A water cup without sealing of cup lid and manufacturing method thereof

Abstract

The present invention discloses a cup lid seal-free water cup and a manufacturing method thereof, the manufacturing method comprising: (i) inner plug processing process: (11) stretching and forming a plate material and then subjecting it to a first shaping process; (12) subjecting it to a second punch shaping process; (13) subjecting it to a third punch shaping process; (14) turning it into a finished inner plug product; (15) injecting and molding the finished inner plug product into a plastic inner lid in an insert manner, and then assembling it into a cup lid; (ii) cup body mouth processing process: (21) welding and forming the mouth structure of the semi-finished cup body; (22) performing two rough grinding processes; (23) performing three fine grinding processes on the mouth of the cup body, and thus obtaining a cup body that can be sealably assembled with the cup lid. The present invention adopts a specific processing technology to control the dimensional accuracy of the inner plug and the mouth within 0.02 mm, thereby effectively ensuring the sealing of the connection between the inner plug and the mouth; and because the use of a silicone ring in the cup lid is eliminated, the defect that the silicone ring is easy to hide dirt and is not easy to clean after long-term use is overcome.

Description

Technical Field

[0001] The invention relates to the field of daily-use water cups, and in particular to a water cup without a seal on the cup cover and a manufacturing method thereof. Background Art

[0002] A water cup is an important container that can meet people's drinking needs and exists in every corner of people's daily life. Usually, a water cup consists of a cup body and a cup cover, and the cup cover and the cup body are connected by a thread. When drinking water is needed, the user first holds the cup body tightly with one hand, and then loosens the cup cover from the cup body with the other hand to take the cup cover off the cup body, thereby achieving the need for drinking water; when drinking water is finished, the user still needs to hold the cup body tightly with one hand, and then use the other hand to screw the cup cover into the thread at the upper end of the cup body to close the cup cover, thereby achieving the airtightness of the cup body.

[0003] At present, the strategy of sealing water with a silicone ring is widely adopted at home and abroad. The cup body is sealed by a silicone ring embedded in the cup cover. The role of the silicone ring in the cup cover is mostly to enhance the airtightness of the cup cover to prevent the gap between the cup cover parts from being large, resulting in water leakage. It has a simple structure, reliable connection, and good sealing performance. However, after long-term use of the water cup, dirt has accumulated on the sealing ring, which is not easy to clean; and the sealing ring is easily damaged after long-term use, which seriously affects the airtightness of the cup cover. Therefore, how to provide a water cup without silicone ring sealing has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0004] The technical problem solved by the present invention is: in view of the technical defects existing in the above-mentioned prior art, a cup lid without sealing and a manufacturing method thereof are proposed.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention is to provide a method for manufacturing a water cup with a cup lid without sealing, comprising the following steps:

[0007] (1) Stainless steel plug processing technology:

[0008] (11) After the stainless steel sheet is stretched and formed, it is subjected to vacuum tempering treatment, and then tempered by a hydraulic press for the first shaping, and mold pressing is used to obtain a semi-finished inner plug;

[0009] (12) The semi-finished inner plug is subjected to a second punching shaping, and the flatness is controlled within 0.1 mm;

[0010] (13) The semi-finished inner plug is subjected to a third punching shaping and a second edge pressing shaping to control the flatness of the semi-finished inner plug within 0.05 mm;

[0011] (14) Using a CNC machine tool to turn the flatness of the semi-finished inner plug into within 0.03 mm, the inner plug is obtained as a finished product;

[0012] (15) The inner plug finished product is injection molded into the plastic inner cover in the form of an insert when the inner cover is formed, and then assembled with the cover body to form a cup cover;

[0013] (II) Mouth treatment process of the cup body:

[0014] (21) welding the mouth structure of the semi-finished cup body into shape in an arc-mouth overlap manner;

[0015] (22) Use a grinding belt wheel to feed from the side to roughly grind the mouth of the cup body, and grind it twice, grinding off 0.1 mm each time;

[0016] (23) Use emery cloth to feed from the side to fine-grind the mouth of the cup body, and fine-grind it three times with a 0.1 mm margin. The flatness is controlled within 0.03 mm, and the cup body that can be sealed and assembled with the cup cover is obtained.

[0017] Furthermore, in the method for manufacturing the water cup with a seal-free cup lid, the temperature of the vacuum tempering treatment process in step (11) is 800-900° C., and the insulation time is 1.5 hours.

