JPH067975B2 - Casting model manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a model used when casting a press die or the like by a full molding method.

(Prior Art) JP-A-62-1 as a method for designing a die such as a press die.
The method disclosed in 82806 is known. In this method, the shape of a part such as a bolt is stored in association with another condition such as a mold shape, and the name of the part is entered so that the shape of the part is displayed on the CRT together with the other conditions. Is. Also, although it is not a mold design,
As a technique for automatically creating NC processing data
The one disclosed in No. 2-14208 is known.

A full mold method has been conventionally known as a method for manufacturing a mold whose shape has been determined by the above design method and the like. In this method, a model of the same shape as the mold is created by shaving vanishing material such as Styrofoam, the outside of this model is solidified with resin sand, and then a molten metal is poured into the part of the model to heat and extinguish the model material, This is a method in which a mold having the same shape as the model is obtained.

FIG. 6 shows a lower die portion of a general press die apparatus, and the press die 100 is a steel plate (blank) between the upper die and the upper die.
The shape surface portion 101 for bending and forming is attached to the mounting surface portion 102 fixed to the press machine by a rib 103, and a blank holder 104 is provided on the outside of the shape surface portion 101 to grip the peripheral edge of the steel plate and prevent wrinkles from occurring. The blank holder 104 is supported by a cushion pin 105 attached to a press machine.

(Problems to be Solved by the Invention) The position where the above-described rib 103 is provided is originally a position where the force acting on the shape surface portion 101 can be most effectively received, specifically, the shape surface portion as shown by an imaginary line. It is best to extend downward from the outermost side of 101. Then, the optimum position can be easily determined by the conventional mold design method. However, when the rib 103 is extended downward from the outermost side of the shape surface portion 101, the cushion pin 105
Therefore, the rib 103 must be provided between the cushion pins 105, and the rib cannot be provided at an optimum position. Therefore, the rib becomes thick to cover it and the weight increases.

Further, in the past, since no consideration was given to the processing of the back side surface of the shape surface portion 101, the shape surface portion 101
Is partially thicker than necessary, which also causes an increase in weight.

(Means for Solving the Problems) In order to solve the above problems, according to the present invention, after displaying a shape surface portion of a mold on a screen based on product shape data of a CAD system, the shape surface portion of the mold is While extending the ribs toward the mounting surface of the mold, in consideration of the relationship with the press machine, extend the ribs from the mounting surface of the mold toward the shape surface and extend from the shape surface and the mounting surface. The ribs were joined at the middle to produce the mold shape.

Then, this mold shape is divided into a plurality of block units along a dividing line in a direction orthogonal to the ribs, processing data for each block unit is obtained, and after the foam block material is carved out based on this processing data, The processed foam blocks were joined together.

(Operation) After the shape surface of the mold is displayed on the CRT or the like based on the data in the CAD system, the ribs are extended from the optimum positions of the shape surface and the mounting surface, respectively, and both ribs are joined at the intermediate portion. Thus, for example, the design taking into consideration the following requirements can be easily performed.

Strength requirements for mold structure Avoiding interference with peripheral members such as cushion pins Weight reduction of mold Reduction of material cost Ease of processing Conditions such as size and shape of mold material Improvement of quality of cast products Ribs Since it is divided into multiple blocks by dividing lines in the direction orthogonal to, the conditions such as the length of the machining tool, machining direction, various conditions such as machining setup, constraints, etc. are alleviated further To facilitate processing. In addition, there is no useless wall thickness, and the weight can be reduced.

(Example) Below, the Example of this invention is described based on an accompanying drawing.

First, in the present invention, as shown in FIG. 1, a graphic 2 of a press-shaped product shape portion to be cast on a screen 1 of a CRT or the like.
Is displayed by inputting the existing product shape data into the system, and the figure 3 on the bottom of the press machine body is displayed.
To draw. Then, as shown in FIG. 2, a rib figure 4 is drawn from the optimum position of the figure 2 based on the shape of the shape surface portion, and a rib figure 5 is formed from the optimum position of the figure 3 in consideration of the position of the cushion pin. Plot. Here, the rib patterns 4 and 5 extend from the optimum positions of the shape surface portion and the mounting surface portion, respectively, so that they often do not coincide with each other as shown in the drawing.

Then, as shown in FIG. 3, a rib figure 6 connecting the rib figures 4 and 5 is drawn, and the entire shape of the press die considered to be optimal in shape is completed on the screen 1 of the CRT. When the entire shape of the press die is completed on the screen 1 in this way, the dividing line l is taken into consideration in consideration of the possibility of machining with a machining jig.
₁ , 1 ₂ are set, the entire shape of the press die is divided into a plurality of block diagrams d ₁ , d ₂ , d ₃ , and each block figure d ₁ ,
Processing data is obtained for each of d ₂ and d ₃ . It should be noted that in the embodiment, the block figure is divided into three block figures, but the number is arbitrary, and the dividing direction is also arbitrary, and the point is to divide from a direction that can be processed by a processing jig described later.

Next, as shown in FIGS. 4 (A), (B), and (C), by a machining jig 7 that is NC controlled based on the machining data,
Blocks b ₁ , b ₂ and b ₃ are cut out from a disappearing block such as expanded polystyrene or expanded styrene. Here, each of the blocks b ₁ , b ₂ , b ₃ has the same shape (dimension) as a part of the press die.

After this, the blocks b ₁ , b ₂ , b ₃ obtained as described above are
Are bonded to obtain a disappearing cast model M. Then, the periphery of the model M is solidified with resin sand 8 (sand coated with resin) as shown in FIG. 5, and the molten metal is poured into the model M from the pouring port 9. Then, the model M disappears as gas due to the heat of the molten metal, the portion where the model M was present becomes a molding cavity, and a press die having the same shape as the model M is cast.

(Effects of the Invention) As described above, according to the present invention, when manufacturing a cast model, the model shape is determined by the mold design data itself by the CAD system, so that the optimum shape can be easily obtained. Since the mold figure of the obtained optimum shape can be divided into a plurality of pieces and the NC processing data is created for each block, the thickness is not unnecessarily increased, and the rib is also provided at the optimum position. The weight of the mold can be greatly reduced. Further, it is also possible to automatically carve out a model based on the NC machining data.

[Brief description of drawings]

1 to 3 are views showing a rib drawing process, and FIG.
(A), (B) and (C) are views showing divided blocks of a model, FIG. 5 is a view showing a state of casting using a model, and FIG. 6 is a sectional view of a conventional press die. In the drawings, 1 is a CRT screen, 2 is a figure of a shape surface portion, 3
Is a figure of a mounting surface portion, 4, 5 and 6 are rib figures, 7 is a processing jig, 11 and 12 are dividing lines, b ₁ , b ₂ and b ₃ are blocks,
M is a model.

Claims (1)

[Claims] 1. A method of manufacturing a cast model, wherein a foam block casting model is designed and manufactured by a CAD system, wherein a mold surface portion of a mold is displayed on a screen based on product shape data of the CAD system. After displaying
Considering the relationship between the step of extending the rib from the shape surface portion of the mold toward the mounting surface portion of the mold for display and the press machine, the rib is extended from the mounting surface portion of the mold toward the shape surface portion. The step of displaying and displaying, the step of joining the rib extending from the shape surface portion and the rib extending from the mounting surface portion at an intermediate portion to generate a mold shape, and the mold shape created by the above step is orthogonal to the rib. Divide into a plurality of block units along the dividing line in the direction to obtain processing data for each block unit, cut out the foam block material based on this processing data, and join each processed foam block A method of manufacturing a cast model, which comprises the steps of: