JP2000218359A - Molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform trimming of a metallic molding product by removing unnecessary portions such as flash during a molding process, when a metal is molded. SOLUTION: A molten metal is filled in a cavity 18 via a runner 20 and a gate 21, so as to form a metallic molding product A by solidification. An unnecessary portion B integrated with the metallic molding product A exists in the runner 20 and the gate 21. The unnecessary portion B is nipped by a punch 29 and a holder 28 from above and below. When a cavity plate 16 and a floating core plate 14 ascend for mold opening, the punch 29 and the holder 28 are integrally displaced downward relatively against the floating core plate 14 and the metallic molding product A, because a lock arm 31 is fitted with a stopper 29b at a primary stage. The unnecessary portion B nipped with the punch 29 and the holder 28 receives a true shearing action on a boundary face of the punch 29 and the holder 28 from the metallic molding product A, so as to be cut.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding apparatus for molding a molded product by filling and solidifying a molten molding material into a cavity through a runner and a gate, and particularly to a molded product solidified in a runner and a gate. The present invention relates to a technique for trimming by removing unnecessary parts such as gates that are integrally connected to a molded product. The present invention is suitable mainly for thixomolding or die-cast molding to be filled with a molten metal as a molding material, but is not limited to such a material, and a synthetic resin is used as a molding material. Is also good.

[0002]

2. Description of the Related Art In conventional thixomolding or die-casting molding, when performing trimming to remove unnecessary portions such as gates remaining on the peripheral portion of a metal molded product formed at the stage of opening the mold, the mold opening is performed. In a post-process, burrs are manually removed, or burrs are mechanically removed using a trimming press. However, manually removing unnecessary parts such as burrs is troublesome and time-consuming, and causes low productivity and high product cost. In the case of a trimming press, the initial cost of the machine itself is high,
In addition, since the molding is performed in a post-process, the productivity is also low.

In the case of resin injection molding which is neither thixomolding nor die casting, injection molding dies have been proposed in which unnecessary parts such as gates are removed during the molding process, not after opening the mold. This will be described with reference to FIG. The cavity 53 is formed by the contact between the cavity plate 51 and the core 52. As shown in FIG. 8A, the cavity 53 is filled with the molten resin supplied from the sprue 54 via a runner (runner) 55 and a gate 56. After the cavity 53 is filled with the molten resin, while the resin still has fluidity, the seal pin 57 is raised to enter the gate 56 as shown in FIG. 58
Into the resin molded product in the cavity 53. Since the resin 58 in the gate portion is erased by being embedded in the molded product in advance, no unnecessary portion such as the gate remains in the molded product taken out by opening the mold.

Japanese Patent Application Laid-Open No. 48-13450 discloses a gate cutting device for an injection mold as follows. This will be described with reference to FIG. The contact between the cavity plate 61 and the core 62 causes the cavity 6
3 is formed. The molten resin supplied from the sprue 64 is supplied to the cavity 6 through the runner 65 and the gate 66.
Fill 3 The molten resin is solidified in the cavity 63 to form a molded product. Next, the mold is opened. The molded product 69 in the cavity 63 is cut at the location of the gate 66 by the shearing force of the cutting pin 67 by pushing the cutting pin 67 into the gate 66 immediately before. The resin portion cut from the molded product 69 is hooked on the tip of the cutting pin 67 and the escape portion 6 of the cavity plate 61 is formed.
Pushed to 8. Immediately after this, the mold is opened. In this case, the cured resin molded product 69 is cut smoothly at the base of the resin portion in the gate 66 by the shearing force of the cutting pin 67.

In the prior art shown in FIGS. 8 and 9 described above,
Since unnecessary portions such as gates are removed during the molding process, trimming in a later process is not required, and productivity is improved. Further, it is effective in reducing the product cost.

[0006]

The above-mentioned prior arts all involve injection molding of a molten resin. 8, the resin 58 in the gate 56 can be pressed into the resin molded product in the cavity 53 only during the period when the resin has fluidity. Therefore, this conventional technology cannot be applied to thixomolding or die-casting technology, which has the property that molten metal, not molten resin, rapidly cools and solidifies in the cavity in a short time and loses fluidity. It is. That is, even if the seal pin is protruded in the gate immediately after filling the cavity with the molten metal, the metal in the gate must be pressed into the molded product because the molten metal has already been solidified at the stage of intrusion. Cannot be performed, and unnecessary parts such as gates remain.

