KR100759501B1 - Barrel for a catapult and it's manufacturing process - Google Patents

Abstract

The present invention relates to a barrel for an injection molding machine and a method for manufacturing the same, preparing a barrel body penetrated therein; Mixing the molded powder by mixing silicon carbide, carbon, and a binder; Manufacturing a bush to be inserted into the barrel body by extruding the molding powder; Firing the extruded bush; Removing foreign matter from the fired bush; Adhering the barrel body and the bush with an adhesive and then fixing them by heating them; The barrel for the injection molding machine was prepared by grinding the fixed barrel inner diameter.

Therefore, the barrel inner diameter is provided with a bush made of silicon carbide having high wear resistance and corrosion resistance, so that the barrel inner circumferential surface is not easily corroded or abraded even under excessive pressure, high temperature, and friction with raw materials, thereby greatly extending the life of the barrel. do.

Barrel, barrel body, coupling hole, bush, silicon carbide, through hole

Description

Barrel for injection machine and its manufacturing method {Barrel for a catapult and it's manufacturing process}

1 is a schematic cross-sectional view showing a barrel for the present invention injection molding machine

* Description of the symbols for the main parts of the drawings *

10: barrel 11: barrel body

12: coupling hole (barrel body) 13: bush

14: through hole

The present invention relates to a barrel for an injection molding machine, and more particularly, to an injection molding machine barrel and its manufacturing method which improved the surface hardness of the barrel inner peripheral surface.

The basic function of the injection molding machine is to open and close the mold, melt the resin, fill the cavity of the mold with high pressure, and take out the molded article after cooling. Looking at the mechanical configuration for performing the function of such an injection molding machine is composed of an injection device, a clamping device, a driving device, a control device.

Here, the injection device of the injection machine is a device for melting a resin and measuring a predetermined amount and injecting it into a mold, which includes a hopper for storing a plastic material to be supplied to a barrel, a barrel for melting and injecting a plastic material supplied from a hopper, and a barrel It is composed of a nozzle coupled to the tip of the nozzle to form a flow path of the molten resin in close contact with the sprue bush (bush) of the mold during injection.

The barrel of the above-mentioned injection apparatus of the injection molding machine is manufactured as follows. Usually, the material for preparing the barrel is prepared by forging or casting, and the mechanical properties are improved through temper heat treatment, and the inner diameter of the material through roughing and finishing. Machine the outer diameter and the outer diameter within the error range. Barrel molded products that undergo such a process improves the surface hardness through nitriding heat treatment, and the nitrided heat treatment barrel is polished and plated, and then assembled, inspected, and shipped.

Nitriding heat treatment is applied to all steel grades by obtaining a nitrogen compound layer on the surface by using ammonia gas or nitrogen gas on the surface, and it is mainly used for surface treatment.In addition to nitriding heat treatment, vacuum heat treatment, ion nitriding heat treatment, carburizing, high frequency, etc. This is also used.

However, the barrel for the injection molding machine according to the above-described general heat treatment has a high heat treatment cost, but the effect is not so great. The barrel has a high injection pressure, excessive shear force, high temperature, which acts on the inner circumferential surface of the barrel each time the injection machine is operated. Various problems are caused by a solid resin causing sliding friction on the barrel surface, and the above-described heat treatment of the barrel is practically impossible to solve these problems, and thus, the barrel for a conventional injection molding machine is usually about once a year. The trend is changing.

An object of the present invention for solving the above problems is that the barrel inner peripheral surface is very high so that even if a high injection pressure, high temperature, high friction force generated inside the barrel by a screw and resin, the barrel for the injection machine is not easily worn And to provide a method for producing the same.

The present invention barrel for achieving the above object, the barrel for the injection machine, the barrel body is penetrated through; The outer circumferential surface is fixed to the barrel inner circumferential surface, characterized in that consisting of a bush formed of silicon carbide.

