure that the gripper 701 moves along an arc trajectory with a bending point of the parison tube 101 as a center.

The side of the gripper 701 may further be provided with a fixing frame, the inner wall of the fixing frame is provided with a rail limiting mechanism for assisting in positioning the movement track of the gripper 701, and the fixing frame is fixedly connected with the side wall vertical plate 607.

The cutting device is arranged at one side of the blowing device and comprises a knife edge which moves along a horizontal or circular track and is used for cutting off the upper positioning tube 103 at the upper end of the bottle mouth 102 after the plastic bent bottle is blown.

Referring to fig. 1 to 3, the processing apparatus described above is used to implement a method for stretch blow molding of a plastic curved bottle, which includes: extruding, die assembling, shearing, blowing and cutting a bottle opening, wherein the die assembling is specifically realized by the following steps:

s1, fixing a billet tube, fixing the upper end of the billet tube 101 when the extrusion of the billet tube 101 reaches a specified length, and fixing the lower end of the billet tube 101 by a bending mechanism positioned at the lower end of the billet tube 101;

s2, stretch bending, wherein the bending mechanism drives the blank tube 101 to bend, so that the blank tube 101 is bent at a bending point by a specified angle;

and S3, closing the mold, namely closing the mold closing device containing the bent cavity of the plastic bent bottle, cutting off the blank pipe 101 by the lower end of the mold closing device corresponding to the lower cutting edge 608 at the tail end of the bent blank pipe 101, and closing and bonding the lower end head of the blank pipe 101 in the mold closing device.

In step S2, the movement trajectory of the bending mechanism at the position where the blank tube 101 is fixed is an arc trajectory with the bending point of the blank tube 101 as the center of the circle.

By combining the traditional plastic bottle extrusion-blowing process and the specific structure of the extrusion-bending-blowing equipment, the complete production flow embodiment of the application is as follows:

A1. extruding, namely extruding the molten plastic raw material downwards into a blank tube 101 in the shape of an extrusion opening 201 through an extruding device;

A2. closing the upper die, and when the billet tube 101 is extruded to reach the designated length, closing the upper die set 602 to fix the upper end of the billet tube 101, and closing the mechanical claw 701 positioned at the lower end of the billet tube 101 to fix the lower end of the billet tube 101;

A3. bending, the mechanical claw 701 drives the embryonic tube 101 to move, so that the embryonic tube 101 is bent at a bending point by a specified angle;

A4. closing the lower die, closing the lower die set 601, cutting off the embryonic tube 101 by a lower cutting edge 608 at the tail end of the embryonic tube 101 after the lower end of the lower die set 601 is correspondingly bent, and closing and bonding the lower end head of the embryonic tube 101 in the die closing device;

A5. shearing materials, namely transversely moving an upper knife edge 202 to cut off the upper end of the embryonic tube 101, and moving a mold closing device to the lower part of the blowing device to ensure that the upper end of the embryonic tube 101 is just opposite to the blowing tube 501;

A6. blowing, namely, flushing high-pressure gas into the upper end of the blank pipe 101 by the gas blowing pipe 501, and simultaneously, extending the gas blowing pipe 501 downwards into the upper positioning pipe 103 of the blank pipe 101 so as to enable the blank pipe 101 to be formed by expansion blowing in a mold closing device;

A7. and opening the lower die set 601 and the upper die set 602, and cutting off the upper positioning pipe 103 at the upper end of the bottle mouth 102 by a cutting device to finish the production of the plastic bent bottle.

The material cutting process of step a5 may be performed at any time after step a2 is completed and before step a6 is started, and the optimal sequence is performed after step a4.

The step a1, step a5, step a6 and step a7 are implemented in the same manner as the conventional extrusion blow process.

In step a1, the size and shape of the extrusion opening 201 can be changed according to program control, so that the thickness and shape of the extruded blank tube 101 are changed correspondingly.

Referring to fig. 3, the bending point of the embryonic tube 101 is located in the present embodiment mainly by 2 ways: firstly, a circular arc-shaped motion track behind the lower end of the embryonic tube 101 is fixed through a mechanical claw 701, so that the embryonic tube 101 is bent at a circular position in a circular arc shape; secondly, when the bending position is close to the bottle opening, the upper end of the blank tube 101 is fixed by the upper mold set 602 and abuts against the bending position, and at this time, the mechanical claw 701 moves to bend the blank tube 101 at the position where the upper mold set 602 abuts against the blank tube 101.

Referring to fig. 4, the bending point of the plastic curved bottle processed by the embodiment is located at the middle section of the bottle body, and the method for positioning the bending point is realized through the movement track of the mechanical claw 701.

Referring to fig. 5, another plastic curved bottle processed in this embodiment is bent at a joint between a bottle mouth and a bottle body, and the method for positioning the bending point is mainly realized by the upper mold set 602 abutting against the parison 101, and meanwhile, the motion trajectory of the gripper 701 is also a circular arc-shaped trajectory along the bending point.

Claims

1. A method for extruding, drawing and blowing a plastic bent bottle comprises the following steps: extruding, die assembling, shearing, blowing and cutting a bottle mouth; the method is characterized in that: the mold closing step is realized by the following steps:

s1, fixing a billet tube, fixing the upper end of the billet tube (101) when the extrusion of the billet tube (101) reaches a specified length, and fixing the lower end of the billet tube (101) by a bending mechanism;

s2, stretch bending, namely bending the blank tube (101) by a bending mechanism to bend the blank tube (101) at a bending point by a specified angle;

s3, closing the mold, namely closing a mold closing device comprising a plastic bent bottle bending cavity, cutting off the billet tube (101) by a lower knife edge (608) at the lower end of the mold closing device corresponding to the tail end of the bent billet tube (101) and enabling the lower end head of the billet tube (101) in the mold closing device to be closed and bonded;

the mould closing device comprises a lower mould set and an upper mould set, wherein the lower mould set comprises a corresponding bending cavity of a plastic bent bottle, the upper mould set is used for fixing the upper end of a billet tube, lower mould closing driving parts are arranged on two sides of the lower mould set, upper mould closing driving parts are arranged on two sides of the upper mould set, the upper mould closing driving parts are a group of elastic mechanisms, the other ends of the elastic mechanisms are connected with the pushing surfaces of the lower mould closing driving parts, the telescopic length difference of the elastic mechanisms is larger than the width of a half billet tube, and the two sides of the upper mould set respectively protrude out of the telescopic length difference of one elastic mechanism of the lower mould set.

2. The extrusion drawing and blow molding method of plastic curved bottles as claimed in claim 1, wherein: in step S2, the movement trajectory of the bending mechanism at the position where the blank tube (101) is fixed is an arc trajectory with the bending point of the blank tube (101) as the center of circle.

3. The extrusion drawing and blow molding method of plastic curved bottles as claimed in claim 1, wherein: after the step S3, the bending mechanism removes the tail (104) of the blank tube (101) cut by the lower blade (608) from the mold clamping device and releases the tail (104) in the recovery area of the tail (104).