Further, as in the prior art shown in FIG. 9, the resin portion in the gate 16 is cut smoothly by projecting the cutting pin 67 toward the escape portion 68 at the gate 66 of the solidified molded product. This is because the material of the molded product is a relatively flexible resin. In this publication, this cutting is referred to as "shearing", but it is more appropriate to forcefully "cut" or "cut" by a sliding pressing force. Due to the shavings, shavings are inevitably generated. If the generated swarf remains at that location, no further swarf will proceed, and the escape portion 68 for escaping the swarf is definitely required.
The presence of the escape portion 68 confirms that the generation of shavings and thus the mode of shearing is shaving. It is difficult to apply the technique of shaving by moving the cutting pin accompanying the pushing of the cutting pin in the molded product as it is to the technique of thixomolding or die casting.

[0008] The difficulty of application will be described. When the cutting pin bites into the metal molded product and advances, a crack (crack) occurs in the metal molded product from a position corresponding to the edge of the cutting pin. In addition, unevenness occurs in the dividing plane. The phenomenon that occurs in the process of shaving off unnecessary portions by the cutting pin advancing inside the molded product itself is nothing but that the cutting pin destroys the product structure itself. This destruction of the tissue is accompanied by forced compression of the tissue by the tip of the cutting pin and forced cutting of the combined components of the tissue by the edge of the cutting pin. If the molded product is made of a resin that has a flexible structure, such destruction of the structure is performed smoothly with little resistance, so the trace that the cutting pin has advanced inside the molded product should be smooth. Become. However, if the molded product is made of a hard-structured metal, the resistance to tissue destruction is significantly higher.
Considering the factors of the high resistance, the two phenomena described above are the forced compression or crushing of the tissue by the tip of the cutting pin and the forcing by the edge of the cutting pin against the combined components of the tissue. There is a main factor in the former, ie, forcible compression (crushing), of division, that is, interface shearing.
Since the resistance to tissue destruction is quite high, a large force is required to push the cutting pin into the pin, and the metal between the edge of the cutting pin and the metal Cracks will form in the molded product. The cracks increase in depth as the cutting pin advances, and the number of generated cracks increases. In addition, due to the large drag, the movement of the cutting pin to enter is not smooth, and an abnormal reciprocating operation (chatter) occurs in a direction perpendicular to the entering direction, so that unevenness occurs in the divided section. For the reasons described above, it is very difficult to apply the shaving method in which the cutting pin is inserted into the inside of the molded product itself shown in FIG. 9 to the technique of thixomolding or die casting as it is.

An object of the present invention is to solve the above-mentioned problems.

[0010]

The molding apparatus according to the first aspect of the present invention has the following configuration. That is, first, a molten molding material is filled into a cavity via a runner and a gate and solidified to form a molded product in the cavity. The molten molding material solidifies in the runner and the gate, resulting in an unnecessary portion connected to the molding product. Open the mold after molding the molded product, but not after this mold opening,
In the process of opening the mold, the unnecessary portion is clamped, and the unnecessary portion is sheared from the molded product by displacing the clamped portion relative to the molded product along the clamping direction. According to this configuration, since the holding portion holding the unnecessary portion is relatively displaced with respect to the molded product along the holding direction, the respective boundary surfaces between the formed product and the unnecessary portion are slid along the surface direction. In this way, it is possible to shear unnecessary parts from the molded product.

The molding apparatus according to the second aspect has the following configuration. That is, the floating core plate is arranged on the core back plate so as to freely contact and separate from the core plate, and the cavity plate is arranged on the floating core plate so as to freely contact and separate from the core plate. The cavity plate and the floating core plate which are in contact with each other can be fixed by the first locking means. A cavity is formed at a position where the floating core plate and the cavity plate are in contact with each other. A runner and a gate for supplying a molten molding material to the cavity are provided on the holder. This holder is provided inside the floating core plate. The holder is provided so as to be fixed to the core back plate, and is provided so as to be vertically displaceable relative to the floating core plate. Further, a punch is arranged on the holder so as to be able to freely contact and separate. The punch is provided on the cavity plate so as to be relatively displaceable. The punch and the holder that are in contact with each other can be fixed by the second lock means. An unnecessary portion solidified in the runner and the gate is held between the punch, the holder and the second locking means. Further, an unnecessary portion held by the punch and the holder is relatively displaced together with the punch and the holder with respect to the molded product in the cavity between the cavity plate and the floating core plate fixed by the first locking means, thereby forming the molded product. It is configured so that unnecessary portions are sheared. According to this configuration, it is possible to shear the unnecessary portion from the molded product by sliding each boundary surface between the molded product and the unnecessary portion along the surface direction.

