JPH0569080A - Method for inspecting inner part of mold for precision casting - Google Patents

Abstract

PURPOSE:To specify the cause of breakage of a core by easily and surely inspecting the inner part of a mold before a casting process and particularly, smoothly confirming whether the core breaks or not in the case of inserting the core in the mold. CONSTITUTION:A member 3 for inspection hole and a metal plate 4 are connected with an objective part for inspection in a formed part 2, and after the tip part (the surface of the metal plate 4) of the member 3 for inspection hole is made to the exposing condition at the time of casting, by dissolving the member 3 for inspection hole together with the above formed part 2, the inspection hole 6a is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precision casting method (wax method) such as the lost wax method, and in particular, to inspect the inside of a precision casting mold used for casting a product having a hollow portion. Regarding the inspection method to do.

[0002]

2. Description of the Related Art The wax casting method is advantageous in that it is easy to mass-produce complex three-dimensional shapes and has high dimensional accuracy and few internal defects. It is widely used to manufacture mechanical parts that are difficult to manufacture by machining.

By the way, in a mechanical part such as a turbine blade cast by the above wax casting method, a hollow part may be provided inside the part in order to increase cooling capacity and reduce weight. In the case where this hollow portion is manufactured by the above wax casting method, conventionally, there is known a method of embedding a ceramic core in a molded product formed by brazing or the like and performing casting. The basic steps will be briefly described.

In order to cast a thin hollow component by the brazing mold casting method, first, a core is formed corresponding to the shape of the hollow portion of the component to be cast using ceramics such as fused silica as a raw material.

Next, the core is assembled inside a mold in which a void having the same shape as the outer surface contour of the component to be cast is formed. Then, a melted material such as a brazing material is injected into the voids through a flow path formed in the mold to form a molded product in which the core is embedded (molding step).

A plurality of molded products molded as described above are assembled into a dendritic shape, and a ceramic layer is coated around the assembly by an investment method or a ceramic shell molding method to mold a model (coating step). Then, the molded product embedded in the model is eluted while leaving the core (dewaxing step), and then the model is removed.
The organic components remaining inside are removed by firing at a temperature of 00 to 1200 ° C., and then the molten metal is poured into the voids formed in the model (mold) by elution of the molded product (casting step).

After pouring the molten metal, after waiting for the molten metal to cool, the mold is dropped to take out a casting tree in a dendritic form, and the casting tree is cut off so that the external contour is the same as the predetermined part shape, Obtain a cast product in which a core is cast. Then, by immersing the cast product in an alkaline solution to dissolve the core, a hollow portion having a predetermined shape is formed in the cast product.

[0008]

However, when a cast product having a hollow portion is cast as described above, the core made of ceramics is brittle and has low strength.
The core may be broken due to the impact received during the manufacturing process. Then, in this case, the product obtained by the flat-angle casting was rejected, and the yield was lowered. In particular, once the core has been insert-molded and the coating has been applied, the core cannot be seen from the outside, so breakage of the core is detected until the cast product is inspected by X-ray inspection after casting. It is difficult to determine whether the cause is the casting process or the previous dewaxing process, for example, so it is easy to take appropriate measures to prevent breakage of the core. Was not.

The present invention has been made in view of the above circumstances, and it is an object of the present invention that the inside of a mold can be easily and surely inspected before the casting step. It is possible to smoothly confirm whether or not the core is broken when the core is inserted, and to provide an inspection method in a precision casting mold that can easily identify the cause of the core breakage. is there.

[0010]

In order to achieve the above object, the present invention is produced by molding a molded product having the same shape as the product, coating the molded product, and then eluting the molded product. An inspection method for inspecting the inside of a precision casting mold, wherein an inspection window member is connected to an inspection target portion of the molded product, and the tip of the inspection window member is exposed during the coating. After being kept in the state, the inspection window member is eluted together with the molded product to form an inspection window, and the state inside the mold is inspected by using this inspection window.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, the turbine blade will be described, but it goes without saying that the present invention is not limited to this.

