Patent Application
20140212610
The present invention relates to a foam-molding parts manufacturing method, foam-molding parts, and a foam-mold, which are for obtaining molding parts by injecting a foaming resin material into a foaming mold.
Heretofore, a foaming agent such as butane gas, methane gas, water, nitrogen, carbon dioxide gas, or the like is infiltrated into a resin, or melt kneading or chemical reaction is mechanically induced, thereby manufacturing a foaming resin. Thereafter, the manufactured foaming resin is subjected to injection or extrusion molding within a mold using an injection molding machine, extrusion molding machine, or the like, thereby processing foam-molding parts having a desired shape and foaming ratio. However, in the event of increasing a forming diameter to increase a foaming ratio such as with Styrofoam or the like used in packing material, this causes a problem in that partition walls between foaming cells are thinned, and the strength of the foaming parts is markedly lowered.
Also, in recent years, there has been used a method wherein nitrogen or carbon dioxide gas in a supercritical state under high-pressure high temperature is infiltrated into a resin material, the pressure and temperature are adjusted to obtain foam-molding parts in which a great number of forming diameters having a micron size are included (see PTL 1). In the event of employing this method, cell diameters have a micron size, and accordingly, lowering of molding parts strength is reduced. However, in general, it has been difficult to increase foaming ratio, and weight reduction owing to foaming remains in 10% or so, and accordingly, which causes a problem in that economic effects such as material cutback and so forth are small. Further, there yet remains a problem in that warpage called box warpage, due to inward falling of a wall starting at a corner portion that occurs with common molding parts due to a small foaming ratio.
Further, there has been used a molding method called core back wherein, with foam-molding, after a foaming resin is injected into a mold, the capacity of the mold is expanded to increase the foaming ratio.
With core back foam-molding, in addition to a method for subjecting the entirety to core back, there has also been used a method for partially performing core back (see PTL 2 and PTL 3). With the core back method, deterioration in strength is suppressed by the thickness of a cross section increasing to increase cross-sectional rigidity in accordance with increase in the foaming ratio.
PTL 1: U.S. Pat. No. 4,473,665
However, with the core back molding method, the capacity of a mold is expanded, and accordingly, the mold has to be moved entirely or partially. In the event that component shapes include a hole shape, an undercut shape, a nipping shape made up of a cavity and a core, a curvature of an edge face, and so forth, it has been difficult to create a desired shape due to, such as occurrence of burring, instability of shape precision, damage of mold and component shape, and so forth.
Also, though there has been devised a technique for preventing a mold from moving at the time of core back operation using an oil cylinder or the like by a portion of the shape of the mold having a nested configuration (see PTL 3), this causes a problem in that the mold configuration becomes complicated, and flexibility of mold design is reduced, and accordingly, it is difficult to apply this technique to many components.
A foam-molding parts manufacturing method according to the present invention is a foam-molding parts manufacturing method, wherein a the fixed-side mold plate and a movable-side mold plate are closed, thereby forming a cavity within a mold, and a foaming resin is injected into the cavity, and then, the capacity of the cavity is expanded to promote foaming within the cavity, and after cooling, the fixed-side mold plate and the movable-side mold plate are opened to extract molding parts from the cavity;
with expansion of the capacity of the cavity being performed by moving a movable core forming a portion of the cavity relative to the cavity while closing the fixed-side mold plate and the movable-side mold plate.
Also, the foam-molding part according to the present invention is a box-shaped foam-molding part made up of a top face portion and a side face portion, wherein a weight reduction ratio of the side face portions is smaller as to a weight reduction ratio of the top face portion.
Also, a foam-mold according to the present invention is a foam-mold configured to inject a foaming resin into a cavity to form foam-molding parts, including a main parting made up of a fixed-side mold plate and a movable-side mold plate, a sub parting made up of a movable-side mold plate and a second movable-side mold plate or a sub parting made up of the fixed-side mold plate and the second fixed-side mold plate, and a movable core forming a portion of the cavity, wherein the movable core moves relative to the cavity in the direction of expanding the cavity while opening the sub parting.
With the present invention, there are provided two partings of a main parting and a sub parting, and a movable-side mold plate being configured of multiple plates, and accordingly, a particular driving source for core back operation does not have to be provided, and economic effects and flexibility of mold design are improved.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Embodiments of the present invention will be described with reference to the following drawings.
