A method for forming a concave rib and a neck-in of a cup body

Abstract

The application discloses a concave rib and mouth shrinkage forming method of a cup body, and comprises the following processing steps: water swelling, shrinkage, head cutting and thread rolling. By using the method, the water swelling can be carried out by using a conventional mold, the manufacturing cost and material cost of the water swelling mold are reduced, and the cup body blank after water swelling does not generate marks, so that the quality is ensured. The concave rib and the neck are formed at one time by using a shrinkage mold in the second step, the working procedure is reduced, the processing efficiency is high, and the quality is stable. The problems in the prior art are solved.

Description

Technical Field

[0001] This invention belongs to the field of water cup manufacturing and processing technology, and particularly relates to a method for forming concave ribs and a spiral shape of the mouth of a cup. Background Technology

[0002] As attached Figure 1 As shown, to give water cups more diverse shapes, some products have concave ribs (ring grooves) on their surface. Currently, the industry commonly uses water expansion molding for these ribs. However, due to insufficient water pressure, the ribs often result in large, rounded arcs, which are not aesthetically pleasing. Furthermore, the ribs require reshaping and corner trimming after water expansion to achieve the desired shape, leading to numerous manufacturing steps and low production efficiency. In addition, the following drawbacks exist: water expansion molding places high demands on the mold and yields poor output; because the ribs face inwards, demolding after water expansion is difficult, necessitating a double-opening Haver mold structure (making the mold complex). This means that movable Haver blocks (sliders) must be installed at the corresponding positions from the ribs to the cup rim to allow for removal of the cup after expansion. However, the Haver blocks result in poor overall integrity of the mold cavity due to the excessive number of parts (gap between parts). After molding under water pressure, noticeable marks are left on the cup surface near the Haver blocks, resulting in cups with poor appearance. Summary of the Invention

[0003] The purpose of this invention is to provide a method for forming the concave ribs and rim of a cup, which simplifies the process, increases efficiency, and ensures stable quality.

[0004] To achieve the above objectives, the present invention adopts the following technical solution.

[0005] A method for forming the concave ribs and rim of a cup by spin forming, characterized by the following processing steps:

[0006] Step 1: Water Expansion

[0007] Take a round tube of a preset length and place it into the water expansion mold of the water expansion equipment. Use water pressure to form the round tube into a cup body blank, forming the head, shoulder and cup body.

[0008] Step 2: Shrunk

[0009] The spinning process uses a spinning mold, which includes a connecting flange fixed to the rotating power unit of the equipment and a mold rod fixed to the connecting flange. A fixing block is provided on the outer step of the top of the mold rod, and a mold core extending outward is provided in the blind hole at the center of the top of the mold rod. A pressure block is provided on the top of the mold core. The pressure block, mold core and mold rod are fixedly connected by bolts. A top head fixedly connected to the lifting mechanism of the equipment is provided above the pressure block to control the opening and closing of the mold.

[0010] The fixed block has a top surface that is flush with the top surface of the mold rod to form a sliding surface, and the outer side of its upper section is a concave platform, while the outer side of its lower section is flush with the mold rod.

[0011] The pressing block has a straight section on the upper side and a conical section on the lower side, which are adapted to the head and shoulder of the cup body blank, respectively, and there is an accommodating space between the bottom surface of the pressing block and the sliding surface.

[0012] It also includes a demolding mechanism, comprising an outer slider that is at least three-parted and movable within an accommodating space; an inner slider located between the outer slider and the mold core, wherein the outer surface of the inner slider and the inner surface of the outer slider are mutually cooperating inclined surfaces; at least three circumferentially evenly arranged ejector pins that are movable vertically within the through holes of the pressure block, wherein the ejector pins are longer than the through holes and their lower ends abut against the top surface of the inner slider; and a demolding elastic ring located in a groove on the outer side of the outer slider to provide elastic restoring force for the outer slider to contract inward.

