Plasticizing and injection molding equipment for an exhaust type injection molding machine

Abstract

The present invention discloses a plasticizing and injection molding device for an exhaust type injection molding machine, belonging to the technical field of injection molding. It includes a housing, a melting cavity surrounded by the housing, and a feeding bin arranged on one side of the housing and communicated with the inner cavity of the housing. A control bin is arranged at the top outside the housing. A heating screw which is driven by the control bin and controls heating is vertically arranged in the melting cavity. A hopper communicated with the melting cavity is arranged above the housing. The plasticizing and injection molding device of the exhaust type injection molding machine of the present invention has high exhaust efficiency, most of the volatile gases are condensed and recovered, is environmentally friendly, and has a low operation threshold.

Description

Technical Field

[0001] The present invention relates to the technical field of injection molding, and particularly relates to a plasticizing and injection molding device for an exhaust type injection molding machine. Background Art

[0002] For special plastic materials such as biodegradable plastics, engineering plastics PA, PC, ABS, AS, PCTG, PET, PBT and other high-moisture plastics, they need to be dehumidified and dried before production. During the plasticizing process of plastics, it is very difficult to completely meet the standards for treating small molecule gases, moisture, and volatiles through drying and dehumidifying equipment; the dehumidifying and drying process has a high temperature, a long time, a low efficiency, and a low qualified rate of products. In addition, for some injection molded products with low requirements, the proportion of recycled materials in the recycling application is very high. These recycled materials are high-moisture materials and are prone to excessive degradation. During injection molding processing, small molecule gases are extremely easy to generate, the production process is not smooth, the gases are stored in the products, and the quality is difficult to meet the standards. The screw of the existing exhaust type injection molding machine adopts a reciprocating exhaust screw, which is divided into front and rear two stages, while the screw of a common injection molding machine has only one stage. The first stage has a feeding section, a compression section, and a metering section; the second stage has a decompression section, a compression section, and a metering section. The material enters from the feeding port and is conveyed through the feeding section of the first-stage screw after entering the first-stage screw. The plasticized material in the compression section has been plasticized into a viscoelastic state, and then the melt is thinned by an over-shearing element provided at the end of the first stage, and the gas adheres to the surface of the melt layer and enters the decompression section of the second-stage screw. Due to the sudden increase in the depth of the screw groove in the decompression section and the increase in volume, an exhaust hole is opened on the barrel of the decompression section, and this hole is usually connected to the atmosphere or a vacuum pump storage tank. The melt pressure in the screw groove of the decompression section suddenly drops to zero or negative pressure, and the water vapor and various vaporized volatile matter bubbles compressed in the polymer melt burst, then break away from the melt and are discharged from the exhaust port. However, most of the gases discharged by such exhaust type injection molding machines are directly discharged into the atmosphere, increasing the health risks of personnel operation and the difficulty of achieving production and environmental protection standards. And if materials such as activated carbon are added outside the exhaust port for adsorption, it is easy to block the exhaust port and reduce the efficiency of extrusion and exhaust. Summary of the Invention

[0003] In order to solve the problems existing in the prior art, the present invention provides a plasticizing and injection molding device for an exhaust type injection molding machine. The technical solution of the present invention is as follows:

[0004] A plasticizing and injection molding device for an exhaust type injection molding machine, comprising a housing, a melting cavity surrounded by the housing, and a feeding bin provided on one side of the housing and communicating with the inner cavity of the housing; a control bin is provided at the top outside the housing; a heating screw vertically provided in the melting cavity and controlled by the control bin to heat; a hopper communicating with the melting cavity is provided above the housing;

[0005] An exhaust duct communicating with the melting cavity and the outside of the housing is spirally provided in the housing from top to bottom.

[0006] Further, the exhaust duct located above the melting chamber is provided with a plurality of air inlets communicating with the melting chamber; an exhaust port communicating with the exhaust duct is provided below the housing; inside the melting chamber, a closing plate that is controlled to rotate by the control chamber is provided close to the inner wall of the housing.

