阅读说明：本技术 一种具有气体保护的注射成形模具及其使用方法 (Injection molding mold with gas protection function and using method thereof ) 是由 王海英 程志骏 杨芳 申雨晗 于 2021-08-17 设计创作，主要内容包括：本发明公开了一种具有气体保护的注射成形模具,属于注射成形设备技术领域,该装置通过充气组件保证模穴内充满保护气体,注射过程中相当于在原料周围形成一层气体保护膜,有效避免原料与氧气反应产生爆炸的问题,同时用于钛及钛合金的工件制作时通过该气体保护膜的保护可以有效避免氧化,生产效率高、成本低,生产成品质量更佳。本发明还提供了一种注射成形模具的使用方法,该方法确保注射成形喂料填充模穴后冷却定形之前不接触含氧的气氛,保证工作的安全。本发明解决现在技术所存在的钛及钛合金易发生氧化,极大增加使用成本；注射成形时易发生爆炸事故的问题,作用效果显著,适于广泛推广。(The invention discloses an injection molding die with gas protection, which belongs to the technical field of injection molding equipment. The invention also provides a using method of the injection molding die, which ensures that the injection molding feed is not contacted with oxygen-containing atmosphere after filling the die cavity and before cooling and shaping, and ensures the safety of work. The invention solves the problems that titanium and titanium alloy in the prior art are easy to be oxidized, and the use cost is greatly increased; the problem of easy explosion accident during injection molding, obvious effect and wide popularization.)

1. An injection mold with gas shield, comprising:

the front die body (1) comprises a first die cavity (111), a feeding cavity (112) communicated with the first die cavity (111), and a feeding hole (121) connected with one end, far away from the first die cavity (111), of the feeding cavity (112);

the rear mould main body (2) is detachably connected with the front mould main body (1) and comprises a second mould cavity (211) matched with the first mould cavity (111);

the pushing assembly (3) is connected with the rear die main body (2) in a sliding mode and used for pushing the formed green body (5) out of the second die cavity (211), and a gap is formed between the pushing assembly (3) and the rear die main body (2);

the inflation assembly (4) comprises an air conveying pipeline (41) used for conveying protective gas (6), and the air conveying pipeline (41) penetrates through the front die main body (1) and is communicated with the feeding cavity (112).

2. An injection-molding mold with gas shielding according to claim 1, wherein the front mold body (1) comprises:

the front die insert (11) is abutted against the rear die main body (2), a first groove (113) is formed in the front die insert (11), a first sealing piece (13) is arranged in the first groove (113), and the first die cavity (111) and the feeding cavity (112) are both arranged on the front die insert (11);

the front die comprises a front die frame (12), wherein the front die frame (12) is connected with a front die insert (11) and a rear die main body (2), a first accommodating groove matched with the front die insert (11) is formed in the front die frame (12), a feeding hole (121) is formed in the front die frame (12), and a gas conveying pipeline (41) penetrates through the front die frame (12) and the front die insert (11) in sequence.

3. An injection-moulding mould with gas protection according to claim 2, characterised in that the rear mould body (2) comprises:

the rear mold insert (21) is abutted to the front mold insert (11) and is in sliding connection with the pushing assembly (3), a second groove (212) matched with the first groove (113) is formed in the rear mold insert (21), a second sealing element (23) abutted to the first sealing element (13) is arranged in the second groove (212), and the second mold cavity (211) is arranged on the rear mold insert (21);

the rear mold frame (22) is connected with the front mold frame (12) and the rear mold insert (21), a second accommodating groove matched with the rear mold insert (21) and a mounting hole (221) used for accommodating the pushing assembly (3) are formed in the rear mold frame (22), and a gap is formed between the mounting hole (221) and the pushing assembly (3).

4. Injection mould with gas shield according to claim 3, characterized in that said ejector assembly (3) comprises:

a push plate (31) connected to the rear mold frame (22) and disposed in the mounting hole (221);

and the pushing piece (32) is connected with the pushing plate (31) and is in sliding connection with the rear mold insert (21), and the pushing piece (32) penetrates through the rear mold insert (21) and is abutted to the green body (5).

5. The gas-shielded injection molding apparatus as claimed in claim 3, wherein the rear mold body (2) is provided with a pressure monitor for obtaining information on the air pressure in the first mold cavity (111) and the second mold cavity (211).

