JP2898567B2 - Inlay for mold positioning of casting split mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inlay for positioning a mold for a split die made by casting, to which a rubbing process by hand cutting and electric discharge machining is applied.

[0002]

2. Description of the Related Art A split mold is often used to produce a duplicate product having the same shape as a prototype, but the method of manufacturing the split mold is roughly classified into two types, one by machining and one by casting. Is done. The feature of the split mold by machining is that the mold matching accuracy is high. However, it is used for complicated shapes and split molds with the reverse slope of the replicated product (undercut product). Has the disadvantage that it cannot be applied. On the other hand, casting split molds are inferior to machined products in terms of mold matching accuracy, but have a high ability to respond to complex-shaped products and undercut products. There are many cases where a split mold made of a cast made of various alloys such as aluminum and copper is used.

In order to manufacture a casting split mold, first, the original mold is inverted to a rubber split mold, then the casting mold is inverted from the rubber split mold, and finally, the split mold is inverted by casting from the casting mold. After that, it is common to adopt a method of performing a rubbing process thereafter. At the time of manufacturing the split mold, as shown in FIG. 3, an in-row (an uneven fitting portion) is often provided for positioning at the time of mold matching. In the example of this figure, the insert-side in-row (convex fitting portion) 10 and the receiving-side in-row (concave fitting portion) 10 'are arranged at the corners of the divided surfaces of the lower die 8 and the upper die 7, respectively. Have been. Inlay 10 on the insertion side
As shown in FIG. 4, the shape is generally a conical shape or a pyramidal shape having a top portion cut horizontally, and the receiving spigot has a concave shape corresponding to these shapes.

[0004] As described above, the casting split mold has a certain degree of warpage or distortion in the as-cast state due to the repetition of the reversing step in the manufacturing process and solidification shrinkage and heat shrinkage caused by casting. In many cases, when the molds are aligned in an as-cast state, there arises a problem in the accuracy of the alignment such that a gap 12 is formed on the divided surface of the upper die 7 and the lower die 8 as shown in FIG. In order to correct this, in general, mold matching by hand cutting (hand-grinding) or discharge rubbing in which dies are rubbed by electric discharge machining are performed. In recent years, a procedure has often been adopted in which after a certain degree of mold contact accuracy is secured by hand-grinding, the mold contact accuracy is further improved by discharge grinding.

In this case, first, handrailing is performed. However, in consideration of securing the positioning accuracy of the mold registration at the time of handrailing, it is preferable that the slope of the side surface of the above-mentioned inlay is steep. In other words, when handrailing, cutting is performed on the side surface (graded portion) of the inlay in order to adjust the die contact. However, since it is a delicate manual operation, accidental excessive cutting is performed. Many,
In this case, the steeper the slope of the inlay side surface, the smaller the damage due to excessive cutting. This can be easily explained as follows.

FIGS. 8 and 9 are partially enlarged cross-sectional views showing the effect of excessive cutting during handrailing. FIG. 8 shows a case where the slope of the side face of the inlay is steep (the side face of the inlay with respect to the sliding direction). 9 shows a case where the slope of the inlay side surface is gentle (when the angle θ of the inlay side surface with respect to the sliding direction is large). In both figures (a), if the part shown by the dotted line on the side surface of the insertion side inlay 10 is mistakenly excessively cut, this excessively cut part will be in contact with the insertion side inlay 10 at the time of mold matching as shown in FIG. The gap 14 between the side surface and the receiving side insert 10 ′ becomes a cause of misalignment. Here, both excess amount of cutting of FIG When (excessive cutting portion of the thickness) x ₁ is equal to the width (the type of spacing in displacement direction) [Delta] W ₁ of die matching at the gap 14 (= x ₁ / cos
8) is smaller in FIG. 8 where the slope of the inlay side surface is steep than in FIG. 9 where the slope of the inlay side surface is gentle, and the misalignment is also small.

[0007] If the slope of the spigot side surface is steep,
When the split mold is set on the electric discharge machine at the time of the subsequent electric discharge rubbing, the deviation resistance of the mold increases,
This is also preferable in that misalignment is less likely to occur. Table 1, when an excess amount of cutting x ₁ of spigot side during mating Ri handrail is 0.05 mm, the angle θ of the spigot side for lapping direction, die matching when the gap width ΔW caused by excessive cutting _This shows the relationship with ₁ .

