KR20190043762A - Manufacturing method of plunger tip for die casting - Google Patents

Abstract

The present invention relates to a method of manufacturing a plunger for diecasting. The method includes: upper and lower part forging processes of forging a material for an upper part (210) forming the front end of a plunger tip (200) and a material for a lower part (220) combined with a plunger rod (103) with a corresponding standard by pressing each of the materials with a forge press; upper and lower part bonding processes of bonding the lower end of the upper part (210) and the upper end of the lower part (220) through frictional welding; and a treatment process of adding a mechanical property by thermally treating and polishing the plunger tip (200) with the upper and lower parts (210, 220) bonded. Therefore, since the upper part (210) and the lower part (220) of the plunger tip are forged with different kinds of materials, the present invention is capable of improving quality and performance and shortening a conventional internal and external groove treatment process to increase productivity.

Description

Technical Field [0001] The present invention relates to a method of manufacturing a plunger tip for a die casting,

The present invention relates to a method of manufacturing a plunger tip for die casting, and more particularly, to manufacturing a plunger tip to be coupled to a plunger rod of a die casting machine, the upper end portion and the lower end portion are separately formed by using a different material, So as to improve the mechanical and physical properties of the plunger tip and shorten the process of forming the inner and outer diameter grooves.

In general, die casting is a precision casting method in which a metal melt is injected into a metal mold having a desired shape to produce metal parts.

In general, the die casting process is performed by injecting molten metal into a die coated with a lubricant, holding the die at a predetermined pressure to solidify the casting, opening the die to remove the mold, and removing the casting to complete the metal part.

Metals used in die casting mainly use alloys such as aluminum, zinc, copper, tin, and magnesium, and are poured by pneumatic or hydraulic pressure using a die casting machine to cool and solidify. Due to the advantage of mass production of metal parts, diecasting is produced by diecasting of various metal parts used in various fields such as automobile, electric, optical, and architectural.

1, a conventional die casting machine includes a mold 102 for forming a cavity corresponding to a desired casting shape, a sleeve 101 formed in a straight line to form a hollow communicating with the cavity, Respectively. One side of the sleeve 101 is provided with a nozzle 104 for injecting molten metal into the cavity 101. The plunger rod 103 is provided in the hollow of the sleeve 101 to reciprocate by pneumatic or hydraulic pressure. A plunger tip (200) is coupled to the tip of the plunger rod (103) to inject the molten metal into the cavity at a high pressure.

Examples of the known technology include a mold sleeve in which an injection port is formed at an upper end thereof as disclosed in Korean Utility Model Registration No. 20-0351599, a nozzle part positioned at the upper end of the injection port and injecting the molding material into the injection port side, And a plunger tip for moving the molding material toward the cavity by a predetermined amount while reciprocating right and left by the piston rod when the mold is injected into the mold sleeve.

As another example, in Korean Utility Model Registration No. 20-0357100, a polygonal mounting portion connected to a piston rod is integrally formed continuously at the rear end of an injection portion for pushing a molding material injected into a sleeve by a predetermined amount, Wherein a hollow portion is formed in the mounting portion so as to be able to receive the shrinkage state and impact when the metal is injected, and a screw hole for screwing the end portion of the piston rod is formed in the mounting portion so as to communicate with the hollow portion, To thereby form a plunger tip for die casting which injects the molten metal introduced into the sleeve into the cavity of the mold while being transported along the sleeve.

Such a diecasting plunger tip generally forms a cylindrical body having an engagement groove for receiving the tip of the plunger rod. In the prior art, as shown in FIG. 5, a raw material is cast to form a main body, and then the inside and outside diameter are manufactured to a target standard through a CNC groove processing process.

For example, a method of manufacturing a plunger tip for a die casting known in Korean Patent No. 10-0594369 includes casting a raw material of a plunger tip to a predetermined diameter and length, A step of primary machining to have a machining allowance necessary for precision machining, a step of heat treating the primary machined workpiece, and a step of secondary precision machining of the heat treated workpiece to the diameter and length of the final plunger tip.