[0007] Further, a plurality of through holes corresponding to and communicating with the respective air inlets are provided on the closing plate; the distance between the respective air inlets is not less than the diameter of the air inlets.

[0008] A feed inlet communicating with the hopper is provided on the closing plate; when the closing plate rotates to make the feed inlet communicate with the hopper, the respective through holes are staggered from the respective air inlets, and the closing plate covers the respective air inlets.

[0009] Further, there are a plurality of the exhaust ducts; an air collecting duct that collects the respective exhaust ducts and communicates with the exhaust port is provided inside the lower part of the housing; the exhaust ducts are close to the outer wall of the housing and do not intersect with each other.

[0010] Further, the melting chamber includes a first-stage plasticizing section above and a second-stage plasticizing section below; the air inlets are opened on the exhaust ducts at the position of the first-stage plasticizing section.

[0011] The heating screw includes a first-stage screw located in the first-stage plasticizing section and a second-stage screw located in the second-stage plasticizing section; the first-stage screw and the second-stage screw respectively match the diameters of the first-stage plasticizing section and the second-stage plasticizing section.

[0012] Further, an AC port that penetrates up and down is provided on the first-stage screw.

[0013] Further, an electromagnetic plate that is controlled and connected to the control chamber is provided in the closing plate from top to bottom; inside the first-stage screw at the position of the AC port, a receiving groove with a diameter not less than that of the AC port is provided around the AC port; an elastic member whose two ends are respectively fixed to the inner wall of the receiving groove is provided in the receiving groove, and a magnetically conductive cover plate covering the AC port is fixed on the elastic member.

[0014] Further, a discharge port communicating with the injection hopper is provided at the bottom of the housing at the position of the injection hopper; a nozzle is provided at one end of the injection hopper away from the discharge port.

[0015] Further, a lifting plate that moves up and down horizontally is provided in the inner cavity of the injection hopper at the upper end position of the discharge port; the lifting plate divides the inner cavity above the injection hopper into a condensation cavity; an escape port that communicates the exhaust duct with the condensation cavity is provided on the outer wall of the housing at the position of the condensation cavity.

[0016] Further, a plurality of slide rails connected to the lifting plate are provided on the bin wall of the injection bin on the peripheral side of the lifting plate, and the lowermost ends of the slide rails are higher than the upper end of the discharge port.

[0017] Based on the above technical solutions, the technical effects that the present invention can achieve are as follows:

[0018] 1. The exhaust duct of the present invention guides the discharged volatile gas to perform heat exchange on the outer wall of the housing. After cooling and liquefying, it is discharged along the exhaust duct, realizing the collection of volatile gas during the exhaust injection molding process.

[0019] 2. The equipment main body of the present invention is vertically arranged. During the downward melting and compaction process, the gas escaping from the material moves upward and converges. Compared with the horizontally arranged main body, the gas can be more conveniently separated from the material, avoiding the problem that the exhaust port is too small caused by the horizontal arrangement, and the screw is likely to re-mix the gas into the material during the material conveying process.

[0020] 3. The closing plate of the present invention can open and close the air inlet and the hopper, avoiding the direct escape of the volatile gas from the hopper, and also avoiding the molten material from overflowing into the exhaust duct before leaving the first-stage plasticizing section, causing blockage.

[0021] 4. The communication port of the present invention can quickly reduce the pressure, promoting the escape of the volatile gas below. And after the material enters the second-stage plasticizing section, the residual volatile gas in the material during the conveying process can still escape upward from the communication port of the present invention, reducing the probability of the gas being re-mixed into the material.