[0008]

[Table 1]

[0009] Discharge rubbing is performed subsequent to the above-mentioned hand rubbing. In consideration of ensuring the positioning accuracy after the discharge rubbing, contrary to the above, the inlay has a gentle slope on its side surface. Something is preferred. That is, in electric discharge machining at the time of electric discharge rubbing, due to its characteristics,
Since the surface with a steep gradient is preferentially removed, if the side surface of the inlay is steep, the side surface portion is preferentially excessively removed, and a gap is generated at the time of mold matching after discharge rubbing,
The misalignment is likely to occur. This can be easily explained as follows.

FIGS. 10 and 11 are partially enlarged sectional views showing the effect of preferentially removing the inlay side surface during discharge sliding, and FIG. 10 shows a case where the slope of the inlay side surface is steep. (When the angle θ of the inlay side surface with respect to the sliding direction is small), FIG. 11 shows a case where the slope of the inlay side surface is gentle (when the angle θ of the inlay side surface with respect to the sliding direction is large). Both figures
(a) is a mold matching state before discharge rubbing. At this time, the side surfaces of the insertion-side insert 10 and the receiving-side insert 10 'are in close contact with each other. In the discharge rubbing, the upper mold and the lower mold are used as a negative electrode and a positive electrode, respectively.
When the distance between the _two reaches the dielectric breakdown distance x2, an arc is generated between the two and the removal of the surface is started.
Write between the side surfaces having a gradient than between the horizontal plane of the spigot is to reach the breakdown distance x ₂ first.

[0011] Thus, by the time between the horizontal plane reaches the breakdown distance x ₂ is as shown in both FIG. (B), already a broken line curve between the side surface are preferentially removed, the preferential removal portion (Priority The thickness P = x ₂ −x ₂ sin θ of the removed portion is shown in both figures.
As shown in (c), the gap 16 between the side surfaces of the insertion-side inlay 10 and the receiving-side inlay 10 'at the time of the mold matching after the discharge rubbing is performed, thereby causing a mold misalignment.
Here, the dielectric breakdown distance x ₂ in both FIG. Are equal, the width of die matching at the gap 16 (distance in the shift direction of the mold)
ΔW ₂ (= (x ₂ −x ₂ sin θ) / cos θ) is smaller in FIG. 11 where the slope of the inlay side is gentler than in FIG. 10 where the slope of the inlay side is steep, and the misalignment is reduced. Table 2 below shows the dielectric breakdown distance x ₂ during discharge rubbing.
Is 0.2 mm, the relationship between the angle θ of the inlay side surface with respect to the sliding direction and the width ΔW ₂ of the gap at the time of mold alignment caused by preferential removal of the inlay side surface is shown.

[0012]

[Table 2]

[0013]

As described above, the slope of the side surface of the inlay is required to secure the positioning accuracy of the split die at the time of handrailing and at the time of setting the split die to the electric discharge machine. The steepness is preferably steep. On the other hand, it is preferable that the slope of the side face of the inlay is gentle to ensure the positioning accuracy after the discharge rubbing. , It was not possible to satisfy both preferred gradients at the same time.

For this reason, in order to minimize the gap caused by the discharge sliding and to reduce the mold misalignment after the discharge sliding to a level at which there is no practical problem, if the slope of the side face of the inlay is made gentle, the hand sliding and the discharge are prevented. When setting the split mold to the processing machine, misalignment is likely to occur,
Conversely, if the steepness of the side surface of the spigot is steep to reduce the gap caused by excessive cutting during handrailing and to prevent mold misalignment when setting the split die to the electric discharge machine, the mold after electric discharge grinding There was a problem that the alignment accuracy deteriorated. It was also considered to provide two types of inlays having different side slopes. However, in this case, the number of necessary inlays was doubled, and there was a problem that workability deteriorated.

The present invention solves the above-mentioned conventional problems,
In addition to ensuring the positioning accuracy of the split die by hand and the setting of the split die to the electric discharge machine, the positioning of the casting split die can be ensured as well as the positioning accuracy after the discharge. The purpose is to provide inlays for use.