Korean Utility Model Registration No. 20 - 0351599 (May 28, 2004) Korean Utility Model Registration No. 20 - 0357100 (July 21, 2004) Korean Registered Patent No. 10 - 0594369 (Jun. 30, 2006) Korean Patent No. 10 - 1693277 (2017.01.06)

The plunger tip for die casting to which the conventional technique as described above is applied is formed by integrally forming a cap-shaped main body having an engaging groove for receiving a tip end of a plunger rod. As shown in the flow chart of FIG. 5, To complete the plunger tip body by casting and then subjecting the plunger tip body to a heat treatment through an inner and outer diameter groove forming process.

Therefore, in the prior art, since the plunger tip is cast using the same material, it is impossible to differentiate the tip end of the plunger tip, which directly contacts the molten metal, and the mechanical characteristic of the rear end coupled to the plunger rod. As a result, the abrasion condition in the die casting machine working process may cause the service life and maintainability of the plunger tip, which appear differently at the front end and the rear end, to be significantly lowered.

As known in the art, the plunger tip is required to have high dimensional accuracy due to its characteristics of being a component that operates at a high speed and a high pressure along the inner diameter of the sleeve by being coupled with the plunger rod in a high temperature environment by the molten metal. In the prior art, The CNC grooving process such as cutting and roughing needs to be additionally performed inside and outside, which requires a long time for machining, resulting in a problem of deteriorating productivity.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art,

A method of manufacturing a plunger tip for pressurizing a molten metal injected into a sleeve of a die casting machine and coupling the plunger rod to a plunger rod for injection into a mold,

1. A method of manufacturing a plunger tip (200) that presses a molten metal injected into a sleeve (101) of a die casting machine to be coupled to a plunger rod (103) for injection into a mold (102)

An upper end forging process in which the material of the upper end portion 210 forming the tip end of the plunger tip 200 and the material of the lower end portion 220 coupled to the plunger rod 103 are respectively pressed by a forging press and forging the material into a corresponding standard, and,

A lower end of the forged upper end 210 and an upper end of the lower end 220 are joined by friction welding,

And a machining process for imparting mechanical properties by heat-treating and polishing the plunger tip 200 to which the upper and lower ends 210 and 220 are joined.

Further, in the processing step,

A pretreatment step of heating and cooling the plunger tip 200 that has undergone the upper and lower bonding processes to remove internal stress,

A first polishing step of polishing the surface of the joining portion A of the upper and lower ends 210 and 220 of the plunger tip 200 subjected to the pre-

A heat treatment step of hardening the surface of the plunger tip 200 after the pre-treatment and the first polishing step,

And a second polishing step of polishing the surface of the plunger tip 200 subjected to the heat treatment process.

The upper end portion 210 and the lower end portion 220 of the plunger tip 200 to be forged by the upper end forging process and the lower end forging process are made of different materials,

The material of the upper portion 210 is one selected from the group consisting of SKD61, nitrided steel, beryllium copper, and high steel,

The material of the lower end portion 220 is composed of one selected from the group consisting of SKD61, nitrided steel, beryllium copper, high-strength steel, SS41, S45C, and copper.

Accordingly, it is possible to achieve the object of providing a method of manufacturing a plunger tip in which the upper end portion and the lower end portion are made of the same or different materials, thereby shortening the inner and outer diameter groove forming process according to the prior art.

The present invention is different from the construction in which the plunger tip is integrally formed by using the same material in the casting method in the method of manufacturing the plunger tip according to the prior art, and the upper end portion and the lower end portion are separately formed by the forging method, Thereby manufacturing a plunger tip.

Particularly, since the upper end of the plunger tip which is directly contacted with the molten metal and the lower end coupled with the plunger rod can be constituted of different materials, economical gain due to material cost reduction as well as different mechanical characteristics are imparted, The effect of extending the life time is derived.

In addition, by improving the physical properties such as the mechanical properties and the fineness of the tissue through the processing including the upper part forging process and the lower part forging process, the upper and lower bonding process, and the pre-process and second polishing process, There is an advantage that it can be manufactured.

