A method for eliminating flash at the parting line of the wheel opening on both sides of the bumper of an automobile

Abstract

The application discloses a method for eliminating the parting surface flash of the wheel opening part of the automobile bumper, which comprises the following mold repairing methods: S1, large inclined ejector rod dismounting; S2, one-time mold closing and repairing; S3, large inclined ejector rod assembling; and S4, two-time mold closing and repairing. The two-time mold closing is to form a forced interference contact state between the inclined inner parting surface on the movable mold large inclined ejector rod and the corresponding inclined inner parting surface with a repairing allowance on the fixed mold by using the mold closing force of a mold closing machine, so that the inclined inner parting surface parts on both sides of the fixed mold are forced to be slightly deformed and displaced to the outside direction of both sides. A certain thickness of the equal-height pad is laid between the equal-height blocks of the movable mold and the fixed mold during mold closing, so as to control the amount of forced slight deformation displacement. Coloring inspection is carried out in the forced slight deformation displacement state, and the close contact between the inclined inner parting surfaces of the movable mold and the fixed mold in the forced slight deformation displacement state is ensured by grinding and repairing. The application eliminates the parting surface flash of the wheel opening part of the automobile bumper.

Description

Technical Field

[0001] This invention relates to the field of automobile bumper manufacturing technology, and specifically to a method for eliminating flash on the parting surface of the wheel well area on both sides of an automobile bumper. Background Technology

[0002] The bumper is a major component of the automotive bumper assembly, characterized by its complex structure, high precision, and varied, curved shape. With the further development of the automotive industry, higher demands are being placed on the appearance quality of car bumpers; for example, the parting line cannot be designed on the outer surface of the product. To address this, existing technology improves the position of the parting surface at the wheel wells on both sides of the bumper injection mold, shifting the parting line to an invisible area, achieving an internal parting effect.

[0003] However, existing injection molds for car bumpers with internal parting structures still have the following problems when in use: After the injection mold is manufactured and assembled, although strict testing and mold repair can ensure the tight contact of the parting surfaces on both sides of the wheel opening, during actual injection molding, the internal cavity of the mold is subjected to injection pressure, which causes the mold cavity to expand and deform to both sides of the wheel opening. This results in gaps between the tight contact surfaces of the parting surfaces on both sides of the mold, leading to the generation of injection flash. This increases the workload of flash removal and grinding, and reduces the efficiency of car bumper injection molding production. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a method for eliminating flash on the parting surface of the wheel well area on both sides of an automotive bumper. The aim is to eliminate flash on the parting surface of the wheel well area on both sides of the automotive bumper injection mold, reducing the workload of flash removal and grinding, and improving the efficiency of automotive bumper injection molding production. The specific technical solution is as follows:

[0005] A method for eliminating flash on the parting surface of the wheel well portion of an automobile bumper, wherein the injection mold used to produce the automobile bumper includes a punch as a moving mold and a die as a fixed mold, and a plurality of equal-height blocks are provided between the moving mold and the fixed mold to ensure that the horizontal parting surfaces of the moving mold and the fixed mold are in contact when the upper and lower molds are closed. The parting surface of the injection mold at the wheel well portion of the automobile bumper is an inner parting surface, and the inner parting surface is an inclined inner parting surface inclined at a certain angle relative to the horizontal direction. The moving mold is provided with a large inclined ejector for undercut demolding at the wheel well portion, and a side pull block is provided on the large inclined ejector. The inclined inner parting surface of the moving mold is located on the large inclined ejector. The method for eliminating flash on the parting surface of the wheel well portion of the automobile bumper includes reserving a mold closing and fitting allowance in advance at the position of the inclined inner parting surface of the fixed mold during mold design and manufacturing, and then using the following mold repair methods in sequence after mold manufacturing:

[0006] S1. Removal of large inclined ejectors: Remove the large inclined ejectors and side pull blocks on both sides of the moving mold;

[0007] S2. First mold closing and repair: The moving mold and the fixed mold, after the large inclined ejector and the side pull block have been removed, are closed together. The coloring inspection method is used to check the contact between the horizontal parting surface and the plane of the equal height block when the moving mold and the fixed mold are closed. If the deviation is found, it is repaired and ground to ensure that the parting surface and the plane of the equal height block can achieve tight contact.

