JPH05337621A - Heat insulating lubrication method for injection sleeve - Google Patents

Abstract

PURPOSE:To provide the heat insulating lubrication method for an injection sleeve which improves the lubricity and the heat insulating characteristic and obviates the generation of the intrusion of gases into a casting. CONSTITUTION:A liquid lubricant 2 having lubricity is applied on the inner peripheral surface of the injection sleeve 1 to form a liquid lubricant layer 2 and a heat insulating powder layer 3 is formed on the liquid lubricant layer 2 before the lubricant dries. As a result, a desired amt. of the heat insulating powder 3 is stuck to the sleeve by the wettability possessed by the liquid lubricant layer 2. Since the heat insulating powder layer 3 is provided, the desired heat insulating effect is obtd. The direct contact of the liquid lubricant and a high-temp. molten metal is prevented and the gasification of the lubricant is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulating lubrication method for an injection sleeve, and more particularly, to prevent solidification of a molten metal in the injection sleeve by a heat insulating effect, and at the same time, to provide the injection sleeve and a plunger sliding in the sleeve. The present invention relates to a heat insulating lubrication method for an injection sleeve capable of improving sliding lubricity.

[0002]

2. Description of the Related Art Conventionally, oil or a liquid lubricant in which oil, wax, resin or the like is dispersed in water is applied to an injection sleeve in a casting machine by a technique such as spraying or dropping. ing. However, the conventional method has a drawback in that the oil directly contacts the molten metal at a high temperature and is gasified in the sleeve and is entrained in the molten metal to deteriorate the quality of the cast product. Further, since the liquid lubricant itself does not have sufficient heat insulation, solidification of the molten metal occurs in the injection sleeve, and as a result, the strength of the cast product decreases, the quality varies, and many internal defects occur. It was

In order to overcome such a conventional drawback, Japanese Patent Laid-Open Nos. 1-118353 and 3-204151 disclose a powder having self-lubricating property as a powder by spraying, electrostatic coating or the like. The technique of applying directly to the inner peripheral surface (lubrication surface) of the injection sleeve is described. The thermal stability and heat insulating property of the powder itself are intended to overcome the above drawbacks.

[0004]

However, in the invention described in the above publication, the powder itself has poor lubricity as compared with the liquid lubricant, and therefore the amount of wear on the sliding surfaces of the injection sleeve and the plunger increases. There are drawbacks. In addition, there is a drawback that the adhesive force of the powder to the injection sleeve is extremely weak, and the powder is released from the injection sleeve by the flow of molten metal or air during pouring or injection from the ladle, and the heat insulating effect cannot be obtained. Furthermore, since the amount of powder that can be attached to the injection sleeve is naturally limited, there is a disadvantage that a sufficient powder layer is not formed, the thickness is thin, and a sufficient heat insulating effect cannot be obtained. In addition, self-lubricating powders of boron, graphite, molybdenum disulfide, etc. are generally expensive, and their detachment from the sleeve is a problem in terms of casting cost.

Therefore, an object of the present invention is to provide a method for adiabatic lubrication of an injection sleeve that improves both lubricity and heat insulation properties and does not cause mixing of oil decomposition gas into products.

[0006]

In order to achieve the above object, the present invention comprises: (a) applying a liquid lubricant having lubricity to the inner peripheral surface of an injection sleeve to form a liquid lubricant layer; b) A heat insulating lubrication method for an injection sleeve, which comprises a step of forming a powder layer by depositing heat insulating powder on the liquid lubricant layer before the liquid lubricant dries.

[0007]

The liquid lubricant layer is first formed on the inner peripheral surface of the injection sleeve, and the heat insulating powder layer is formed thereon. Therefore, a large amount of the heat insulating powder layer can be attached due to the viscosity of the lubricant. Therefore, it is possible to prevent or reduce the release of the heat insulating powder from the injection sleeve due to the air or the molten metal, and it is possible to exert a sufficient heat insulating effect. In addition, the heat of the molten metal is not directly transferred to the liquid lubricant due to the presence of the heat-insulating powder layer, and it is possible to prevent the gasification of the oil, which is the main component of the liquid lubricant, by heat, and to significantly reduce the mixture of gas into the product The quality of the product can be maintained and improved. Further, the presence of the heat-insulating powder layer prevents the molten metal from coming into contact with the sleeve, so that melting damage of the sleeve can be prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a heat insulating lubrication method for an injection sleeve according to the present invention will be described with reference to FIG. First, the liquid lubricant is applied to the inner peripheral surface of the injection sleeve 1 by spraying or dripping to form the liquid lubricant layer 2. As the liquid lubricant, an oil such as a vegetable oil or a mineral oil, or an emulsion-type water-soluble lubricant in which oil is dispersed in water is used.
The liquid lubricant may further contain solid lubricant such as graphite in oil.

Next, before the liquid lubricant layer 2 is dried, heat insulating powder is applied onto the liquid lubricant layer 2 to form a heat insulating powder layer 3. As the heat-insulating powder, for example, a powder mixture obtained by mixing inexpensive talc (talc) and resin powder in a desired ratio, celite (diatomaceous earth), or the like is used. Other mica or vermiculite may be used. The resin powder is formed of, for example, paraffin, polyethylene, acrylic, or vegetable wax.