[0022] 5. At the end of the material plasticization stage of the present invention, when the injection is about to be carried out, the volatile gas is basically volatilized. The volatile gas entering the condensation chamber from the escape port starts to liquefy, and the volume shrinks, prompting the lifting plate to rise. The internal cavity pressure of the injection bin below decreases, generating a suction force on the plasticized material, assisting the material to enter the injection bin from the discharge port and reducing the resistance. Description of the Drawings

[0023] Figure 1 is the front view structural schematic diagram of the plasticizing and injecting device of the exhaust injection molding machine of the present invention;

[0024] Figure 2 is the structural schematic diagram of the exhaust duct of the plasticizing and injecting device of the exhaust injection molding machine of the present invention;

[0025] <able> Figure 3 is the A-A sectional view of the plasticizing and injecting device of the exhaust injection molding machine of the present invention;

[0026] Figure 4 is the B-B sectional view of the plasticizing and injecting device of the exhaust injection molding machine of the present invention;

[0027] Figure 5It is an enlarged view C of the plasticizing and injection molding device of the exhaust type injection molding machine of the present invention;

[0028] Figure 6 It is a sectional view taken along line D-D of the plasticizing and injection molding device of the exhaust type injection molding machine of the present invention;

[0029] In the figure: 1 - housing; 11 - control chamber; 12 - hopper; 13 - feed inlet; 14 - exhaust port; 2 - melting cavity; 21 - first - order screw; 22 - closing plate; 221 - through - hole; 222 - exhaust passage; 223 - air inlet; 224 - air - collecting passage; 225 - communication port; 226 - accommodating groove; 227 - elastic member; 228 - cover plate; 26 - second - order screw; 3 - injection hopper; 31 - discharge port; 32 - condensation cavity; 33 - slide rail; 34 - lifting plate; 35 - sealing ring; 36 - nozzle; 37 - escape port. Specific embodiments

[0030] The content of the present invention will be further described below with reference to the accompanying drawings of the specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0031] As Figure 1 and Figure 3 shown, this embodiment provides a plasticizing and injection molding device for an exhaust type injection molding machine, including a housing 1, a melting cavity 2 surrounded by the housing 1, and an injection hopper 3 provided on one side of the housing 1 and communicating with the inner cavity of the housing 1. A control chamber 11 is provided at the top outside the housing 1. A heating screw driven and controlled by the control chamber 11 is vertically provided in the melting cavity 2. A hopper 12 communicating with the melting cavity 2 is provided above the housing 1. An exhaust passage 222 communicating with the melting cavity 2 and the outside of the housing 1 is spirally provided in the housing 1 from top to bottom.

[0032] Preferably, the exhaust passage 222 above the melting cavity 2 is provided with a plurality of air inlets 223 communicating with the melting cavity 2. An exhaust port 14 communicating with the exhaust passage 222 is provided below the housing 1. A closing plate 22 controlled to rotate by the control chamber 11 is provided inside the melting cavity 2 and closely attached to the inner wall of the housing 1.

[0033] Preferably, the closing plate 22 is provided with a plurality of through - holes 221 corresponding to and communicating with the respective air inlets 223; the distance between the respective air inlets 223 is not less than the diameter of the air inlet 223. The closing plate 22 is provided with a feed inlet 13 communicating with the hopper 12; when the closing plate 22 rotates to make the feed inlet 13 communicate with the hopper 12, the respective through - holes 221 are offset from the respective air inlets 223, and the closing plate 22 covers the respective air inlets 223.

[0034] Preferably, as Figure 2As shown, the exhaust channels 222 include multiple ones. Inside the lower part of the housing 1, an air collecting channel 224 is provided to collect the exhaust channels 222 and communicate with the exhaust port 14. The exhaust channels 222 are closely attached to the outer wall of the housing 1 and do not intersect with each other.

[0035] Preferably, as Figures 4 - 6 shown, the melting cavity 2 includes a first-stage plasticizing section above and a second-stage plasticizing section 25 below. The air inlet 223 is opened on the exhaust channel 222 at the position of the first-stage plasticizing section. The heating screw includes a first-stage screw 21 located in the first-stage plasticizing section and a second-stage screw 26 located in the second-stage plasticizing section 25. The first-stage screw 21 and the second-stage screw 26 respectively match the diameters of the first-stage plasticizing section and the second-stage plasticizing section 25. Preferably, the first-stage screw 21 is provided with a communication port 225 that penetrates up and down.

