CN102861877A

CN102861877A - Die-casting technique of sand core

Info

Publication number: CN102861877A
Application number: CN2011101896906A
Authority: CN
Inventors: 吴玉荣
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-07-07
Filing date: 2011-07-07
Publication date: 2013-01-09

Abstract

The invention mainly aims at providing a die-casting technique of sand core aiming at the shortcomings of the prior art, wherein the die-casting technique of the sand core is low in cost and simple in processes, and can cast the parts of which the inner shapes are complex. The technique comprises the following steps: (1) under 60-80 DEG C, pre-heating the mold for manufacturing the sane core; (2) installing molding sand in the mold which is pre-heated, closing the mold, and sintering, wherein the sintering temperature is controlled to be 180-220 DEG C; after sintering for 3-5min, getting the molding sand core outside, wherein the molding sand core is manufactured according to the structure of the sectional chamber of the part to be processed; (3) coating the mixture of the glass of water and talcum powder on the surface of the molding sand core, and drying at 75-85 DEG C for 15 min; (4) fixing the sand core manufactured in the step (3) in the section chamber of the mold, and then casting; and (5) processing the surface, which is polished, grinded, subjected to the chrome free treatment before casting, and coating.

Description

The core extrusion process

Technical field

The present invention relates to a kind of extrusion process, refer in particular to a kind of technique of utilizing core to carry out die casting as molding sand.

Background technology

Existing for the relatively simple foundry goods of interior shape, the traditional compression casting i.e. high ﹑ that presses is cast to the compression mod die cavity with the molten metal of molten condition down at a high speed, and under high pressure Cheng Xing ﹑ crystallization acquisition product, then the system of loosing core of mould is comparatively simple, easily meets design requirement.But for the very complicated foundry goods of interior shape, if still adopting traditional pressure casting process method processes, namely press ﹑ the molten metal of molten condition to be cast to the compression mod die cavity under at a high speed at height, and under high pressure Cheng Xing ﹑ crystallization obtains product, then the system of loosing core of mould will be very complicated, even can't meet design requirement, but at this moment according to the performance requirement of product, must adopt again the production technology of compression casting.Therefore just must improve the processing method of this compression casting.

The inventor has proposed a kind of new core extrusion process namely for the problems referred to above, has overcome well the problem that the internal structure complex parts are difficult to carry out die casting.

Summary of the invention

The present invention is directed to the disappearance of prior art existence, its main purpose provides the core extrusion process that a kind of cost is lower, technique simply can be carried out to the complex-shaped part in inside die-casting process.

For achieving the above object, the present invention adopts following technical scheme: the core extrusion process, this technique comprises the steps:

(1) under 60～80 ℃, the mould that is used for the making core is carried out the pre-heat treatment;

(2) mould of above-mentioned preheating is dressed up molding sand, and carry out the matched moulds sintering, its temperature is controlled at 180～220 ℃, and sintering took out the moulding core after 3～5 minutes, and wherein the moulding core is made according to the cavity structure of need processing parts;

(3) with above-mentioned moulding core surface-coated bath of glass and talcous mixture, then 75～85 ℃ of lower oven dry 15 minutes;

(4) core of making in the step (3) is fixed in the mold cavity, carry out again die casting, namely in fast shot speed: 2.0～3.0 m/s, slow shot speed: 0.2～0.3 m/s, the fast shot point: the aluminium liquid that under 250～330mm with the molten condition temperature is 630～670 ℃ is cast to the compression mod die cavity, and at pressure 600～700 kgf/c ㎡ high pressure compacted unders, its dwell time is 8～11s, crystallization obtains foundry goods, behind the casting complete, core just has been wrapped in the foundry goods, breaks core into pieces, just formed the cavity part in the foundry goods, wherein mold temperature is 220～280 ℃ in the said process;

(5) carry out surface treatment, namely polish, the Trend of Chrome-free before the grinding, application processes and application.

After the present invention adopts technique scheme, its beneficial effect is: by the improvement to extrusion process, namely rationally determine injection power, injection speed, dwell time etc., easily fragmentation, part core place organize a series of technical barriers such as loose when compression casting to have captured core, thereby guaranteed technically the smooth moulding of this part, made all technical of this part all meet or exceed designing requirement.This technological innovation is equivalent to the advantage of compression casting and gravitational casting has all been concentrated in together, and by adopting the core technology, it is complicated to have solved this part die cavity shape matching, the die casting die too complicated technical barrier of system of loosing core; Processing method by compression casting has guaranteed that the properties of product all meets or exceeds designing requirement again.Simultaneously, reduce the die casting cost, improved production efficiency.The core core that can be used for serving as the internal structure complexity, can not realize pulled core structure wherein, and because smooth sclerosis, heat-resisting after the oven dry of core surface-coated has very strong anti-impact force, the loose property of core feedback is also better after the die casting.In addition, this core extrusion process also can be cast by a type more, saves Modeling Material and environmental contamination reduction; Technique is also relatively simple simultaneously, is easy to realize mechanization and automation.