6. The injection mold with gas protection as claimed in claim 5, wherein a pressure gauge (42) electrically connected to the pressure monitor and a flow meter (43) for acquiring flow information of the protection gas (6) are provided on the gas transmission pipeline (41).

7. Injection mould with gas shield according to claim 3, characterised in that said first recess (113) is a closed annular recess arranged outside said first mould cavity (111).

8. Injection mould with gas shield according to claim 3, characterized in that the shielding gas (6) is one or more of nitrogen, argon, helium.

9. A method of using an injection molding die for the injection molding die of any one of claims 3 to 8, comprising:

step 1, connecting the front mold main body (1) with the rear mold main body (2), wherein the first sealing element (13) is abutted against the second sealing element (23), at the moment, the protective gas (6) enters the feeding cavity (112) through the gas transmission pipeline (41) and flows towards the feeding hole (121) with low pressure, and the first mold cavity (111) and the second mold cavity (211) are filled with air;

step 2, an injection port (8) communicated with a raw material storage device is abutted against the feed port (121), and at the moment, the flow direction of the protective gas (6) is changed, so that the first mold cavity (111) and the second mold cavity (211) are filled with the protective gas and air is exhausted;

step 3, after the air is exhausted, starting to inject raw materials into the first mold cavity (111) and the second mold cavity (211) and exhausting the protective gas (6);

4, solidifying the raw materials into the green body (5) after the injection is finished;

and 5, separating the front mold main body (1) from the rear mold main body (2), and controlling the pushing assembly (3) to eject the green body (5) to complete one-time injection.

10. Use of an injection mould according to claim 9, characterised in that the pressure of the protective gas (6) in step 1 is greater than one atmosphere and less than the injection pressure of the injected material; the flow rate of the protective gas (6) in the injection process is 0.1-10L/min.

Technical Field

The invention relates to the technical field of injection molding equipment, in particular to an injection molding mold with gas protection and a using method thereof.

Background

The specific gravity of titanium and titanium alloy is almost half of that of iron metal, has low density, good corrosion resistance, high specific strength and satisfactory biocompatibility, is widely applied in the fields of aviation, aerospace, chemical engineering, biomedicine and the like, brings great economic benefits to human society, particularly replaces ineffective bones such as false teeth, tooth roots, artificial limbs and the like for bone reinforcement in human implants, and is a good material which can benefit human beings. However, the biggest problem in powder metallurgy technology is how to reduce or avoid the oxidation, and the cost for reducing the oxidized titanium or titanium alloy back to metal is huge and not economical according to the observation of the standard generation Free Energy-temperature diagram of oxide drawn by Gibbs Free Energy (Gibbs Free Energy), which is the disadvantage of the powder metallurgy process of titanium and titanium alloy, and compared with the iron family material, the advantage of processing cost is lost. It is not surprising that the advantages of titanium and titanium alloys in conventional bulk processing are much higher than in powder metallurgy, which was first known by practitioners of powder metallurgy.

Metal Powder injection molding (MIM) is a well-known Metal processing technology, and MIM products in China occupy more than half of the worldwide sales, and the technical capability is also the world cover. At present, most metal materials still stay in the field of iron-based metal materials, titanium and titanium alloy are rarely adopted, the material cost of titanium is high, the operational risk of fine titanium and titanium alloy powder is high, and explosion accidents occur when the injection feeding enters a mold cavity of a mold because the titanium and titanium alloy feeding is not properly heated when scientific research units/school laboratories/product production companies listen to injection molding.

Disclosure of Invention

In view of the above-mentioned drawbacks, the present invention provides an injection molding mold with gas protection and a method for using the same, so as to solve the problems in the prior art that titanium and titanium alloy are easily oxidized, and oxidized titanium or titanium alloy is reduced back to metal, which greatly increases the use cost; the problem of explosion accident is easy to occur when the injection feeding material enters the die cavity of the die because the temperature rise operation of the titanium and titanium alloy feeding material is not proper during the injection molding.