[0036] Preferably, an electromagnetic plate controlled and connected to the control chamber 11 is provided in the closing plate 22 from top to bottom. Inside the first-stage screw 21 at the position of the communication port 225, a receiving groove 226 with a diameter not less than that of the communication port 225 is provided around the communication port 225. An elastic member 227 with both ends fixed to the inner wall of the receiving groove 226 is provided in the receiving groove 226, and a magnetically conductive cover plate 228 covering the communication port 225 is fixed on the elastic member 227. Preferably, the cover plate 228 forms a dynamic seal with the inner wall of the receiving groove 226.

[0037] Preferably, as Figure 1 and Figure 3 shown, at the bottom of the housing 1 at the position of the injection bin 3, a discharge port 31 communicating with the injection bin 3 is provided. A nozzle 36 is provided at one end of the injection bin 3 away from the discharge port 31.

[0038] Preferably, inside the inner cavity of the injection bin 3 at the upper end position of the discharge port 31, a lifting plate 34 moving up and down horizontally is provided. The lifting plate 34 divides the inner cavity above the injection bin 3 into a condensation cavity 32. On the outer wall of the housing 1 at the position of the condensation cavity 32, an escape port 37 communicating the exhaust channel 222 with the condensation cavity 32 is provided. Preferably, a sealing ring 35 that fits with the inner wall of the injection bin 3 is provided on the outer periphery of the lifting plate 34.

[0039] Preferably, a plurality of slide rails 33 connected to the lifting plate 34 are provided on the bin wall of the injection bin 3 on the circumferential side of the lifting plate 34, and the lowermost ends of the slide rails 33 are higher than the upper end of the discharge port 31.

[0040] Based on the above structure, for the plasticizing and injection molding equipment of the exhaust-type injection molding machine of the present invention, the motor and the speed reducer assembly in the control chamber 11 control the rotation of the heating screw and the closing plate 22. After the material enters the melting chamber 2 from the hopper 12, the closing plate 22 rotates to close the feed port 13 and the air inlet 223. The heating screw heats and melts the material and conveys it downward during rotation. After the material is conveyed to the second-order screw 26 by the first-order screw 21, the closing plate 22 continues to rotate, so that the through port 221 communicates with the air inlet 223, and the feed port 13 remains closed. The pressure in the melting chamber 2 drops rapidly, and the generated volatile gas enters the exhaust passage 222 from the air inlet 223. Due to the rapid drop in pressure, it tends to liquefy. And the gas entering the exhaust passage 222 undergoes long-term heat transfer with the outer wall of the relatively low-temperature housing in the exhaust passage 222 with a long path due to the spiral, and further continuously liquefies until it reaches the gas collecting passage 224 at the bottom and is collected and processed from the exhaust port 14, avoiding the direct discharge of the volatile gas into the air.

[0041] When the air inlet 223 is opened, the electromagnetic plate in the closing plate 22 generates a magnetic force to attract the cover piece 228, causing the elastic member 227 to deform, and the cover piece 228 leaves the AC port 225, further reducing the air pressure at the second-order screw 26, prompting the gas in the material to escape, flowing rapidly into the first-order screw 21 from the AC port 225, and entering the exhaust passage 222 to achieve full discharge of the gas.

[0042] Part of the gas enters the condensation chamber 32 from the escape port 37. When the material reaches the discharge port 31, most of the gas in the material has volatilized. The condensation chamber 32 loses continuous gas exchange, and part of the gas stored in the chamber reversely enters the exhaust passage 222, and part starts to liquefy through heat transfer with the outside world. The air pressure in the condensation chamber 32 drops, the lifting plate 34 rises, the pressure in the injection bin 3 decreases, forming a suction force on the material at the discharge port 31, prompting the material to enter the injection bin 3, reducing the resistance of material transfer, and the heating screw continuously rotates to push and extrude the material for injection molding.

[0043] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the purpose of the present invention.

