JP2007326114A - Die apparatus for casting and method for manufacturing casting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the yield of a manufactured casting while restraining the development of a cold shut and a shrinkage cavity. <P>SOLUTION: A die apparatus 1 for casting is provided with a first runner 21 extending toward a cavity 9 side (the arrow mark Z1 direction) from a sprue 10; a second runner 22 (the arrow mark Y1-Y2 direction) of the cavity 9 so as to temporarily retain molten metal 12 flown in from the first runner 21 side; and a plurality of wall parts 28 projected in a rib-form for dividing toward the cavity 9 side while partially receiving the flow of the molten metal 12 advancing to the width direction of the cavity 9 in the second runner 22. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a casting mold apparatus for obtaining a casting by cooling and solidifying molten metal in a mold and a method for manufacturing the casting.

  Coupled with the remarkable development of mobile communication technology in recent years, mobile terminals such as mobile PCs (personal computers) and notebook PCs have become widespread. Such mobile terminals are constantly required to be light, thin, and small in consideration of portability, and die casing materials such as magnesium alloys are used for the material of the casing in consideration of recyclability and strength. ing.

  By the way, since the molten metal of the above-mentioned material has high fluidity and fast solidification rate by cooling, for example, when casting a relatively large-sized thin housing for a notebook PC, the inside of the cavity of the mold It is necessary to consider the injection of materials into That is, if a large flow rate difference or backflow occurs in the injected molten metal flow in a thin-walled cavity with a large area, defects such as hot water boundaries and shrinkage cavities are formed in the cast product. .

Therefore, by forming a recess in the runner along the width direction of the cavity so as to temporarily block the flow of the molten metal toward the cavity side, the operation that the molten metal overflows from the recess is used. There has been proposed a casting method in which the timing of supplying molten metal into the inside is as much as possible (see, for example, Patent Document 1).
Japanese Patent No. 3427060

  However, in the casting method of the above document, the concave portion in the runner advances in the width direction of the cavity, collides with the terminal portion of the concave portion, and the influence of the flow of the molten metal flowing back and the inhibition action by the concave portion is shaken off first. Due to the influence of the flow of molten metal traveling toward the cavity, the flow of molten metal injected into the cavity may be disturbed. For this reason, further improvement of prevention measures such as a hot water boundary and shrinkage nest is also required for the above-described casting method.

  The present invention has been made in order to solve such a problem, and a mold apparatus for casting capable of improving the yield of a cast product to be manufactured while suppressing the occurrence of a hot water boundary and a shrinkage nest as much as possible. It aims at providing the manufacturing method of a casting.

  In order to achieve the above object, a casting mold apparatus according to the present invention temporarily retains a first runner extending from a gate toward a cavity and a molten metal flowing in from the first runner side. And a second runner extending along the width direction of the cavity so as to widen the flow path width of the first runner, and a flow of the molten metal that proceeds in the width direction of the cavity within the second runner. And a wall portion that branches toward the cavity side while receiving it.

  The casting production method according to the present invention is a casting production method using a casting mold apparatus, and the molten metal is injected into the first runner extending from the gate toward the cavity. And a wall portion for receiving a part of the flow of the molten metal traveling in the width direction of the cavity, and extending along the width direction of the cavity so as to widen the flow path width of the first runner, and The step of flowing the molten metal from the first runner side into the second runner having an action of temporarily retaining the molten metal, and the flow into the second runner and progress in the width direction of the cavity Branching toward the cavity while partially receiving the flow of molten metal by the wall, and whether the molten metal branched to the cavity by the wall and the first runner side Filling the cavity through the gate with the molten metal that has flowed into the second runner and proceeding toward the cavity; cooling and solidifying the molten metal filled in the cavity; and obtaining a casting; It is characterized by having.

  That is, in the present invention, the flow of the molten metal that flows in from the first runner side and proceeds in the width direction of the cavity in the second runner can be rectified while being received by the wall portion and can be advanced toward the cavity side. . Therefore, according to the present invention, since the molten metal rectified through the wall portion can be injected into the cavity, it is possible to suppress the turbulence of the molten metal flow in the cavity. , Cracks, nests and the like can be suppressed.