In addition, as in the prior art, there is an advantage in that the machining time can be shortened and the productivity can be improved by improving the disadvantage that the CNC grooving process such as cutting and roughing is additionally performed after casting the plunger tip integrally.

1 is a schematic cross-sectional view of a typical die casting machine;
2 is a process flow diagram of a method for manufacturing a plunger tip for die casting according to the present invention.
3 is a perspective view and a cross-sectional view of a plunger tip according to an embodiment of the method for manufacturing a plunger tip for die casting according to the present invention, the upper end forging process and the lower end forging process, and the upper and lower end bonding process.
4 is a front, rear, and cross-sectional view of a plunger tip completed by a method for manufacturing a plunger tip for die casting according to the present invention.
5 is a process flow diagram of a conventional method of manufacturing a plunger tip.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the construction and operation of a method of manufacturing a plunger tip for die casting according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description, a detailed description of parts that can be easily implemented by those skilled in the art may be omitted.

FIG. 1 is a schematic cross-sectional view of a general die casting machine, FIG. 2 is a process flow chart of a method of manufacturing a plunger tip for die casting according to the present invention, FIG. 3 is a top end forging process, 4 is a perspective view, rear perspective view, and cross-sectional view of the plunger tip completed by the method for manufacturing a plunger tip for die casting according to the present invention, and Fig. 5 is a cross- Fig. 3 is a flow chart of a method of manufacturing a plunger tip according to the present invention.

The method of manufacturing a plunger tip for die casting to which the technique of the present invention is applied is to manufacture a plunger tip 200 to be coupled to a plunger rod 103 for pressurizing a molten metal injected into a sleeve 101 of a die- The upper end portion 210 and the lower end portion 220 are separately formed by a forging method using mutually different materials and mutually joined by friction welding so that the mechanical and physical characteristics of the plunger tip 200 are improved, It is a technology related to a method of manufacturing a plunger tip for shortening an inner diameter groove forming process.

As shown in FIG. 2, the method for manufacturing a plunger tip for die casting according to the present invention includes an upper end forging process, a lower end forging process, an upper and lower end joining process, and a machining process.

The upper end forging process and the lower end forging process are performed by forging press the material of the upper end portion 210 forming the tip end of the plunger tip 200 and the material of the lower end portion 220 joining the plunger rod 103 respectively, .

In the present invention, the upper end portion 210 and the lower end portion 220 of the plunger tip 200 are each forged in a forging manner different from the conventional casting method used for manufacturing the plunger tip.

Forging is a molding method in which a solid metal material is compressed between forced tools to give a plastic deformation to the metal material. After the material is heated to a certain temperature, the shape of the desired standard is formed by a mechanical method in which the material is pressurized with a hammer or a press.

The upper end forging process and the lower end forging process of the present invention are performed by molding the upper end portion 210 and the lower end portion 220 of the plunger tip 200 into respective shapes and simultaneously densifying the particle density of the solid metal material and uniformizing the structure . Therefore, it is possible to produce a product having significantly improved mechanical properties as compared with a plunger tip produced by conventional general casting.

An upper end portion 210 of the plunger tip 200 formed by the upper end forging process and a lower end portion 220 of the plunger tip 200 formed by the lower end forging process Since the groove can be formed with high dimensional precision in the process of forging the material by the forging press, it is possible to shorten the process of manufacturing the inner and outer diameter grooves such as the conventional casting method.

3, the upper end portion 210 and the lower end portion 220 of the plunger tip 200 are opposed to each other. In the upper end forging process and the lower end forging process, Lt; / RTI > This is intended to elucidate the ease of pressure welding by friction welding in the upper and lower end bonding processes to be described later, and to exclude thermal deformation.

Meanwhile, in the present invention, the upper end portion 210 and the lower end portion 220 of the plunger tip 200 to be forged by the upper end forging process and the lower end forging process are made of different materials.

Specifically, the upper end portion 210 of the plunger tip 200 is put into the upper end forging process using one selected from the group consisting of SKD61, nitrided steel, beryllium copper, and high-speed steel.