In accordance with another aspect of the present invention, there is provided a barrel manufacturing method for an injection molding machine, the method comprising: preparing a barrel body through which an inside penetrates; Mixing the molded powder by mixing silicon carbide, carbon, and a binder; Manufacturing a bush to be inserted into the barrel body by extruding the molding powder; Firing the extruded bush; Removing foreign matter from the fired bush; Adhering the barrel body and the bush with an adhesive and then fixing them by heating them; And grinding the fixed barrel inner diameter.

Another feature of the barrel manufacturing method for the injection molding machine of the present invention, the firing step of the bush, the silicon powder is put into the extruded bush and put into a firing furnace and heated to 1400-1600 ℃, the carbon in the bush and the silicon injected It is made by exothermic reaction.

Therefore, the barrel inner diameter is provided with a bush made of silicon carbide having high wear resistance and corrosion resistance, so that the barrel inner circumferential surface is not easily corroded or abraded even under excessive pressure, high temperature, and friction with raw materials, thereby greatly extending the life of the barrel. do.

Specific features and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings.

1 is a schematic cross-sectional view showing a barrel 10 for an injection molding machine of the present invention, which is composed of a barrel body 11 and a bush 13 inserted into the barrel body 11.

The barrel body 11 prepares a steel tube of which the inner diameter is not processed, processes the coupling hole 12 in the center of the steel pipe by a machine such as a deep hole drilling machine, and the coupling hole 12 of the barrel body 11. The inner diameter of) depends on the capacity of the injection molding machine and the outer diameter of the screw.

In the engagement hole 12 of the barrel body 11, a bush 13, which is a feature of the present invention, is inserted and fixed. A through hole 14 is formed in the center of the bush 13 so that the screw can be inserted therein, and the outer circumferential surface thereof is fixedly supported around the coupling hole 12 of the barrel body 11.

The bush 13 is made of a mixture of silicon carbide (SiC), carbon (C), and binder (bar), 85% silicon carbide (SiC) powder, 15% carbon (C), binder 10 Percentages are mixed, usually mixed and then ground and powdered. The bush 13 forming material thus prepared is introduced into an extruder and extruded in the form of a pipe. The outer diameter and the inner diameter of the pipe are manufactured in consideration of the inner diameter of the barrel body 11 and the outer diameter of the screw.

Such a bush 13 is baked in its entirety with silicon carbide according to the characteristics of this invention. Among the ceramics, silicon carbide has high strength, high hardness and wear resistance, and has thermal characteristics such as excellent oxidation resistance, corrosion resistance, low thermal conductivity, high thermal shock resistance due to thermal expansion coefficient, and high temperature strength. The bush 13 fired with silicon carbide having such characteristics is formed by inserting silicon into an extruded bush, and then putting the silicon in a firing furnace and heating it to a high temperature. The bush extruded by mixing silicon carbide powder, carbon, and a binder is extruded. When silicon is added to the substrate and heated to a high temperature of 1400 ° C. to 1600 ° C., silicon carbide is generated by the exothermic reaction of carbon (C) contained in the bush and silicon (Si) injected into the bush 13. Is more closely adhered to the silicon carbide grains accounting for 85% of the bush (13).

Since silicon is usually melted immediately after 1400 ° C, when silicon is injected into the bush and heated to a high temperature, carbon and molten silicon of the bush exothermicly react to generate new silicon carbide. The produced silicon carbide serves to fix the silicon carbide grains that make up the majority of the bush, and thus the entire bush is calcined with silicon carbide. The bush 13 is adhered to the barrel body 11 and fixed to the barrel 13 so that the barrel 10 is provided.

Since the barrel 10 is made of silicon carbide having excellent abrasion resistance and corrosion resistance, the barrel 10 may be subjected to excessive pressure, high temperature, and frictional resistance with the raw material by molten resin and screw inside the barrel. The inner circumferential surface is not easily corroded or worn, which eventually prolongs the life of the barrel 10 significantly.

The barrel for the present invention as described above is manufactured by the following method.

First, prepare the barrel body 11 penetrated inside. In the preparing of the barrel body 11, the periphery of the steel pipe is processed, and the inside thereof is processed by a machine such as a deep hole drilling machine to make a coupling hole 12 in the center thereof.