[0013] The specific steps for twisting are as follows:

[0014] S1: In the open mold state, the cup blank is placed on the mold, and the shoulder of the cup blank is limited downward by the conical section of the pressure block;

[0015] S2: Start the equipment lifting mechanism. Under the action of the equipment lifting mechanism, the top head presses down the top rod, and the inner slider is pressed. Under the action of the inclined plane, the outer slider expands outward and the annular groove formed by the concave platform is used for the forming of the concave rib. The round straight section of the pressure block is used for the spin forming of the head.

[0016] S3: Start the rotating mechanism of the equipment. The mold and cup blank rotate under the action of the rotating mechanism. The rotary cutting wheel feeds into the cup blank to rotate the cup body at the preset position and head, so that the concave ribs and head are shaped. At this time, the concave ribs on the cup body and the diameter of the head reach the preset size to match the cup lid, and at the same time, the weld seam at the head and concave ribs is smooth. The order of the concave ribs and head rotation can be changed.

[0017] S4: The retracting cutter wheel retracts and stops the rotation of the equipment's rotating mechanism, and the equipment's lifting mechanism rises. The top head moves away from the pressure block, and the ejector rod is no longer under force. Under the action of the demolding elastic ring, the outer slider retracts inward so that its outer side does not protrude from the recess. Under the action of the inner inclined surface of the outer slider, the inner slider moves upward so that the ejector rod moves upward and its upper end extends out of the top surface of the pressure block. At this time, the outer slider no longer jams the concave rib of the cup blank, and the cup blank can be removed to complete the demolding.

[0018] Step 3: Decapitation

[0019] The excess part of the head of the cup body blank is horizontally removed using a cutting device to make the head reach the preset length and form the cup mouth;

[0020] Step 4: Thread rolling

[0021] Use a thread rolling machine to roll threads on the rim of the cup to create threads for screwing onto the cup lid.

[0022] The above technical solution uses conventional molds for water expansion, which reduces the manufacturing and material costs of the water expansion molds. Furthermore, the cup blanks will not leave marks after water expansion, ensuring quality. By using a spin-shrinking mold, concave rib forming and mouth shrinking can be processed simultaneously, and smooth demolding can be achieved, reducing the number of processes, increasing processing efficiency, and ensuring stable quality. This solves the problems existing in the prior art.

[0023] Preferably, a gap is provided between the mold core and the blind hole of the mold rod to accommodate the demolding spring, providing elastic force for the inner slider to move upward.

[0024] By adopting the above technical solution and setting a demolding spring, it can be ensured that the inner slider moves upward quickly during demolding, thus guaranteeing demolding efficiency and quality.

[0025] Preferably, the main body of the mandrel contracts inward in the downward direction to form an insertion part, and a first step surface is formed between the insertion part and the main body; when the mold is closed, the insertion part is inserted into the head of the cup blank to limit its radial swaying, and the first step surface and the conical section of the pressure block cooperate to limit the cup blank's vertical jumping.

[0026] By adopting the above technical solution, it can be ensured that the cup blank will not move randomly during the processing, ensuring stable rotation, thereby guaranteeing the processing quality.

[0027] Preferably, the bottom surface of the insertion part has a downward protrusion with a guide part, and the top surface of the pressure block has a corresponding guide groove.

[0028] By adopting the above technical solution, it can be ensured that the mandrel and the pressure block are concentric, thereby ensuring the stability of the rotation of the mold and the cup blank.

[0029] Preferably, the bottom surface of the pressure block is provided with a first groove, and the pressure block is fitted onto the top of the mold core through the first groove; the bottom surface of the pressure block is also provided with a second groove to increase the stroke distance of the inner slider.

[0030] By adopting the above technical solution, the first groove can ensure a more stable connection between the mold core and the pressure block; the second groove can ensure that the inner slider has enough space to move upward.

[0031] Preferably, the push rod is inverted T-shaped, and the T-shaped head is placed between the inner slider and the pressure block to restrict the push rod from coming out of the through hole; the upper surface of the inner slider is provided with a groove to accommodate the T-shaped head.

[0032] Using the above technical solution, the ejector pin will not come out during the processing, and by setting a groove on the inner slider to accommodate the T-shaped head, its influence can be avoided and the space for the inner slider to move upward can be reduced.

[0033] Preferably, the mold core, pressure block, fixing block, outer slider, and inner slider are made of Cr12 mold steel.

[0034] By adopting the above technical solution and using Cr12 mold steel as the material for these parts, their service life can be increased, while reducing the replacement cost after mold damage.

[0035] As a preferred option, the release elastic ring is made of beef tendon.

[0036] Using the above technical solution, the release elastic ring is made of TPU (tough PU) material, which has better wear resistance and elasticity.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows: by adopting the above technical solution, water swelling is carried out using conventional molds, which reduces the manufacturing cost and material cost of water swelling molds, and the cup blank after water swelling will not produce marks, ensuring quality; by using a spin-shrinking mold to form the concave ribs and the narrowing in step two at one time, the number of processes is reduced, the processing efficiency is high, and the quality is stable; the problems existing in the prior art are solved. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the molding method of the present invention.

[0039] Figure 2 This is a cross-sectional structural diagram of the open state of the rotary mold in step two.

[0040] Figure 3 This is a cross-sectional structural diagram of the closed state of the rotary mold in step two.

[0041] Figure 4 This is a cross-sectional structural diagram of the compression block. Implementation

[0042] To make the technical solution of the present invention clearer, the following description is provided in conjunction with the appendix. Figures 1 to 4 This invention will be described in detail below. It should be understood that the specific embodiments described in this specification are merely for explaining the invention and are not intended to limit the scope of protection of the invention.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0044] This invention relates to a method for forming the concave ribs of a cup body and the spin-forming of the rim, such as... Figure 1 As shown, the specific steps are as follows:

[0045] Step 1: Water expansion. Take a round tube 100 of the preset length and put it into the water expansion mold of the water expansion equipment. Use water pressure to form the round tube into a cup body blank, forming the head 101, shoulder 102 and cup body 103.

[0046] Step Two: Spinning. Place the cup body blank onto the spinning mold, start the equipment to close the mold and fix the cup body blank, and start the equipment's rotation power device to make the mold rotate and drive the cup body blank to rotate. The shrinking wheels approach the predetermined position of the cup body 103 or the head 101 in turn to spin and shape the concave rib 104 on the cup body and the diameter of the head 101 to reach the preset size to match the cup lid. After spinning, the weld seam at the head 101 and the concave rib 104 will be very smooth, avoiding the difficulty of handling the weld seam in subsequent polishing. The spinning order of the head 101 and the concave rib 104 can be changed. This process can complete the processing of the head 101 and the concave rib 104 in one operation, with very high processing efficiency and stable quality. While using a conventional water expansion mold structure, it also avoids the defects of water expansion processing that will produce marks on the concave rib.

[0047] Step 3: Cut off the head. Use a cutting device to horizontally cut off the excess part of the head 101 of the cup body blank, so that the head 101 reaches the preset length and forms the cup mouth 105.

[0048] Step 4: Thread rolling. Use a thread rolling machine to roll threads on the cup mouth 105 to create threads 106 for screwing with the cup lid.