In
Also, reference numeral 7 is a movable core which performs core back operation, a surface 71 thereof makes up a portion of the cavity. The movable core 7 is fixed to the second movable-side mold plate 4. Reference numeral 8 is a non-movable core (insert block) of which the position is not changed at the time of core back operation (at the time of movement of a second movable-side mold plate), reference numeral 9 is an outer slide which forms an undercut shape, connects to the movable-side mold plate 3, and operates in conjunction with opening/closing of the main parting, and reference numeral 10 denotes an ejector pin.
According to the present Specification, a moveable core means a core that moves relative as to a cavity, in the direction of expanding the capacity of a cavity for forming foam-molding parts, before opening the main parting which is the contact face between the fixed-side mold plate and the movable-side mold plate.
Reference numeral 11 denotes a slant core which processes undercut, reference numeral 12 denotes a first ejector plate which connects to the ejector pin and slant core, and reference numeral 13 denotes a second ejector plate which connects to the first ejector plate 12. Also, reference numeral 14 denotes a return pin which returns the ejector plates to a predetermined position at the time of mold clamping.
Reference numeral 15 denotes an ejector plate driving unit which is disposed within the movable-side attachment plate, adjacent to the second ejector plate 13 at the time of mold clamping and at the time of core back operation (at the time of movement of the second movable-side mold plate). Reference numeral 16 denotes a punching pin forming a hole shape for a component, and reference numeral 17 denotes a punching pin driving unit which presses the punching pin against the fixed-side mold plate.
Further, reference numeral 18 denotes a core back amount regulating bolt which connects the movable-side mold plate 3 and second movable-side mold plate 4 to regulate core back operation amount, and reference numeral 19 denotes a movable-side mold plate pressing driving unit which presses the movable-side mold plate 3 against the fixed-side mold plate 5 side at the time of core back operation (at the time of movement of the second movable-side mold plate). Reference numerals 20 and 21 are main parting fixing units which fix the main parting at the time of core back operation (at the time of movement of the second movable-side mold plate).
At the time of core back operation (at the time of movement of the second movable-side mold plate), the sub parting 2 which is a contact face between the movable-side mold plate 3 and the second movable-side mold plate 4 is opened, the movable core 7 moves in the mold opening direction along with the sub parting, which increases the cavity capacity for forming molding parts to promote foaming.
At this time, the main parting is prevented from opening by the movable-side mold plate pressing driving unit 19 pressing the movable-side mold plate 3 against the fixed-side mold plate 5, and also by operations of the main parting fixing units 20 and 21.
Also, the main parting is prevented from opening, and accordingly, the outer slide 9 is prevented from moving at the time of core back operation (at the time of movement of the second movable-side mold plate).
The ejector plate driving unit 15 presses the first and second ejector plates 12 and 13 in the fixed-side mold plate direction, and accordingly, since the ejector plates 12 and 13 do not move as to the return pin 14, the slant core 11 is also prevented from moving. Similarly, the ejector pin 10 connected to the ejector plates is also prevented from moving during core back operation.
As illustrated in
In
With the present invention, in the event that an undercut shape is processed at the slant core, as described in
The movable core moves by the amount indicated in
Next, the operation of a mold according to the present invention will be described with reference to
After the foaming resin is filled, as illustrated in
At the time of core back operation, the punching pin 16 making up a hole shape of a component is pressed against the cavity plate 5 by the punching pin driving unit, and accordingly, the punching pin 16 is prevented from moving from the position illustrated in
Similarly, with the slant core 11 forming an undercut at the time of core back, the ejector plate driving unit 15 presses the second ejector plate 13 in the direction of the return pin 14, and accordingly, the first ejector plate 12 is prevented from moving from the position illustrated in
The movement amount for core back is regulated by a core back amount regulating bolt, in the event that the movable-side platen of the molding machine has moved equal to or greater than the stroke of the core back regulating bolt, the main parting 1 is opened, and foaming toward the cavity plate side occurs. In general, the movement amount for core back is controlled by the molding machine, which is set within the stroke of the core back amount regulating bolt.
In
Accordingly, with the mold configuration according to the present invention, the main parting is not opened at the time of core back operation (at the time of movement of the second movable-side mold plate), and accordingly, occurrence of burring is prevented in the main parting area, and a foam-molding part having suitable shape precision can be obtained.