Claims

1. A plasticizing and injection molding device for an exhaust type injection molding machine, characterized in that It includes a housing (1), a melting cavity (2) surrounded by the housing (1), and a charging bin (3) provided on one side of the housing (1) and communicating with the inner cavity of the housing (1); a control bin (11) is provided at the top outside the housing (1); a heating screw rod which is driven by the control bin (11) and controls heating is vertically arranged in the melting cavity (2); a hopper (12) communicating with the melting cavity (2) is provided above the housing (1). An exhaust passage (222) which is spirally arranged from top to bottom in the housing (1) and communicates with the melting cavity (2) and the outside of the housing (1) respectively is provided. A plurality of air inlets (223) communicating with the melting cavity (2) are provided in the exhaust passage (222) above the melting cavity (2); an exhaust port (14) communicating with the exhaust passage (222) is provided below the housing (1); a closing plate (22) which is controlled to rotate by the control bin (11) is provided in the melting cavity (2) and closely attached to the inner wall of the housing (1). A plurality of through holes (221) corresponding to and communicating with each air inlet (223) are provided on the closing plate (22); the distance between each air inlet (223) is not less than the diameter of the air inlet (223). A feed inlet (13) communicating with the hopper (12) is provided on the closing plate (22); when the closing plate (22) rotates to make the feed inlet (13) communicate with the hopper (12), each through hole (221) is staggered from each air inlet (223), and the closing plate (22) covers each air inlet (223). A plurality of exhaust passages (222) are included; an air collecting passage (224) which collects each exhaust passage (222) and communicates with the exhaust port (14) is provided inside the lower part of the housing (1); the exhaust passages (222) are closely attached to the outer wall of the housing (1) and do not intersect with each other. The melting cavity (2) includes a first-stage plasticizing section above and a second-stage plasticizing section (25) below; the air inlets (223) are opened on the exhaust passage (222) at the position of the first-stage plasticizing section. The heating screw rod includes a first-stage screw rod (21) located in the first-stage plasticizing section and a second-stage screw rod (26) located in the second-stage plasticizing section (25); the first-stage screw rod (21) and the second-stage screw rod (26) respectively match the diameters of the first-stage plasticizing section and the second-stage plasticizing section (25).

2. The plasticizing and injection molding device of the exhaust type injection molding machine according to claim 1, characterized in that, An alternating current port (225) which penetrates up and down is provided on the first-stage screw rod (21).

3. The plasticizing and injection molding device of the exhaust type injection molding machine according to claim 2, characterized in that, An electromagnetic plate which is controlled and connected with the control bin (11) is provided in the closing plate (22) from top to bottom; in the first-stage screw rod (21) at the position of the alternating current port (225), a receiving groove (226) with a diameter not less than the alternating current port (225) is provided around the alternating current port (225); an elastic member (227) with two ends respectively fixed to the inner wall of the receiving groove (226) is provided in the receiving groove (226), and a magnetically conductive cover plate (228) covering the alternating current port (225) is fixed on the elastic member (227).

4. The plasticizing and injection molding device of the exhaust type injection molding machine according to claim 1, characterized in that, At the bottom of the housing (1) at the position of the charging bin (3), there is a discharge port (31) communicating with the charging bin (3); at one end of the charging bin (3) away from the discharge port (31), there is a nozzle (36).

5. The plasticizing and injection molding device of the exhaust type injection molding machine according to claim 4, characterized in that, Inside the inner cavity of the charging bin (3) at the upper end position of the discharge port (31), a lifting plate (34) moving up and down horizontally is provided; the lifting plate (34) divides the inner cavity above the charging bin (3) into a condensation cavity (32); on the outer wall of the housing (1) at the position of the condensation cavity (32), there is an escape port (37) connecting the exhaust duct (222) with the condensation cavity (32).

6. The plasticizing and injection molding device of the exhaust type injection molding machine according to claim 5, characterized in that, On the bin wall of the charging bin (3) on the peripheral side of the lifting plate (34), there are a plurality of slide rails (33) connected to the lifting plate (34), and the lowermost end of each slide rail (33) is higher than the upper end of the discharge port (31).

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