The invention provides an injection molding mold with gas protection, comprising:

the front die body comprises a first die cavity, a feeding cavity communicated with the first die cavity and a feeding hole connected with one end, far away from the first die cavity, of the feeding cavity;

the rear die main body is detachably connected with the front die main body and comprises a second die cavity matched with the first die cavity;

the pushing assembly is connected with the rear die main body in a sliding mode and used for pushing the formed green body out of the second die cavity, and a gap is formed between the pushing assembly and the rear die main body;

and the inflation assembly comprises an air conveying pipeline for conveying protective gas, and the air conveying pipeline penetrates through the front die main body and is communicated with the feeding cavity.

Preferably, the front mold body includes:

the front die insert is abutted against the rear die main body, a first groove is formed in the front die insert, a first sealing piece is arranged in the first groove, and the first die cavity and the feeding cavity are both arranged on the front die insert;

the front die comprises a front die frame, a front die insert and a rear die body, wherein the front die frame is connected with the front die insert and the rear die body simultaneously, a first accommodating groove matched with the front die insert is formed in the front die frame, the feed inlet is formed in the front die frame, and the gas transmission pipeline sequentially penetrates through the front die frame and the front die insert.

Preferably, the rear mold body includes:

the rear die insert is abutted against the front die insert and is in sliding connection with the pushing assembly, a second groove matched with the first groove is formed in the rear die insert, a second sealing element abutted against the first sealing element is arranged in the second groove, and a second die cavity is formed in the rear die insert;

the rear die frame is connected with the front die frame and the rear die insert, a second accommodating groove matched with the rear die insert and a mounting hole used for accommodating the pushing assembly are formed in the rear die frame, and a gap is formed between the mounting hole and the pushing assembly.

Preferably, the jacking assembly comprises:

the top push plate is connected with the rear die frame and arranged in the mounting hole;

and the pushing piece is connected with the pushing plate and is in sliding connection with the rear mold insert, and the pushing piece penetrates through the rear mold insert and is abutted to the green body.

Preferably, a pressure monitor for acquiring air pressure information in the first mold cavity and the second mold cavity is arranged on the rear mold body.

Preferably, a pressure gauge electrically connected with the pressure monitor and a flow meter for acquiring the flow information of the protective gas are arranged on the gas transmission pipeline.

Preferably, the first groove is a closed annular groove arranged outside the first mold cavity.

Preferably, the protective gas is one or more of nitrogen, argon and helium.

The present invention also provides a method of using the injection molding mold of any one of the above aspects, comprising:

step 1, connecting the front mold main body with the rear mold main body, wherein the first sealing element is abutted against the second sealing element, at the moment, the protective gas enters the feeding cavity through the gas transmission pipeline and flows towards the feeding hole with low pressure, and the first mold cavity and the second mold cavity are filled with air;

step 2, an injection port communicated with a raw material storage device props against the feeding hole, at the moment, the flow direction of the protective gas is changed, the first mold cavity and the second mold cavity are filled with the protective gas, and air is discharged;

step 3, after air is exhausted, starting to inject raw materials into the first mold cavity and the second mold cavity, and exhausting the protective gas;

4, after the injection is finished, solidifying the raw materials into the green body;

and 5, separating the front mold main body from the rear mold main body, and controlling the pushing assembly to eject the green body to complete one-time injection.

Preferably, the pressure of the protective gas in the step 1 is more than one atmosphere and less than the injection pressure of the injection raw material; the flow rate in the protective gas injection process is 0.1-10L/min.

According to the scheme, the injection molding mold with the gas protection function ensures that the injection molding feed is not contacted with the oxygen-containing atmosphere after filling the mold cavity and before cooling and shaping, and ensures the safety of work. The inflation assembly ensures that the mold cavity is filled with protective gas, a layer of gas protection film is formed around the raw material in the injection process, the problem of explosion caused by the reaction of the raw material and oxygen is effectively avoided, meanwhile, oxidation can be effectively avoided through the protection of the gas protection film when the inflation assembly is used for manufacturing workpieces of titanium and titanium alloy, the production efficiency is high, the cost is low, and the quality of the finished products is better. The invention also provides a using method of the injection molding die, which solves the problems that titanium and titanium alloy are easy to oxidize in the prior art, oxidized titanium or titanium alloy is required to be reduced back to metal, and the using cost is greatly increased; the problem of explosion accident is easy to occur when the injection feeding material enters the die cavity of the die because the temperature rise operation of the titanium and titanium alloy feeding material is not proper during the injection molding. The invention has obvious effect and is suitable for wide popularization.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural view of a conventional injection molding die;