In the above-described molding apparatus, unlike the conventional mode of forcible shaving by a sliding pressing force, the shearing is a true meaning, so that the solidified metal structure is formed. Even if the cutting is performed, the cutting can be smoothly performed with little resistance, and no swarf is substantially generated. In addition, no crack (crack) occurs in the molded product at the shearing point, and no unevenness occurs in the cross section. Therefore, the division surface due to shearing becomes smooth. This technique is suitable for thixomolding and die casting.

According to a third aspect of the present invention, based on the premise of the second aspect, the relative displacement direction of the punch is set to be slightly larger than the draft angle of the side surface of the molded product in the cavity. According to this configuration, the punch moves away from the side surface of the molded product as the relative displacement advances, so that the cross section on the molded product side due to shearing becomes extremely smooth.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a molding apparatus according to the present invention will be described below in detail with reference to the drawings. In the following embodiments, a thixomolding device will be described as an example of a molding device.

FIG. 1 is a sectional view showing the structure of a thixomolding apparatus as a molding apparatus according to an embodiment. As shown in FIG. 1, a core back plate 13 is attached to a base 11 via a leg 12. The floating core plate 14 is placed on the core back plate 13 so as to be able to freely contact and separate along the vertical direction. Guide rail 1 protruding upward from the side of core back plate 13
Guide 14 on the side of the floating core plate 14 with respect to 3a
a is fitted slidably in the vertical direction. Further, the guide block 13 fixed to the upper surface of the core back plate 13
The vertical hole of the floating core plate 14 is fitted to b in a vertically slidable manner. A compression spring 15 is provided between the upper surface of the core back plate 13 and the lower surface of the floating core plate 14 for vertically separating the two plates. A cavity plate 16 is placed on the floating core plate 14 so as to be able to freely contact and separate along the vertical direction. The back plate 17 is fixed to the upper surface of the cavity plate 16. Cavity plate 1
A cavity 18 is formed between the recess on the lower surface of 6 and the upper surface of the floating core plate 14. A sprue 19 is formed from the upper surface of the back plate 17 to the lower surface of the cavity plate 16, and a runner (runner) 20 is formed so as to communicate with the sprue 19. A lock arm (cam) 22 as a first lock means is pivotally mounted on a side of the cavity plate 16 around a horizontal axis, and a stopper 14b for engaging the lock arm 22 is provided on the floating core plate 14. It is provided on the side. The lock arm 22 engaged with the stopper 14b is configured to be engaged with the upper end of the guide rail 13a so as to maintain the locked posture. A compression spring 23 for engaging and disengaging the lock arm 22 with respect to the stopper 14b is provided on a side portion of the cavity plate 16. Extruded plates 24 and 25 in a fixed state in contact with each other are arranged between the base 11 and the core back plate 13. A vertically extending ejector pin 26 whose lower end base portion is sandwiched between the extrusion plates 24 and 25 is provided with a cavity 18.
The ejector pin 27 is also provided so as to release an unnecessary portion from the sprue 19 and the runner 20. The guide block 13 is formed in the vertical hole of the floating core plate 14.
The holder 28 is provided in a state of being placed and connected on the upper surface of b. The runner 20 and the gate 21 are formed on the upper surface of the holder 28. Runner 20 is formed to communicate with cavity 18 via gate 21. A punch 29 which comes into contact with and separates from the upper surface of the holder 28 is provided in a recess on the lower surface of the cavity plate 16 so as to be vertically movable. A guide rod 30 for guiding the vertical movement of the punch 29 is vertically slidably fitted in the vertical hole of the cavity plate 16, and the lower end thereof is fixed to the punch 29. The guide rod 30 is driven by a compression spring 33. A lock arm (cam) 31 as a second lock means is pivotally mounted on the side of the holder 28 around the horizontal axis. Is provided. The lock arm 31 engaged with the stopper 29b is configured to be engaged with a locker 16a provided in a concave portion on the lower surface of the cavity plate 16 so as to maintain the lock posture. On the side of the holder 28, a compression spring 32 for engaging and disengaging the lock arm 31 with respect to the stopper 29b is provided.