The specific embodiment

The present invention is described in detail below in conjunction with specific embodiment:

Embodiment 1: a kind of core extrusion process, this technique comprises the steps:

(2) mould of above-mentioned preheating is dressed up molding sand, and carry out the matched moulds sintering, its temperature is controlled at 180 ℃, and sintering took out the moulding core after 5 minutes, and wherein the moulding core is made according to the cavity structure of need processing parts;

(4) core of making in the step (3) is fixed in the mold cavity, carry out again die casting, namely in fast shot speed: 3.0 m/s, slow shot speed: 0.3 m/s, the fast shot point: the aluminium liquid that under the 330mm with the molten condition temperature is 670 ℃ is cast to the compression mod die cavity, and at pressure 700 kgf/c ㎡ high pressure compacted unders, its dwell time is 8s, crystallization obtains foundry goods, behind the casting complete, core just has been wrapped in the foundry goods, breaks core into pieces, just formed the cavity part in the foundry goods, wherein mold temperature is 220 ℃ in the said process;

Embodiment 2: a kind of core extrusion process, this technique comprises the steps:

(2) mould of above-mentioned preheating is dressed up molding sand, and carry out the matched moulds sintering, its temperature is controlled at 220 ℃, and sintering took out the moulding core after 3 minutes, and wherein the moulding core is made according to the cavity structure of need processing parts;

(4) core of making in the step (3) is fixed in the mold cavity, carry out again die casting, namely in fast shot speed: 2.0 m/s, slow shot speed: 0.2 m/s, the fast shot point: the aluminium liquid that under the 250mm with the molten condition temperature is 630 ℃ is cast to the compression mod die cavity, and at pressure 600 kgf/c ㎡ high pressure compacted unders, its dwell time is 11s, crystallization obtains foundry goods, behind the casting complete, core just has been wrapped in the foundry goods, breaks core into pieces, just formed the cavity part in the foundry goods, wherein mold temperature is 280 ℃ in the said process;

Embodiment 3: a kind of core extrusion process, this technique comprises the steps:

(2) mould of above-mentioned preheating is dressed up molding sand, and carry out the matched moulds sintering, its temperature is controlled at 200 ℃, and sintering took out the moulding core after 4 minutes, and wherein the moulding core is made according to the cavity structure of need processing parts;

(4) core of making in the step (3) is fixed in the mold cavity, carry out again die casting, namely in fast shot speed: 2.5 m/s, slow shot speed: 0.25 m/s, the fast shot point: the aluminium liquid that under the 290mm with the molten condition temperature is 650 ℃ is cast to the compression mod die cavity, and at pressure 650 kgf/c ㎡ high pressure compacted unders, its dwell time is 10s, crystallization obtains foundry goods, behind the casting complete, core just has been wrapped in the foundry goods, breaks core into pieces, just formed the cavity part in the foundry goods, wherein mold temperature is 250 ℃ in the said process;

Of the present invention focusing on, by the improvement to extrusion process, namely rationally determine injection power, injection speed, dwell time etc., easily fragmentation, part core place organize a series of technical barriers such as loose when compression casting to have captured core, thereby guaranteed technically the smooth moulding of this part, made all technical of this part all meet or exceed designing requirement.This technological innovation is equivalent to the advantage of compression casting and gravitational casting has all been concentrated in together, and by adopting the core technology, it is complicated to have solved this part die cavity shape matching, the die casting die too complicated technical barrier of system of loosing core; Processing method by compression casting has guaranteed that the properties of product all meets or exceeds designing requirement again.Simultaneously, reduce the die casting cost, improved production efficiency.The core core that can be used for serving as the internal structure complexity, can not realize pulled core structure wherein, and because smooth sclerosis, heat-resisting after the oven dry of core surface-coated has very strong anti-impact force, the loose property of core feedback is also better after the die casting.In addition, this core extrusion process also can be cast by a type more, saves Modeling Material and environmental contamination reduction; Technique is also relatively simple simultaneously, is easy to realize mechanization and automation.

The above, it only is preferred embodiment of the present invention, be not that technical scope of the present invention is imposed any restrictions, so every foundation technical spirit of the present invention all still belongs in the scope of technical solution of the present invention any trickle modification, equivalent variations and modification that above embodiment does.

Claims

1. core extrusion process, it is characterized in that: this technique comprises the steps: