Method for evaporative pattern precise composite casting

A compound casting and lost foam technology, which is applied in the direction of casting molding equipment, casting molds, and casting mold components, can solve the problems that the appearance quality is not as good as the surface quality of precision casting products, the internal quality of products is not as good as precision casting, and the price is high. Achieve the effect of avoiding shrinkage cavity or shrinkage porosity, saving processing time and reducing production cost

Inactive Publication Date: 2009-12-02
郑州神牛铸造有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in actual production, some product orders are very small, such as less than 10 pieces. In this case, the price of the product is not as high as the price of the mold used for production.
If other casting processes are used, such as lost foam casting, although the model can be made by hand without making metal molds, the internal quality of the product is definitely not as good as precision casting, especially steel castings, because it is not cavity gravity pouring during the pouring process, and The appearance quality is not up to the surface quality of precision casting products

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Example 1: Lost foam precision composite casting method,

[0023] (1) Use polystyrene foam to make a model

[0024] Polystyrene foam plastic has a honeycomb closed cell structure, with a density of 0.015-0.025g / cm 3 For the low-density products in the range, use the foam to make the same model as the product using the wire cutting platform; and combine the pouring system.

[0025] (2) Apply surface repair agent on the surface of the model

[0026] The surface repairing agent can be the surface repairing agent for lost foam sold on the market, or paraffin wax. Paraffin wax requires a melting point of 56-64℃, ash content (mass fraction) ≤0.03%, and linear shrinkage rate: 0.6-1.5%. The purpose of painting is to fill the gaps between the beads on the surface of the polystyrene foam model to improve the surface quality of the model, and then to improve the surface quality of the casting. After painting, use a steel ruler or blade to smooth it.

[0027] (3) Making shells, includi...

Embodiment 2

[0041] Example 2: Lost Foam Precision Compound Casting Method:

[0042] (1) Use polystyrene foam to make a model, same as the first embodiment;

[0043] (2) Surface repair agent is applied to the surface of the model, same as the first embodiment;

[0044] (3) Making shells, including making surface layer shells, transition layer shells and back layer shells:

[0045] a. Refractory coatings should be prepared before making the shell, including surface coating, transition coating and back coating.

[0046] The composition of the surface layer coating is: 10kg silica sol, 36~40kg zircon powder with a particle size of 320 mesh, 16ml wetting agent, 12ml defoamer, density 2.7~2.8g / cm 3 , The viscosity of Tu-4 is 36~38s; SiO in silica sol 2 The weight percentage is 30%, the same below;

[0047] The composition of the transition layer coating is: 10kg silica sol, 17-19kg mullite powder with a particle size of 200 mesh, and a density of 1.82~1.85g / cm 3 ; Tu-4 viscosity is 28~30s;

[0048]...

Embodiment 3

[0056] Example 3: Lost Foam Precision Compound Casting Method:

[0057] (1) Use polystyrene foam to make a model, same as the first embodiment;

[0058] (2) Surface repair agent is applied to the surface of the model, same as the first embodiment;

[0059] (3) Making shells, including making surface layer shells, transition layer shells and back layer shells:

[0060] a. The composition of the surface layer coating, the transition layer coating and the back layer coating is the same as the first embodiment;

[0061] b. Production of shell surface layer, shell transition layer and shell back layer:

[0062] Shell surface layer: Put the model in the pre-wetting agent for 2 to 3 seconds, remove it, then immerse it in the surface paint bucket, rotate the model so that every corner of the model can be evenly coated with paint, take it out, and hang it on a specific When the paint on the model is not dripping or dripping, sprinkle 120 mesh zircon sand on the surface layer paint on the s...

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Abstract

The invention discloses a method for evaporative pattern precise composite casting. The method comprises the following steps: making a mould by polystyrene foam to form a casting system; coating a surface modifying agent on the surface of the mould; preparing a mould shell including a surface layer mould shell, a transitional layer mould shell and a back layer mould shell; taking the mould out after placing the mould in a pre-wetting agent for 2 to 3s, dipping the mould in a container filled with surface layer coating, turning the mould so as to evenly coat the mould, sprinkling zircon sand on the mould, and drying the mould for 4 to 6h to prepare a surface layer mould shell; dip-coating the surface layer mould shell by a transitional layer coating, sprinkling and drying the sand for 8 to 12h; preparing the transitional layer mould shell and the back layer mould shell by the similar method; sealing pulp by the back layer coating, and drying for 14 to 18h; roasting the mould at a temperature of between 950 and 1,050 DEG C, and keeping warm for 30 to 60min; and pouring the molten metal in the mould shell to form a casting. The method has the advantages of preparing the metallic mould without the conventional precise casting, saving processing time, lowering cost and simultaneously ensuring the product quality.

Description

1. Technical Field: [0001] The invention relates to a casting method, in particular to a lost foam precision composite casting method. 2. Background technology: [0002] Traditional investment casting is also called lost wax casting. Cast products are often more precise and complex, close to the final shape of the part, and can be used directly without processing or with little processing. It is an advanced near-net-shape process. The general process flow is: making molds to press investment molds, taking out investment combination modules, immersing the modules in the paint bucket on the coating, sanding, and drying the shell, repeating the coating, sanding and drying several times to form a certain thickness Mold shell, remove the wax in the shell, and then roast the shell, pour molten metal, shell and clean. Due to the need to make metal molds, this process is suitable for the production of larger batches of products. However, in actual production, some products have very few ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22C9/04B22C3/00
Inventor 姚万林王海洋
Owner 郑州神牛铸造有限公司
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