High-pressure forming die for diaphragm stretch forming

Abstract

The application discloses a high-pressure forming die for diaphragm stretch forming, which comprises an upper die set, a lower die set and a pre-pressing and shaping assembly. The upper die set is provided with an upper die base, an upper clamping plate and a heating device. A pressure air window is formed in the middle part of the upper clamping plate, and the heating device is arranged opposite to the pressure air window. The lower die set is arranged opposite to the upper die set and can form a closed cavity between the two in a closed die state. The lower die set is provided with a lower die base, a die core fixing plate set and a lower clamping plate. A plurality of driving devices are installed on the lower die base and connected with the lower clamping plate. The die core fixing plate set is fixed with a die core. A profiling convex part for diaphragm stretch forming is arranged on the top of the die core. A through window for the die core to pass through is formed in the middle part of the lower clamping plate. The pre-pressing and shaping assembly comprises pre-pressing convex parts arranged on the lower clamping plate on both sides of the through window and pre-pressing concave parts arranged on the upper clamping plate on both sides of the pressure air window. The diaphragm stretch forming effect and forming yield can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-pressure forming die, in particular to a high-pressure forming die for diaphragm stretch forming. BACKGROUND

[0002] The IML (InMoldingLabel) process is to print ink on the inner surface of the polymer diaphragm, to heat-form the 3D shape of the product from the printed diaphragm, and then to cut the shape and inner hole, and then to put it into the injection mold cavity, to inject the resin into the mold, to form the product with the diaphragm, to ensure the structure and performance of the plastic part, and to bring beautiful patterns and superior performance to the surface of the product. High-pressure heat forming is one of the important links in the IML process, and the general practice is to place the diaphragm below the heating device, to heat the diaphragm evenly to make it completely soft, to pressurize the upper and lower molds, and finally to form and demold the diaphragm. The shape of the formed diaphragm is the modeling surface of the product.

[0003] At present, the existing mold for high-pressure heat forming generally uses upper and lower clamping plates to clamp the diaphragm around, and uses a mold core to stretch form the diaphragm. Although the diaphragm will soften and deform to some extent after heating before clamping, the deformation amount will not be too much, and the diaphragm clamped by the upper and lower clamping plates will still be in a flat shape, and the stretchable space of the diaphragm is small. When stretching the diaphragm with super high stretch demand, the height difference of the mold core is too large, even exceeding the limit of the diaphragm stretch, resulting in thinning of the diaphragm after stretching, and serious wrinkling, tearing and other adverse phenomena. Therefore, it is necessary to improve the existing technology to overcome the defects in the prior art. SUMMARY

[0004] The problem to be solved by the present application is to provide a high-pressure forming die for diaphragm stretch forming to overcome the defects of thinning, wrinkling, tearing and other adverse phenomena of the diaphragm with super high stretch demand when stretched by the existing mold.

[0005] The technical scheme adopted by the present application to solve its technical problem is: a high-pressure forming die for diaphragm stretch forming, comprising: an upper die set, a lower die set and a pre-pressing and shaping assembly;

[0006] The upper die set has an upper die seat, an upper clamping plate below the upper die seat and a heating device arranged between the upper die seat and the upper clamping plate, the middle part of the upper clamping plate is provided with a pressure window, and the heating device is arranged opposite to the pressure window;

[0007] The lower die set is oppositely arranged with the upper die set and can form a closed cavity between the two in the closed die state; the lower die set has a lower die seat, a die core fixed plate set fixedly connected with the lower die seat and a lower clamping plate movably arranged above and below the die core fixed plate set, a plurality of driving devices are installed on the lower die seat, and the driving devices are connected with the lower clamping plate; the die core fixed plate set is fixed with a die core, the top of the die core is provided with a profiling convex part for stretching and forming the diaphragm, and a through window for the die core to pass through is formed in the middle of the lower clamping plate.

[0008] The pre-pressing shaping assembly comprises pre-pressing convex parts arranged on the lower clamping plate on both sides of the through window and pre-pressing concave parts arranged on the upper clamping plate on both sides of the air pressure window.