When the barrel body 11 is prepared as described above, the bush 13 to be inserted is manufactured. First, a molding powder for molding an extrudate in the form of a pipe is prepared. The molded powder is composed of silicon carbide (SiC), carbon (C) and binder, and the mixing ratio is 85% silicon carbide (SiC), 15% carbon (C) and binder 10 % Is suitable. When three raw materials are prepared, they are mixed and pulverized by a grinder, and then made into particles of a predetermined size through a powder process.

When the molding powder prepared in this way is prepared, it is put into the hopper of the extruder and the bush in the form of a pipe is manufactured while undergoing a general extrusion process. Here, the outer diameter of the bush and its inner diameter are manufactured in consideration of the outer diameter of the barrel body 11 and the outer diameter of the screw. That is, the outer peripheral surface of the bush and the inner circumferential surface of the barrel body 11 should be coated with adhesive, and the inside of the bush should be equipped with a screw. In consideration of manufacturing.

The extruded pipe bush is dried while rotating in the atmosphere for approximately 40-60 hours. The cooled bush is cold treated to stabilize internal tissues.

Since the extruded bush 13 is not fired, it cannot maintain high hardness. Since the silicon carbide granules forming the majority of the bush are simply bonded by a binder, they cannot withstand high injection pressure and frictional force, and thus, extrusion The molded bush 13 goes through a firing process.

Therefore, when the bush 13 is extruded, silicon powder is added and heated to fix the silicon carbide grains. That is, silicon powder is put into the extruded bush, and then put into a firing furnace and heated to a high temperature. In this case, the heating temperature is about 1400 ° C., which is the melting temperature of silicon, and when heated to about 1450 ° C., silicon carbide is generated by exothermic reaction between the carbon of the bush and the silicon powder injected therein, and the silicon carbide solidifies the silicon carbide particles throughout the bush. Let's do it.

The bush () fired with silicon carbide in this manner sufficiently withstands high injection pressure, high temperature, and high frictional force generated inside the barrel by screws and resin. In this way, when the bush 13 is fired with silicon carbide, it is removed from the firing furnace and cooled, and the remaining silicon and other foreign matters are removed from the inner and outer peripheral surfaces of the cooled bush.

When the foreign matter such as silicon remaining on the outer peripheral surface and inner peripheral surface of the bush is removed, the barrel body 11 and the bush 13 are adhered with an adhesive. When the barrel body 11 and the bush 13 are adhered to each other by being heated and fixed, the heating time and the heating temperature are set differently according to the adhesive. When the barrel 10 is manufactured after the bush 13 is inserted into the coupling hole 12 of the barrel body 11, the barrel 10 is polished to minimize internal frictional resistance caused by resin and screws. . The barrel 10 of the present invention thus produced is improved in wear resistance and corrosion resistance by the bush 13 fired from silicon carbide.

As described above, the present invention is provided with a bush made of silicon carbide having a high wear resistance and corrosion resistance at the barrel inner diameter, so that the barrel inner circumferential surface is not easily corroded or worn under excessive pressure, high temperature, and friction with raw materials. It will greatly extend the life of the barrel.

Claims (3)

In the barrel for the injection machine, Barrel body penetrated inside; Barrel for injection machine, characterized in that the outer circumferential surface circumference is fixed to the inner circumferential surface of the barrel body, the bush formed of silicon carbide. By manufacturing a barrel for the injection machine made of a barrel body penetrated inside, and a bush formed on the inner peripheral surface of the barrel body around the outer circumference and formed of silicon carbide, Preparing a barrel body penetrated therein; Mixing the molded powder by mixing silicon carbide, carbon, and a binder; Manufacturing a bush to be inserted into the barrel body by extruding the molding powder; Firing the extruded bush; Removing foreign matter from the fired bush; Adhering the barrel body and the bush with an adhesive and then fixing them by heating them; Polishing the barrel inner diameter fixed; barrel manufacturing method for an injection molding machine characterized in that consisting of. The method of claim 2, In the firing step of the bush, a silicon powder is injected into the extruded bush and put in a firing furnace and heated to 1400-1600 ℃, carbon injection method of the barrel production method characterized in that the carbon in the bush made by exothermic reaction. .

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