Blow mold quick exhaust method

Abstract

The invention discloses a method for rapid exhaust of a blow molding mold, which belongs to the field of mold technology. The method comprises a mold cavity provided with a blow pin hole, a plurality of exhaust grooves are axially provided on the inner wall of the blow pin hole, the diameter of the exhaust groove is 1 / 16 of the circumference of the blow pin hole, and there is a gap between the exhaust groove and the outlet end of the blow pin hole. When the blow pin is inserted into the blow molding mold for pressure maintenance, it is ensured that no air leaks from the exhaust groove. When exhausting, the blow pin is retracted, and a part of the high-pressure gas in the blow-molded product is discharged from the exhaust valve along the blow pipe through the inside of the blow pin, and another part of the high-pressure gas enters the exhaust groove from the tapered part of the blow pin head, and is directly discharged into the atmosphere without passing through pipelines and valves, so the exhaust path is short and the exhaust efficiency is high. The invention solves the problem of slow exhaust of existing blow molding molds, and improves the blow molding production efficiency by reducing the exhaust time.

Description

Technical Field

[0001] The invention belongs to the technical field of molds and relates to a rapid exhaust method for a blow molding mold of an automobile oil tank. Background Art

[0002] With the requirement of lightweight automobiles, plastics are used more and more widely in automobiles. Automobile fuel system is a field where plastics are widely used, among which fuel tank is a typical representative. Automobile plastic fuel tank is the hollow blow molding part with the largest output for automobiles at present. Its development is a symbol of high technology and high added value of plastic hollow blow molding products. Compared with metal fuel tanks, automobile plastic fuel tanks have greater freedom of shape design, light weight, good corrosion resistance, especially in cold areas, can prevent metal corrosion caused by ice and salt, and the production process is simple and efficient. Plastic fuel tanks are currently made by blow molding. Generally, the blank tube is placed in the mold, and then the blow needle is inserted into the blow needle hole of the model cavity to blow high-temperature and high-pressure gas into the blank in the model cavity to make the blank into shape. During blow molding, it is generally necessary to discharge the gas in the cavity in time. Due to the large volume of automobile fuel tanks, there is more gas in the cavity. The compressed air inside the automobile fuel tank blow-molded products must be discharged before opening the mold, otherwise the automobile fuel tank plastic products that lose the mold restriction will be burst by the internal high-pressure gas. The existing blow molding mold exhaust is mainly discharged through the inner hole of the blow needle when the blow molding is completed, but the inner hole of the blow needle is very small. It takes about 10 seconds to completely discharge the gas in the automobile fuel tank after molding, which affects the production efficiency. Summary of the invention

[0003] The problem solved by the present invention is to provide a method for quickly exhausting a blow molding mold, so as to solve the problem of slow exhausting of the existing blow molding mold and improve the blow molding production efficiency by reducing the exhausting time.

[0004] In order to solve the above problems, the technical solution adopted by the present invention is: it includes a model cavity provided with a blow pin hole, and a plurality of exhaust grooves are axially provided on the inner wall of the blow pin hole, the diameter of the exhaust groove is 1 / 16 of the circumference of the blow pin hole, and there is a gap between the exhaust groove and the outlet end of the blow pin hole. When the blow pin is inserted into the blow pressure maintaining device, it is ensured that no air leaks from the exhaust groove. When exhausting, the blow pin retreats, and a part of the high-pressure gas in the blow-molded product is discharged from the exhaust valve along the blow pipe through the inside of the blow pin, and another part of the high-pressure gas enters the exhaust groove from the tapered part of the blow pin head, and is directly discharged into the atmosphere without passing through the pipeline and valve, so the exhaust path is short and the exhaust efficiency is high.

[0005] In the above technical solution, a more specific technical solution may also be: it also includes a blow needle provided with a plurality of blow holes, and the plurality of blow holes are provided on the conical needle head of the blow needle.

[0006] Furthermore, the interval between the exhaust groove and the outlet end of the blow needle hole is the same as the length of the conical needle head of the blow needle.

[0007] Furthermore: the interval between the exhaust groove and the outlet end of the blow pin hole is 10 mm.

[0008] Further: the number of the blowing holes is twenty-eight.

[0009] Furthermore: the exhaust groove is semicircular, and the blowing hole is circular.