[0008] S3. Large Angled Ejector Assembly: Reattach the removed large angled ejector and side pull block to the moving mold.

[0009] S4. Secondary mold closing and repair: The car bumper injection mold containing the moving mold and the fixed mold is installed on the mold closing machine for mold closing. The contact between the moving mold and the fixed mold at the inclined inner parting surface when they are closed is checked by the coloring inspection method. If the contact exceeds the tolerance, grinding and repair are performed to ensure tight contact between the inclined inner parting surfaces.

[0010] In step S4, the secondary mold closing process utilizes the clamping force of the mold closing machine to close the mold, creating a forced interference contact between the inclined inner parting surface on the large inclined top of the moving mold and the corresponding inclined inner parting surface with fitting allowance on the fixed mold. Under this forced interference contact, the inclined inner parting surfaces on both sides of the fixed mold undergo forced micro-deformation and displacement towards the outer sides. Note that during mold closing, a certain thickness of leveling pad is placed between the leveling blocks of the moving and fixed molds to control the amount of forced micro-deformation displacement. The coloring inspection is performed under the forced micro-deformation displacement state, and grinding and fitting ensure a tight contact between the inclined inner parting surfaces of the moving and fixed molds under the forced micro-deformation displacement state.

[0011] Preferably, the mold repair method further includes the following steps after step S4, the secondary mold closing, and the repair:

[0012] S5. Online verification and repair of the third mold closing: The car bumper injection mold containing the moving mold and the fixed mold is installed on the injection molding machine for mold closing. The contact between the moving mold and the fixed mold at the inclined inner parting surface when they are closed is checked by the coloring inspection method. If the contact exceeds the tolerance, online grinding and repair are performed to ensure tight contact between the inclined inner parting surfaces.

[0013] The above-mentioned three mold closings are mainly used to verify the second mold closing and repair. Therefore, even if grinding and repair are required, the workload of grinding and repair is small. Thus, online grinding and repair can be carried out on the injection molding machine, which also ensures the final quality of the tight contact between the inclined inner parting surfaces.

[0014] Preferably, a dial indicator is installed on the outer side of the cavity near the wheel opening on both sides of the fixed mold. The measuring head of the dial indicator is in contact with the outer surface of the cavity near the wheel opening on the fixed mold, thereby enabling the monitoring of the forced micro-deformation displacement of the inclined inner parting surface at the corresponding position on the fixed mold.

[0015] Preferably, the first mold closing is performed on a mold closing machine.

[0016] In this invention, the colorant used for color inspection is red lead oil-based paint or Prussian blue oil-based paint, and the thickness of the colored coating is not greater than 0.005 mm. The coating thickness is inspected using a test block with grooves, and the groove depth of the test block is not greater than 0.005 mm.

[0017] Preferably, after the coloring inspection and mold repair, the coloring contact area of ​​the corresponding contact surface is guaranteed to be not less than 90%.

[0018] As a further improvement of the present invention, the size of the mold fitting allowance reserved at the inclined inner parting surface of the fixed mold is obtained by the following method: first, a finite element model of the injection mold is established, then the interference boundary condition is set to form a forced interference contact state between the inclined inner parting surface on the large inclined top of the moving mold and the corresponding inclined inner parting surface on the fixed mold, and then finite element calculation is performed to obtain the size of the mold fitting allowance reserved at the inclined inner parting surface of the fixed mold.

[0019] Preferably, the allowance for mold closing and fitting reserved on the inclined inner parting surface of the fixed mold along the vertical direction is 0.2 to 0.4 mm.

[0020] Preferably, the thickness of the contour pad is 0.2 to 0.4 mm.

[0021] In this invention, the secondary mold closing in step S4 is performed by opening and lifting the mold twice to ensure that the mold closing action is in place.

[0022] The beneficial effects of this invention are:

[0023] First, the present invention provides a method for eliminating flash on the parting surface of the wheel well on both sides of an automobile bumper. By adjusting the inclined parting surface of the mold under a forced micro-deformation displacement state, the wheel well on both sides of the cavity will pre-expand outward after the mold is closed when the mold is officially used. The reaction force of the forced micro-deformation displacement is sufficient to offset the injection pressure inside the cavity of the mold, ensuring that there is no gap on the inclined parting surface under the mold closing injection state and no flash on the parting surface of the wheel well after injection.