As with the present invention, with a portion where a movable portion and a non-movable portion at the time of core back operation (at the time of movement of the second movable-side mold plate) are mixed, a minute groove is formed in a boundary thereof, but this groove is minute, and accordingly, influence to be given on the strength of a molding part and so forth is very small.
Also, the internal configuration of a molding part accomplished by employing the foam-mold and manufacturing method according to the present invention is, as a feature, configured of a portion where the foaming density of a movable core portion denoted by reference numeral 29 denotes high, and a portion where the foaming density of non-movable portions denoted by reference numerals 30 and 31 is low. Further, almost no thickness change occurs regarding a side portion (lateral wall) having thickness in the vertical direction as to the mold opening/closing direction of an edge face, or the like, and accordingly, the foaming density is lowered as a feature.
An undercut portion of molding parts accomplished by employing the foam-mold and manufacturing method according to the present invention has a feature wherein the foaming density is low, and accordingly, deterioration in strength is very small. Also, in the event of a box shape illustrated in
Specifically, as illustrated
Also, the movement amount of the movable core (core back movement amount) indicated with A, and the movement amount of the movable core of the edge face of the side face portion (core back movement amount) indicated with B have relationship indicated with the following expression.
[Math.1]
C≧1.0 mm, A≧B, D≧2.0 mm (Expression 1)
The movable core can be moved in a smoother manner by adding a combining slope (slant) to the movable core and insert block 45 (details will be described later). In the event of having this combining slope, the movement amount of the movable core (core back movement amount) indicated with A becomes greater than the movement amount of the movable core (core back movement amount) of the edge face of the side face portion indicated with B. In the even of adding no combining slope, the movement amount of the movable core (core back movement amount) indicated with A becomes equal to the movement amount of the movable core (core back movement amount) of the edge face of the side face portion indicated with B.
Also, C indicates the thickness in the core back direction (top face portion) before core back, and D indicates the thickness of the side face portion.
In the event that the thickness D of the edge face portion of the side face portion is thinner than 2.0 mm, cooling solidification advances in a portion subjected to molding at the insert blocks 45 and 46 where core back of the edge face portion 39 of the side face portion is not performed. Therefore, at the time of the movable core moving in the core back direction, a portion that moves in the core back direction, and a portion that does not move occur within the thickness of the edge face portion of the side face portion formed of the insert blocks 45 and 46, shearing stress acts on a boundary around the center of the thickness, and internal stress occurs. This internal stress becomes a cause of deformation after cooling. Further, there may be a case where cooling solidification on an outer-side portion where core back movement is not performed advances, and internal resin viscosity increases, and accordingly, even if core back operation is performed, the resin surface does not follow core back, and predetermined shape precision is not obtained.
With the present invention, as a result of having advanced research, internal stress that causes deformation as to the edge face portion of the side face portion after core back operation can be reduced, and deformation of molding part can be eliminated by setting the thickness D of the side face portion to 2.0 mm or more. Also, a full curvature (semicircular shape) on the edge face portion of the side face portion after core back can be processed with suitable precision.
In
As illustrated in
Also, with the side face portion as well, while a great number of fine cells are formed on an inner face portion 49, the number of cells formed on the portion of an outer side face portion 50 is small. With the present invention, a boundary portion of the movable core which performs core back movement is provided within the thickness of the edge face portion of the side face portion, and accordingly, a configuration having a different cell formation can be manufactured within the cross section illustrated in
In
As illustrated in
At the time of filling a foaming resin material within a mold, mold clamping force of a molding machine acts on a mold, and accordingly, the outer slider 9 is pressure welded on the movable core 7. Also, heretofore, the combining slope has 0 degree, and accordingly, the movable core 7 moves while sliding with the outer slide 9 at the time of core back operation.
In the event that pressure welding force from the outer slide to the movable core is strong, the movable core is prevented from moving, and accordingly, core back operation is prevented from being performed. Also, upon forcibly moving the moving core with strong force, this causes a problem in that scraping occurs, and the outer slide and movable core are damaged.
With the present invention, as a feature thereof, a slope indicated with the following expression is provided to a combining slope indicated with E in
[Math.2]
0.5 degrees≧E≧5 degrees (Expression 2)
With the present invention, the combining slope E between the outer slide 9 and the movable core 7 illustrated in
Also, the combining slope is set to a range of between 0.5 degrees and 5 degrees, a resin is prevented from intruding into a clearance between the movable core and slide generated at the time of core back operation (at the time of movement of the second movable-side mold plate), and defective shapes such as occurrence of burring or the like can be prevented.