FIG. 2 is a schematic structural diagram of an injection molding mold with gas shield according to the present invention;

FIG. 3 is a schematic structural view of a gas passage formed by a prior art seal rubber ring;

FIG. 4 is a schematic structural diagram of a gas passage formed in an injection molding mold with gas shielding according to the present invention;

FIG. 5 is a schematic structural diagram of the injection mold with gas shield in the use process of step 1 according to the present invention;

FIG. 6 is a schematic structural diagram of the injection mold with gas shield in the use process of step 2 according to the present invention;

FIG. 7 is a schematic structural diagram of the injection mold with gas shield in the state of step 3 during use according to the present invention;

FIG. 8 is a schematic structural diagram of the injection mold with gas shield in the use state of step 4 according to the present invention;

fig. 9 is a schematic structural diagram of another injection molding mold with gas protection according to the present invention.

In FIGS. 1-9:

1. a front mold body; 2. a rear mold body; 3. a pushing assembly; 4. an inflation assembly; 5. green bodies; 6. a shielding gas; 7. parting the surface; 8. an injection port; 11. a front mold insert; 12. a front mold frame; 13. a first seal member; 21. a rear mold insert; 22. a rear mold frame; 23. a second seal member; 31. pushing the plate; 32. pushing the piece; 41. a gas transmission pipeline; 42. a pressure gauge; 43. a flow meter; 111. a first mold cavity; 112. a feed cavity; 113. a first groove; 121. a feed inlet; 211. a second mold cavity; 212. a second groove; 221. and (7) installing holes.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, the conventional MIM mold has no absolute air tightness on the substantially parting surface 7, and the clearance between all the moving parts and the insert of the mold causes air to enter, which means that no oxygen can be guaranteed, so that there is a great risk in injection molding of titanium and titanium alloy, and oxygen may contact with the high-temperature titanium and titanium alloy feeding part to be rapidly oxidized to cause explosion, which has been the accident in many college laboratories and mass production units.

Example 1

Referring to fig. 2 to 9, an embodiment of an injection mold with gas shield according to the present invention will now be described. The injection molding mold with gas protection comprises a front mold body 1, a rear mold body 2, a pushing component 3 and an inflating component 4, wherein the front mold body 1 comprises a first mold cavity 111, a feeding cavity 112 communicated with the first mold cavity 111, and a feeding hole 121 connected with one end of the feeding cavity 112 far away from the first mold cavity 111; the rear mould body 2 is detachably connected with the front mould body 1 and comprises a second mould cavity 211 matched with the first mould cavity 111; the pushing component 3 is connected with the rear die main body 2 in a sliding manner and is used for pushing the formed green body 5 out of the second die cavity 211, and a gap is formed between the pushing component 3 and the rear die main body 2; the inflation assembly 4 comprises an air duct 41 for conveying the protective gas 6, and the air duct 41 penetrates through the front mold body 1 and is communicated with the feeding cavity 112.

For convenience of description, please refer to fig. 2, a rectangular coordinate system is established with any point in space as an origin, the moving direction of the pushing member 32 as a Z-axis, and the direction perpendicular to the Z-axis as an X-axis, wherein the X-axis indicates left and right directions, i.e., a horizontal direction, and the Z-axis indicates up and down directions, i.e., a vertical direction.

The surface of the front die main body 1, which is contacted with the rear die main body 2, is a parting surface 7, and the surface of the rear die main body 2, which is contacted with the front die main body 1, is a parting surface 7; after the front mold body 1 and the rear mold body 2 are connected, a cavity formed by the first mold cavity 111 and the second mold cavity 211 is a mold cavity, and the mold cavity is arranged according to the shape of a required workpiece. The feed port 121 is abutted against the injection port 8, and the raw material is injected into the mold cavity through the injection port 8. The gas transmission pipeline 41 is communicated with a gas storage tank, and protective gas 6 is stored in the gas storage tank. The gas line 41 delivers protective gas 6 to the inlet chamber 112 during operation of the device. The positive pressure of the protective gas 6 can be 1.5-1.8 atmospheres, and excessive pressure requires more gas flow, so that the waste of gas resources is caused, and the injection pressure is generally 60Mpa, namely 600 atmospheres, so that the protective gas 6 adopts the positive pressure greater than 1 atmosphere, thereby effectively avoiding air backflow, maximally utilizing the gas resources and avoiding the waste of resources.

