CN1130160A

CN1130160A - Expansive gypsum type material and its technology for producing model

Info

Publication number: CN1130160A
Application number: CN 95106974
Authority: CN
Inventors: 张绍兴; 王薇薇
Original assignee: NANCHANG AVIATION INDUSTRY COLLEGE
Current assignee: NANCHANG AVIATION INDUSTRY COLLEGE
Priority date: 1995-07-20
Filing date: 1995-07-20
Publication date: 1996-09-04
Anticipated expiration: 2015-07-20
Also published as: CN1045582C

Abstract

Basic components of the material are gypsum 35-45%, aluminate cement 15-25%, and additive 30-50%, and on compounding, water 40-60% of basic components is added and swelling agent is 0.1-6% of basic components. Making of the mould is to cast the sample by pouring expanded gypsum type material and the obtained intermediate model is used to duplicate a metal mould by the procedure similar to the sample. This mould-making material and its process make up such a mould with dimensions in various directions expanded to larger than the sample by a certain amount so as to compensate the solidifying shrinkage of metal in gypsum mould during casting to control dimension accuracy of casting.

Description

A kind of technology of expand gypsum type material and analogue formation thereof

The present invention relates to casting technology field, relate in particular to a kind of foundry pattern and make material and manufacture craft.

How casting and press working Modelling form through mechanical workout with strand, and this method die cost height is very uneconomical for the short run castings production, and lose market easily because of the process-cycle is oversize.Now, people are when the trial-production product innovation, attempt directly to adopt exemplar to turn over system, in the hope of reducing expenses, shorten fabrication cycle, and the required state of the art of this method is low, more suitable for working ability with the medium or small factory that lacks qualified technical personnel, this method of utilizing the direct polygram casting model of exemplar is good with gypsum model especially, and institute's mold type only need be polished and process (as removing dead head) on a small quantity and be got final product.But gypsum model baking and twice contraction of metal cools can cause the foundry pattern size decreases and not reach the making requirement.According to document announcement, the domestic people of having adopts the luminite cement of 50% gypsum and 50% to be deployed into the expansion gypsum and makes, but this gypsum is too little because of swell increment, also is not enough to compensate the shrinkage of gypsum and metal, the effect that does not still reach.Chinese patent publication number CN1049619A, also adopted a kind of expansion gypsum material that model is made, but organism contain the most higherly in its composition, may decompose during baking, can influence mould strength or surface smoothness, thereby to have relatively high expectations, larger-size foundry goods also is difficult to reach requirement.

The purpose of this invention is to provide a kind of novel expansion gypsum type material and the technology of analogue formation thereof, the not high problem of dimensional precision when using the exemplar reconstructed model to solve.

Expansion gypsum type material of the present invention, its composition comprises gypsum and luminite cement, special character is that its fundamental component is: gypsum 35-45% (weight percent), luminite cement 15-25% (weight percent), additive 30-50% (weight percent): adding water during allotment is 40-60% (weight percent) of fundamental component, and swelling agent is 0.1-6% (weight percent) of fundamental component.Additive in the above-mentioned fundamental component can be konilite and/or wollastonite.Swelling agent in the above-mentioned composition can be a gelatin.

The present invention adopts exemplar to make the mould prototype with the technology of expansion gypsum type material analogue formation, pours into a mould required metal pattern with the casting mold gypsum model, and its difference is to have adopted following making step:

1) with the uniform above-mentioned expansion gypsum type material of mediation exemplar is watered and the gypsum model that obtains to expand;

2) in expansion gypsum die cavity, water casting mold gypsum or other material and obtain the operation mid-module;

3), become the gypsum model of last casting metal model after the demoulding baking with casting mold gypsum pouring operation mid-module;

4) be the required metal pattern of model cast with gypsum model at last.

Now reaching embodiment in conjunction with the accompanying drawings elaborates to the technology of expansion gypsum type material of the present invention and analogue formation thereof:

Accompanying drawing 1 to accompanying drawing 4 is operation sketches of analogue formation of the present invention.Wherein (1), (5) are box-frames.

Embodiment one: gypsum 35% (weight percent), luminite cement 15% (weight percent), konilite 25% (weight percent), the wollastonite 2% (weight percent) with fundamental component is combined into powder mixture earlier, the swelling agent gelatin that will be equivalent to 0.1% (weight percent) of fundamental component again joins in the water of 40% (weight percent) that be equivalent to fundamental component, pour in the compound of above-mentioned fundamental component after stirring a little, promptly form the expansion gypsum type material again through stirring.During Modelling (accompanying drawing 1 is to accompanying drawing 4), be model with exemplar (2) earlier, the expansion gypsum type material is watered and the gypsum model (3) that obtains to expand it, expansion gypsum model (3) is sprayed water and controlled its injection flow rate, make it to expand into desired size, be that model burns filling casting mold gypsum material with it then, obtain exemplar similar figures---the operation mid-module (4) that has amplified than exemplar size, be model pouring casting mold gypsum material with operation mid-module (4) again, obtain pouring gypsum type (6), after gypsum model (6) dried (250 ℃ of temperature), promptly can be used to pour into a mould required metal pattern (7).

Embodiment two: fundamental component adopts gypsum 45% (weight percent), luminite cement 25% (weight percent), konilite 30% (weight percent) to be combined into powder mixture, after the gelatin that will be equivalent to 6% (weight percent) of fundamental component joins and stirs a little in the water of 60% (weight percent) that be equivalent to fundamental component, pour the compound of fundamental component into, stir once more and promptly form required expansion gypsum type material.This routine model production method step can with embodiment one identical (accompanying drawing 1 is to accompanying drawing 4).

The technology of expansion gypsum type material of the present invention and analogue formation, can make the model all directions size that makes require on demand to expand 0.1-8%, thereby the gypsum model that can remedy casting metal effectively shrinks and metal freezing shrinks, and reaches the purpose of control casting dimension accuracy.

Claims

1, a kind of expansion gypsum type material, its composition comprises gypsum and luminite cement, it is characterized in that its fundamental component is: gypsum 35-45% (weight percent), luminite cement 15-25% (weight percent), additive 30-50% (weight percent); Adding water during allotment is 40-60% (weight percent) of fundamental component, and swelling agent is (0.1-6% (weight percent) of fundamental component.

2, expansion gypsum type material according to claim 1 is characterized in that additive can be konilite and/or wollastonite.

3, expansion gypsum type material according to claim 1 is characterized in that swelling agent can be a gelatin.

4, a kind of technology with expansion gypsum type material analogue formation. adopt exemplar to make the mould prototype, pour into a mould required metal pattern, it is characterized in that having adopted following making step with the casting mold gypsum model:

(1) with the described expansion gypsum type material of the uniform claim 1-4 of mediation exemplar (2) is watered and the gypsum model (3) that obtains to expand;

(2) in expansion gypsum model (3) chamber, water casting mold gypsum or other material and obtain operation mid-module (4);

(3), become the gypsum model (6) of last casting metal model after the demoulding baking with casting mold gypsum pouring operation mid-module (4);

(4) use gypsum model (6) to be the required metal pattern (7) of model cast at last.