[0018] Furthermore, in the method for manufacturing a water cup with a lid that does not require sealing, the step (14) uses a precision CNC machine tool to machine the flatness of the inner plug of the semi-finished product to within 0.02 mm.

[0019] Furthermore, in the method for making a water cup with a cup lid and no seal, the mouth of the semi-finished cup body in step (22) is fixed on a horizontal grinding machine with the shoulder positioned thereon for rough grinding.

[0020] Furthermore, in the method for making a water cup with a lid that does not require sealing, the fine grinding in step (23) uses 1200# emery cloth.

[0021] Furthermore, in the method for making a water cup with a lid that does not require sealing, the fine grinding process in step (23) is: grinding off 0.02-0.03 mm for the first time, grinding off 0.02-0.03 mm for the second time, and grinding off 0.04-0.06 mm for the third time.

[0022] The second aspect of the present invention is to provide a cup lid seal-free water cup made by the method described above, comprising a cup lid and a cup body, wherein the cup lid comprises a lid body, an inner lid and an inner plug, wherein:

[0023] The inner plug is injection-molded in the inner cover in an insert manner;

[0024] The mouth of the cup body is tightly connected to the inner cover on its outer side by a threaded connection; and

[0025] The mouth is in abutting connection with the inner plug above it.

[0026] Furthermore, in the cup cover seal-free water cup, the cup cover also includes a top plate embedded in the top of the cover body;

[0027] The bottom edge of the top plate abuts against the top of the inner cover, and the inner cover is embedded in the inner wall of the cover.

[0028] Furthermore, in the cup lid seal-free water cup, the cross section of the inner cover is a "concave"-shaped structure, and its circumferential inner wall is provided with an internal thread; and the circumferential outer wall of the mouth of the cup body is provided with a corresponding external thread.

[0029] Furthermore, in the cup lid seal-free water cup, the cross section of the inner plug is a groove structure, and the top end thereof extends outward along its circumference to form a ring.

[0030] The present invention adopts the above technical solution, which has the following technical effects compared with the prior art:

[0031] (1) It is made by adopting a specific processing technology, and the processing size accuracy of the inner plug of the cup lid and the mouth of the cup body is controlled within 0.02mm, which effectively ensures the sealing of the connection between the inner plug and the mouth;

[0032] (2) By inserting the inner plug into the inner cover by injection molding, the mouth of the cup body is tightly sealed with the inner cover and the inner plug respectively, and on the basis of ensuring the sealing performance, the use of a silicone ring in the cup cover is eliminated, thus overcoming the defect that the silicone ring is easy to hide dirt and is difficult to clean after long-term use;

[0033] (3) At the same time, the silicone ring structure design is cancelled, which avoids the defect that the silicone ring set in the existing cup cover is damaged after long-term use, thereby affecting the air tightness of the cup cover;

[0034] (4) The cup cover does not require a silicone ring to seal the water cup, has a novel and simple structural design, is flexible and convenient to operate, has a low production cost, and has good promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the structure of a cup cover in a water cup sealed without a silicone ring according to the present invention;

[0036] Figure 2 This is a schematic diagram of the structure of a cup body in a water cup sealed by a cup cover without a silicone ring according to the present invention;

[0037] Figure 3 This is a schematic diagram of the overall assembly structure of a cup lid without a silicone ring to seal a water cup according to the present invention;

[0038] Wherein, each figure is marked as:

[0039] 10-cup cover, 11-top plate, 12-cover body, 13-inner cover, 14-inner plug; 20-cup body, 21-mouth. DETAILED DESCRIPTION

[0040] The purpose of the present invention is to provide a cup lid without silicone ring sealing water cup, which comprises a cup lid 10 and a cup body 20, wherein the cup lid 10 comprises a lid body 12, an inner lid 13 and an inner plug 14, wherein the inner lid 13, the inner plug 14 and the top plate 11 are made of stainless steel, the inner lid 13 is made of plastic, and the inner plug 14 is integrally injection molded in a manner of being embedded in the inner lid 13. The cup lid without silicone ring sealing water cup is mainly manufactured by adopting a specific processing technology, and the processing size accuracy of the inner plug of the cup lid and the mouth of the cup body is controlled within 0.02mm, so as to ensure the sealing of the connection between the inner plug of the cup lid and the mouth of the cup body.