Next, the operation of the molding apparatus (thixo molding apparatus) according to the embodiment configured as described above will be described. FIG. 2 shows a state in which the molten metal is filled in a mold clamping state. In the mold clamping state, the ejector pins 26 and 27 descend together with the push-out plates 24 and 25 to the lower limit. In particular, the upper end surface of the ejector pin 26 is
, That is, the lower surface of the cavity 18.
The lower surface of the cavity plate 16 contacts the upper surface of the floating core plate 14 to form a cavity 18 therebetween, and the lower surface of the punch 29 contacts the upper surface of the holder 28 to communicate with the cavity 18 therebetween. A runner 20 and a gate 21 are formed. Locker 1
6a, the hook at the tip of the lock arm 31 of the holder 28 is engaged with the stopper 29b of the punch 29, whereby the punches 29 that are in contact with each other are held by the holder 28.
It is fixed to. The hook of the tip of the lock arm 22 of the cavity plate 16 is engaged with the stopper 14b of the floating core plate 14 by the guide rail 13a.
And the floating core plate 14 are fixed. The lower surface of the floating core plate 14 is in contact with the upper surface of the core back plate 13 due to the clamping force of the molding device.

In such a mold clamping state, the molten metal supplied from the sprue 19 is filled into the cavity 18 via the runner 20 and the gate 21. The filled molten metal solidifies rapidly in a short time and the cavity 18
Inside the gate 21 and the runner 20, an unnecessary portion B unnecessary for the metal molded product A is formed. At this stage, the metal molded product A and the unnecessary portion B are connected integrally and in series.

When the metal molded product A is obtained by solidification of the molten metal in the cavity 18, the metal molded product A is then obtained.
Open the mold to remove the mold. This mold opening process is 2
Can be divided into two parts. The first step is a step of cutting the unnecessary portion B from the metal molded product A, and the second step is a step of taking out the metal molded product A. These two processes are continuous.

First, a first process of cutting the unnecessary portion B from the metal molded product A will be described with reference to FIG. The cavity plate 16 and the floating core plate 14, which are locked in the close contact state by the lock arm 22 by the extension of the compression spring 15, move up with respect to the core back plate 13 as shown by an arrow Y. At this time, the floating core plate 1
The four guides 14a are vertically guided by the guide rails 13a of the core back plate 13. Extruded plate 2
4, 25 and the ejector pins 26, 27 are also raised together by the same amount. Holder 28 and punch 2 locked in close contact by internal lock arm 31
The lock state with 9 is maintained. Since the holder 28 is fixed to the guide block 13b and the guide block 13b is fixed to the core back plate 13, the holder 2
8 does not rise. The punch 29 fixed to the position-fixed holder 28 via the lock arm 31 keeps the state in which it is in close contact with the current holder 28 and does not rise regardless of the elevation of the cavity plate 16.
As a result, the guide rod 30 fixing the holder 28 to the lower end is displaced downward relative to the cavity plate 16. Holder 28 and punch 29 forming gate 21 and runner 20 by close contact
Is displaced downward relative to the floating core plate 14 integrally. In the gate 21 and the runner 20, there is an unnecessary portion B that is unnecessary for the molded product.
That is, the punch 29 and the holder 28 are displaced downward relative to the metal molded product A in the cavity 18 while holding the unnecessary portion B from above and below. Since the holding direction is the up-down direction and the displacement direction is also the up-down direction, it can be said that the displacement direction is the holding direction. Then, due to the displacement of the unnecessary portion B with respect to the metal molded product A, the unnecessary portion B is cut from the metal molded product A. The details of this cutting will be described later (see FIG. 5).

As described with reference to FIG. 3, when the cavity plate 16 and the floating core plate 14, which are in close contact with each other, rise integrally with respect to the punch 29 and the holder 28, the lockers 16a in the recesses of the cavity plate 16 are the same. As a result, the lock arm 31 moves away from the vertical side surface of the locker 16a to correspond to the tapered surface,
The lock arm 31 is tilted outward by the extension of the compression spring 32, and comes off the stopper 29 b of the punch 29. Further, the lock arm 22 of the other cavity plate 16 is also raised, and the lower end thereof is located on the guide rail 13.
a approaches the tapered surface at the upper end.