FIG. 1 shows a molded product 2 formed by inserting a ceramic core 1 into a cavity in an injection molding die and injecting a molten wax (wax) into the molding (insert molding). . Then, a cylindrical inspection window member 3 made of the same material as or a material similar to that of the molded product 2 is adhered to a portion of the molded product 2 to be inspected (a portion where the core 1 is likely to be broken). . Further, a disc-shaped metal plate 4 is adhered to the tip surface of the inspection window member 3. A rod-shaped body 5 is fixed to the center of the metal plate 4 (see FIGS. 2 and 3). The metal plate 4 to which the rod-shaped body 5 is fixed
Alternatively, the rod-shaped body 5 may be inserted into the round bar-shaped inspection window member 3 in advance, and may be bonded to the molded product 2. In this case, the metal plate 4 and the round bar-shaped inspection window member 3
Since and are firmly connected, they are easy to handle in handling or in the step of adhering to a molded product and the coating step.

In this way, as shown in FIG. 1, in a state where the inspection window member 3 and the metal plate 4 are bonded to the molded product 2 including the core 1, the coating process is started. That is,
The model 6 is formed by adhering the binder slurry to the outer surface of the molded article 2 and further sprinkling it with refractory particles. At this time, as shown in FIG. 2, the surface of the metal plate 4 is exposed by wiping off the slurry and the refractory particles adhering to it every time coating is performed.

Next, after the model 6 is dried, the process goes to the dewaxing step, and the molded product 2 embedded in the model 6 is
The core 1 is left to elute. At this time, the inspection window member 3
Also, since the gold plate 4 is also eluted and the gold plate 4 is removed, the inspection window 6a is formed in the model 6 (see FIG. 3).

Then, by visually observing the inside of the model 6 using the inspection window 6a formed in the model 6, it is inspected whether or not the core 1 is broken (or the surface is peeled). In this case, if breakage (peeling) of the core 1 is confirmed,
It can be seen that the cause of breakage (peeling) of the core 1 lies in the condition of the casting process, especially the dewaxing process. Therefore, the process before the casting process is checked, and the breakage (peeling) of the core 1 is performed.
It is only necessary to elucidate the cause of this and take countermeasures.
If the breakage (peeling) of the core 1 is not confirmed, it is understood that the breakage (peeling) of the core 1 is in the condition of the casting process, and the breakage (peeling) of the core 1 is prevented by reviewing the casting process. You can

In addition to visually inspecting the inside of the model 6 through the inspection window 6a, an inner surface of the model 6 may be inspected by inserting a fiberscope or the like inside.

[0017]

As described above, according to the present invention, a precision casting mold produced by molding a molded product having the same shape as the product, coating the molded product, and then eluting the molded product. A method for inspecting the inside of a molded article, which comprises connecting an inspection window member to an inspection target portion of the molded product, and exposing the tip of the inspection window member during the coating. , Is to form an inspection window by eluting the inspection window member together with the molded product, and the state of the inside of the mold is inspected by using this inspection window, so that the inside of the mold is before the casting step. Can be easily and reliably inspected, especially when the core is inserted in the mold, it can be confirmed smoothly whether the core is broken or not, It is easy to identify the cause and easy to take countermeasures.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a molded product assembling process showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a coating process.

FIG. 3 is an explanatory diagram after a dewaxing step.

[Explanation of symbols]

 2 Molded product 3 Inspection window member 6 Model (mold) 6a Inspection window

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Fumie Nishiwaki 1230 Kamijideya, Okegawa City, Saitama Prefecture Mitsubishi Material Co., Ltd. Okegawa No. 2 Works

Claims (1)

[Claims] 1. An inspection method for inspecting the inside of a precision casting mold produced by molding a molded product having the same shape as a product, coating the molded product, and then eluting the molded product. , The inspection window member is connected to an inspection target portion of the molded product, and the tip of the inspection window member is exposed during the coating, and then the inspection window member together with the molded product. The method for inspecting in a precision casting mold is characterized in that an inspection window is formed by eluting the.