[0041] See also Figure 1-2 As shown, the inner plug 14 is injection-molded in the inner cover 13 in an insert manner, that is, the inner plug 14 is injection-molded in the inner cover 13 in an insert manner when the inner cover 13 is formed, so as to reduce the cumulative tolerance of assembly in order to control the flatness; the mouth 21 of the cup body 20 is tightly connected to the inner cover 13 on its outside by threaded connection, and the mouth 21 is in abutting connection with the inner plug 14 above it.

[0042] See also Figure 1-2 As shown, the inner plug 14 is an important component for sealing water. In order to further improve the sealing performance of the assembly of the cup cover 10 and the cup body 20, the inner cover 13 and the inner plug 14 are produced by an injection molding machine through a precision mold through existing processing technology, and their dimensional accuracy can be controlled within 0.02 mm. Preferably, the flatness tolerance of the inner plug 14 is within the range of 0.02 mm, and the water sealing tolerance of the part where the molded mouth 21 contacts the plane of the inner plug 13 is also controlled within the range of 0.02 mm. In this way, the cup cover 10 and the cup body 20 are tightly connected together by threaded connection under the action of mutual force to achieve a sealing effect.

[0043] Please continue reading Figure 1 As shown, the cup cover 10 further includes a top plate 11 embedded in the top of the cover body 12, and the bottom edge of the top plate 11 abuts against the top of the inner cover 13. The inner cover 13 is embedded in the inner wall of the cover body 12.

[0044] Please continue reading Figure 1 and Figure 3As shown, the cross section of the inner cover 13 is a "concave"-shaped structure, and its circumferential inner wall is provided with internal threads; and the circumferential outer wall of the mouth 21 of the cup body 20 is provided with corresponding external threads, and the inner cover 13 and the mouth 21 of the cup body 20 are tightly connected together by threaded connection under the action of mutual force to achieve a sealing effect. In addition, the cross section of the inner plug 14 is a groove structure, and its top extends outward along its circumference to form a ring, that is, the horizontal section of the top of the inner cover 13 is embedded in the groove on the outer circumference of the inner plug 14, and the horizontal section of the top of the inner cover 13 is arranged corresponding to the mouth 20.

[0045] Please continue reading Figure 1 and Figure 3 As shown, by injection molding the inner plug 14 in the inner cover 3 in an insert manner, the mouth 21 of the cup body 20 is tightly sealed and connected with the inner cover 13 and the inner plug 14 respectively, on the basis of ensuring the sealing performance of the cup cover 10 and the cup body 20 after being covered, the application of the silicone ring in the cup cover is eliminated, and the defects of the existing silicone ring that is easy to hide dirt and difficult to clean after long-term use are overcome. At the same time, due to the elimination of the silicone ring structure design, the defect that the silicone ring set in the existing cup cover is damaged after long-term use, which affects the airtightness of the cup cover, is avoided.

[0046] The preparation method of the present invention is described in detail and specifically by specific examples below to provide a better understanding of the present invention, but the following examples do not limit the scope of the present invention.

[0047] Example 1

[0048] This embodiment provides a method for manufacturing a water cup with a lid that does not require sealing, which specifically includes the following steps:

[0049] (1) Stainless steel plug processing technology:

[0050] (11) After the stainless steel sheet is stretched and formed, it is subjected to vacuum tempering treatment at a temperature of 800°C for 1.5 hours, and then tempered by a hydraulic press for the first shaping. The nominal pressure of the main cylinder is adjusted to 400KN, the main cylinder pressure is adjusted to 11MPa, the lower cylinder pressure is adjusted to 8MPa, the nominal pressure of the material withdrawal cylinder is 6KN, and the nominal pressure of the lower cylinder is 65KN. The semi-finished inner plug is obtained by die pressing;

[0051] (12) The semi-finished inner plug is subjected to a second punching shaping. The nominal force of the punch press is selected to be a 450KG punch press, the nominal force stroke is adjusted to 3.5mm, the slider stroke is adjusted to 72mm, the cylinder pressure of the lower cylinder is adjusted to 0.6Mpa, the motor speed is adjusted to 60 rpm, and the flatness is controlled within 0.1mm;

[0052] (13) The semi-finished inner plug is subjected to a third punch shaping, with a 450KG punch press as the punch press, the nominal force stroke adjusted to 3.0mm, the slider stroke adjusted to 70mm, the lower cylinder pressure adjusted to off, and the motor speed adjusted to 50 rpm; and a second edge pressing shaping is performed, with a 250KG punch press as the punch press, the nominal force stroke adjusted to 2.8, the slider stroke adjusted to 65mm, the lower cylinder pressure adjusted to off, and the motor speed adjusted to 90 rpm, so that the flatness of the semi-finished inner plug is controlled within 0.05mm;

[0053] (14) Using a CNC machine tool to turn the flatness of the semi-finished inner plug into within 0.03 mm, the inner plug is obtained as a finished product;

[0054] (15) The finished inner plug is injection molded into the plastic inner cover in the form of an insert when the inner cover is formed, and then assembled with the cover body to form a cup cover;

[0055] (II) Mouth treatment process of the cup body:

[0056] (21) welding the mouth structure of the semi-finished cup body into shape in an arc-mouth overlap manner;

[0057] (22) The mouth of the semi-finished cup body is fixed on the horizontal grinding machine with the shoulder positioned, and the mouth of the cup body is roughly ground by using a grinding belt wheel to feed from the side. The rough grinding is performed twice, and 0.1 mm is ground off each time;

[0058] (23) Use 1200# emery cloth to feed from the side to fine-grind the mouth of the cup body, and fine-grind it three times with a 0.1mm margin. The first time, use a 180-mesh abrasive belt at a speed of 1500 rpm to grind off 0.02mm; the second time, use a 320-mesh abrasive belt at a speed of 2000 rpm to grind off 0.03mm; the third time, use 180-mesh nylon at a speed of 2500 to grind off 0.05mm, and the mouth of the cup body that can be sealed and assembled with the finished inner plug is obtained.

[0059] Example 2

[0060] This embodiment provides a method for manufacturing a water cup with a lid that does not require sealing, which specifically includes the following steps:

[0061] (1) Stainless steel plug processing technology:

[0062] (11) After the stainless steel sheet is stretched and formed, it is subjected to vacuum tempering treatment at a temperature of 860°C for 1.5 hours, and then tempered by a hydraulic press for the first shaping. The nominal pressure of the main cylinder is adjusted to 400KN, the main cylinder pressure is adjusted to 11MPa, the lower cylinder pressure is adjusted to 8MPa, the nominal pressure of the material withdrawal cylinder is 6KN, and the nominal pressure of the lower cylinder is 68KN. The semi-finished inner plug is formed by die pressing;

[0063] (12) The semi-finished inner plug is subjected to a second punching shaping. The nominal force of the punch press is selected to be a 450KG punch press, the nominal force stroke is adjusted to 3.5mm, the slider stroke is adjusted to 72mm, the cylinder pressure of the lower cylinder is adjusted to 0.58Mpa, the motor speed is adjusted to 72 rpm, and the flatness is controlled within 0.1mm;

[0064] (13) The semi-finished inner plug is subjected to a third punch shaping process, with a 450KG punch press as the punch press, the nominal force stroke adjusted to 3.0mm, the slider stroke adjusted to 70mm, the lower cylinder pressure adjusted to off, and the motor speed adjusted to 55 rpm; and a second edge pressing shaping process is performed, with a 250KG punch press as the punch press, the nominal force stroke adjusted to 2.8, the slider stroke adjusted to 65mm, the lower cylinder pressure adjusted to off, and the motor speed adjusted to 100 rpm, so that the flatness of the semi-finished inner plug is controlled within 0.05mm;

[0065] (14) Using a CNC machine tool to turn the flatness of the semi-finished inner plug into within 0.03 mm, the inner plug is obtained as a finished product;

[0066] (15) The finished inner plug is injection molded into the plastic inner cover in the form of an insert when the inner cover is formed, and then assembled with the cover body to form a cup cover;

[0067] (II) Mouth treatment process of the cup body:

[0068] (21) welding the mouth structure of the semi-finished cup body into shape in an arc-mouth overlap manner;

[0069] (22) The mouth of the semi-finished cup body is fixed on the horizontal grinding machine with the shoulder positioned, and the mouth of the cup body is roughly ground by using a grinding belt wheel to feed from the side. The rough grinding is performed twice, and 0.1 mm is ground off each time;

[0070] (23) Use 1200# emery cloth to feed from the side to fine-grind the mouth of the cup body, and fine-grind it three times with a 0.1mm margin. The first time, use a 180-mesh abrasive belt at a speed of 1500 rpm to grind off 0.02mm; the second time, use a 320-mesh abrasive belt at a speed of 2000 rpm to grind off 0.02mm; the third time, use 180-mesh nylon at a speed of 2500 to grind off 0.06mm, thus obtaining a finished cup mouth that can be sealably assembled with the finished inner plug.