[0049] The spinning die used in the above method, such as Figure 2-4As shown, the device includes a connecting flange 1 fixed to the rotating power unit of the equipment and a mold rod 2 fixed to the connecting flange. A mold core 3 extending outwards is provided in a blind hole at the center of the top of the mold rod 2. A pressure block 4 is provided on the top of the mold core 3, and a top head 7 fixedly connected to the lifting mechanism of the equipment is provided above the pressure block 4. The pressure block 4, mold core 3, and mold rod 2 are fixedly connected by bolts. A fixing block 5 is provided on the outer step of the top of the mold rod 2. The fixing block 5 and the top surface of the mold rod 2 are flush to form a sliding surface. The upper outer end of the fixing block 5 is a recessed platform 51, and the lower outer end is flush with the mold rod 2. The upper outer section of the pressure block 4 is a straight section, and the lower outer section is a conical section, which are adapted to the head 101 and shoulder 102 of the cup body blank, respectively. The diameter of the straight section is a preset size after the head is shrunk, which is smaller than the inner diameter of the head 101. There is an accommodating space between the bottom surface of the pressure block 4 and the sliding surface. The bottom surface of the pressure block 4 is also provided with a first groove 41. The pressure block 4 is fitted onto the mold core 3 through the first groove 41. The top section includes a demolding mechanism 6, comprising an outer slider 61, an inner slider 62, ejector pins 63, and a demolding elastic ring 64. The outer slider 61 is divided into at least three equal parts and is movably disposed in the accommodating space between the bottom surface of the pressure block 4 and the sliding surface. The inner slider 62 is disposed between the outer slider 61 and the mold core 3. The outer surface of the inner slider 62 and the inner surface of the outer slider 61 are mutually cooperating inclined surfaces. Under the cooperation of these inclined surfaces, the outer slider 61 contracts inward, causing the inner slider 62 to move upward. The inner slider 62 is pressed downward, forcing the outer slider 61 to expand outward. At least three circumferentially evenly arranged ejector pins 63 are movably disposed in the through holes 43 of the pressure block 4, and the ejector pins 63 are longer than the through holes 43, with their lower ends abutting against the top surface of the inner slider 62. The demolding elastic ring 64 is disposed in the groove on the outer side of the outer slider 61, providing elastic recovery force for the outer slider 61 to contract inward. In this embodiment, the material is TPU (toughened PU), which is wear-resistant, highly elastic, and suitable.

[0050] like Figure 2 As shown, the main body 71 of the top head 7 contracts inward in the lower direction to form an insertion part 72, and a first step surface is formed between the insertion part 72 and the main body 72; when the mold is closed, the insertion part 72 is inserted into the head 101 of the cup blank to limit its radial swaying, and the first step surface and the conical surface of the pressure block 4 cooperate to limit the cup blank's jumping in the vertical direction.

[0051] like Figure 2 As shown, in order to ensure that the ejector head 7 and the pressure block 4 are concentric when the mold is closed, the bottom surface of the insertion part 72 is provided with a guide part 73 protruding downwards, and the top surface of the pressure block 4 is provided with a corresponding guide groove 44.

[0052] like Figure 2 As shown, in the mold-open state, the ejector head 7 disengages from the pressure block 4, and the ejector rod 63 is no longer under force. At this time, the outer slider 61 contracts inward and remains in place under the action of the demolding elastic ring 64. The outer side of the inner slider 62 does not protrude from the recess 51, which facilitates the placement and removal of the cup blank. The inner slider 62 moves upward, causing the ejector rod 63 to move upward and its upper end to extend out of the top surface of the pressure block 4.

[0053] like Figure 3 As shown, in the mold-closed state, the ejector head 7 presses down, and the upper end of the ejector rod 63 extending from the top surface of the pressure block 4 is forced to move downward, thereby causing the inner slider 62 to move downward and the outer slider 61 to expand outward. At this time, the annular groove formed by the outer slider 61 and the recess 51 is the cavity for the concave rib forming.

[0054] Since the mold core 3, pressure block 4, fixing block 5, outer slider 61, and inner slider 62 are in a state of sliding friction during mold use, Cr12 mold steel is used to improve the service life of these components. For example, the fixing block 5 and mold core 3 can also be integrally formed with the mold rod 2 in actual use, but considering the service life and replacement cost, the fixing block 5 and mold core 3 are designed as independent parts and made of Cr12 mold steel.

[0055] like Figure 4 As shown, in order to ensure the travel distance of the inner slider 62 moving up and down, the bottom surface of the pressure block 4 is also provided with a second groove 42.

[0056] To ensure that the ejector pin 63 does not easily fall out during production, the ejector pin 63 is designed in an inverted T-shape, and the T-shaped head is placed between the inner slider 62 and the pressure block 4 to restrict the ejector pin 63 from coming out of the through hole 43. Based on this, the upper surface of the inner slider 62 is provided with a groove to accommodate the T-shaped head, so as to prevent the T-shaped head from affecting the movable stroke of the inner slider 62.

[0057] To ensure that the inner slider 62 can move upward smoothly during demolding, a gap is provided between the mold core 3 and the blind hole of the mold rod 2 to accommodate the demolding spring 65. The demolding spring 65 provides elastic restoring force for the inner slider 62 to move upward.