[0024] Secondly, the present invention provides a method for eliminating flash on the parting surface of the wheel well on both sides of an automobile bumper. The size of the mold fitting allowance reserved at the inclined inner parting surface position of the fixed mold is obtained by finite element calculation, and is reserved according to the finite element calculation structure during actual mold manufacturing. The inclined inner parting surface allowance is formed by CNC machining, which can greatly reduce the workload during mold fitting and improve the efficiency of mold repair. Attached Figure Description

[0025] Figure 1 This is a flowchart illustrating a method for eliminating flash on the parting surface of the wheel well area on both sides of an automobile bumper, according to the present invention.

[0026] Figure 2 This is a schematic diagram of a structure with an inner parting surface set on the injection mold of a car bumper;

[0027] Figure 3 This is a schematic diagram (top view of the moving mold) showing the structure of setting contour blocks and contour pads between the moving mold and the fixed mold in an injection mold.

[0028] In the diagram: 1. Car bumper, 2. Wheel well, 3. Moving mold, 4. Fixed mold, 5. Contour block, 6. Inner parting surface, 7. Contour pad, 8. Dial indicator, 9. Large slanted ejector. Detailed Implementation

[0029] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0030] like Figures 1 to 3 The illustration shows an embodiment of a method for eliminating flash on the parting surface of the wheel well portion on both sides of a car bumper according to the present invention. The injection mold used to produce the car bumper includes a punch (moving mold 3) and a die (fixed mold 4). A plurality of equal-height blocks 5 are provided between the moving mold 3 and the fixed mold 4 to ensure that the horizontal parting surfaces of the moving mold 3 and the fixed mold 4 are in contact when the molds are closed. The parting surface of the injection mold at the wheel well portion 2 on both sides of the car bumper 1 is an inner parting surface 6, and the inner parting surface 6 is relative to the horizontal... The inclined inner parting surface 6 is tilted at a certain angle. The moving mold 3 is provided with a large inclined ejector 9 for undercut demolding of the wheel opening portion 2. The large inclined ejector 9 is provided with a side pull block (not shown in the figure). The inclined inner parting surface 6 of the moving mold 3 is located on the large inclined ejector 9. The method to eliminate the flash of the parting surface of the wheel opening portion 2 on both sides of the car bumper 1 includes reserving a mold closing and fitting allowance in advance at the position of the inclined inner parting surface 6 of the fixed mold 4 during mold design and manufacturing, and then using the following mold repair methods in sequence after mold manufacturing:

[0031] S1. Removal of large inclined ejectors: Remove the large inclined ejectors 9 and side pull blocks on both sides of the moving mold 3;

[0032] S2. First mold closing and repair: The moving mold 3, after the large inclined ejector 9 and the side pull block have been removed, is closed with the fixed mold 4. The coloring inspection method is used to check the contact between the horizontal parting surface of the moving mold 3 and the fixed mold 4 when they are closed, as well as the contact between the planes of the equal height block 5. If there is any deviation, it is repaired and ground to ensure that the parting surface and the plane of the equal height block 5 can achieve tight contact.

[0033] S3, Large Angled Ejector Assembly: Reattach the removed large angled ejector 9 and side pull block to the moving mold 3;

[0034] S4. Secondary mold closing and repair: The injection mold of the car bumper 1, which includes the moving mold 3 and the fixed mold 4, is installed on the mold closing machine for mold closing. The contact between the moving mold 3 and the fixed mold 4 at the inclined inner parting surface 6 when they are closed is checked by the coloring inspection method. If the contact exceeds the tolerance, grinding and repair are performed to ensure tight contact between the inclined inner parting surface 6.

[0035] In step S4, the secondary mold closing process utilizes the clamping force of the mold closing machine to close the mold, creating a forced interference contact between the inclined inner parting surface 6 on the large inclined ejector 9 of the moving mold 3 and the corresponding inclined inner parting surface 6 with a fitting allowance on the fixed mold 4. Under this forced interference contact, the inclined inner parting surfaces 6 on both sides of the fixed mold 4 undergo forced micro-deformation and displacement towards the outer sides. Note that during mold closing, a certain thickness of leveling pad 7 is placed between the leveling blocks 5 of the moving mold 3 and the fixed mold 4 to control the amount of forced micro-deformation displacement. The coloring inspection is performed under the forced micro-deformation displacement state, and grinding and fitting ensure a tight contact between the inclined inner parting surfaces 6 of the moving mold 3 and the fixed mold 4 under the forced micro-deformation displacement state.