[0071] Example 3

[0072] This embodiment provides a method for manufacturing a water cup with a lid that does not require sealing, which specifically includes the following steps:

[0073] (1) Stainless steel plug processing technology:

[0074] (11) After the stainless steel sheet is stretched and formed, it is subjected to vacuum tempering treatment at a temperature of 900°C for 1.5 hours, and then tempered by a hydraulic press for the first shaping. The nominal pressure of the main cylinder is adjusted to 380-400KN, the main cylinder pressure is adjusted to 11MPa, the lower cylinder pressure is adjusted to 8MPa, the nominal pressure of the material withdrawal cylinder is 6KN, and the nominal pressure of the lower cylinder is 70KN. The semi-finished inner plug is obtained by die pressing;

[0075] (12) The semi-finished inner plug is subjected to a second punching shaping. The nominal force of the punch press is a 450KG punch press, the nominal force stroke is adjusted to 3.5mm, the slider stroke is adjusted to 72mm, the cylinder pressure of the lower cylinder is adjusted to 0.6Mpa, the motor speed is adjusted to 80 rpm, and the flatness is controlled within 0.1mm;

[0076] (13) The semi-finished inner plug is subjected to a third punching shaping, with a 450KG punch press as the punch press, the nominal force stroke adjusted to 3.0mm, the slider stroke adjusted to 70mm, the lower cylinder pressure adjusted to off, and the motor speed adjusted to 50 rpm; and a second edge pressing shaping is performed, with a 250KG punch press as the punch press, the nominal force stroke adjusted to 2.8, the slider stroke adjusted to 65mm, the lower cylinder pressure adjusted to off, and the motor speed adjusted to 96 rpm, so that the flatness of the semi-finished inner plug is controlled within 0.05mm;

[0077] (14) Using a CNC machine tool to turn the flatness of the semi-finished inner plug into within 0.03 mm, the inner plug is obtained as a finished product;

[0078] (15) The finished inner plug is injection molded into the plastic inner cover in the form of an insert when the inner cover is formed, and then assembled with the cover body to form a cup cover;

[0079] (II) Mouth treatment process of the cup body:

[0080] (21) welding the mouth structure of the semi-finished cup body into shape in an arc-mouth overlap manner;

[0081] (22) The mouth of the semi-finished cup body is fixed on the horizontal grinding machine with the shoulder positioned, and the mouth of the cup body is roughly ground by using a grinding belt wheel to feed from the side. The rough grinding is performed twice, and 0.1 mm is ground off each time;

[0082] (23) Use 1200# emery cloth to feed from the side to fine-grind the mouth of the cup body, and fine-grind it three times with a 0.1mm margin. The first time, use a 180-mesh abrasive belt at a speed of 1500 rpm to grind off 0.03mm; the second time, use a 320-mesh abrasive belt at a speed of 2000 rpm to grind off 0.03mm; the third time, use 180-mesh nylon at a speed of 2500 to grind off 0.04mm, thus obtaining a finished cup mouth that can be sealably assembled with the finished inner plug.

[0083] Comparative Example

[0084] The cup with a sealing ring made by the existing conventional processing technology includes the following steps: (i) the existing conventional inner plug forming process is: cutting - forming - trimming - pressing - cleaning; (ii) the conventional cup mouth processing process is: welding - sanding - cleaning; each process is an existing conventional technology and will not be repeated here.

[0085] Performance Test:

[0086] The sealing performance test (60° warm water, tested according to national standards) was performed on the cup lid seal-free water cups made from the above-mentioned Example 1, Example 2, Example 3 and the comparative example.

[0087] The test results show that during normal use, the cup lid seal-free water cup made by the present invention has the same good sealing performance as the existing cup with a sealing ring; however, the existing cup with a sealing ring is damaged after a period of use, which seriously affects the airtightness of the cup lid, while the cup lid seal-free water cup made by the present invention still has good sealing performance during the same period of time.

[0088] The cup lid seal-free water cup provided by the present invention has a plastic inner lid and inner plug whose dimensional accuracy can be controlled within 0.02 mm after being produced by an injection molding machine using a precision mold; the stainless steel inner plug, as an important part of water sealing, has a controller accuracy within 0.02 mm after being processed and formed by multiple processes using high-precision equipment such as a hydraulic punch, a stretching machine, and a CNC machine.