When the cavity plate 16 and the floating core plate 14 further rise, the position where the lock arm 31 of the holder 28 comes into contact with the tapered surface of the rocker 16a becomes lower, and the lock arm 31 is extended by the extension of the compression spring 32. The tilt of the outward opening advances, and the lock arm 31 comes off the stopper 29b of the punch 29. That is, the locked state of the punch 29 with respect to the holder 28 via the lock arm 31 is released. At substantially the same time, the lock arm 22 of the cavity plate 16 slides on the tapered surface of the guide rail 13a and tilts outward by expansion of the compression spring 23, and the lock arm 22 comes off from the stopper 14b of the floating core plate 14. That is, the locked state of the cavity plate 16 with respect to the floating core plate 14 via the lock arm 22 is released. As the cavity plate 16 and the floating core plate 14 are raised, the extruding plates 24 and 25 are raised by the same amount, and the ejector pins 26 and 27 are set to be raised by the same amount.

When the cavity plate 16 is further raised, the lock arms 22 and 31 are released as shown in FIG.
Since only the floating core plate 14 does not rise, the mold opening is performed. That is, the cavity plate 16 is separated upward from the floating core plate 14, and the floating core plate 14 and the cavity plate 1
A space appears between them. FIG. 4 shows a state where the mold opening is completed. At the same time, the ejector pins 26 and 27 further rise, the ejector pin 26 pushes up the metal molded product A and releases the mold, and the ejector pin 27 pushes up the unnecessary portion B and releases the mold. Utilizing the space between the floating core plate 14 and the cavity plate 16, the released metal molded product A and the unnecessary portion B are removed from the molding apparatus.

Next, the operation of cutting the unnecessary portion B from the metal molded product A will be described in detail with reference to FIG. FIG. 5 (a)
The unnecessary portion B is sandwiched between the punch 29 and the holder 28 from above and below as shown in FIG. An end surface 29a on the cavity 18 side of the punch 29 and an end surface 28a on the same side of the holder 28 are flush with each other.
“a” is also flush with the boundary surface between the metal molded product A and the unnecessary portion B. The punch 29 and the holder 28 holding the unnecessary portion B from above and below are integrated into a metal molded product A.
5B and 5C, the punch 2 is continuously displaced in the holding direction, that is, downward.
9. The holder 28 is displaced downward, and the metal molded product A
, The unnecessary portion B is sheared only along the boundary surface at the boundary surface.

There are actually two boundary surfaces. A boundary surface C1 on the metal molded product A side and a boundary surface C2 on the unnecessary portion B side. Both are indicated by dotted lines. An area surrounded by a two-dot chain line and indicated by a reference symbol D is an undivided area D in which the metal molded product A and the unnecessary part B are still integrated and not yet divided.
Is shown. In the case of FIG. 5A, the punch 29 and the holder 28 have not yet started to be displaced, and the entire region between the boundary surface C1 of the metal molded product A and the boundary surface C2 of the unnecessary portion B is an undivided region D. ing. The end surface 29a of the punch 29 and the end surface 28a of the holder 28 are flush with both boundary surfaces C1 and C2. In the case of FIG. 5B, the punch 29 and the holder 28
Is slightly displaced downward, and the interface C of the metal molded product A
1 is separated from the boundary C2 of the unnecessary part B, and a part F of the lower end of the boundary C2 of the unnecessary part B is separated from the boundary C1 of the metal molded product A. Then, in both of the remaining undivided regions D, both boundary surfaces C
1 and C2 are still integrated. Hereinafter, as the process proceeds from FIG. 5B to FIG.
As the area increases, the undivided area D decreases,
Finally, both boundary surfaces C1 and C2 are completely separated.

The cutting of the unnecessary portion B from the metal molded product A according to this embodiment is shearing as originally intended. That is, shearing is because the cutting is performed along the tangential direction of the working surface. In shearing, FIG.
Is different from the conventional mode of forcible scraping by a sliding pressing force as shown in FIG. 1, the atom on the boundary surface C1 of the metal forming product A and the atom on the boundary surface C2 of the unnecessary portion B The bond is dissociated. In other words, since the shearing is a true meaning, even if the solidified metal structure is cut, the cutting can be smoothly performed with little resistance, and substantially no shavings are generated. In addition, no crack (crack) occurs in the metal molded product A, and no irregularities occur in the cross section. Therefore, the division surface due to shearing becomes smooth.