[0036] Preferably, the mold repair method further includes the following steps after step S4, the secondary mold closing, and the repair:

[0037] S5. Online verification and repair of the third mold closing: The car bumper injection mold containing the moving mold and the fixed mold is installed on the injection molding machine for mold closing. The contact between the moving mold and the fixed mold at the inclined inner parting surface 6 when they are closed is checked by the coloring inspection method. If the contact exceeds the tolerance, online grinding and repair are performed to ensure tight contact between the inclined inner parting surface 6.

[0038] The above-mentioned three mold closings are mainly used to verify the second mold closing and repair. Therefore, even if grinding and repair are required, the workload of grinding and repair is small. Thus, online grinding and repair can be carried out on the injection molding machine, which also ensures the final quality of the tight contact between the inclined inner parting surfaces 6.

[0039] Preferably, a dial indicator 8 is installed on the outer side of the cavity near the wheel opening portion 2 on the fixed mold 4. The measuring head of the dial indicator 8 is in contact with the outer surface of the cavity near the wheel opening portion 2 on the fixed mold 4, thereby enabling the monitoring of the forced micro-deformation displacement of the inclined inner parting surface 6 at the corresponding position on the fixed mold 4.

[0040] Preferably, the first mold closing is performed on a mold closing machine.

[0041] In this embodiment, the colorant used for color inspection is red lead oil-based paint or Prussian blue oil-based paint, and the thickness of the colored coating is not greater than 0.005 mm. The coating thickness is inspected using a test block with grooves, and the groove depth of the test block is not greater than 0.005 mm.

[0042] Preferably, after the coloring inspection and mold repair, the coloring contact area of ​​the corresponding contact surface is guaranteed to be not less than 90%.

[0043] As a non-further improvement to this embodiment, the size of the mold fitting allowance reserved at the inclined inner parting surface 6 of the fixed mold 4 is obtained by the following method: First, a finite element model of the injection mold is established, then the interference boundary condition is set to form a forced interference contact state between the inclined inner parting surface 6 on the large inclined ejector 9 of the moving mold 3 and the corresponding inclined inner parting surface 6 on the fixed mold 4, and then finite element calculation is performed to obtain the size of the mold fitting allowance reserved at the inclined inner parting surface 6 of the fixed mold 4.

[0044] Preferably, the allowance for mold fitting on the inclined inner parting surface 6 of the fixed mold 4 in the vertical direction is 0.2 to 0.4 mm.

[0045] Preferably, the thickness of the contour pad 7 is 0.2 to 0.4 mm.

[0046] In this embodiment, in the secondary mold closing in step S4, the mold closing is performed by opening and pushing twice to ensure that the mold closing action is in place.

[0047] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for eliminating flash on the parting surface of the wheel well area on both sides of an automobile bumper, characterized in that, An injection mold for producing car bumpers includes a punch as a moving mold and a die as a fixed mold. Several equal-height blocks are provided between the moving and fixed molds to ensure that their horizontal parting surfaces are in contact during mold closing. The parting surface of the injection mold at the wheel wells on both sides of the car bumper is an inner parting surface, which is an inclined inner parting surface tilted at a certain angle relative to the horizontal direction. The moving mold is provided with a large inclined ejector for undercut demolding at the wheel wells, and a side pull block is provided on the large inclined ejector. The inclined inner parting surface of the moving mold is located on the large inclined ejector. The method for eliminating flash on the parting surface at the wheel wells on both sides of the car bumper includes reserving a pre-existing mold closing allowance at the inclined inner parting surface of the fixed mold during mold design and manufacturing, and then sequentially employing the following mold repair methods after mold manufacturing: S1. Removal of large inclined ejectors: Remove the large inclined ejectors and side pull blocks on both sides of the moving mold; S2. First mold closing and repair: The moving mold and the fixed mold, after the large inclined ejector and the side pull block have been removed, are closed together. The coloring inspection method is used to check the contact between the horizontal parting surface and the plane of the equal height block when the moving mold and the fixed mold are closed. If the deviation is found, it is repaired and ground to ensure that the parting surface and the plane of the equal height block can achieve tight contact. S3. Large Angled Ejector Assembly: Reassemble the disassembled large angled ejector and side pull block onto the moving mold. S4. Secondary mold closing and repair: The car bumper injection mold containing the moving mold and the fixed mold is installed on the mold closing machine for mold closing. The contact between the moving mold and the fixed mold at the inclined inner parting surface when they are closed is checked by the coloring inspection method. If the contact exceeds the tolerance, grinding and repair are performed to ensure tight contact between the inclined inner parting surfaces. In step S4, the secondary mold closing process utilizes the clamping force of the mold closing machine to close the mold, creating a forced interference contact between the inclined inner parting surface on the large inclined top of the moving mold and the corresponding inclined inner parting surface with fitting allowance on the fixed mold. Under this forced interference contact, the inclined inner parting surfaces on both sides of the fixed mold undergo forced micro-deformation and displacement towards the outer sides. Note that during mold closing, a certain thickness of leveling pad is placed between the leveling blocks of the moving and fixed molds to control the amount of forced micro-deformation displacement. The coloring inspection is performed under the forced micro-deformation displacement state, and grinding and fitting ensure a tight contact between the inclined inner parting surfaces of the moving and fixed molds under the forced micro-deformation displacement state.

