JPS5855853B2 - How to cut out a model for vacuum molding - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for cutting out a model for vacuum molding.

Conventionally, when using self-hardening molds to model box-shaped products with cores, such as floor slab products, etc., it was difficult to cut out the wooden molds, so the core was made separately. was fixed to the mold with a hanger.

Hanging the core required a lot of man-hours, including molding the core, coating the core, fixing it to the mold, and checking the wall thickness, and also caused variations in dimensional accuracy.

In addition, it is necessary to make the draft angle of the bead part of a box-shaped product with a core large.If the draft angle is increased and the molding is made with a large draft angle, the fluidity of the sand will deteriorate, and the sand directly under the bead part will deteriorate. Due to poor filling, the product often had deviations, convexities, and other defects, requiring post-processing.

For this reason, recently, box-shaped products with this ridge core (
In this case, the reduced pressure molding method is being adopted, and this molding method allows the core to be molded integrally with the mold, thereby improving molding productivity and product dimensional accuracy.

However, the problem of difficulty in cutting the mold has not yet been resolved.

This invention aims to provide a method for cutting out a model for vacuum molding which facilitates cutting even if the draft of the model is small. Therefore, the present invention is characterized by the fact that the draft of the model for vacuum molding is 0. For cores below 57100, amplitude 0.03
The point is that the mold is cut while applying pie-break vibration of ~0.5 mm.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

This example shows an example of molding a mold for a floor slab product. In FIGS. 1 to 4, reference numeral 1 denotes a pattern table, into which models of the side walls, ribs, beads, etc. of the floor slab are set in advance.

2 is a side wall model, 3 is a rib model, and 4 is a bead model.

One-piece molding is possible (for rubbing, the method of fixing the ball-shaped model 4 is to provide a dowel 5 on the ball-shaped model 4 or the rib model 3, and then attach the dowel 5 to the other side (i.e., the rib model or ball-shaped model on the side where no dowel is provided). A fixing means is provided that provides a recess into which the dowel 5 can be removably fitted.

In this case, place each model in the pattern table 1.
After sorting, vacuum molding is performed as follows.

First, the plastic film 6 is placed over the side wall model 2, the rib model 3, and the beveled model 4, and at the same time, the valve 7 on the pattern metal side is actuated to bring each model f into close contact with each other by reducing pressure through the cavity of the pattern table 1.

This state is shown in FIG. 5I. Next, the casting flask 8 is placed on the pattern table 1.
and filled with dry silica sand (see ■ in the same figure).
The surface of the sand is covered with a plastic film 9, and the valve 10 of the eight casting flasks is activated to reduce the pressure inside the mold, and the valve I on the pattern table 1 side is closed to introduce the atmosphere, and the sand is held down by the atmospheric pressure. The plastic film 6 that hardens and covers the pattern base remains in its shape and adheres closely to the sand side.

This state is shown in (■) in the same figure. Note that when filling the sand, a vibration molding machine is used so that the sand can be filled right below the ball-shaped model 4.

After molding, the mold is removed, but first the pattern table 1,
The side wall model 2 and the rib model 3 are cut out.

At this time, since the rib model 3 is dowel-fitted with the beveled model 4, the knob model 3 is easily removed by pulling out the knob model 3 in the vertical direction to release the fitted state.

The state of this cutting die is shown in ■ in the same figure. Next, the ball-shaped model 4 is cut out in the horizontal direction.

During this cutting process, the ball-shaped model 4 is subjected to vibration while being cut out using a pie break.

The amplitude of the pie break used at this time is 0.03 to 0.
The range shall be 5 mm.

In other words, as is clear from the test results shown in the table below, when the amplitude is smaller than 0.03 mm, the ball-shaped model 4
It was difficult to cut out the mold, and therefore, the cutting slope of Model 4 (in the drawing, perpendicular to the plane of the paper) had to be made larger than 0.000 in order to be able to cut out the mold.

When an amplitude of 0.5 mm or more is applied, the film 6 of the mold is likely to be torn.

If all models 2, 3, and 4 are removed in this way, the fifth
As shown in FIG. V, a mold 11 with no tearing of the film 6 is completed.

As described above, this invention provides a vacuum molding model with a draft angle of 0.
Core I for ball-shaped models of 57100 or less, amplitude 0.03
The mold is cut while applying pie-break vibration of ~0.5 yxm, and in order to maintain good fluidity of the sand, the draft angle is extremely small, and even if the core is tightly attached to the film due to reduced pressure, the vibration is small. Since the die cutting operation is performed simultaneously while applying vibration, there is no gap between the film and the film, and there is no damage to the film due to vibration.
The mold can be cut out, making it possible to apply a model with a core to vacuum molding as well as enabling high-precision molding.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a box-shaped product model used in carrying out the method of this invention, Fig. 2 is a sectional view taken along the line X-X in Fig. 1, and Fig.
The figure is a sectional view taken along the Y-Y line in the same figure, Figure 4 is a sectional view taken along the Z-Z line in ζ of the same figure, and Figures I to V are explanations showing the sequential process of vacuum molding using the same model. It is a diagram. 1...Pattern stand, 2...Side wall model,
Bu model, 4... ball model. 3...

Claims (1)

[Claims] 1. A method for cutting out a vacuum molding model, which comprises cutting the core of the vacuum molding model with a draft angle of 0.57100 or less while applying pie-break vibration with an amplitude of 0.03 to 0.5.