[0010] Due to the adoption of the above technical scheme, the present invention has the following beneficial effects compared with the prior art: by designing and processing an exhaust groove on the inner wall of the blow pin hole, when exhausting, the high-pressure gas in the blow-molded product is directly discharged into the atmosphere from the exhaust groove without passing through the air pipe and the air valve, the fluid resistance is small, the exhaust speed is fast, and the exhaust efficiency can be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a cross-sectional view of the present invention.

[0012] Figure 2 yes Figure 1 K-direction cross-sectional view.

[0013] Figure 3 yes Figure 1 H-section view.

[0014] Figure 4 It is a working schematic diagram of the blow molding of the present invention.

[0015] Figure 5 It is a schematic diagram of the working of the present invention during exhaust.

[0016] In the figure: 1. model cavity; 2. blow pin hole; 3. exhaust groove; 4. blow pin; 5. blow hole. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with the accompanying drawings:

[0018] like Figures 1 to 5The blow mold rapid exhaust method shown includes a mold cavity 1 provided with a blow pin hole 2, a plurality of exhaust grooves 3 are axially provided on the inner wall of the blow pin hole 2, the diameter of the exhaust groove 3 is 1 / 16 of the circumference of the blow pin hole 2, there is a gap between the exhaust groove 3 and the outlet end of the blow pin hole 2, and the blow pin 4 is inserted into the exhaust groove 3 to ensure that there is no leakage from the exhaust groove 3 when the blow pin 4 is inserted into the blow pressure maintenance. When exhausting, the blow pin 4 is retracted, and a part of the high-pressure gas in the blow molded product is discharged from the exhaust valve along the blow pipe through the inside of the blow pin 4, and another part of the high-pressure gas enters the exhaust groove 3 from the tapered part of the head of the blow pin 4, and is directly discharged into the atmosphere without passing through the pipeline and valve, so that the exhaust path is short and the exhaust efficiency is high; it also includes a blow pin 4 provided with a plurality of blow holes 5, and the plurality of blow holes 5 are arranged at the conical needle head of the blow pin 4; exhaust The interval between the groove 3 and the outlet end of the blow pin hole 2 is the same as the length of the tapered needle head of the blow pin 4; in this example, the interval between the exhaust groove 3 and the outlet end of the blow pin hole 2 is 10 mm, and the optimal length of the tapered needle head of the blow pin 4 is also 10 mm. The diameter of the exhaust groove 3 is 1 / 16 of the circumference of the blow pin hole 2, so there are eight exhaust grooves 3 distributed on the inner wall of the blow pin hole 2. Since multiple exhaust grooves 3 are used as the main exhaust path, it is no longer necessary to use the inner hole of the blow pin 4 as the main exhaust path, so that multiple small blowing holes 5 can be opened on the needle head to increase the diffusion during blow molding. When the wind force remains unchanged, the wind speed during blow molding is softer. Twenty-eight blowing holes 5 is the best solution; the exhaust groove 3 is semicircular, and the blowing hole 5 is circular.

Claims

1. A method for rapid exhaust of a blow mold, comprising a mold cavity provided with a blow pin hole, characterized in that: A plurality of exhaust grooves are axially arranged on the inner wall of the blow pin hole, the diameter of the exhaust groove is 1 / 16 of the circumference of the blow pin hole, there is a gap between the exhaust groove and the outlet end of the blow pin hole, and also includes a blow pin provided with a plurality of blowing holes, the plurality of blowing holes are arranged on the conical needle head of the blow pin; there is a gap between the exhaust groove and the outlet end of the blow pin hole, when the blow pin is inserted into the blow pressure maintaining device, it is ensured that no air leaks from the exhaust groove, when exhausting, the blow pin retreats, and a part of the high-pressure gas in the blow-molded product is discharged from the exhaust valve along the blow pipe through the inside of the blow pin, and another part of the high-pressure gas enters the exhaust groove from the tapered part of the blow pin head, and is directly discharged into the atmosphere without passing through pipelines and valves.

2. The method for rapid exhaust of a blow mold according to claim 1, characterized in that: The interval between the exhaust groove and the outlet end of the blow needle hole is the same as the length of the conical needle head of the blow needle.

3. The method for rapid exhaust of a blow mold according to claim 2, characterized in that: The interval between the exhaust groove and the outlet end of the blow pin hole is 10 mm.

4. The method for rapid exhaust of a blow mold according to claim 3, characterized in that: The number of the blowing holes is twenty-eight.

5. The method for rapid exhaust of a blow mold according to claim 4, characterized in that: The exhaust groove is semicircular, and the blowing hole is circular.

Images