2. The method for eliminating flash on the parting surface of the wheel well area on both sides of an automobile bumper according to claim 1, characterized in that, The mold repair method further includes the following steps after step S4, the secondary mold closing, and the repair: S5. Online verification and repair of the third mold closing: The car bumper injection mold containing the moving mold and the fixed mold is installed on the injection molding machine for mold closing. The contact between the moving mold and the fixed mold at the inclined inner parting surface when they are closed is checked by the coloring inspection method. If the contact exceeds the tolerance, online grinding and repair are performed to ensure tight contact between the inclined inner parting surfaces.

3. A method for eliminating flash on the parting surface of the wheel well area on both sides of an automobile bumper according to claim 1, characterized in that, A dial indicator is installed on the outer side of the cavity near the wheel opening on both sides of the fixed mold. The measuring head of the dial indicator is in contact with the outer surface of the cavity near the wheel opening on the fixed mold, thereby enabling the monitoring of the forced micro-deformation displacement of the inclined inner parting surface at the corresponding position on the fixed mold.

4. A method for eliminating flash on the parting surface of the wheel well area on both sides of an automobile bumper according to claim 1, characterized in that, The first mold closing is performed on a mold closing machine.

5. A method for eliminating flash on the parting surface of the wheel well area on both sides of an automobile bumper according to claim 1, characterized in that, The coloring agent used in the coloring inspection method is red lead oil-based paint or Prussian blue oil-based paint, and the thickness of the colored coating is not greater than 0.005 mm. The coating thickness is checked using a test block with grooves, and the groove depth of the test block is not greater than 0.005 mm.

6. The method for eliminating flash on the parting surface of the wheel well on both sides of an automobile bumper according to claim 1, after performing the coloring inspection method and mold repair, ensures that the coloring contact area of ​​the corresponding contact surface is not less than 90%.

7. A method for eliminating flash on the parting surface of the wheel well area on both sides of an automobile bumper according to claim 1, characterized in that, The size of the mold fitting allowance reserved at the inclined inner parting surface of the fixed mold is obtained by the following method: First, a finite element model of the injection mold is established. Then, the interference boundary condition is set to form a forced interference contact state between the inclined inner parting surface on the large inclined top of the moving mold and the corresponding inclined inner parting surface on the fixed mold. Then, finite element calculation is performed to obtain the size of the mold fitting allowance reserved at the inclined inner parting surface of the fixed mold.

8. A method for eliminating flash on the parting surface of the wheel well area on both sides of an automobile bumper according to claim 1, characterized in that, The allowance for mold fitting on the inclined inner parting surface of the fixed mold along the vertical direction is 0.2 to 0.4 mm.

9. A method for eliminating flash on the parting surface of the wheel well area on both sides of an automobile bumper according to claim 1, characterized in that, The thickness of the contour pad is 0.2 to 0.4 mm.

10. A method for eliminating flash on the parting surface of the wheel well area on both sides of an automobile bumper according to claim 1, characterized in that, In the secondary mold closing process of step S4, the mold closing is performed by opening and lifting the mold twice to ensure that the mold closing action is in place.

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