In
With the present invention, as indicated in F in
[Math.3]
0.01 mm≦F≦0.05 mm (Expression 3)
Also, with the present invention, the outer slide 58 is configured to come into contact with the core mold plate 60 at a portion 61, and provides a clearance, denoted by reference numeral 62, along with the movable core holding insert block 59. Therefore, force to be applied to the outer slide at the time of mold clamping is not directly applied to the movable core and movable core holding insert block.
A gap in a range between 0.01 mm and 0.05 mm is taken as a clearance F illustrated in
Further, with the present invention, the clearance F is managed, and accordingly, at the time of filling a resin and at the time of core back operation, the resin is prevented from entering the clearance portion, and occurrence of burring or the like is prevented, and accordingly, suitable shape precision can be obtained.
Reference numeral 19 denotes a core mold plate pressing driving unit, and a spring 63 is provided within the unit. At the time of core back operation (at the time of movement of the second movable-side mold plate), the spring 63 presses a movable-side mold plate denoted by reference numeral 3 against a fixed-side mold plate 5, and accordingly, a main parting 1 is not opened. At the same time, the spring 63 attempts to separate the second movable-side mold plate from the movable-side mold plate 3, and accordingly, a sub parting denoted by reference numeral 2 is opened by the worth of core back movement amount.
Accordingly, with the present invention, the spring is provided to a movable-side mold plate driving unit, and accordingly, without opening the main parting at the time of core back operation (at the time of movement of the second movable-side mold plate), the movable core alone can be moved by desired core back amount, and a suitable foam-molding part can be obtained.
An elastic member 66 is mounted on the main parting fixing unit, which is elastically deformed at the time of the main parting 1 being closed, and implemented in a hole provided to a movable-side mold plate 3. A fixed-side mold plate 5 and the movable-side mold plate 3 are fixed by the force of elastic deformation. Fixing force according to elastic deformation can be changed by regulating elastic deformation amount beforehand, and accordingly, the main parting can be adjusted so as to not open, according to the size or weight of mold at the time of core back operation (at the time of movement of the second movable-side mold plate).
With the present invention, at the time of core back operation (at the time of movement of the second movable-side mold plate), at least one unit of the units illustrated in
In
A state before core back operation after resin filling is a state illustrated in
At the time of core back operation, the return pin attempts to separate from the first ejector plate 12 in the cavity plate direction by core back amount worth. However, the spring of the ejector plate driving unit according to the present invention presses the movable pin 69, and accordingly, the movable pin 69 presses the second ejector plate 13, and moves by the core back amount gap worth denoted by reference numeral 67.
Therefore, according to the present invention, the ejector plates can maintain positions thereof by the ejector plate driving unit at the time of core back, and accordingly, the slant core and ejector pin connected to the ejector plates are prevented from moving.
In
With an existing mold configuration, it is difficult to perform the undercut processing, and forming of a punching hole, a nipping shape, a curvature of the side face portion, or the like, and accordingly, this is a configuration wherein the movable side of the entire molding part is subjected to core back movement by the main parting alone. As a result thereof, the internal configuration of a molding part forms generally the same foaming configuration at the cross-sectional portion subject to core back movement, as illustrated in
With an existing mold configuration, one main parting is employed, and accordingly, the entirety of the movable side of a mold moves at the time of core back operation.
Therefore, the component edge face is configured of a mold plate on the fixed side and a mold plate on the movable side being combined with a fitting configuration illustrated in
The mold configuration of the side face portion has a fitting configuration, and accordingly, with the edge faces of the side face portion, a circular shape can be added to only the outer side or inner side, and a curvature (semicircular shape) is not added to the side face portion unlike the present invention.
Further, with an exiting mold configuration, the entirety of the mold on the movable side moves at the time of core back movement, and accordingly, in the event that a component includes a punching hole, nipping shape, or undercut shape, a gap is opened in a mold simultaneously with movement of a core, and accordingly, burring occurs, or shape damage or the like occurs at a slant core portion. Therefore, with an existing mold configuration, it has been difficult to perform the undercut processing, and forming of a punching hole, a nipping shape, curvature (semicircular shape) of the side face portion, or the like.