[0016]

According to the present invention, there is provided an inlay which serves as a positioning reference at the time of upper / lower die alignment of a casting split die subjected to hand cutting and rubbing by electric discharge machining between the dies. The steep slope of the side surface is steep to ensure the positioning accuracy of the split die when hand-cutting and setting the split die in the electric discharge machine. There is provided a mold-matching / positioning spigot for a split mold made of casting, which is combined with a gentle slope portion having a gentle side surface gradient to ensure mold-matching positioning accuracy.

[0017]

The inlay according to the present invention has two types of gradient portions having different side gradients as described above. In handrailing, the positioning accuracy at the time of mold matching is ensured by the steep slope portion where the mold misalignment due to excessive cutting is small. Also, when setting the split die in the electric discharge machine at the time of the subsequent electric discharge rubbing, the steep slope increases the die deviation resistance, making it difficult for mold deviation to occur, and increasing the positioning accuracy. Secured.
On the other hand, the positioning accuracy of the mold after the discharge rubbing is ensured by the gentle slope portion where the excessive priority removal by the discharge rubbing is small. Therefore, by providing the inlay of the present invention on the split surface of the split mold, the occurrence of misalignment due to excessive cutting or the like during the rubbing operation is effectively suppressed.

In applying the inlay of the present invention to an actual split die, it is preferable to standardize a basic gradient design and to prepare in advance models of a plurality of sizes of inlays. Can be used for split dies of any size. The shape of the inlay according to the present invention is a round shape as shown in FIG. 1 (a) (a cross-sectional shape is circular).
The most common one is a rectangular one as shown in FIG. 1B (a square cross-sectional shape). Symbol 2 in the figure is a steep part,
3 is a gentle slope portion. Note that the inlay 1 in the drawing is an inlay (convex fitting portion) on the insertion side, and the inlay (concave fitting portion) on the receiving side has a concave shape corresponding to these shapes.

The feature of the round shape is that, when handrailing for temporary positioning of the split mold, etc., it is easy to correct the fit of the inlay with a rotary tool or the like, and the workability is good. It also has the disadvantage that it is too easy to cause problems. The square type is inferior to the round type in that the workability of handrailing is inferior, but has the characteristic that cutting errors are less likely to occur.

As shown in FIGS. 1 (a) and 1 (b), the arrangement of the two types of gradients, the steep gradient and the gentle gradient, is such that the lower part (the side closer to the dividing plane) is the steep part 2 and the upper part is (Far side from the dividing plane)
Is a gentle slope portion 3, and conversely, as shown in FIG. 1 (c), the lower portion (the side closer to the split surface) is a gentle slope portion 3 and the upper portion (the side farther from the split surface) is a steep slope portion 2. However, the former is preferable in that the size of the inlay can be made compact.

Many combinations can be considered for setting the gradient of the two most important gradient portions in the present invention. The data shown in Tables 1 and 2 above, the actual workability, and From the generally accepted tolerance of 0.1 mm or less for the amount of misalignment (guitch) at the divided surface position, the sum of the amount of misalignment of the upper and lower dies caused by hand-sliding of the split mold and discharge-sliding Is set to 0.05 to 0.06 mm or less (the remaining 0.04 to 0.06 mm obtained by subtracting the 0.05 to 0.06 mm from the allowable value 0.1 mm).
05mm is the allowable local deformation of the mold such as casting distortion),
As shown in FIG. 2, the angle θ _A of the inlay side surface in the steeply sloped portion 2 with respect to the mold sliding direction is 0 ° or more and 15 ° or less, and the angle θ _B of the gentle incline portion 3 with respect to the mold sliding direction is 60 °. It is preferable that the angle be not less than 85 °.

[0022]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Embodiment) A casting split die was prepared in which four inlays each having the shape and dimensions shown in FIG. The fabrication conditions are as follows. First, as a master model (prototype), dimensions 50mm x 40mm
Using a doll of about × 20 mm, an inverted rubber mold of this master model was produced using silicone rubber. Next, a casting mold was inverted from the inverted rubber mold using a ceramic mold material kneaded with an ethyl silicate-based binder. A split mold was cast from this casting mold using 275C beryllium copper alloy. The dimensions of the resulting casting split mold are 100 mm x 80 mm x 60 with the upper and lower dies together.
mm.