By the way, although not described in the above description of the forming apparatus with reference to FIG. 1, a draft is provided for the metal molded product A, and the guide rod 30 having the punch 29 attached to the lower end is made to have a draft. It is preferable to mount on the cavity plate 16 so as to slide along.
In this case, the punch 29 also moves along the draft. The operation in this case will be described with reference to FIG. 6, an arrow Y1 indicates a holder 28 relative to the metal molded product A.
, And the arrow Y2 indicates the same direction of displacement of the punch 29. The displacement direction Y2 of the punch 29 is along the sliding direction of the guide rod 30 and thus the direction of the draft of the metal product A. Also, the end surface 28a of the holder 28
Is vertical, while the end face 29 of the punch 29 is
“a” is along the displacement direction Y2, and the upper end of the end surface 28a of the holder 28 is located on an extension of the direction “a”.

FIG. 6A shows that the holder 28 has a vertical arrow Y.
Although the displacement is started in one direction and the punch 29 is about to start displacing in the diagonal arrow Y2 direction, the entire area of the boundary surface C1 of the metal molded product A and the boundary surface C2 of the unnecessary part B is not divided. This is the area D. The punch 29 and the holder 28 are displaced while holding the unnecessary portion B from above and below. FIG. 6B shows a state in which the relative displacement between the punch 29 and the holder 28 has advanced. The punch 29 also moves in the horizontal X2 direction away from the metal molded product A. A portion E of the upper end side of the oblique boundary surface C1 of the metal molded product A is cut off from the boundary surface C2 of the unnecessary portion B, and a portion F of the lower end side of the oblique boundary surface C2 of the unnecessary portion B is corrected in the vertical direction. It is separated from the boundary surface C1 of the metal molded product A. Hereinafter, as the state proceeds from FIG. 6B to FIG. 6C, the area of the divided portions E and F increases and the undivided area D decreases, and finally both boundary surfaces C1 and C2 are completely divided. To reach. When the punch 29 is displaced in the oblique direction along the draft angle of the metal molded product A, the metal molded product A
Is trimmed smoothly.

As a further development, it is conceivable to slightly increase the inclination angle of the punch 29 so that the direction of displacement of the punch 29 becomes slightly divergent with respect to the draft angle of the metal molded product. This will be described with reference to FIG.
The upper end of the end surface 28a of the holder 28 is located on the extension line a of the end surface 29a of the punch 29. The displacement direction Y3 of the punch 29 along the guide rod 30 is the end face 29a of the punch 29.
Is not parallel to the extension line a, but has a divergent inclination direction that is further away from the extension line a as it goes downward. The end face 29a of the punch 29 has a draft angle of the metal molded product A. The angle between the displacement direction of the punch 29 and the draft angle, that is, the angle θ formed by the line a and the line b is, for example, about 1 to 2 °. is there.

The holder 28 and the punch 29 which hold the unnecessary part B of the metal molded product A from above and below are displaced in synchronization with each other. The direction of displacement of the holder 28 is a vertical arrow Y
1 direction. The direction of displacement of the punch 29 is the direction of the oblique arrow Y3. The punch 29 is displaced downward, and is also displaced in the direction of the horizontal arrow X3. When the holder 28 is displaced to the alternate long and short dash line A, the punch 29 is also displaced to the alternate long and short dash line A. At this time, the end face 29a of the punch 29 is shifted in the direction of the arrow X3 from the end face 29a when the solid line A is present. When the holder 28 is displaced to the two-dot chain line c, the punch 29 is also displaced to the two-dot chain line c, and the end surface 29a of the punch 29 at this time is further shifted in the arrow X3 direction from the end surface 29a at the one-dot chain line a. When the holder 28 is displaced to the three-dot chain line d, the punch 29 is also displaced to the three-dot chain line d, and the end face 29a of the punch 29 at this time is further shifted in the direction of arrow X3 than the end face 29a at the two-dot chain line c. . As a result, the unnecessary portion B is sheared from the metal molded product A.
Is formed by the movement of the punch 29 in the displacement direction Y3 at an angle slightly larger than the draft angle, that is, the movement of the punch 29 in the direction away from the side surface of the metal molded product A. Very smooth and good finish without scratches.