As described above, a pushing-cut hold and a nipping hole which have to be molded as molding parts are connected to a punching insert block and a nipping insert block, the punching insert block and nipping insert block are moved in the core back direction by the driving unit according to a spring or the like to maintain positions thereof before core back operation. Therefore, there is no occurrence of burring in the punching hole and nipping hole portions, and shape precision can be improved.
Also, according to the present invention, the curvature (semicircular shape) can be processed on the side face portion, which has heretofore been impossible. With an armored cover or a component which a user handles, curvature adding is needed to prevent user damage, and according to the present invention, application use can be expanded to components which are needed for full R (semicircular shape) processing.
Further, with regard to the undercut shape portion, the driving unit such as a spring or the like is provided within a sub parting on the movable side so as to be in conjunction with the operation of the main parting regarding the outer slide portion, and accordingly, a position thereof is prevented from moving at the time of core back operation (at the time of movement of the second movable-side mold plate). Therefore, there is no occurrence of burring, and more suitable shape precision can be obtained as compared to an existing configuration. Also, the side face portion has an undercut, which is configured wherein, with a shape which has to be processed at a slant core, the slant core is connected to an ejector plate, and the ejector plate is sandwiched by a return pin and a driving unit such as a spring or the like provided within a movable-side attachment plate. Therefore, the position of the slant core is prevented from moving at the time of core back operation (at the time of movement of the second movable-side mold plate), and accordingly, deformation or damage of a slant shape portion which has occurred with an existing mold configuration is prevented from occurring. Also, there is no occurrence of burring, and a more suitable shape precision can be obtained as compared to an existing configuration.
In the first embodiment, an embodiment is described wherein a movable-side plate is divided into multiple plates, and a sub parting that opens at the time of core back operation (at the time of movement of a second movable-side mold plate) is provided on the movable side. Similarly, dividing a fixed-side plate into multiple plates and providing a sub parting on the fixed side can also express similar advantages.
In
Also, reference numeral 87 denotes a movable core which performs core back operation, a surface 871 thereof makes up a portion of the cavity. Reference numeral 810 denotes an ejector pin.
Reference numeral 812 denotes an ejector plate which connects to the ejector pin, and reference numeral 813 denotes a core which forms a movable-side forming portion. Also, reference numeral 814 is a return pin which returns the ejector plate to a predetermined position at the time of mold clamping.
Reference numeral 815 denotes a fixed-side mold plate press driving unit that pressed the fixed-side mold plate 85 toward the movable-side mold plate 83 side at the time of core back operation (at the time of operation of the second fixed-side mold plate).
At the time of core back operation, the sub parting 82 which is a contact face between the movable-side mold plate 83 and the second fixed-side mold plate 84 is opened, and the movable core 87 moves along with the sub parting in the direction of expanding the cavity capacity.
Also, a configuration may be made wherein, at the same time that the sub parting opens, another core (insert block) that is separate from the movable core can be moved in the direction of increasing cavity capacity, whereby the cavity capacity for forming molding parts can be increased, and foaming is facilitated. In
Also, in the event of the sub parting 82 opening, the outer slide 89 moves toward a slide support 88 connected to the second fixed-side mold plate mold opening direction, and the outer slide moves in the direction of expanding the cavity capacity by a slide spring 811. The ejector 810 connected to the ejector plate does not operate during the core back operation.
Next, a mold operation according to the present invention will be described with reference to
After the foaming resin is filled, as illustrated in
According to this operation, the movable-side mold plate and fixed-side mold plate are moved in the mold-opening direction G, and the second movable-side mold plate 84 and the movable core 87 fixed in the second movable-side mold plate 84 are moved by the same amount as to the cavity, relative to the direction of increasing the cavity capacity (here, the opposite direction I as the mold-opening direction). Also, At the same time that the sub parting is opened, the outer slide also is moved in the direction H of increasing the cavity capacity.
In
Accordingly, with the mold configuration according to the present invention, the main parting is not opened at the time of core back operation, and accordingly, occurrence of burring is prevented in the main parting area, and a foam-molding part having suitable shape precision can be obtained.
Molding was performed using a mold according to the present invention (mold having a curvature on the side face portion described in
Molding was performed under the conditions in Table 1 using a foaming resin material wherein a PC+ABS resin is melted within a mold cylinder, nitrogen gas is injected into the melted resin material under high pressure, and nitrogen is melted as a foaming agent. Note that the employed molding machine was a JSW350 Ton molding machine.