After the gap created between the upper and lower mold split surfaces obtained as described above is corrected by handrailing until a certain degree of mold matching accuracy is obtained,
It was set in an electric discharge machine and subjected to electric discharge cutting for a thickness of about 0.15 mm to complete the rubbing. No rattling in the displacement direction was observed in the split mold after the discharge rubbing in a state where the upper and lower dies were aligned. In addition, a molded product produced by using silicone rubber from the casting split mold was cut at an arbitrary position, and the obtained cross section was measured for the amount of displacement between the upper and lower molds at the division surface position (Guichi). The measurement was performed at 20 locations on 10 sections, and all were evaluated as absolute values without adding + or-signs. As a result, the deviation between the upper and lower molds at the position of the dividing plane is 0.02 mm on average and 0.0 mm on standard deviation.
3 mm, and the maximum value was 0.11 mm.

COMPARATIVE EXAMPLE A casting split mold having four inlays each having the shape and dimensions shown in FIG. 7 near the four corners of the divided surface was manufactured under the same conditions as in the above embodiment. The obtained casting split mold was subjected to handrailing and discharge grinding in the same manner as in the example. In the casting split mold after the discharge rubbing, rattling of about 0.1 mm was confirmed in the displacement direction in a state where the upper and lower dies were matched. A molded product was made three times from this casting split mold using silicone rubber, and the upper and lower mold displacements at the split surface positions were examined. It turned out to be bad. In addition, the amount of displacement three times is 0.0 on average.
It was 5 mm, the standard deviation was 0.07 mm, and the maximum value was 0.23 mm, and the mold matching accuracy was lower than that of the above-described embodiment using the spigot according to the present invention.

[0026]

As described above, according to the inlay according to the present invention, by having two types of slope portions having different side slopes, it is possible to use the split mold at the time of handrailing and the splitting to the electric discharge machine. It is possible to secure the positioning accuracy of the mold alignment at the time of setting the mold and the positioning accuracy after the discharge sliding. Therefore, by providing the spigot of the present invention on the divided surface of the split mold, it is possible to simply and effectively suppress the occurrence of mold misalignment due to excessive cutting or the like during the rubbing operation.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of an inlay according to the present invention.

FIG. 2 is a side view of the inlay according to the present invention.

FIG. 3 is a perspective view showing a casting split mold provided with an inlay.

FIG. 4 is a perspective view showing an example of a conventional inlay.

FIG. 5 is a cross-sectional view showing mold matching in an as-cast state.

FIG. 6 is a side view showing the shape and dimensions of the inlay used in the example.

FIG. 7 is a side view showing the shape and dimensions of the inlay used in the comparative example.

FIG. 8 is a partially enlarged cross-sectional view showing the effect of excessive cutting during handrailing.

FIG. 9 is a partially enlarged cross-sectional view showing the effect of excessive cutting during handrailing.

FIG. 10 is a partially enlarged cross-sectional view showing the effect of preferentially removing the inlay side surface during discharge sliding.

FIG. 11 is a partially enlarged cross-sectional view showing an effect of preferentially removing an inlay side surface during discharge sliding.

[Explanation of symbols]

1 ... In-row (the product of the present invention), 2 ... steep slope section, 3 ... gentle slope section, 7 ... upper mold, 8 ... lower mold, 10 ... in-row (conventional product)

Claims (4)

(57) [Claims] Claims: 1. An in-row which serves as a positioning reference when aligning upper and lower dies by hand cutting and rubbing by electric discharge machining between the dies. A steep part with a steep slope to ensure mold alignment positioning accuracy at the time and when setting the split die to the electric discharge machine, and a side surface to ensure mold alignment positioning accuracy after rubbing by electric discharge machining An inlay for mold matching positioning of a split mold made of casting, which has a gentle slope portion with a gentle slope. 2. The angle of the side face of the spigot in the steeply inclined portion with respect to the direction of rubbing is not less than 0 ° and not more than 15 °,
2. The spigot according to claim 1, wherein the angle of the side face of the spigot at the gentle slope portion with respect to the rubbing direction is not less than 60 ° and not more than 85 °. 3. The spigot according to claim 1, wherein the cross-sectional shape is circular or square. 4. The spigot according to claim 1, wherein a steeply inclined portion is formed on a side close to the dividing surface of the casting split mold, and a gentlely inclined portion is formed on a side far from the dividing surface.