  As described above, according to the present invention, there are provided a casting mold apparatus and a casting manufacturing method capable of improving the yield of a casting to be manufactured while suppressing the occurrence of a hot water boundary and a shrinkage nest as much as possible. be able to.

The best mode for carrying out the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 is a view schematically showing a casting mold apparatus according to the first embodiment of the present invention, and FIG. 2 shows a state in which molten metal is filled in the cavity of this casting mold apparatus. FIG.
As shown in FIGS. 1 and 2, a casting mold apparatus 1 is a casting apparatus that employs a so-called cold chamber method, and includes a mold 5 as a mold body having a fixed mold 2 and a movable mold 3, and a sleeve. 7 and a plunger 8 disposed so as to be movable forward and backward with respect to the inside of the sleeve 7.

  The movable mold 3 of the mold 5 is configured to be openable and closable in the directions of the arrows X1-X2, and by being brought into close contact with the fixed mold 2, a cavity 9 as a hollow portion having a reversed shape of a product (cast) is formed. Composed. The fixed mold 2 is provided with a gate 10 for supplying a molten metal (molten metal) 12 such as a magnesium alloy to the cavity 9 side. A sleeve 7 extending in the horizontal direction is connected to the gate 10.

The sleeve 7 is provided with a pouring port 14 for pouring the molten metal 12 therein. Further, a heating device such as a burner may be provided at the bottom of the sleeve 7 in order to ensure the fluidity of the molten metal 12. The plunger 8 disposed in the sleeve 7 so as to be able to advance and retreat is connected to an injection machine (not shown). In addition, a plunger tip 8a for extruding the molten metal 12 to the cavity 9 side at a casting pressure of, for example, about 200 to 700 kg / cm ³ is provided at the distal end portion of the plunger 8 through the radiant power of the injector.

  Next, the structure of the flow path of the molten metal 12 formed in the mold 5 will be described with reference to FIGS. Here, FIG. 3 is a schematic view of the flow path structure of the molten metal 12 in the mold 5 as seen from the plane direction, and FIG. 4 is a cross-sectional view taken along the line AA showing the flow path structure of FIG.

  As shown in FIGS. 3 and 4, the flow path of the molten metal 12 formed in the mold 5 includes a first runner 21 that extends from the gate 10 toward the cavity 9 (in the direction of the arrow Z <b> 1), and a first runner 21. A second runner 22 extending along the width direction (arrow Y1-Y2 direction) of the cavity 9 so as to widen the flow path width of the runner 21, and a gate for injecting the molten metal 12 on the second runner 22 side into the cavity 9 side 23, gas vents 24 and 25, and a chill vent 26.

  The first runner 21 described above is formed to be narrower than the cross-sectional area of the gate 10 when viewed from the flow direction of the molten metal 12, and the cross-sectional area ratio is set to about 1:10. In addition, the cavity 9 in the mold 5 of the present embodiment is configured by a cavity having an inverted shape of a product (cast). The gas vent 24 and the gas vent 25 are provided at both edge portions and end portions on both sides of the cavity 9, respectively, and exhaust gas mixed in the cavity 9. Further, the gas vent 25 has a molten metal pool portion 27.

  The chill vent 26 is formed so that the cross-sectional shape cut along the depth direction (arrow Z1-Z2 direction) of the cavity 9 becomes a zigzag shape in order to form a longer flow path. By solidifying the flow front of the molten metal 12 with the chill vent 26, the solidified body functions as a stopper, and the molten metal 12 is prevented from flowing out of the mold 5. In addition, a predetermined pouring pressure is applied to the molten metal 12, but the mechanical reaction by the solidified body in the chill vent 26 is minimized by the action of the molten metal pool 27 included in the gas vent 25 in front of the chill vent 26. The

  Next, the characteristic structure of the second runner 22 provided in the casting mold apparatus 1 according to the present embodiment will be described in detail based on FIGS. 5 and 6 in addition to FIGS. Here, FIG. 5 is a perspective view showing a casting 5a (mainly a non-product portion) cast in the peripheral portion of the first and second runners 21 and 22, and FIG. 2 is a cross-sectional view schematically showing a cross-sectional structure of a runner 22. FIG.