[0009] Before the die is closed, the lower clamping plate moves upward under the driving of the driving device and is spaced apart from the die core fixed plate set, and the pre-pressing convex part is higher than the profiling convex part; during the die closing process, when the lower clamping plate abuts against the upper clamping plate, the pre-pressing convex part and the pre-pressing concave part cooperate to hold and pre-press the diaphragm; after the die is closed, the die core fixed plate set and the lower clamping plate abut against each other, and the pre-pressing convex part is lower than the profiling convex part, and the closed cavity is filled with high-pressure gas to stretch and form the diaphragm through the profiling convex part.

[0010] As a further improvement of the present application, first inserts are installed on both sides of the through window of the lower clamping plate, and the pre-pressing convex part is formed by the upward protrusion of the top of the first insert; second inserts are installed on both sides of the air pressure window of the upper clamping plate, and the pre-pressing concave part is formed by the upward recess of the bottom of the second insert.

[0011] As a further improvement of the present application, in the closed die state, the pre-pressing convex part can completely project on the profiling convex part.

[0012] As a further improvement of the present application, the ratio of the thickness of the pre-pressing convex part to the thickness of the profiling convex part is R, and R satisfies the relationship: 1 / 2≤R≤2 / 3.

[0013] As a further improvement of the present application, the longitudinal section of the pre-pressing convex part is trapezoidal, which has a plane at the top end and slopes connected on both sides of the plane.

[0014] As a further improvement of the present application, a positioning insert is installed on the pre-pressing convex part in the vertical direction and is used for inserting into a positioning hole on the diaphragm, and a plug hole matched with the positioning insert is arranged in the pre-pressing concave part.

[0015] As a further improvement of the present application, the mold core is provided with a plurality of exhaust holes along the edge of the profiling convex part, and the mold core fixing plate set is provided with an exhaust groove, and the plurality of exhaust holes are communicated with the exhaust groove.

[0016] As a further improvement of the present application, a plurality of equal-height screws are installed between the lower clamping plate and the mold core fixing plate set, so as to limit the height of the upward movement of the lower clamping plate driven by the driving device.

[0017] As a further improvement of the present application, the heating device adopts a ceramic heating module, and the driving device adopts a pneumatic cylinder.

[0018] As a further improvement of the present application, the upper mold base is provided with an air inlet for filling high-pressure gas into the sealed cavity and a pressure relief port for exhausting the sealed cavity.

[0019] The present application has the beneficial effect that the present application provides a high-pressure forming mold for diaphragm stretch forming, by providing a pre-pressing convex part on the lower clamping plate and a pre-pressing concave part on the upper clamping plate, when the lower clamping plate and the upper clamping plate are in close contact during the mold closing process, the diaphragm is clamped and pre-pressed by the pre-pressing convex part and the pre-pressing concave part, and then the mold is completely closed and high-pressure gas is filled, and the diaphragm is stretch formed by the profiling convex part on the mold core. The diaphragm is first shaped close to the product form, leaving a certain amount of stretching, and has a certain buffer before complete stretch forming. This buffer greatly reduces the damage caused by forced stretching of the diaphragm, effectively improves the stretching effect of the diaphragm, prevents the diaphragm from being stretched thin or torn, and improves the stretch forming yield. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a front view of the high-pressure forming mold for diaphragm stretch forming of the present application.

[0021] Figure 2 It is a perspective view of the lower mold set in the present application.

[0022] Figure 3 It is a perspective view of the upper mold set in the present application.

[0023] Figure 4 It is a perspective view of the lower clamping plate, the mold core and the first insert in the present application.

[0024] Figure 5 It is a perspective view of the lower mold set without the mold core in the present application.

[0025] Figure 6 It is a perspective view of the lower mold set after the mold closing in the present application.

[0026] Figure 7Fig. 2 is a sectional view of the upper clamp plate, the lower clamp plate, the first insert and the second insert after the mold is closed according to the present application;

[0027] Figure 8 Fig. 3 is a right view of the lower clamp plate, the mold core and the first insert after the mold is closed according to the present application.

