CN117549531A

CN117549531A - Blow molding die head

Info

Publication number: CN117549531A
Application number: CN202311622731.5A
Authority: CN
Inventors: 罗俊人; 戚丽伟
Original assignee: Hangzhou Well Pack Material Co ltd
Current assignee: Hangzhou Well Pack Material Co ltd
Priority date: 2023-11-29
Filing date: 2023-11-29
Publication date: 2024-02-13

Abstract

The invention discloses a blow molding die head, which comprises a die head; the mold core is fixedly connected in the die; a gap between the die and the die core forms a material conveying channel; the outer wall of the mold core is formed with a plurality of spiral flow passages which are uniformly arranged; the method is characterized in that: the inner wall of the die is provided with at least one circular groove which is coaxially arranged. The chance of melt re-mixing is provided in the die head, so that the difference between the melts in the individual flow channels is effectively reduced before the melts enter the final mixing stage; the die core is different from the conventional die core in design and adjustment, the runner is originally arranged on the die core, the manufacturing difficulty and cost of the die core can be improved in further processing and design, the die core is designed on the die, the inner wall structure of the die is single, the die core is easy to process and manufacture, and the cost is lower.

Description

Blow molding die head

Technical Field

The invention belongs to the field of plastic machinery, and particularly relates to a blow molding die head.

Background

The film is susceptible to longitudinal film marks on the surface during extrusion processing, known as flow lines. The formation of the flow channel line can affect the quality of the film to a certain extent, and the strength of the film in longitudinal tearing is reduced. The main reason for the occurrence of the runner line is that when the plastic melt is led into the machine head from the extruder, after the plastic melt enters the equi-number runners of the machine head respectively through the plurality of discharging holes at the lowest part of the machine head, before the die orifice of the extruder head, the melt from the individual runners has the difference of original inertia or rheology, so that the trace of the mixture generated when the melt is welded is formed. While attempts have been made to improve such problems by adjusting the process conditions or the design of the abrasive article, limitations remain significant.

The Chinese patent document with publication number of CN209409296U discloses a double-spiral groove multifunctional blow molding die, which comprises a die head body, an adjusting ring arranged on the die head body, a die arranged in the adjusting ring and a spiral body positioned below the die, wherein an outer spiral groove is arranged on the outer side surface of the spiral body, and an inner spiral groove is arranged on the inner side surface of the die head body. According to the invention, the spiral grooves are respectively arranged on the spiral body and the machine head body, so that the pressure of the machine head is increased, the uniformity of discharging and the consistency of film thickness are improved, and the film adjusting time is shortened, thereby reducing the generation of waste materials; the longitudinal and transverse stretching of the film tends to be balanced, so that the strength and the stretching degree of the film are greatly improved; the capacity of the machine head is increased, and the yield is further improved; can be suitable for various different materials, has wide application range, and reduces transformation cost.

In order to make the discharging uniform, the spiral grooves are respectively formed in the outer wall of the mold core and the inner wall of the die, and most of the melt still can be fed along the spiral grooves under the action of pressure, and the difference of the primary inertia or rheology of the melt in each spiral groove cannot be eliminated, so that a runner line can still be generated.

Disclosure of Invention

In order to overcome the flow channel lines on the surface during film extrusion in the prior art, one purpose of the invention is to provide a blow molding die head, wherein grooves are arranged on the inner wall of the die head, so that melts in different flow channels are led into the grooves to be effectively mixed, the primary inertia during melt flow is disturbed, and the existence of the flow channel lines due to overlarge difference between the melts in different flow channels during final material mixing is further reduced.

In order to achieve the above purpose, the present invention is realized by the following technical scheme: a blow molding die comprising a die; the mold core is fixedly connected in the die; a gap between the die and the die core forms a material conveying channel; the outer wall of the mold core is formed with a plurality of spiral flow passages which are uniformly arranged; the inner wall of the die is provided with at least one circular groove which is coaxially arranged.

The plastic melt flows out from the lower ends of the flow channels under the action of pressure, fills the flow channels, the material conveying channels and the grooves, and flows out from the upper ends of the material conveying channels under the continuous action of pressure to form a film. In the process, the melt in each runner flows into the groove under the action of pressure to generate mixing, and flows upwards synchronously along with the whole flow of the melt, so that the primary inertia of the flow of the melt in each runner is disturbed, the difference of the melt in each runner is reduced, and the runner line is avoided after material mixing.

Preferably, the cross section of the groove is semicircular, and no dead angle exists in the upward flow process of the melt, so that the melt is prevented from accumulating.

Preferably, the depths of the grooves are respectively unequal, that is, the amounts of the melts flowing into the grooves in the runners are respectively unequal, and the runners are mixed in different mixing proportions, so that the melt difference in the runners is further reduced.

Further, an arc angle is formed at the joint of the groove and the inner wall of the die; the smoothness of melt flow is ensured, the abrasion of the die is reduced, and the melt accumulation can be prevented.

Preferably, the number of the grooves is three, and the distances between two adjacent grooves are equal.

Preferably, the depth of the groove located in the middle is greater than the depth of the other two grooves.

Preferably, two grooves at both ends are respectively aligned with the upper end and the lower end of the flow channel; and the melt in the runner is convenient to enter the groove for full mixing.

Compared with the prior art, the invention has the beneficial effects that: the chance of melt re-mixing is provided in the die head, so that the difference between the melts in the individual flow channels is effectively reduced before the melts enter the final mixing stage; the die core is different from the conventional die core in design and adjustment, the runner is originally arranged on the die core, the manufacturing difficulty and cost of the die core can be improved in further processing and design, the die core is designed on the die, the inner wall structure of the die is single, the die core is easy to process and manufacture, and the cost is lower.

Drawings

FIG. 1 is a schematic diagram of the structure of the present invention;

FIG. 2 is a schematic view of the mold core and the die according to the present invention.

In the figure: 10. a mold core; 101. a flow passage; 102. a material dividing channel; 20. a die; 201. a groove.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and detailed description, wherein it is to be understood that, on the premise of no conflict, the following embodiments or technical features may be arbitrarily combined to form new embodiments.

In the description of the present invention, it should be noted that, for the azimuth words such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the azimuth and positional relationships are based on the azimuth or positional relationships shown in the drawings, it is merely for convenience of describing the present invention and simplifying the description, and it is not to be construed as limiting the specific scope of protection of the present invention that the device or element referred to must have a specific azimuth configuration and operation.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features. Thus, the definition of "a first", "a second" or "a second" feature may explicitly or implicitly include one or more such feature, and in the description of the invention, the meaning of "a number" is two or more, unless otherwise specifically defined.

In the present invention, unless explicitly stated and limited otherwise, the terms "assembled," "connected," and "connected" are to be construed broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; or may be a mechanical connection; can be directly connected or connected through an intermediate medium, and can be communicated with the inside of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

Referring to fig. 1-2, a die head is shown to include a die core 10 and a die 20. A distribution hole is formed in the center of the lower end of the mold core 10; the outer wall of the mold core 10 is formed with a plurality of flow passages 101 which are uniformly arranged and are arranged along a spiral line; the lower end of the flow channel 101 is provided with a material distributing channel 102 which is obliquely arranged and communicated with the top end of the inner wall of the distributing hole; the material distribution channels 102 are uniformly arranged along the circumferential direction; three circular grooves 201 are formed in the inner wall of the die 20.

The high-temperature plastic melt is extruded into the distribution holes under the action of high pressure, then evenly flows into the distribution channel 102, enters the lower end of the flow channel 101 through the distribution channel 102, flows upwards from the lower end of the flow channel 101 along with continuous injection of the high-temperature plastic melt, fills the material conveying channel, and finally outputs a circular tube type film at the top end of the material conveying channel. In this process, the melt flowing in the flow channels 101 will also flow into the grooves 201 under the pressure, and at the same height, the melt in each flow channel 101 enters into the grooves 201 at the same time, and the melt in the grooves 201 is mixed under the driving of the melt flowing upwards, and flows upwards synchronously with the melt flowing upwards. Therefore, the primary inertia of the melt flow is disturbed, and the existence of flow channel lines caused by overlarge difference between the melts in different flow channels in final material mixing is further reduced.

The above embodiments are merely illustrative embodiments of the present invention, but the technical features of the present invention are not limited thereto, and any changes or modifications made by those skilled in the art within the scope of the present invention are included in the scope of the present invention.

Claims

1. A blow molding die comprising a die; the mold core is fixedly connected in the die; a gap between the die and the die core forms a material conveying channel; the outer wall of the mold core is formed with a plurality of spiral flow passages which are uniformly arranged; the method is characterized in that: the inner wall of the die is provided with at least one circular groove which is coaxially arranged.

2. The die of claim 1, wherein: the cross section of the groove is semicircular.

3. The die of claim 1, wherein: the depth of each groove is not equal.

4. The die of claim 1, wherein: and an arc angle is formed at the joint of the groove and the inner wall of the die.

5. The die of any one of claims 1-4, wherein: the number of the grooves is three, and the distances between two adjacent grooves are equal.

6. The die of claim 5, wherein: the depth of the groove positioned in the middle is larger than that of the other two grooves.

7. The die of claim 5, wherein: the two grooves at the two ends are respectively aligned with the upper end and the lower end of the flow channel.

8. The die of claim 6, wherein: the two grooves at the two ends are respectively aligned with the upper end and the lower end of the flow channel.

9. The die of any one of claims 1-4, wherein: the two grooves at the two ends are respectively aligned with the upper end and the lower end of the flow channel.