  That is, as shown in FIGS. 3 to 6, the second runner 22 (the cast portion 22 a in FIG. 5) includes the gate 10 (the cast portion 10 a [biscuit] in FIG. 5) and the first runner 21 (in FIG. 5). It has a hollow portion for temporarily retaining the molten metal 12 flowing from the casting portion 21a) side. Further, the second runner 22 extends in the two directions (arrow Y1-Y2 directions) along the width direction of the cavity 9 at the end portion of the first runner 21 toward the center of the cavity 9 in the width direction. Further, the cavity 9 side (arrow Z1 direction side) in the second runner 22 is a flow path through which the molten metal 12 flows.

  Further, in the second runner 22, a wall portion (see FIG. 5) that branches toward the cavity 9 while partially receiving the flow of the molten metal 12 traveling in the width direction of the cavity 9 in the second runner 22. 5 casting portions 28a [groove portions]) 28 are provided. The wall portion 28 is formed in a state in which the inner wall surface of the second runner 22 is partially protruded in a rib shape (rectangular plate shape) in the opening / closing direction of the mold 5 (arrow X1-X2 direction). Specifically, the wall portion 28 is provided so that the inner wall surface of the fixed mold 2 protrudes toward the movable mold 3 (in the direction of the arrow X1).

  Further, as shown in FIG. 3, a plurality of wall portions 28 are provided at predetermined intervals along the width direction of the cavity 9. These wall portions 28 are formed so that the thickness direction (arrow Y1-Y2 direction) faces the width direction of the cavity 9 (arrow Y1-Y2 direction). As a result, as shown in FIG. 3, the flow of the molten metal that flows in from the first runner 21 side and proceeds in the width direction of the cavity 9 in the second runner 22, that is, the flow front 29 is While being received, it can be rectified and advanced toward the cavity 9 (arrow Z1 direction).

  Here, as shown in FIG. 6, these wall portions 28 correspond to the width T2 of the flow path in the opening / closing direction (arrow X1-X2 direction) of the mold 5 (mold body) in the second runner 22. The protrusion height T1 in the opening / closing direction is preferably formed so as to be within a range of 60% to 80%. In addition, the wall portion 28 has a length P1 in the depth direction of 50% or more and 80% or less with respect to the length P2 of the cavity 9 in the second runner 22 in the depth direction (Z1-Z2 direction). It is desirable that it be formed so as to be within the range. Thereby, since the molten metal 12 rectified through these wall portions 28 can be injected into the cavity 9, it is possible to suppress the flow (flow front 29) of the molten metal 12 in the cavity 9 from being disturbed.

Next, a method for producing a cast using the casting mold apparatus 1 having such a structure will be described.
As shown in FIG. 1 to FIG. 6, first, after applying a release agent to a part of the mold 5 that becomes the cavity 9, the movable mold 3 is driven to come into close contact with the fixed mold 2. Form. Next, as shown in FIG. 1, for example, a molten magnesium alloy (molten metal 12) is pumped out of the heating furnace by the feeder, and the pumped molten metal 12 is fed into the sleeve 7 from the pouring inlet 14.

  Next, as shown in FIG. 2, the plunger 8 (plunger tip 8 a) is rapidly moved to the stationary mold 2 side (in the direction of the arrow X <b> 1) by an injection machine, so that the molten metal 12 in the sleeve 7 passes through the gate 10 and the mold 5. Press fit inside. Thus, the molten metal 12 flows into the second runner 22 through the first runner 21 extending from the gate 10 toward the cavity 9 side. Here, the plurality of wall portions 28 receive the flow of the molten metal 12 flowing into the second runner 22 and proceeding in the width direction (Y1-Y2 direction) of the cavity 9 while partially receiving the flow of the melt 9 (arrows). Branch (divide) toward (Z1 direction). Thereby, as shown in FIG. 3, the flow (flow front 29) of the molten metal 12 toward the cavity 9 side is rectified.

  Thereafter, the molten metal 12 branched to the cavity 9 side by the wall portion 28 and the molten metal 12 flowing from the first runner 21 side and proceeding to the cavity 9 side through the second runner 22 pass through the gate 23 to the cavity 9. Filled in. Furthermore, after the molten metal 12 filled in the cavity 9 dissipates heat to the mold 5 side and cools and solidifies, the plunger 8 (plunger tip 8a) is pulled back to the initial position, then the movable mold 3 is opened and the fixed mold 2 side is opened. Separate. At this time, the cooled and solidified casting is pushed out by an ejector pin (not shown) provided in the movable mold 3 and released from the movable mold 3 side. Further, unnecessary parts of the casting thus obtained are divided through a punch press, so that only a portion corresponding to the cavity 9 is taken out as a product, and the remaining part is recovered for recycling. The

  As described above, in the casting mold apparatus 1 according to the present embodiment, a plurality of flows of the molten metal 12 that flow in from the first runner 21 side and proceed in the width direction of the cavity 9 in the second runner 22 are performed. It can be rectified while being received by the wall portion 28 and can be advanced toward the cavity 9 side. Therefore, according to the casting mold apparatus 1 of the present embodiment, since the molten metal 12 rectified through the plurality of wall portions 28 can be injected into the cavity 9, the disturbance of the flow of the molten metal 12 in the cavity 9 can be suppressed, Thereby, it is possible to suppress the occurrence of hot water, hot water boundaries, sink marks, cracks, nests and the like in the cast product.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
Here, FIG. 7 shows a cast 35a (mainly a non-product part) cast in the peripheral part of the first and second runners 21 and 32 provided in the casting mold apparatus according to the second embodiment. FIG. 8 is a cross-sectional view schematically showing a cross-sectional structure of the second runner 32. 7 and 8, the same constituent elements as those provided in the casting mold apparatus 1 (mold 5) of the first embodiment are denoted by the same reference numerals and the description thereof is omitted. .

  As shown in FIGS. 7 and 8, the casting mold 35 of the casting mold apparatus according to this embodiment includes a movable mold 33 instead of the movable mold 3 of the casting mold 5 of the first embodiment. 2 runners 32 (the cast portion 32a in FIG. 7). The second runner 32 uses the inner wall surface of the second runner as a part for temporarily retaining the molten metal 12 flowing from the first runner 21 side in the opening / closing direction (arrow X1) of the mold 35 (mold body). A stepped portion 38 that is partially recessed in the −X2 direction and formed so that the recessed portion 38a extends along the width direction of the cavity 9 (arrow Y1-Y2 direction). Specifically, the stepped portion 38 is formed in such a manner that the inner wall surface of the movable mold 33 is partially recessed in a direction away from the fixed mold 2 side (arrow X1 direction).

  Here, such a stepped portion 38 has a side wall surface on the cavity 9 side in the recessed portion 38a as viewed from the direction in which the stepped portion 38 extends (the direction of the arrow Y1-Y2) of the mold 35 (mold body). Tapered (an imaginary vertical plane along the opening and closing direction of the mold 35 is 30 degrees or more and 45 degrees or less with respect to the opening / closing direction (arrow X1-X2 direction) at an angle α of 30 degrees or more and 45 degrees or less. (Taper obtained by laying down) 37 is formed.

  That is, in the casting die apparatus according to this embodiment, the stepped portion 38 having an enhanced function of temporarily retaining the flow of the molten metal 12 toward the cavity 9 is provided in the width direction (Y1-Y2 direction) of the cavity 9. By providing in the 2nd runner 32 so that it may follow, it becomes possible to arrange the supply timing of the molten metal 12 in the cavity 9 using the operation which the molten metal 12 overflows from this level | step-difference part 38. FIG. Therefore, according to the casting mold apparatus of the second embodiment, the effect of aligning the supply timing of the molten metal 12 into the cavity 9 and the molten metal 12 rectified through the plurality of wall portions 28 are injected into the cavity 9. Combined with the effect that can be achieved, it is possible to more reliably suppress the flow of the molten metal 12 in the cavity 9 from being disturbed, thereby enhancing the deterring effect of the hot water boundary, shrinkage nest, etc. that can occur in the product.