[0028] The following description is made in conjunction with the accompanying drawings:

[0029] 1, upper die holder; 101, air inlet; 102, pressure relief port; 2, upper clamp plate; 201, air pressure window; 3, heating device; 4, lower die holder; 5, mold core fixing plate set; 501, exhaust groove; 6, lower clamp plate; 601, through window; 7, driving device; 8, mold core; 801, profiling convex part; 802, exhaust hole; 9, first insert; 901, pre-pressing convex part; 10, second insert; 1001, pre-pressing concave part; 11, positioning pin; 12, leveling screw; 13, connecting plate; 100, diaphragm. DETAILED DESCRIPTION

[0030] The following description is made in conjunction with the accompanying drawings:

[0031] Referring to Figures 1 to 8 , the present application provides a high-pressure forming mold for diaphragm stretch forming, comprising: an upper mold set, a lower mold set and a pre-pressing and shaping assembly installed between the upper mold set and the lower mold set.

[0032] Referring to Figure 3 , the upper mold set has an upper die holder 1, an upper clamp plate 2 below the upper die holder 1 and a heating device 3 arranged between the upper die holder 1 and the upper clamp plate 2. The heating device 3 is fixed to the bottom of the upper die holder 1, and the bottom of the upper die holder 1 is also fixed with a connecting plate 13 arranged around the heating device 3. The upper clamp plate 2 is fixed to the bottom of the connecting plate 13 through an upper backing plate, and a mold cavity is formed in the upper mold set in this way. The middle part of the upper clamp plate 2 is provided with an air pressure window 201, the middle part of the upper backing plate is a hollow area, and the heating device 3 inside the mold cavity is arranged opposite to the air pressure window 201.

[0033] Optionally, the heating device 3 in the present application adopts a ceramic heating mold set.

[0034] Referring to Figure 1 and Figure 2 , the lower mold set is arranged opposite to the upper mold set and can form a sealed cavity between the two in the closed mold state, i.e. the lower mold set covers the bottom of the upper mold set, so that the mold cavity inside the upper mold set forms a sealed cavity. The lower mold set has a lower die holder 4, a mold core fixing plate set 5 fixedly connected with the lower die holder 4 and a lower clamp plate 6 movable up and down relative to the mold core fixing plate set 5, arranged in order from bottom to top.

[0035] The lower die seat 4 is composed of a locking plate and a bottom plate fixed on the top of the locking plate.

[0036] In the embodiment, the mold core fixing plate group 5 is specifically composed of a mold core fixing plate and a lower base plate fixed on the top of the mold core fixing plate, the top of the mold core fixing plate is fixed with the mold core 8, the mold core 8 is arranged opposite to the air pressure window 201, and the middle part of the lower base plate is provided with a hollow area for the mold core 8 to pass through. The top of the mold core 8 is provided with a profiling convex part 801 for stretch forming the diaphragm 100, the shape of the profiling convex part 801 is consistent with the shape of the product finally stretch formed by the diaphragm 100, and in the embodiment, the profiling convex part 801 is specifically as shown in the drawing, that is, the top surface is an arc-shaped curved surface modeling upward, and the two ends extend in the left-right direction, and there is a large height difference between the highest point and the lowest point. Figure 4

[0037] Further, the lower clamping plate 6 is movably arranged above the mold core fixing plate group 5, and the middle part is provided with a through window 601 for the mold core 8 to pass upward. The lower die seat 4 is vertically installed with a plurality of driving devices 7, and the plurality of driving devices 7 are connected with the lower clamping plate 6 for driving the lower clamping plate 6 to move up and down.

[0038] Optionally, the driving device 7 in the application adopts a pneumatic cylinder.

[0039] In addition, a plurality of equal-height screws 12 are installed between the lower clamping plate 6 and the mold core fixing plate group 5, and the height of the lower clamping plate 6 driven upward by the driving device 7 is limited by the plurality of equal-height screws 12.