With Embodiment 3 through Embodiment 5, with regard to the initial top face portion thickness, side face portion thickness, and slide combining slope, a mold was manufactured in accordance with the above-mentioned embodiment. As a result thereof, an R shape without steps was formed on the side face portion, and no mold burring occurred.
With Embodiment 1 and Embodiment 2, a mold without slid combining slope was manufactured, and molding was performed. With Embodiment 1, a minute step occurred on a portion of the edge face, and with Embodiment 1 and Embodiment 2, there was mild mold burring on a portion thereof. However, neither of those is sufficient to cause a problem in the quality.
Also, any of Embodiments 1 through 5 had a configuration illustrated in
Molding was performed using a mold according to the present invention (mold having a curvature on the side face portion described in
With Embodiment 1 through Embodiment 5, a PC+ABS resin was employed, but here, core back molding was performed with a resin material of PPE+PS, and a material including 30% of PBT glass fiber.
With any of the Embodiments, the slide combining slope was 0.5 degrees or more, and no mold damage was not observed even when performing core back operation.
With Embodiment 7 and Embodiment 10 wherein the thickness of the side face portion is thinner than 2 mm, a minute step occurred on a portion of the edge face, which was not enough to cause a problem regarding quality.
This occurrence of a minute step can be conceived because the cooling speed of the edge faces of the side face portion was fast, the resin viscosity was increased due to cooling, and accordingly, at the time of core back operation, the resin did not move following the surface of a mold performing core back.
With Embodiments 6, 8, and 9, the thickness of the side face portion was thicker than the initial thickness of the top face portion, and also equal to or greater than 2 mm. The viscosity increase speed at the time of cooling of the side face portion was able to be smaller than that of the top face portion at the time of core back operation (at the time of movement of the second movable-side mold plate) of the top face portion, and accordingly, the resin followed the mold surface performing core back, and a very suitable shape was obtained.
Also, with the present invention, as indicated in Embodiments 8 and 9, it was found that a foaming component with high shape precision is obtained by performing the foam-mold and manufacturing method according to the present invention on even a material including glass filler of which the viscosity increase speed at the time of cooling is fast.
Molding was performed using a mold according to the present invention (mold having a curvature on the side face portion described in
With Table 3, the rigidity and deformation amount evaluations were measured by applying load of 300 g to the center of the top face portion of a box shape of width 250 mm*depth 250 mm*height 40 mm. Also, Comparative Example 1 is a normal molding part, and the rigidities of Embodiments 11 through 13 were compared with the rigidity of the normal molding part serving as a reference.
As results of Table 3, at the time of performing the foam-mold and manufacturing method according to the present invention, as indicated in Embodiment 13, the deformation amount was able to be reduced as compared to the normal molding part while performing 24% weight reduction by selecting suitable thickness and core back amount before core back operation.
According to Embodiments of the present invention in Table 3, the initial thickness, and the final thickness after core back operation were set to predetermined amount, the punching hole, nipping shape, undercut shape portion, and edge faces of the side face portion were configured of a foam-mold according to the present invention, and subjected to molding, and accordingly, damage of a mold did not occur.
Also, since there was no occurrence of burring, a molding part with high shape precision and also with both of weight reduction and rigidity was able to be obtained.
Molding was performed using a mold according to the present invention (mold having a curvature on the side face portion described in
The mold clamping force was 300 t, and mold compression deformation amount due to the mold clamping force was 0.02 mm.
In Table 4, with Embodiments 15 and 16 wherein a clearance between the slide and movable core indicted with H in
With Embodiment 14, clearance was set to zero. Minute scraping, not enough to cause a problem regarding quality occurred at the mold the time of the movable core moving. Also, as with Embodiment 17, in the event that clearance was set to 0.06 mm, though not enough to cause a problem regarding quality, little burring occurred between the slide and movable core.
Molding was performed using a mold according to the present invention (mold having a curvature on the side face portion described in
According to Embodiment 18 through Embodiment 21 of the present invention indicated in Table 5, in the case of molding using the foam-mold and manufacturing method according to the present invention, with all of the four types of materials, the weight reduction ratio of the side face portion as to the weight reduction ratio of the top face portion having the thickness in the core back movement direction was 50% or less. Accordingly, the foaming ratio of the side face portion was controlled by performing the mold configuration and manufacturing method according to the present invention, whereby deterioration in strength due to foaming was able to be reduced to a small value.