  The present invention has been specifically described above with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the magnesium alloy is exemplified as the molten metal. However, for example, an aluminum alloy or the like can be applied as the molten metal. Moreover, although the said embodiment demonstrated the casting mold apparatus of the cold chamber system, you may apply the casting mold apparatus which takes a hot chamber system.

  Further, in the above embodiment, the product to be cast has not been described in detail, but the present invention is used for a notebook PC, a portable audio device, a cellular phone, etc., for example, a thin wall having a thickness of 2 mm or less. The housing can be suitably manufactured.

Next, an example explains the present invention.
[Example 1]
In Example 1, a casting as a product was manufactured using the casting mold apparatus 1 (mold 5) of the first embodiment having the second runner 22 shown in FIGS. Here, in the rectangular dimension of the wall portion 28 of the second runner 22 shown in FIG. 6, while T1 is fixed at 1 mm and P2 is fixed at 10 mm, the values of T2 and P1 are changed to change the dimension ratio. The product yield was considered. As a comparative example, an example in which the wall portion 28 is deleted from the second runner 22 is illustrated. Casting conditions were such that AZ91D was used as the molten metal 12, the cycle time was 30 sec, the injection speed was 5 m / s, and the molten metal temperature was 700 ° C.
The results of Example 1 are shown in Table 1.

  As is clear from Table 1, the protruding height T1 / T2 × 100 (%) of the wall portion is within 60% to 80%, and the depth length P1 / P2 × 100 (%) of the wall portion 28 is A product that falls within the range of 50% or more and 80% or less (Example 1-5) can obtain a high yield of 90%, and a product whose dimensional ratio of the wall portion 28 is outside the above range shows a decrease in yield. It was. Further, in Comparative Example 1 without the wall portion 28, the yield rate was 40% or less, which is half or less.

[Example 2]
In Example 2, a casting as a product was manufactured using the casting mold apparatus (mold 35) of the second embodiment having the second runner 32 shown in FIGS. Here, the angle α of the taper 37 of the stepped portion 38 of the second runner 32 shown in FIG. 6 was changed, and the filling state of the molten metal into the product and the appearance of the product were considered. Casting conditions were such that AZ91D was used as the molten metal 12, the cycle time was 30 sec, the injection speed was 5 m / s, and the molten metal temperature was 700 ° C. Further, as the wall portion 28, a wall having a protrusion height T1 / T2 × 100 (%) of 60% and a depth length P1 / P2 × 100 (%) of 65% was applied.
The results of Example 2 are shown in Table 2.

  As can be seen from Table 2, when the angle α of the taper 37 of the stepped portion 38 falls within the angle range of 30 ° or more and 45 ° or less, the filling state of the molten metal and the appearance of the product are good, and the taper angle outside this range. Smaller cracks were generated due to lack of emphasis, and those with larger taper angles outside this range were not emphasized, causing generation of cups and nests.

The figure which shows typically the die apparatus for casting which concerns on the 1st Embodiment of this invention. The figure which shows the state which has filled the molten metal in the cavity of the casting die apparatus of FIG. The schematic diagram which looked at the structure of the flow path of the molten metal in the casting_mold | template in the casting die apparatus of FIG. 1 from the plane direction. FIG. 4 is a cross-sectional view taken along the line AA showing the structure of the flow path of FIG. 3. The perspective view which shows the casting cast by the peripheral part of the 1st, 2nd runner provided in the metal mold | die apparatus for casting of FIG. Sectional drawing which shows schematically the cross-section of the 2nd runner of the casting die apparatus of FIG. The perspective view which shows the casting cast by the peripheral part of the 1st, 2nd runner provided in the casting die apparatus which concerns on the 2nd Embodiment of this invention. Sectional drawing which shows schematically the cross-sectional structure of the 2nd runner of the casting die apparatus of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Mold apparatus for casting, 2 ... Fixed mold, 3,33 ... Movable mold, 5,35 ... Mold, 9 ... Cavity, 10 ... Pouring gate, 12 ... Molten metal, 21 ... First runner, 22, 32 ... First 2 runners, 23 ... gate, 28 ... wall, 29 ... flow front, 37 ... taper, 38 ... step, 38a ... dent.