The use method of the injection molding die comprises the following steps:

s1, connecting the front mold body 1 and the rear mold body 2 to form a complete mold cavity, injecting protective gas 6 into the feeding cavity 112, wherein the protective gas 6 enters the feeding cavity 112, namely the glue inlet position of the mold cavity, through the gas transmission pipeline 41, flows towards the feeding hole 121 with low pressure, namely the filling opening, and does not flow into the mold cavity, and at the moment, the first mold cavity 111 and the second mold cavity 211 are filled with air;

the pressure of the protective gas 6 in the S1 is more than one atmosphere and less than the injection pressure of the injection raw material; the flow rate of the protective gas 6 in the injection process is 0.1-10L/min.

S2, the injection port 8 connected to the raw material storage device is against the feed port 121, and no injection is performed, at this time, the flow direction of the protective gas 6 is changed, the first mold cavity 111 and the second mold cavity 211 are filled with the protective gas and the air is exhausted, wherein the air is exhausted through the gap between the upper and lower parting surfaces 7 and the gap between the ejector 32 and the rear mold insert 21, and the pressure of the protective gas 6 is greater than one atmosphere and less than the injection pressure, so that the air is prevented from flowing back to the mold cavity;

s3, after air is discharged, injecting raw materials into the first mold cavity 111 and the second mold cavity 211, and discharging protective gas 6, where the injection pressure is large, that is, the injection pressure of the titanium and titanium alloy feed is large, so that the protective gas 6 can be smoothly discharged, one end of the gas transmission pipeline 41 connected to the feeding cavity 112 is a gas inlet, and the gas inlet may be a round opening with a diameter of 0.005mm-0.015mm, for example, 0.01mm, and since the diameter of the gas inlet is small, the injected raw materials cannot flow in, and the protective gas 6 discharges the protective gas 6 to the gap between the upper and lower parting surfaces 7 and the gap between the pushing member 32 and the rear mold insert 21;

s4, solidifying the raw materials into a green body 5 after the injection, wherein, for example, the titanium and titanium alloy feed is solidified into the green body 5, and no air enters the process because the protective gas 6 is continuously injected;

and S5, stopping the injection of the protective gas 6, separating the front mold main body 1 from the rear mold main body 2, controlling the pushing assembly 3 to eject the green body 5, and completing one-time injection to prepare the next mold.

Compared with the prior art, the injection molding mold with gas protection applies micro protective gas 6 flow with positive pressure lower than injection pressure to the mold cavity, ensures that the injection molding feed is not contacted with oxygen-containing atmosphere after filling the mold cavity and before cooling and shaping, and ensures the safety of work. The inflation component 4 ensures that the mold cavity is filled with the protective gas 6, a layer of gas protective film is formed around the raw material in the injection process, the problem of explosion caused by the reaction of the raw material and oxygen is effectively avoided, meanwhile, the oxidation can be effectively avoided through the protection of the gas protective film when the inflation component is used for manufacturing workpieces of titanium and titanium alloy, the production efficiency is high, the cost is low, and the quality of the produced finished products is better.

Example 2

As a specific implementation manner of the embodiment of the present invention, please refer to fig. 2 to 9 together, the structure of the injection molding mold with gas shielding provided in this embodiment is substantially the same as that of embodiment 1, except that the front mold body 1 includes a front mold insert 11 and a front mold frame 12, wherein the front mold insert 11 abuts against the rear mold body 2, a first groove 113 is disposed on the front mold insert 11, a first sealing member 13 is disposed in the first groove 113, and both the first mold cavity 111 and the feeding cavity 112 are disposed on the front mold insert 11; the front mold frame 12 is simultaneously connected with the front mold insert 11 and the rear mold main body 2, a first accommodating groove matched with the front mold insert 11 is formed in the front mold frame 12, the feed inlet 121 is formed in the front mold frame 12, and the gas transmission pipeline 41 sequentially penetrates through the front mold frame 12 and the front mold insert 11. The gas transmission pipeline 41 can be 90 degrees settings with the feeding chamber 112, or the gas transmission pipeline 41 and the feeding chamber 112 are acute angle settings, that is the gas transmission pipeline 41 is inclined downwards to set up, this kind of setting can effectively avoid the raw materials to pour into the gas transmission pipeline 41 in, avoids the gas transmission pipeline 41 to block, guarantees its long-term result of use.