Note that it is common knowledge that mechanical strength such as an elastic ratio or tensile strength or the like is reduced along with increase in the foaming ratio or weight reduction ratio.
Results of molding using the molds described in
As indicted in Table 6, in the case of molding using the foam-mold and manufacturing method according to the present invention, with all of the four types of materials, the weight reduction ratio of the undercut edge face shape portion made up of the slant core as to the weight reduction ratio of the top face portion having the thickness in the core back movement direction was 40% or less. Accordingly, according to the present invention, the foaming ratio of the undercut edge face shape portion made up of the slant core was controlled, whereby deterioration in strength due to foaming was able to be reduced to a small value.
Also, with the four types of materials in the boundary between the slant core and the movable core, the width was 0.02 mm through 1.5 mm, and the depth was 0.02 mm through 0.5 mm.
Note that a minute step formed on the boundary between the slant core and the movable core which is a feature of the molding part according to the present invention was minute as indicated in Embodiment 22 through Embodiment 25, and influence on the shape precision and component strength was very small.
Results of molding using molds forming the punching insert block and nipping insert block described in
The steps in the boundaries between the punching insert block, nipping insert block, and movable core were, with the four types of materials, 0.02 mm through 1.5 mm in width, and 0.02 mm through 0.5 mm in depth, which were the same step amount as the step between the slant core and movable core according to the present invention indicated in the embodiments in the above Table 6.
As with the step at the slant core, a minute step formed on the boundaries between the punching insert block, nipping insert block, and movable core which is a feature of the molding part according to the present invention was minute as indicated in Embodiment 26 through Embodiment 29, and influence on the shape precision and component strength was very small.
Note that, with other than the materials indicated in the Embodiments of the present invention in Tables 1 through 7, the present invention is effective as to existing techniques, and accordingly, the present invention is not restricted to the range indicated with the Embodiments.
Molding was performed using a mold according to the present invention (mold described in
Molding was performed under the conditions in Table 1 using a foaming resin material wherein, for three types of resin which are PC+ABS, PBT-GF 30%, and PPE+PS, resin is melted within a mold cylinder, nitrogen gas is injected into the melted resin material under high pressure, and nitrogen is melted as a foaming agent. Note that the employed molding machine was a JSW350 Ton molding machine.
With Embodiments 30 through 34, the formed portions formed by the movable core and outer slide have a weight reduction ratio that is greater as compared to other portions.
Molding was performed using a mold according to the present invention (mold described in
For the five different types of resin materials in Embodiments 35 through 39, the molding conditions under which molding is performed with the mold and molding method according to the present invention, and the width and depth of minute indentation lines that occur in the boundary between the movable-core and outer slide and fixed-side mold plate illustrates in
The width of the groove for any of the materials is 0.13 mm or less, and the depth of the groove is also approximately 0.01 mm, whereby the levels thereof are such that influence to be given on the strength of a molding part is not a problem. Also, even in a case of applying the present invention to an external part which calls for an external view, the minute indentation lines are of a level that do not pose a problem as to external view quality.
This occurrence of a minute step can be conceived because the cooling speed of the boundary faces of the movable core and outer slide and fixed side mold plate was fast, the resin viscosity was increased due to cooling, and accordingly, at the time of the movable core and the outer slide moving, the resin did not move following the surface of a moving mold.
Also, with the present invention, as indicated in Embodiments 33 and 37, it was found that a foaming component with high shape precision is obtained by performing the foam-mold and manufacturing method according to the present invention on even a material including glass filler of which the viscosity increase speed at the time of cooling is fast.
Molding was performed using a mold according to the present invention (mold described in
The mold clamping force was 350 t, and mold compression deformation amount due to the mold clamping force was 0.1 mm.
In Table 10, with Embodiments 41 and 42 wherein a clearance between the slide and fixed-side mold plate indicted with 891 in
Also, with the PBT material indicated in Embodiments 43 and 44, in the event that clearance was set to −0.02, burring did not occur, and movement of the outer slide was also favorable.
Note that, with other than the materials indicated in the Embodiments of the present invention in Tables 8 through 10, the present invention is effective as to existing techniques, and accordingly, the present invention is not restricted to the range indicated with the Embodiments.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2011-190374, filed Sep. 1, 2011, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-190374 | Sep 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/005438 | 8/29/2012 | WO | 00 | 2/28/2014 |