Claims (12)

A first runner extending from the gate toward the cavity,
A second runner extending along the width direction of the cavity so as to temporarily retain the molten metal flowing in from the first runner side and to widen the flow path width of the first runner;
A wall portion for branching toward the cavity side while partially receiving the flow of the molten metal progressing in the width direction of the cavity in the second runner;
A casting die apparatus comprising:   2. The casting mold according to claim 1, wherein the wall portion is formed in a state in which an inner wall surface of the second runner is partially protruded in a rib shape in the opening and closing direction of the mold body. apparatus.   A plurality of the wall portions are provided at predetermined intervals along the width direction of the cavity, and the thickness direction of these wall portions is directed to the width direction of the cavity. Item 3. A mold apparatus for casting according to item 1 or 2.   The projecting height in the opening / closing direction of each wall portion is in the range of 60% to 80% with respect to the width of the flow path in the opening / closing direction of the mold body in the second runner, and the second 4. The casting gold according to claim 3, wherein a length of each wall portion in the depth direction is within a range of 50% or more and 80% or less with respect to a length of the cavity in the depth direction of the runner. Mold device.   The second runner is partially recessed in the opening / closing direction of the mold body as a part for temporarily retaining the molten metal flowing in from the first runner side, and The casting mold apparatus according to any one of claims 1 to 4, further comprising a step portion formed so that the recessed portion extends along the width direction of the cavity.   The stepped portion has a taper in which the cavity side wall surface in the recessed portion as viewed from the extending direction of the stepped portion is inclined at an angle of 30 ° to 45 ° with respect to the opening / closing direction of the mold body. 6. A casting mold apparatus according to claim 5, comprising: A method for producing a casting using a casting mold apparatus,
Injecting molten metal through the gate into the first runner extending from the gate toward the cavity;
A wall portion for receiving a part of the flow of the molten metal traveling in the width direction of the cavity, and extending along the width direction of the cavity so as to widen the flow path width of the first runner; A step of causing the molten metal to flow from the first runner side to the second runner having a function of retaining the target,
A step of branching toward the cavity side while partially receiving the flow of the molten metal flowing into the second runner and proceeding in the width direction of the cavity by the wall portion;
Filling the cavity through the gate with the molten metal branched to the cavity side by the wall and the molten metal flowing from the first runner side and proceeding to the cavity side in the second runner;
Cooling and solidifying the molten metal filled in the cavity to obtain a casting;
A method for producing a casting, characterized by comprising:   8. The casting production according to claim 7, wherein the wall portion is formed in a state in which the inner wall surface of the second runner is partially protruded in a rib shape in the opening and closing direction of the mold body. Method.   A plurality of the wall portions are provided at predetermined intervals along the width direction of the cavity, and the thickness direction of these wall portions is directed to the width direction of the cavity. Item 9. A method for producing a casting according to Item 7 or 8.   The projecting height in the opening / closing direction of each wall portion is in the range of 60% to 80% with respect to the width of the flow path in the opening / closing direction of the mold body in the second runner, and the second 10. The casting according to claim 9, wherein a length of each wall portion in the depth direction is within a range of 50% or more and 80% or less with respect to a length of the cavity in the depth direction of the runner. Production method.   The second runner is partially recessed in the opening / closing direction of the mold body as a part for temporarily retaining the molten metal flowing in from the first runner side, and The method for producing a cast according to any one of claims 7 to 10, further comprising a step portion formed so that the recessed portion extends along the width direction of the cavity.   The stepped portion has a taper in which the cavity side wall surface in the recessed portion as viewed from the extending direction of the stepped portion is inclined at an angle of 30 ° to 45 ° with respect to the opening / closing direction of the mold body. The method for producing a casting according to claim 11, comprising:

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