[0040] Referring to Figure 2 and Figure 3 , the pre-pressing shaping assembly includes two pre-pressing convex parts 901 and two pre-pressing concave parts 1001, the two pre-pressing convex parts 901 are arranged on the lower clamping plate 6 and located on the left and right sides of the through window 601, that is, the two pre-pressing convex parts 901 are outside the left and right ends of the profiling convex part 801, and the pre-pressing convex part 901 protrudes upward compared with the top surface of the lower clamping plate 6. The two pre-pressing concave parts 1001 are arranged on the upper clamping plate 2 and located on the left and right sides of the air pressure window 201, the pre-pressing concave part 1001 is arranged opposite to the pre-pressing convex part 901 in one-to-one correspondence, and the shapes are matched.

[0041] Referring to Figure 2 , Figure 6 and Figure 7 ​Before the mold is closed, the lower clamping plate 6 is driven by the driving device 7 to move upward and keep a spaced distribution with the mold core fixing plate group 5, and the pre-pressing convex part 901 is higher than the profiling convex part 801. In this way, when the lower clamping plate 6 abuts against the upper clamping plate 2 during the mold closing process, the diaphragm 100 is clamped and pre-pressed by the pre-pressing convex part 901 and the pre-pressing concave part 1001 to be shaped close to the product form, so that the diaphragm 100 has a certain amount of stretching to have more stretching space to cope with the stretching height of the profiling convex part 801, so that the diaphragm 100 has a buffer before being completely stretched and formed, which greatly reduces the damage to the diaphragm 100 caused by forced stretching, effectively improves the stretching effect of the diaphragm 100 and protects the diaphragm 100 from being thinned and torn, and improves the stretching and forming yield.

[0042] After the mold is completely closed, the mold core fixing plate group 5 abuts against the lower clamping plate 6, at this time the profiling convex part 801 is pushed upward to be in the pressure air window 201, in this state, the pre-pressing convex part 901 is lower than the profiling convex part 801, after the high-pressure gas is filled in the sealed cavity, the diaphragm 100 is stretched and formed by the profiling convex part 801.

[0043] Again refer to Figure 2 and Figure 3 , the lower clamping plate 6 is provided with the first insert 9 on both sides of the through window 601, and the pre-pressing convex part 901 is formed by the top of the first insert 9. The upper clamping plate 2 is provided with the second insert 10 on both sides of the pressure air window 201, and the pre-pressing concave part 1001 is formed by the bottom of the second insert 10. The pre-pressing and shaping assembly is made into an insert form and installed on the upper clamping plate 2 and the lower clamping plate 6, which can be conveniently replaced and adjusted.

[0044] Refer to Figure 4 , the longitudinal section of the pre-pressing convex part 901 is trapezoidal, and the surface shape is close to the shape of the product to be stretched and formed. The surface of the pre-pressing convex part 901 specifically includes a plane at the top and slopes connected on both sides of the plane. This structure design can significantly improve the stability of pre-pressing and shaping, and can avoid damaging the diaphragm 100.

[0045] It is worth mentioning that, refer to Figure 8 , in the mold closed state, the pre-pressing convex part 901 can be completely projected on the profiling convex part 801 from the perspective of the right view, that is, the top edge contour of the profiling convex part 801 is completely above the top edge contour of the pre-pressing convex part 901. In this way, every part of the diaphragm 100 can be stretched by the pre-pressing convex part 901 to produce a certain amount of deformation during the stretching process, and effective stretching is obtained.

[0046] The ratio of the thickness of the pre-pressing convex part 901 to the thickness of the profiling convex part 801 is R, preferably, R satisfies the relationship: 1 / 2≤R≤2 / 3, so as to reasonably control the pre-pressing deformation of the diaphragm 100, and avoid that the pre-pressing deformation is too much or too little to affect the stretching forming effect.