In this embodiment, the rear mold body 2 includes a rear mold insert 21 and a rear mold frame 22, wherein the rear mold insert 21 abuts against the front mold insert 11 and is slidably connected to the pushing assembly 3, a second groove 212 adapted to the first groove 113 is formed on the rear mold insert 21, a second sealing member 23 abutting against the first sealing member 13 is arranged in the second groove 212, and the second mold cavity 211 is arranged on the rear mold insert 21; the rear mold frame 22 is connected with the front mold frame 12 and the rear mold insert 21, a second accommodating groove matched with the rear mold insert 21 and a mounting hole 221 for accommodating the pushing assembly 3 are formed in the rear mold frame 22, and a gap is formed between the mounting hole 221 and the pushing assembly 3. The rear mould main body 2 is provided with a pressure monitor for acquiring air pressure information in the first mould cavity 111 and the second mould cavity 211, the pressure monitor can be a pressure sensor for acquiring pressure information in the mould cavities, and the pressure in the mould cavities is controlled to be always greater than 1 atmosphere by controlling the flow of the protective gas 6 in the gas transmission pipeline 41, so that air is prevented from entering the mould cavities. It is within the scope of the present disclosure to achieve the performance benefits associated with the pressure monitor described above.

In this embodiment, the first groove 113 is a closed annular groove disposed outside the first mold cavity 111, or a local seal groove disposed along the periphery of the mold cavity in the parting surface 7, and the shape of the first seal 13 is adapted to the shape of the first groove 113. The first sealing element 13 and the second sealing element 23 can be sealing rubber rings and are used for preventing the protective gas 6 from flowing to the parting surface 7 and reducing the loss of the protective gas 6, and the first sealing element 13 and the second sealing element 23 are used as exhaust ports of the mold cavity, so that the mold cavity can be reasonably filled with materials when the materials are filled, and the influence of the gas in the mold cavity on the shape of the green body 5 is avoided. When the first sealing member 13 and the second sealing member 23 are both closed ring structures arranged along the periphery of the mold cavity, if the residual gas pressure is too high due to the filling material in the mold cavity and is higher than the gas pressure of the input protective gas 6, which is exemplarily higher than 1.8 atmospheric pressure, the gas presses the first sealing member 13 and the second sealing member 23, and an exhaust passage is formed between the first sealing member 13 and the second sealing member 23 and is exhausted, so that the pressure in the mold cavity is ensured to be stable. Because the pressure of the protective gas 6 in the mold cavity is greater than the atmospheric pressure and the opening conditions of the first sealing element 13 and the second sealing element 23 are that the mold cavity internal pressure is too high, the first sealing element 13 and the second sealing element 23 are opened only in one direction in the use process, and the backflow of external gas, particularly air, is effectively prevented. It is within the scope of the present disclosure that the performance of the first seal 13 and the second seal 23 may be achieved.

In this embodiment, the pushing assembly 3 includes a pushing plate 31 and a pushing member 32, wherein the pushing plate 31 is connected to the rear mold frame 22 and disposed in the mounting hole 221; the ejector 32 is connected to the ejector plate 31 and slidably connected to the rear mold insert 21, and the ejector 32 penetrates the rear mold insert 21 and abuts against the green compact 5. The pushing piece 32 can be a cylinder, and after the green body 5 is formed, the pushing piece 32 is started to push out the green body 5; the pushing member 32 may be an ejector pin, the pushing plate 31 is a supporting plate for fixing the pushing member 32, and the pushing plate 31 is slidably connected to the rear mold frame 22, that is, the pushing member 32 slides up and down in the vertical direction in the mounting hole 221 to drive the pushing member 32 to move up and down, so as to realize the function of pushing out the green compact 5. It will be understood that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations and positional relationships that are based on the orientation or positional relationship shown in the drawings, are used only for convenience in describing and simplifying the present invention, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention.

