JPH0323031A - Method for forming consumable pattern for consumable casting - Google Patents

Abstract

PURPOSE:To quicken forming of a mold and to reduce the cost thereof by using the consumable pattern for casting impregnating and fixing wax to a paper pattern. CONSTITUTION:The paper pattern forming the shape of the aimed casting product by using the paper lost at the time of burning the mold or at the time of pouring the molten metal, is dipped into liquid wax for paraffin or lost wax and sufficiently boiled and impregnated with wax. After taking out this paper pattern from the liquid wax, this is dewaxed in a furnace at about 100 deg.C and cooled, and the wax is fixed to the paper pattern to make the consumable pattern. By this method, this may be used in any consumable casting method, and the forming cost of mold is reduced and the quick forming of mold can be obtd.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to an evanescent molding method used in investment, casting or plaster mold casting, etc., particularly an evanescent molding method using paper as the main material of the mold. Regarding C. [Prior Art] In general, in the so-called investment casting method such as investment casting or plaster casting, a mold is formed using beeswax, paraffin, pine resin, or synthetic wax, and this wax mold is used to form a mold for casting. created and used.

In the investment casting method, first a master model is formed from wood, etc., then a plaster or metal negative mold is made based on the master model, and wax is injected or press-fitted into this negative mold to create a wax mold. This wax mold is used to create and use an investment mold or plaster mold for casting.

The investment casting method allows for the production of highly accurate molds using precision molds or wax molds made from the same, and also enables the production of cast products with small dimensional tolerances. Since the wax mold is integrated, there is no deterioration in dimensional accuracy due to mold matching in other casting methods, there is no need to use a core, and there is no need to consider the draft angle. It is used in various precision castings.

In addition, in the approximate investment casting method, SP using styrofoam
Processes, ■processes, etc. are known. [Problems to be Solved by the Invention]However, in the conventional investment casting method, a master model is made of wood or the like in order to obtain an investment mold such as a wax mold or a styrene mold, and based on this master model, metal or It was necessary to prepare negative molds made of plaster, and the production of these master models and the negative molds required special techniques and a lot of labor. As a result, this investment casting method requires a lot of work and effort in the pre-processing process before obtaining a cast product, and has been considered unsuitable for obtaining cast products simply and in a short time. Furthermore, since the production of the master model requires a special technique and an intermediate mold, the production of the casting mold is relatively expensive.

Furthermore, with this investment casting method, it is necessary to form and prepare a wax mold, etc., within a range that will not deform it with investment materials, plaster materials, etc., and there is a natural limit to the molding of cast products with thin parts or thin string-like parts. ．． The investment mold used in the investment casting method according to the present invention is
To provide a vanishing mold that is directly formed using paper, unlike conventional wax molds, which does not require special techniques such as manufacturing a parent model, and eliminates the trouble of manufacturing an intermediate negative mold. It is an object. [Means for Solving the Problems] In order to achieve the above purpose, the investment mold for investment casting according to the present invention is made by creating a mold using paper that will be burnt out, and then using the paper used as the mold to After being impregnated with wax, the paper was dewaxed, cooled, and the wax was fixed on the paper to form a fugitive mold. Next, in the invention according to claim 2, the paper to be the fugitive type is made of ashless paper to form the fugitive type. [Function] The evanescent molding method according to the present invention has the above-mentioned characteristic structure, and after forming a mold by simply folding paper or cutting and pasting paper to form a mold, wax is applied. After impregnating the paper into the mold, a fugitive mold can be formed by dewaxing and cooling. In addition, since this disappearing mold is made of paper with wax fixed to it, it gives the mold a shape-retaining force that prevents the mold from breaking or deforming due to investment sand, etc. Furthermore, since the wax is fixed to the fugitive mold, the paper forming the fugitive mold is prevented from absorbing moisture when molding with investment sand, plaster, etc., and the shape does not collapse.

[Example] A typical method for forming an investment mold for investment casting according to the present invention will be described below. First of all, the paper used for the vanishing ogata is one that will be destroyed when the mold is fired or poured. As long as it disappears without burning when the mold is fired or poured, it may have any material characteristics, degree of processing, etc. In particular, it is preferable that the paper used for forming the fugitive mold does not contain inorganic substances as a sizing material, paper strength enhancing material, or filler so that ash, which may cause roughness of the surface of the cast product, does not remain on the mold surface.

From this point of view, it is best to use filter paper that is generally used for analysis, etc., and this filter paper is usually ashless. This paper is used to create the shape of the desired cast product. To create this paper pattern, we use the usual origami method. Another method is to form the paper into the desired shape while adhering it with an adhesive. The adhesive used here must be one that disappears together with the paper mold when the mold is fired or poured.

The paper pattern thus formed is immersed in wax or a wax solution for lost wax, and is thoroughly boiled to impregnate the paper with wax. It is preferable to boil the paper mold using this wax liquid so that the liquid is 20 to 30° C. higher than the melting point of the wax material used.

After the paper mold impregnated with wax in this way is taken out from the 1 liter solution, the wax adhering to the surface of the paper mold is removed.

This dewaxing IA embedding is meaningful for making precise paper molds, and in particular prevents the surface of the cast product from becoming wavy due to the wax material adhered to it. This dewaxing is preferably carried out in a furnace at around 100°C. The dewaxed paper mold is then removed from the oven and cooled to fix the wax to the paper mold to form a fugitive mold. The investment mold obtained in this way is used to prepare the mold in the same manner as in the conventional investment casting method. The mold used in the above investment casting method is completed by covering the investment sand, gypsum, etc. with investment sand, gypsum, etc., and then heating the mold and removing the investment mold. Or
After covering the fugitive mold with investment sand and plaster, it is heated to melt and flow out the wax in the fugitive mold to complete the mold, and by pouring hot water for casting into the mold, the fugitive paper is made. Use it so that it is completely burnt out.

Therefore, the investment mold obtained above can be used in any investment casting method, and can be used in any conventional investment casting method. From this point of view, the vanishing mold obtained above can be used in the same way as a regular wax mold, after the necessary treatments such as making a tree and sprucing it. [Effect] The method of forming an investment mold for investment casting according to the present invention does not require any use of a parent model, negative mold, etc., and creates an investment mold for direct casting, so the mold forming cost is low. This made it possible to form molds quickly. In addition, since there was no need to create a parent model, molds could be formed without the need for special engineers. Furthermore, since the vanishing mold is formed by folding paper, it has the advantage of being able to easily create even complex three-dimensional vanishing molds. In addition, unlike regular wax molds, the paper plays a reinforcing role, making the fugitive mold less likely to break or deform, making it easier to handle. It has the feature of being less likely to collapse.

From this point of view, it is particularly effective in making molds for cast products with thin walled parts or thin string-like parts. In addition, since the wax is sufficiently fixed to the fugitive paper, the fugitive paper will not be deformed by moisture from investment sand, plaster, etc. during molding, and it also has the advantage of not causing roughness on the surface of the cast product. are doing.

Claims (1)

[Scope of Claims] 1. A method for forming an investment mold for investment casting, which comprises impregnating wax into a formed paper pattern, dewaxing it, cooling it, and fixing the wax to the paper pattern. 2. The method for forming an investment mold for investment casting according to claim 1, wherein the paper of the paper mold is ashless paper.