[0047] Referring to Figure 4 , the pre-pressing convex part 901 is vertically provided with a positioning pin 11, and the pre-pressing concave part 1001 is provided with a plug hole matched with the positioning pin 11. The diaphragm 100 is provided with a positioning hole, and when the diaphragm 100 is placed, the positioning pin 11 is inserted through the positioning hole on the diaphragm 100, so as to position the diaphragm 100.

[0048] Referring to Figure 4 and Figure 5 , the mold core 8 is vertically provided with a plurality of exhaust holes 802 along the edge of the profiling convex part 801, the mold core fixing plate top of the mold core fixing plate set 5 is provided with an exhaust groove 501, and the end of the exhaust groove 501 extends to the edge of the mold core fixing plate, and the plurality of exhaust holes 802 are communicated with the exhaust groove 501. After the high-pressure gas is filled in the sealed cavity, the gas between the diaphragm 100 and the profiling convex part 801 can be discharged outward through the exhaust holes 802 and the exhaust groove 501 under high pressure, so as to avoid the forming failure caused by the gas bubbles between the diaphragm 100 and the profiling convex part 801.

[0049] The upper mold base 1 is provided with a gas inlet 101 for filling high-pressure gas into the sealed cavity and a pressure relief port 102 for exhausting the sealed cavity.

[0050] Further description of the application is as follows:

[0051] Before placing the diaphragm 100, the lower clamping plate 6 is driven by the driving device 7 to move upward and is limited by the equal height screw 12;

[0052] Then, the diaphragm 100 to be stretched is placed on the lower clamping plate 6 and is overlapped on the two pre-pressing convex parts 901, the diaphragm 100 is positioned by the positioning pin 11, and the diaphragm 100 is directly above the profiling convex part 801;

[0053] Next, the lower mold set moves upward as a whole and leaves a certain gap with the upper mold set, and after staying for several seconds in this state, the diaphragm 100 is heated by the heating device to completely soften;

[0054] Then, the lower mold set continues to move upward, and the lower clamping plate 6 first touches the upper clamping plate 2, and the diaphragm 100 is pre-pressed and shaped by the pre-pressing convex part 901 and the pre-pressing concave part 1001 clamping the two ends of the diaphragm 100 (as shown in Figure 7 ), and the remaining part of the diaphragm 100 is clamped by the upper and lower clamping plates;

[0055] The next mold closing process, the cylinder stops working, the lower mold continues to move up until the mold core fixing plate group 5 and the lower clamp plate 6 are completely in close contact, at this time the profiling convex part 801 is pushed up to be in the air pressure window 201, the mold cavity is in a closed state; After high-pressure gas is filled into the closed cavity through the gas inlet 101, the diaphragm 100 is stretched by relying on the profiling convex part 801;

[0056] Finally, after the pressure is maintained for a certain period of time, the diaphragm 100 is completely stretched in the mold, and then the air is discharged through the pressure relief port 102. After the upper mold and the lower mold are opened, the stretched and formed diaphragm 100 is taken out, and the forming is completed.

[0057] In the above description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the above description is only a preferred embodiment of the present application, and the present application can be implemented in many other ways different from those described herein, so the present application is not limited to the specific implementation disclosed above. Meanwhile, any person skilled in the art can make many possible changes and modifications to the technical solutions of the present application, or modify equivalent embodiments, without departing from the scope of the technical solutions of the present application, by using the methods and technical contents disclosed above. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical solutions of the present application, shall still fall within the scope of protection of the technical solutions of the present application.