[0058] The specific method of using molds in step two is as follows:

[0059] S1: In the mold-open state, the cup blank is placed on the fixture, and the shoulder 102 of the cup blank is limited downward by the conical section of the pressure block 4.

[0060] S2: Start the lifting mechanism of the equipment. The top head 7 moves down under the action of the lifting mechanism. The guide part 73 is inserted into the guide groove 44 to ensure that the top head 7 and the pressure block 4 are concentric. The bottom surface of the insertion part 72 presses the ejector rod 63 to move down until the bottom surface of the insertion part 72 abuts against the top surface of the pressure block 4. At this time, in the mold closing state, the insertion part 72 is inserted into the head 101 of the cup blank. The cup blank is limited in both the radial and circumferential directions to prevent shaking or jumping. The ejector rod 63 drives the inner slider 62 to move down, which in turn causes the outer slider 61 to move outward and form an annular groove with the concave platform 51 for the forming of the concave rib 104. The round straight section of the pressure block 4 is used for the spin forming of the opening 101.

[0061] S3: Start the rotating mechanism of the equipment. The mold and the cup blank rotate under the action of the rotating mechanism. The rotary cutting wheel 8 feeds to the cup blank to rotate the cup body 103 at the preset position and the head 101, so that the concave rib 104 and the head 101 are shaped by rotation. The order of rotation of the concave rib 104 and the head 101 can be changed.

[0062] S4: The retracting cutter wheel 8 retracts and stops the rotation of the equipment's rotating mechanism, and the equipment's lifting mechanism rises. The top head 7 moves upward away from the pressure block 4, and the ejector rod 63 is no longer under force. The outer slider 61 retracts inward under the action of the demolding elastic ring 64. The inner slider 62 moves upward under the combined action of the inner inclined surface of the outer slider 61 and the elastic force of the demolding spring 65, causing the ejector rod 63 to move upward and its upper end to extend out of the top surface of the pressure block 4. At this time, the outer slider 61 no longer jams the concave rib 104 of the cup blank, and the cup blank can be removed to complete the demolding.

