JPH0237934A - Method for joining lost foam pattern - Google Patents

Abstract

PURPOSE:To easily and accurately form a formed product without any question to the strength by pressing template for applying adhesive to each joining face of the divided pattern to transfer hot melt type adhesive to each joining face, successively facing joining faces between themselves, joining and integrating. CONSTITUTION:Two divided patterns Wa, Wb of foamed polystyrene formed with a metallic mold are shifted to above the adhesive vessel 3 with the joining faces Ta, Tb downward and positioned. The adhesive vessel 3 melts the hot melt type adhesive (q) at the range of the prescribed viscosity in the range of the prescribed temp. When the divided patterns Wa, Wb come to shift, to there, the adhesive (q) is stuck to the top parts of the tenplates 6, 6 and the top faces are press-contacted with pressurizing force at the degree, which is possible to return back to the original shapes of the joining faces Ta, Tb, to stick the adhesive (q) as thin film state. The other side of divided pattern Wb is turned over and both divided patterns are press-contacted and integrated. By this method, both divided patterns are firmly integrated with the min. adhesive and finish work after forming is not necessary and the formed product without any question to the strength can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention is directed to a method of joining fugitive segmented models for casting.

(Prior art) A fugitive model used for fine recess casting is generally molded into the required mold by molding using a molding die or by cutting and molding from a block-shaped foam. In addition, when the shape is particularly complex, a plurality of partially molded models are joined together with an adhesive or the like to form a single model. Incidentally, to join such split models, hot-melt adhesive is applied using a template to the joining surface of one model, and the other model is pressure-welded on top of it. In the split model, a large cedar W is given to the product depending on the amount of WZ adhesive applied. In other words, there is a gap of O,1 between the bonding surface and the template.
If the adhesive is transferred with a gap of mm or more, the amount of adhesive will be too large, and although the divided models can be strongly joined together, the adhesive will get stuck around the periphery of the joint. This results in the creation of accumulation-like protrusions on the circumferential surface of the cast product, which requires a large amount of man-hours to scrape off. If a part is formed, finishing or correction cannot be performed, which means that a split model cannot be used for this type of casting.

On the other hand, if the template is brought into strong contact with the joint surface, the amount of Wi adhesive will be too small.
Although the above-mentioned problems do not arise, on the other hand, when the split models are joined together, a small portion of the adhesive is taken into the recess that exists on the other joint surface, causing a rough shortage of adhesive. The problem is that dents occur around the parts, creating belt-shaped dents in the cast product, and this causes stress concentration in those parts, causing the parts to break, especially in parts where large stress is applied. occurs.

(Problems to be Solved by the Invention) The present invention has been made in view of the above problems, and its purpose is to improve the application of adhesive to the joint surface.
The purpose of this study is to propose a new joining method for joining split models by accurately controlling I.

(Means for Solving the Problems) That is, the present invention provides a method for joining split models to achieve the above-mentioned problems, by pressing a template for applying adhesive onto each joining surface of a fugitive split model for casting. A hot-melt adhesive is transferred to the joint surfaces of the model, and then these joint surfaces are made to face each other to join and integrate the divided models.

(Example) Therefore, the illustrated embodiment will be explained below.

Fig. 1 schematically shows a method for joining split models. First, two split models Wa and Wb (Fig. 3) made of expanded polystyrene, which have been molded in advance using a mold, are attached to a supporting jig 1. .1, and each joint surface Ta, T
ba and move it above the adhesive tank 3 and position it (FIG. 1(a)).

On the other hand, in the adhesive tank 3, the hot melt adhesive q is melted in advance so that the viscosity becomes 2.5 to 3.5 poise centimeters under a temperature range of 105°C to 125°C. When the divided models Wa and Wb are transferred here, the template 6.6, which is formed so that its top coincides with the bonding surfaces Ta and Tb, is raised from the tank 3 with adhesive q attached to its top. Then, the top surface is pressed against the joint surfaces Ta and vb of each of the divided models Wa and Wb within the range of their elastic deformation, that is, the pressure is such that the joint surfaces Ta and Tb can return to their original shapes. , More specifically, the bonding surfaces Ta and Tb are pressed together with pressure such that the bonding surfaces Ta and Tb are compressed by 0.2 mm, and the retained adhesive 3 is transferred to these bonding surfaces Ta and Tb. , Tb are filled with the adhesive q into minute recesses, and a thin film of the adhesive q is applied to the entire surface of the bonding surfaces Ta and Tb (FIG. 1(b)).

After the above adhesive transfer process was completed, one of the divided models was reversed Wllll+80°, and its joint surface Tb was made to face the joint surface Ta of the other divided model Wa (Atsushi 1 (C)). Press them together and integrate them (Fig. 1(d))
) Complete gluing the model.

FIG. 2 shows an example of a device used in this method, in which a gripping jig 1 for gripping the split model W includes a pressure-restricting stud 2 on the surface facing the template support plate 7.
．． 2 is installed upright, and the rod 5 is attached to the end of the rod 5 so that it can be moved out and out of the adhesive tank 3 by means of the cylinder 4.
．． 2 and the stud 8.8 which also controls pressure contact.
is erected to connect the joint surface T of the split model W and the template 6.
The pressure contact force with 6 is adjusted by the height of both studs 2.8.

(Effects) As described above, according to the present invention, since the adhesive is transferred by pressing the template to each joint surface of the fugitive split model, the pressure of the template removes the minute particles present on each joint surface. It is possible to form a uniform thin film of adhesive on the entire joint surface while forcibly filling the recess with adhesive, and by transferring a thin film to both joint surfaces, the mutual adhesion of the adhesive can minimize adhesion. The two halves of the model can be firmly integrated using the adhesive. Moreover, when joining surfaces to be joined, tiny recesses existing on both sides are filled with adhesive, so the adhesive on one side may get into the recesses on the other side, causing a shortage of adhesive, or the split models may Since the adhesive does not protrude to the periphery of the joint surface due to strong pressure, it is possible to easily and accurately mold a molded product without any problems in terms of strength and without the need for finishing processing after molding.

[Brief explanation of the drawing]

Figures 1 (a) to (d) are diagrams showing the joining process of split models that constitute an embodiment of the present invention, Figure 2 is a diagram showing an example of the apparatus used in the same method, and Figure 3 is the same as the above. It is a figure which showed -2 examples of the split model integrated by the method. 1... Gripping jig 2... Stud for pressure welding regulation 3... Adhesive tank 6... Template 8... Sphrad W for pressure welding regulation... Split model ■. ...Jointing surface q...Hot melt adhesive

Claims (1)

[Claims] Press a template for adhesive application onto each joint surface of the fugitive split model for casting to transfer the hot melt adhesive onto each joint surface, and then join the split model with the joint surfaces facing each other. A method for joining evanescent split models, characterized by integrating them into one piece.