Claims

1. A high-pressure forming die for diaphragm stretch forming, characterized by, The utility model relates to a kind of film stretching and forming device, including: Upper die set, with upper die seat (1), upper clamping plate (2) below the upper die seat (1) and heating device (3) between the upper die seat (1) and the upper clamping plate (2) are arranged, the middle part of the upper clamping plate (2) is equipped with pressure air window (201), and the heating device (3) is arranged opposite pressure air window (201); Lower die set, with upper die set opposite arrangement, and can form closed cavity between both in clamping state;The lower die set has lower die seat (4) from lower to upper, and the die core fixed plate group (5) is fixedly connected with the lower die seat (4), and the lower clamping plate (6) can be up and down relative to the die core fixed plate group (5) active, the lower die seat (4) is installed with several drive devices (7), and several drive devices (7) are connected with the lower clamping plate (6);The die core (8) is fixed on the die core fixed plate group (5), and the top of the die core (8) is provided with the contoured convex part (801) for the diaphragm (100) to be stretched and formed, and the middle part of the lower clamping plate (6) is equipped with through window (601) for the die core (8) to pass through; Pre-pressing shaping assembly, including pre-pressing convex part (901) being arranged on the lower clamping plate (6) and located on both sides of the through window (601) and pre-pressing concave part (1001) being arranged on the upper clamping plate (2) and located on both sides of the pressure air window (201); Before clamping, the lower clamping plate (6) is driven to move upwards by the drive device (7), and is kept interval distribution with the die core fixed plate group (5), and makes the pre-pressing convex part (901) higher than the contoured convex part (801);During clamping, when the lower clamping plate (6) is attached to the upper clamping plate (2), the pre-pressing convex part (901) and the pre-pressing concave part (1001) cooperate to hold the diaphragm (100) and pre-pressing shaping;After clamping, the die core fixed plate group (5) and the lower clamping plate (6) are attached to each other, and make the pre-pressing convex part (901) lower than the contoured convex part (801), and the closed cavity is filled with high-pressure gas to stretch and form the diaphragm (100) through the contoured convex part (801).

2. The diaphragm stretch-forming high-pressure forming die according to claim 1, characterized by: The first insert (9) is installed on both sides of the through window (601) where the lower clamping plate (6) is located, and the pre-pressing convex part (901) is formed by the top of the first insert (9) being upwardly convex;The second insert (10) is installed on both sides of the pressure air window (201) where the upper clamping plate (2) is located, and the pre-pressing concave part (1001) is formed by the bottom of the second insert (10) being upwardly concave.

3. The diaphragm stretch-forming high-pressure forming die according to claim 1, characterized by: In the clamping state, the pre-pressing convex part (901) can be completely projected on the contoured convex part (801).

4. The diaphragm stretch-forming high-pressure forming die according to claim 1, characterized by: The ratio of the thickness of the pre-pressing convex part (901) to the thickness of the contoured convex part (801) is R, and R satisfies the relationship: 1 / 2≤R≤2 / 3.

5. The diaphragm stretch-forming high-pressure forming die according to claim 1, characterized by: The longitudinal section of the pre-pressing convex part (901) is trapezoidal, which has a plane at the top end and slopes connected on both sides of the plane.

6. The diaphragm stretch-forming high-pressure forming die according to claim 1, characterized by: The pre-press convex part (901) is vertically provided with a positioning pin (11) for inserting into a positioning hole on the diaphragm (100), and the pre-press concave part (1001) is provided with a plug hole for cooperating with the positioning pin (11).

7. The diaphragm stretch-forming high-pressure forming die according to claim 1, characterized by: The mold core (8) is provided with a plurality of exhaust holes (802) along the edge of the profiling convex part (801), and the mold core fixing plate set (5) is provided with an exhaust groove (501), and the plurality of exhaust holes (802) are communicated with the exhaust groove (501).

8. The diaphragm stretch-forming high-pressure forming die according to claim 1, characterized by: A plurality of equal-height screws (12) are arranged between the lower clamping plate (6) and the mold core fixing plate set (5) to limit the height of the upward movement of the lower clamping plate (6) driven by the driving device (7).

9. The diaphragm stretch-forming high-pressure forming die according to claim 1, characterized by: The heating device (3) is a ceramic heating module, and the driving device (7) is a pneumatic cylinder.

10. The diaphragm stretch-forming high-pressure forming die according to claim 1, characterized by: The upper mold base (1) is provided with an air inlet (101) for filling high-pressure gas into the sealed cavity and a pressure relief port (102) for exhausting the sealed cavity.

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