Although the embodiment has been described by taking the thixomolding apparatus as an example, the present invention may be applied to a die-cast molding apparatus. Although thixomolding and die-casting are used exclusively for molding metal molded products, the present invention may be carried out in a molding apparatus for molding resin molded products.

[0031]

According to the first and second aspects of the present invention, in order to cut an unnecessary portion from a molded product, the unnecessary portion is pinched from above and below, and during the mold opening, the pinched portion is moved in the pinching direction. Along with displacing the molded product relative to the molded product, it gives a true meaning of shearing action to the unnecessary part, and this shear dissociates the unnecessary part from the molded product, so that cracks and irregularities do not occur on the molded product It can be cut under a smooth parting plane.

According to the third aspect of the present invention, since the shearing is performed away from the side surface of the molded product, the quality of the molded product can be improved by making it extremely smooth without damaging the sectional surface on the molded product side due to the shearing. At the same time, the yield can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the structure of a thixomolding device that is a molding device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a clamped state in the thixomolding device of the embodiment.

FIG. 3 is a sectional view showing an initial stage of mold opening in the thixomolding apparatus according to the embodiment;

FIG. 4 is a cross-sectional view showing a state in which the mold opening is completed in the thixomolding apparatus according to the embodiment;

FIG. 5 is an explanatory view showing a state of cutting unnecessary portions from a metal molded product by shearing in the embodiment.

FIG. 6 is an explanatory view showing a state where an unnecessary portion is cut from a metal molded product by shearing when a side surface of the metal molded product has a draft angle;

FIG. 7 is an explanatory view showing a state of cutting unnecessary portions from a metal molded product when shearing is performed at a slightly larger inclination than a side surface of a draft angle of the metal molded product.

FIG. 8 is a cross-sectional view of a resin injection molding apparatus according to a conventional technique.

FIG. 9 is a cross-sectional view of another prior art resin injection molding apparatus.

[Explanation of symbols]

11: base part, 12: leg part, 13: core back plate, 13a: guide rail, 13b: guide block,
14: floating core plate, 14a: guide, 14b: stopper, 15: compression spring, 16: cavity plate, 16a: rocker, 17: back plate, 18
... cavity, 19 ... sprue, 20 ... runner, 21
... gate, 22 ... lock arm (first locking means),
23 ... compression spring, 24, 25 ... extrusion plate, 26,
27: ejector pin, 28: holder, 28a: end face of holder, 29: punch, 29a: end face of punch, 2
9b: stopper, 30: guide rod, 31: lock arm (second locking means), 32, 33: compression spring, A: metal molded product, B: unnecessary part, C1, C2: boundary surface, D: undivided region

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Akira Inoue 4-133, Atobe-Honcho, Yao-shi, Osaka Sharp Manufacturing System Co., Ltd. F-term (reference) 4F201 BA08 BC02 BC25 BC27 BM05 BQ38 BS02 BS04

Claims (3)

[Claims] 1. A molten molding material is filled into a cavity via a runner and a gate and solidified to form a molded product in the cavity, and then unnecessary in the runner and the gate which are integrally connected to the molded product. A molding apparatus configured to shear unnecessary portions from a molded product by displacing the clamped portion relative to the molded product along the clamping direction in a state where the portion is clamped. 2. A floating core plate is arranged on a core back plate so as to be able to contact and separate from the core plate, and a cavity plate is arranged on the floating core plate so as to be able to contact and separate from the core plate. A holder having a runner and a gate for forming a cavity at a contact point between the floating core plate and the cavity plate and supplying a molten molding material to the cavity; The floating core plate is vertically displaceable and is fixed to the core back plate.The punch is placed on the holder so that it can be moved toward and away from the cavity plate. And the second
The unnecessary portion solidified in the runner and the gate is clamped by the punch, the holder and the second locking means, and the cavity plate and the floating core plate fixed by the first locking means are fixed between the two. A molding device configured to shear the unnecessary portion from the molded product by relatively displacing the unnecessary portion sandwiched with respect to the molded product in the cavity. 3. The molding apparatus according to claim 2, wherein the punch is relatively displaced with respect to the cavity plate along a direction inclined by a small angle larger than the draft of the side surface of the molded product in the cavity.