Claims

1. A method for forming the concave ribs and rim of a cup by spin forming, characterized in that... The processing steps include the following: Step 1: Water Expansion Take a round tube (100) of a preset length and put it into the water expansion mold of the water expansion device. Use water pressure to form the round tube into a cup body blank, forming the head (101), shoulder (102) and cup body (103). Step 2: Shrunk The spinning process uses a spinning mold, which includes a connecting flange (1) fixed to the rotating power unit of the equipment and a mold rod (2) fixed to the connecting flange (1); a fixing block (5) is provided on the outer step of the top of the mold rod (2), and a mold core (3) extending outward is provided in the blind hole at the center of the top of the mold rod (2). A pressure block (4) is provided on the top of the mold core (3), and the pressure block (4), the mold core (3) and the mold rod (2) are fixedly connected by bolts; a top head (7) fixedly connected to the lifting mechanism of the equipment is provided above the pressure block (4) for controlling the opening and closing of the mold; The top surface of the fixed block (5) is flush with the top surface of the mold rod (2) to form a sliding surface, and the outer side of its upper section is a recessed platform (51), and the outer side of its lower section is flush with the mold rod (2). The upper part of the pressing block (4) is a straight section and the lower part is a conical section, which are adapted to the head (101) and shoulder (102) of the cup body blank respectively, and there is an accommodating space between the bottom surface of the pressing block (4) and the sliding surface. It also includes a demolding mechanism (6), including an outer slider (61) that is divided into at least 3 equal parts and is movably arranged inside and outside the accommodating space; an inner slider (62) that is located between the outer slider (61) and the mold core (3), with the outer side surface of the inner slider (62) and the inner side surface of the outer slider (61) being mutually cooperating inclined surfaces; at least 3 circumferentially evenly arranged push rods (63) that are movably arranged in the through hole (43) of the pressure block (4), and the push rods (63) are longer than the through hole (43), with their lower ends abutting against the top surface of the inner slider (62); and a demolding elastic ring (64) that is located in the groove outside the outer slider (61) to provide elastic recovery force for the outer slider (61) to shrink inward; The specific steps for twisting are as follows: S1: In the open mold state, the cup blank is placed on the mold, and the shoulder (102) of the cup blank is limited downward by the conical section of the pressure block (4); S2: Start the equipment lifting mechanism. The top head (7) presses down the top rod (63) under the action of the equipment lifting mechanism, and the inner slider (62) is pressed. Under the action of the inclined plane, the outer slider (61) expands outward and the annular groove formed by the concave platform (51) is used for the forming of the concave rib (104). The round straight section of the pressure block (4) is used for the spin forming of the head (101). S3: Start the rotating mechanism of the equipment. The mold and the cup blank rotate under the action of the rotating mechanism. The rotary cutting wheel (8) feeds the cup blank to the preset position of the cup body (103) and the head (101) to rotate and form the concave rib (104) and the head (101). At this time, the concave rib (104) on the cup body and the diameter of the head (101) reach the preset size to match the cup lid. At the same time, the weld at the head (101) and the concave rib (104) is smooth. The order of the concave rib (104) and the head (101) can be changed. S4: The retracting cutter wheel (8) retracts and stops the rotation of the equipment rotation mechanism and raises the equipment lifting mechanism. The top head (7) moves up away from the pressure block (4). The push rod (63) is no longer under force. The outer slider (61) shrinks inward under the action of the demolding elastic ring (64) so ​​that its outer side does not protrude from the concave platform (51). The inner slider (62) moves up under the action of the inner inclined surface of the outer slider (61) so that the push rod (63) moves up and its upper end extends out of the top surface of the pressure block (4). At this time, the outer slider (61) no longer jams the concave rib (104) of the cup blank. The cup blank can be removed to complete the demolding. Step 3: Decapitation The excess part of the head (101) of the cup body blank is horizontally cut off using a cutting device so that the head (101) reaches the preset length and forms the cup mouth (105). Step 4: Thread rolling The cup rim (105) is threaded with a thread rolling machine to produce a thread (106) for screwing into the cup lid.

2. The method for forming the concave ribs and rim of a cup body by spin forming according to claim 1, characterized in that: A gap is provided between the blind hole of the mold core (3) and the mold rod (2) to place the demolding spring (65) and provide elastic force for the inner slider (62) to move upward.

3. The method for forming the concave ribs and rim of a cup body by spin forming according to claim 1, characterized in that: The main body (71) of the top head (7) contracts inward in the downward direction to form a plug (72), and a first step surface is formed between the plug (72) and the main body (71). When the mold is closed, the plug (72) is inserted into the head (101) of the cup blank to limit its radial sway. The first step surface and the conical section of the pressure block (4) cooperate to limit the cup blank's vertical jump.

4. The method for forming the concave ribs and rim of a cup body by spin forming according to claim 3, characterized in that: The bottom surface of the plug (72) is provided with a guide (73) protruding downwards, and the top surface of the pressure block (4) is provided with a guide groove (44).

5. The method for forming the concave ribs and rim of a cup body by spin forming according to claim 1, characterized in that: The bottom surface of the pressure block (4) is provided with a first groove (41), and the pressure block (4) is fitted onto the top of the mold core (3) through the first groove (41); the bottom surface of the pressure block (4) is also provided with a second groove (42) to increase the stroke distance of the inner slider (62).

6. The method for forming the concave ribs and rim of a cup body by spin forming according to claim 1, characterized in that: The push rod (63) is inverted T-shaped, and the T-shaped head is placed between the inner slider (62) and the pressure block (4) to restrict the push rod (63) from coming out of the through hole (43); the upper surface of the inner slider (62) is provided with a groove to accommodate the T-shaped head.

7. The method for forming the concave ribs and rim of a cup body by spin forming according to claim 1, characterized in that: The mold core (3), pressure block (4), fixing block (5), outer slider (61) and inner slider (62) are made of Cr12 mold steel.

8. The method for forming the concave ribs and rim of a cup body by spin forming according to claim 1, characterized in that: The release elastic ring (64) is made of beef tendon.

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