In the present embodiment, the gas transmission pipeline 41 is provided with a pressure gauge 42 electrically connected to the pressure monitor and a flow meter 43 for acquiring flow information of the shielding gas 6. The pressure and flow rate of the protective gas 6 in the gas transmission pipeline 41 are controlled by the pressure information in the die cavity acquired by the pressure monitor, and the acquired pressure information is displayed by the pressure gauge 42, so that the real-time observation of a worker is facilitated. The protective gas 6 is one or more of nitrogen, argon and helium, and can also be inert gas obtained by mixing the rest; the shielding gas 6 is a high purity gas having an oxygen content of less than 1000 PPM.

The rear die main body 2 is placed on the working platform, a tiny gap is formed between the rear die main body 2 and the working platform, after the feeding hole 121 is blocked, the protective gas 6 is filled into the die cavity through the gas transmission pipeline 41, after the die cavity is filled with the protective gas 6, the raw material is injected into the die cavity, the protective gas 6 is extruded out of the die cavity by the raw material, one part of the raw material is extruded out of the space between the first sealing piece 13 and the second sealing piece 23, the other part of the raw material is extruded into the mounting hole 221, meanwhile, the air in the mounting hole 221 is extruded out, the mounting hole 221 is filled with the protective gas 6, the first sealing piece 13 and the second sealing piece 23 are of a one-way gas outlet structure, the raw material is effectively guaranteed not to be in contact with the air in the forming process, and the safety of the forming process is guaranteed.

Compared with the prior art, when the device is applied to titanium and titanium alloy powder injection molding, the front mold body 1 and the rear mold body 2 are connected to form a complete mold cavity, the first groove 113 and the second groove 212 are arranged on the parting surface 7, the first sealing piece 13 and the second sealing piece 23 are filled, and before titanium and titanium alloy feeding is performed each time, the protective gas 6 is filled into the mold cavity and certain pressure is maintained, so that the process of filling the mold cavity with the titanium and titanium alloy feeding is performed in an oxygen-free environment, and the pressure of the protective gas 6 is far smaller than the injection pressure, so that the protective gas 6 can be smoothly discharged out of the mold cavity through the first sealing piece 13 and the second sealing piece 23 in a one-way manner, and the device effectively ensures the safety of the titanium and titanium alloy injection molding process.

The use method of the injection molding die comprises the following steps:

s1, connecting the front mold body 1 and the rear mold body 2 to form a complete mold cavity, abutting the first sealing piece 13 and the second sealing piece 23, and injecting the protective gas 6 into the feeding cavity 112, wherein due to the blocking of the first sealing piece 13 and the second sealing piece 23 on the parting surface 7, the protective gas 6 enters the feeding cavity 112, namely the glue inlet position of the mold cavity, through the gas transmission pipeline 41, flows towards the feeding hole 121 with low pressure, namely the filling opening, and does not flow into the mold cavity, and at the moment, the first mold cavity 111 and the second mold cavity 211 are filled with air;

s2, the injection port 8 connected to the raw material storage device is pressed against the feed port 121, and no injection is performed, at this time, the flow direction of the protective gas 6 is changed, the first mold cavity 111 and the second mold cavity 211 are filled with the protective gas and the air is exhausted, wherein the air is exhausted through the exhaust channel formed between the first sealing element 13 and the second sealing element 23, the gap between the upper and lower parting surfaces 7, and the gap between the pushing element 32 and the rear mold insert 21, and the pressure of the protective gas 6 is greater than one atmosphere and less than the injection pressure, so that the air is prevented from flowing back to the mold cavity;

s3, after the air is discharged, injecting the raw material into the first mold cavity 111 and the second mold cavity 211, and discharging the protective gas 6, wherein the injection pressure is large, i.e. the injection pressure of the titanium and titanium alloy feed is large, so that the protective gas 6 can be smoothly discharged, and the protective gas 6 discharges the protective gas 6 to the exhaust channel formed between the first sealing element 13 and the second sealing element 23, the gap between the upper and lower parting surfaces 7, and the gap between the pushing element 32 and the rear mold insert 21;

s4, solidifying the raw material into a green body 5 after the injection, wherein air does not enter the process because the protective gas 6 is continuously injected;

and S5, stopping the injection of the protective gas 6, separating the front mold main body 1 from the rear mold main body 2, controlling the pushing assembly 3 to eject the green body 5, and completing one-time injection to prepare the next mold.

The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other. Details which are not described in detail in the embodiments of the invention belong to the prior art which is known to the person skilled in the art.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.