The lower end 220 of the plunger tip 200 is supplied to the lower end forging process using one selected from the group consisting of SKD61, nitrided steel, beryllium copper, high steel, SS41, S45C and copper.

The SKD61 is a hot alloy tool steel having high hardness and wear resistance during heat treatment. Cr, W, Si, Mn, V, and Ci, and forms a carbide while undergoing a forging process to improve mechanical properties such as softening resistance, curability and oxidation resistance. Mechanical stress and heat stress intensity due to forging are high.

The nitrided steel is a steel obtained by hardening the surface of the steel by nitriding treatment. It has mechanical characteristics with high abrasion resistance, heat resistance, corrosion resistance, and stress intensity required for precision machine parts. The nitrided steel includes an Al-Cr-Mo system, a Cr-Mo system, a Cr-Mo-V system, and an Al-Cr system depending on the type of alloy element contained therein.

The beryllium copper is alloy of 0.1 to 2.7% beryllium which is excellent in strength and abrasion resistance and has improved mechanical properties such as high strength, elasticity, hardness, abrasion resistance and corrosion resistance. Especially, it is suitable for precision press because it has high mechanical stress intensity due to forging and has no directionality. Deformation is prevented during the age hardening by the heat treatment, and fatigue resistance can be exhibited even for long-term use.

The high-speed steel is a high-speed tool steel which is made of a metal such as Cr, W, V, or Mo by alloying with carbon steel and has mechanical properties such as high hardness and tensile strength.

The SS41 is a general-purpose rolled steel material containing a metal such as C, Si, Mn, etc. and having a maximum content of P and S of 0.050% and a minimum tensile strength of 41 kg / mm ² .

The above-mentioned S45C is a carbon steel for machine structural use, and the content of C is 0.45% and contains a metal such as Si and Mn, and the hardness is improved by the heat treatment.

In the upper end forging process and the lower end forging process, hot, warm or cold forging may be performed according to the recrystallization reaction temperature condition of each material as described above. According to the present invention, the upper end portion 210 and the lower end portion 220 of the plunger tip 200 are selected from different materials from the above-mentioned groups according to the type of the molten metal introduced into the die casting machine, To form an integrated plunger tip (200).

The upper and lower end joining process is a process of friction welding and bonding the lower end of the upper end portion 210 and the upper end of the lower end portion 220 formed through the upper end forging process and the lower end forging process described above to each other.

Friction welding is a pressure welding method in which metals are welded using heat generated by friction. The other side is rotated at a high speed while one side of the upper end 210 or the lower end 220 is fixed and the frictional heat is generated in the vicinity of the lower end of the upper end 210 and the upper end of the lower end 220 The rotation is stopped and both sides are welded to each other by welding.

As shown in the cross-sectional view of FIG. 3, the plane (A) of the upper end portion 210 and the lower end portion 220 of the plunger tip 200 formed by the upper end forging process and the lower end forging process, The plunger tip 200 is molded while keeping the shape of the upper portion 210 and the lower portion 220 without the possibility of thermal deformation of the upper portion 210 and the lower portion 220 except for the corresponding portion. .

The processing step is a step of applying heat and polishing the plunger tip 200 to which the upper end portion 210 and the lower end portion 220 are joined to impart mechanical and physical properties.

As described above, the present invention is characterized in that the upper end portion 210 and the lower end portion 220 of the plunger tip 200 are forged with different materials, and then they are joined together by friction welding to form the upper end portion 210 and the lower end portion 220, The structure of the alloy structure and the structure of the bonding region constituting the bonding layer 220 are non-uniform. Therefore, a machining process is performed to realize stable mechanical characteristics throughout the plunger tip 200.

Specifically, the processing step includes a pretreatment step of heating and cooling the plunger tip 200 that has undergone the upper and lower end bonding processes to remove internal stress, and a pretreatment step of removing the internal stress from the upper and lower ends 210 and 220 of the plunger tip 200 A heat treatment step of hardening the surface of the plunger tip 200 after the pre-treatment and the first polishing step; and a heat treatment step of heat-treating the plunger tip 200 are polished by a second polishing step.