[0089] The process of achieving silicone-free water sealing for the cup cover seal-free water cup is as follows: when the inner cover 13 is formed, the stainless steel inner plug 14 is injection molded inside the plastic inner cover 13 in an insert manner (reducing the cumulative tolerance of assembly to control the flatness), the flatness tolerance of the stainless steel inner plug 14 is controlled within the range of 0.02mm, and the tolerance of the portion where the mouth 21 of the formed cup body contacts the plane of the stainless steel inner plug 14 (the water sealing portion) is also controlled within the range of 0.02mm. In this way, the cup cover 10 and the cup body 20 can be tightly connected together under the action of the mutual force of the threaded connection, thereby achieving an excellent sealing effect.

[0090] The specific embodiments of the present invention are described in detail above, but they are only examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions made to the present invention are also within the scope of the present invention. Therefore, the equalization changes and modifications made without departing from the spirit and scope of the present invention should be included in the scope of the present invention.

Claims

1. A method for making a water cup with a lid that does not require sealing. It is characterized in that The steps include: (I) Internal plug processing technology: (11) After the stainless steel sheet is stretched and formed, it is subjected to vacuum tempering treatment, and then tempered by a hydraulic press for the first shaping, and mold pressing is used to obtain a semi-finished inner plug; (12) The semi-finished inner plug is subjected to a second punching shaping, and the flatness is controlled within 0.1 mm; (13) The semi-finished inner plug is subjected to a third punching shaping and a second edge pressing shaping to control the flatness of the semi-finished inner plug within 0.05 mm; (14) Using a CNC machine tool to turn the flatness of the semi-finished inner plug into within 0.03 mm, the inner plug is obtained as a finished product; (15) The inner plug finished product is injection molded into the plastic inner cover in the form of an insert when the inner cover is formed, and then assembled with the cover body to form a cup cover; (II) Mouth treatment process of the cup body: (21) welding the mouth structure of the semi-finished cup body into shape in an arc-mouth overlap manner; (22) Use a grinding wheel to feed from the side to roughly grind the mouth of the cup body, and grind it twice, grinding off 0.1 mm each time; (23) Use emery cloth to feed from the side to fine-grind the mouth of the cup body, and fine-grind it three times with a 0.1 mm margin. The flatness is controlled within 0.03 mm, and the cup body that can be sealed and assembled with the cup cover is obtained.

2. The method for making a water cup without sealing of the cup lid according to claim 1, It is characterized in that The temperature of the vacuum tempering treatment process in step (11) is 800-900° C., and the insulation time is 1.5 hours.

3. The method for making a water cup without sealing of the cup lid according to claim 1, It is characterized in that In step (14), a CNC machine tool is used to machine the flatness of the semi-finished inner plug to within 0.02 mm.

4. The method for making a water cup without sealing of the cup lid according to claim 1, It is characterized in that In step (22), the mouth of the semi-finished cup body is fixed on a horizontal grinding machine with the shoulder positioned for rough grinding.

5. The method for making a water cup without sealing of the cup lid according to claim 1, It is characterized in that The fine grinding in step (23) uses 1200# emery cloth.

6. The method for making a water cup without sealing of the cup lid according to claim 1, It is characterized in that The fine grinding process in step (23) is as follows: the first grinding removes 0.02-0.03 mm, the second grinding removes 0.02-0.03 mm, and the third grinding removes 0.04-0.06 mm.

7. A cup lid seal-free water cup manufactured by the method according to any one of claims 1 to 6, comprising a cup lid (10) and a cup body (20), It is characterized in that The cup cover (10) comprises a cover body (12), an inner cover (13) and an inner plug (14), wherein: The inner plug (14) is injection-molded in the inner cover (13) in an insert manner; The mouth (21) of the cup body (20) is tightly connected to the inner cover (13) on the outside thereof by means of a threaded connection; and The mouth (21) is in abutting connection with the inner plug (14) above it.

8. The cup lid seal-free water cup according to claim 7, It is characterized in that The cup cover (10) further comprises a top plate (11) embedded on the top of the cover body (12); The bottom edge of the top plate (11) abuts against the top of the inner cover (13), and the inner cover (13) is embedded in the inner wall of the cover body (12).

9. The cup lid seal-free water cup according to claim 7, It is characterized in that The cross section of the inner cover (13) is of a "concave"-shaped structure, and its circumferential inner wall is provided with an internal thread; and the circumferential outer wall of the mouth (21) of the cup body (20) is provided with a corresponding external thread.

10. The cup lid seal-free water cup according to claim 7, It is characterized in that The cross section of the inner plug (14) is a groove structure, and the top end thereof extends outward along its circumference to form a ring.

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