Next, the following experiment was conducted in order to confirm the superiority of the adiabatic lubrication method of the present invention. Items to be examined are heat insulation, lubricity, gas amount, plunger tip life,
Has tensile strength. The heat insulating property was judged by the quality of the bath around based on the appearance inspection of the product. The lubricity was judged by measuring the injection speed. The amount of gas was measured by melting the product by heating and melting the product. The chip life was determined by visual inspection of the chip wear state after 1000 injections. For the tensile strength, the tensile strength of the cast product was judged by an ASTM tensile tester.

The test conditions are as follows. Injection molding machine: 90 tons (Toshiba machine die casting machine) Alloy: ADC10 Hot water temperature: 720 ° C Casting pressure: 750 kg / cm ² Injection speed: 1.0 m / sec Filling rate: 30%

Comparative samples 1 to 3 were prepared. Sample 1 was powder lubricant only, and a mixture of talc (talc) and resin having a mixing ratio of 9: 1 was supplied to the inner peripheral surface of the injection sleeve by air. Sample 2 was an oily lubricant mixed with graphite and was supplied dropwise. Sample 3 was an aqueous suspended colloidal graphite and was supplied by spraying. Samples 4 and 5 were prepared as the products of the present invention. In Sample 4, first, oil was sprayed, and then talc, which is a heat insulating powder, was supplied onto the oil film by air. Sample 5 was prepared by spraying an emulsion-type water-soluble lubricant by spraying, and then forming talc, which is a heat insulating powder, on the lubricant layer by air.

The judgment result

It shows in [Table 1].

In Table 1, double circles ⊚ indicate extremely good judgment results, circles ∘ indicate good judgment results, triangles Δ indicate judgment results in which quality is mixed, and crosses indicate bad judgment results.

[0014]

[Table 1] Thermal insulation Lubricity Gas amount Chip life Tensile strength Sample 1 ○ △ ◎ × ○ Sample 2 × ◎ × ○ × Sample 3 △ × ○ × △ Sample 4 ◎ ◎ ◎ ◎ ◎ ◎ Sample 5 ◎ ○ ○ ○ ○

As is clear from Table 1, the samples 4 and 5 according to the present invention are better judged than the comparative samples 1 to 3 in all aspects of heat insulating property, lubricity, gas amount, chip life and tensile strength. I was able to get the result.

Next, as a sample 6 according to the present invention, an oil-based lubricating oil containing vegetable oil and mineral oil as a main component was sprayed on the inner peripheral surface of the injection sleeve, and then talc was supplied by air onto the oil-based lubricating oil. .. The test conditions are as follows. Injection molding machine: 500 tons (Die-casting machine manufactured by Toshiba Machine) Alloy: A390 Hot water temperature: 720 ° C Casting pressure: 800 kg / cm ² Injection speed: 0.2 m / sec Filling ratio: 60% Good bathing even under such conditions Demonstrate the ability, hot water temperature 7
Even when the temperature was lowered to 00 ° C, the bathing area was still good. Further, the chip life and the gas amount were good as compared with the case where the oil-based lubricating oil was sprayed, and the tensile strength was also improved by 5%.

Next, as sample 7 according to the present invention, an oil-based lubricant layer containing graphite was formed on the inner peripheral surface of the injection sleeve, and then celite (diatomaceous earth) was formed on the lubricant layer by air. The test conditions are as follows. Injection molding machine: 800 tons (Die casting machine made by Ube Industries) Alloy: ADC10 Hot water temperature: 700 ° C Casting pressure: 700kg / cm ² Injection speed: 0.3m / sec Filling rate: 50% Even under these conditions, the hot water flow is good. Yes, gas amount is sample 2
It was reduced by 30%. The injection speed is 0.25m
It was found that casting is possible even if the pressure is reduced to / second.

[0018]

As described above, according to the heat insulating lubrication method for a sleeve of the present invention, the following effects can be exhibited. (1) Since the liquid lubricant is applied to the injection sleeve,
Good lubricity is maintained between the plunger tip and the sleeve, and the problem of wear does not occur. (2) Since the liquid lubricant is first applied to the injection sleeve, the heat-insulating powder layer formed thereon can be adhered relatively strongly and in a large amount due to the viscosity of the lubricant.
Therefore, it is possible to prevent or reduce the release of the heat insulating powder from the injection sleeve due to the air or the molten metal, and it is possible to exert a sufficient heat insulating effect. (3) Since the heat-insulating powder is always formed on the liquid lubricant layer, the heat of the high-temperature molten metal is not directly transferred to the liquid lubricant and gasification of the oil, which is the main component of the liquid lubricant, is performed. Can be prevented, gas mixture into the product can be significantly reduced, and product quality can be maintained and improved. (4) It is not necessary to provide the powder itself with lubricity or adhesiveness, and it is not necessary to use expensive self-lubricating powder as in the past. Therefore, it is advantageous in terms of economy. (5) By selectively using the liquid lubricant and the heat insulating powder in combination, the degree of freedom in selection in terms of heat insulating property, lubricity, price, etc. is increased, and a wide range of use can be provided. (6) Since the molten metal does not directly contact the sleeve due to the heat insulating powder layer, melting damage of the sleeve due to the molten metal can be prevented and the life can be extended.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a heat insulating lubrication state of an injection sleeve according to the present invention.

[Explanation of symbols]

 1: Injection sleeve 2: Liquid lubricant 3: Heat insulating powder 4: Molten metal

Claims (1)

[Claims] 1. A step of applying a liquid lubricant having lubricity to an inner peripheral surface of an injection sleeve to form a liquid lubricant layer, and heat insulating the liquid lubricant layer on the liquid lubricant layer before the liquid lubricant is dried. And a step of forming a powder layer by depositing a conductive powder on the insulating sleeve.