The preprocessing process removes the residual stress formed inside the metal while the upper end portion 210 and the lower end portion 220 of the plunger tip 200 made of different materials pass through the forging process and the bonding process to prevent deformation and warping And to maintain dimensional accuracy. The heat treatment and the air-cooling treatment are repeatedly performed in a predetermined temperature range according to the kind of the material of the upper end portion 210 and the lower end portion 220 and the mechanical properties thereof to remove the residual stress.

The first polishing step polishes the surface of the bonding portion A of the plunger tip 200 integrated by the upper and lower end bonding processes to smooth the texture and gloss difference inevitably expressed by the bonding of the different materials.

In the heat treatment process, the upper end portion 210 and the lower end portion 220 are bonded to each other to cure the entire surface of the integrated plunger tip 200, thereby performing heat treatment to improve the mechanical and physical properties.

The second polishing step polishes the surface over the first half of the plunger tip 200 to complete the final product.

The plunger tip 200 manufactured by the method of manufacturing a plunger tip for die casting according to the present invention having the above-described structure is formed by the upper end 210 of the plunger tip 200 made of different materials as shown in FIG. 4, 1, the tip end of the plunger rod 103 of the die casting machine is coupled to the receiving groove and is inserted into the sleeve 101 in a state of being mounted, And then injects the molten metal into the mold 102. The mold 102 is then rotated.

The method of manufacturing a plunger tip for die casting according to the present invention as described above is characterized in that, in the conventional method of manufacturing the plunger tip, the plunger tip is formed by the casting method using the same material, and the inside and outside surfaces are subjected to the CNC grooving process The upper end portion 210 and the lower end portion 220 made of different materials are separately formed by a forging method and then joined together by friction welding to form the plunger tip 200. [

The plunger tip 200 and the plunger rod 103 can be mechanically and physically provided with the required mechanical and physical properties, respectively, so that the plunger tip 200, and the use life thereof can be remarkably improved, and an economical advantage can be obtained by reducing the material cost.

Particularly, as in the prior art, it is possible to solve the disadvantage that the CNC grooving process such as cutting and roughing is additionally performed after the plunger tip 200 is integrally cast, and the machining time can be shortened and the productivity can be improved It is expected that the possibility of industrial use will be very great.

101: Sleeve
102: Mold
103: plunger rod
104: Nozzle
200: Plunger tip
210:
220:
A:

Claims (3)

1. A method of manufacturing a plunger tip (200) that presses a molten metal injected into a sleeve (101) of a die casting machine to be coupled to a plunger rod (103) for injection into a mold (102)
An upper end forging process in which the material of the upper end portion 210 forming the tip end of the plunger tip 200 and the material of the lower end portion 220 coupled to the plunger rod 103 are respectively pressed by a forging press and forging the material into a corresponding standard, and,
A lower end of the forged upper end 210 and an upper end of the lower end 220 are joined by friction welding,
And a machining step of imparting mechanical properties by heat treating and polishing the plunger tip (200) to which the upper end (210) and the lower end (220) are joined. The method according to claim 1,
In the processing step,
A pretreatment step of heating and cooling the plunger tip 200 that has undergone the upper and lower bonding processes to remove internal stress,
A first polishing step of polishing the surface of the joining portion A of the upper and lower ends 210 and 220 of the plunger tip 200 subjected to the pre-
A heat treatment step of hardening the surface of the plunger tip 200 after the pre-treatment and the first polishing step,
And a second polishing step of polishing the surface of the plunger tip (200) after the heat treatment process. The method according to claim 1,
The upper end portion 210 and the lower end portion 220 of the plunger tip 200 to be forged by the upper end forging process and the lower end forging process are made of different materials,
The material of the upper portion 210 is one selected from the group consisting of SKD61, nitrided steel, beryllium copper, and high steel,
Wherein the material of the lower end portion 220 is one selected from the group consisting of SKD61, nitrided steel, beryllium copper, high steel, SS41, S45C, and copper.

Images