Preparation method of silicone rubber sealing ring and vacuum adsorption fixture for CNC processing

Abstract

The present invention provides a method for preparing a silicone rubber sealing ring. The method provided by the present invention not only improves the physical and mechanical properties of the PDMS material, but also maintains the excellent sealing and chemical stability of the material. For thinner products, a vacuum is formed between the product and the fixture by means of a vacuum suction method combined with a sealing ring, and the product is tightly attached to the fixture panel, which will not cause deformation of the product and is resistant to water absorption, deformation, wear and tear, and has good sealing performance, which can effectively improve the overall service life of the sealing ring.

Description

Technical Field

[0001] The invention belongs to the technical field of jig design, and in particular relates to a method for preparing a silicone rubber sealing ring and a vacuum adsorption jig for CNC machining. Background Art

[0002] In the computer numerical control precision machining (CNC) industry, the vacuum suction product fixing method is usually to wrap the self-cutting sealing ring around itself, and then use negative pressure vacuum to fix the product to the fixture surface. However, for the fixing of thin plate products, the use of conventional commercial Teflon rubber as the sealing ring material will cause the product to deform due to negative pressure due to its too hard characteristics, resulting in vacuum suction failure of the workpiece and material spraying during processing.

[0003] Therefore, providing a sealing ring with an adaptive workpiece structure to ensure that thin workpieces will not be deformed during processing and that the flatness of the product processing is guaranteed has become a problem to be solved. Summary of the invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing a silicone rubber sealing ring and a vacuum adsorption fixture for CNC processing. The silicone rubber sealing ring provided by the present invention can adapt to the structure of the workpiece to ensure that the thin workpiece will not be deformed during processing, and the product processing flatness is guaranteed.

[0005] The present invention provides a method for preparing a silicone rubber sealing ring, the method comprising:

[0006] Putting polydimethylsiloxane and polyvinyl acetate into a reaction kettle;

[0007] The temperature in the reactor is maintained within a set temperature range, and the materials in the reactor are vibrated and mixed using an ultrasonic vibrator to promote a polymerization reaction between the polydimethylsiloxane and the polyvinyl acetate;

[0008] Putting the polymerization product in the reactor into isopropanol to obtain raw rubber material;

[0009] The raw rubber material and the compounding agent are mixed and stirred to obtain a silicone rubber material through mixing;

[0010] A sealing ring is formed based on the silicone rubber material to obtain a sealing ring.

[0011] Preferably, the molecular weight ratio of the polyvinyl acetate to the polydimethylsiloxane is in the range of 0.1:1 to 0.5:1.

[0012] Preferably, the molecular weight of the polydimethylsiloxane ranges from 1000 to 10000.

[0013] Preferably, the set temperature range is 25 degrees Celsius to 100 degrees Celsius; the reaction time of the polymerization reaction ranges from 20 hours to 30 hours.

[0014] Preferably, the compounding agent includes at least one of an accelerator, a filler and an antioxidant.

[0015] Preferably, based on the amount of the raw rubber material, the compounding agent includes: 0.5wt% to 1.5wt% of an accelerator; 10wt% to 30wt% of a filler; and 1wt% to 3wt% of an antioxidant.

[0016] Preferably, the step of performing a sealing ring molding operation based on the silicone rubber material to obtain the sealing ring includes:

[0017] Weighing and shearing the silicone rubber material to obtain a sealing strip;

[0018] The sealing strip is heated and molded to obtain a sealing ring blank;

[0019] The sealing ring blank is deburred to obtain a sealing ring.

[0020] Preferably, the thickness of the sealing ring blank ranges from 0.2 mm to 0.4 mm.

[0021] The present invention also provides a vacuum adsorption fixture for CNC machining, the vacuum adsorption fixture comprising:

[0022] A fixture loading plate is provided with a workpiece placement groove, and a sealing ring receiving groove is provided at the bottom of the workpiece placement groove for cooperating with the vacuum generating assembly;

[0023] The silicone rubber sealing ring prepared by the above preparation method is arranged in the sealing ring receiving groove;

[0024] The vacuum generating assembly comprises a suction head; the suction head is connected to the workpiece, the surface of the fixture loading plate and the space formed by the part of the sealing ring higher than the fixture panel through an air passage.

[0025] Preferably, the diameter of the sealing ring is 0.05 mm to 0.15 mm greater than the depth of the sealing ring accommodating groove.

[0026] Compared with the prior art, the present invention provides a method for preparing a silicone rubber sealing ring, the method comprising: putting polydimethylsiloxane and polyvinyl acetate into a reactor; keeping the temperature in the reactor within a set temperature range, using an ultrasonic vibrator to vibrate and mix the substances in the reactor, and promoting the polymerization reaction of the polydimethylsiloxane and the polyvinyl acetate; putting the polymerization product in the reactor into isopropanol to obtain a raw rubber material; mixing the raw rubber material and the compounding agent, and obtaining a silicone rubber material by mixing; performing a sealing ring molding operation based on the silicone rubber material to obtain a sealing ring. The preparation method provided by the present invention can enhance the toughness and ductility of the sealing ring, and is particularly suitable for the application of vacuum sealing rings. The method provided by the present invention not only improves the physical and mechanical properties of the PDMS material, but also maintains the excellent sealing and chemical stability of the material. For thinner products, it forms a vacuum between the product and the fixture by combining the sealing ring with a vacuum suction method, and the product is tightly attached to the fixture panel, which will not cause the product to deform and is resistant to water absorption, deformation, wear and sealing, and has good sealing performance, which can effectively improve the overall service life of the sealing ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the process flow of preparing the silicone rubber sealing ring provided by the present invention;

[0028] Figure 2 A schematic diagram of the structure of a vacuum adsorption fixture for CNC machining provided by the present invention;

[0029] Figure 3 The AA section view of the jig after the sealing ring and the workpiece are assembled;

[0030] 1- jig loading plate, 2- sealing ring receiving groove, 3- workpiece placement groove, 4- silicone rubber sealing ring, 5- suction head, 6- workpiece, 7- airway. DETAILED DESCRIPTION

[0031] The present invention provides a method for preparing a silicone rubber sealing ring, the method comprising:

[0032] Putting polydimethylsiloxane and polyvinyl acetate into a reaction kettle;

[0033] The temperature in the reactor is maintained within a set temperature range, and the materials in the reactor are vibrated and mixed using an ultrasonic vibrator to promote a polymerization reaction between the polydimethylsiloxane and the polyvinyl acetate;

[0034] Putting the polymerization product in the reactor into isopropanol to obtain raw rubber material;

[0035] The raw rubber material and the compounding agent are mixed and stirred to obtain a silicone rubber material through mixing;

[0036] A sealing ring is formed based on the silicone rubber material to obtain a sealing ring.

[0037] See also Figure 1 , Figure 1 The present invention provides a schematic diagram of the process flow of preparing the silicone rubber sealing ring.

[0038] The present invention firstly mixes polydimethylsiloxane (PDMS) and polyvinyl acetate (PVAC) to carry out polymerization reaction.

[0039] Wherein, the molecular formula of the polydimethylsiloxane is C3H9Si(C2H6SiO2) n C3H9Si, where n ranges from 11 to 110;

[0040] The molecular formula of the polyvinyl acetate is (C4H6O2) n , where n ranges from 1 to 23.

[0041] Specifically, the polydimethylsiloxane and the polyvinyl acetate are put into a reaction kettle;

[0042] The temperature in the reactor is maintained within a set temperature range, and the materials in the reactor are vibrated and mixed using an ultrasonic vibrator to promote a polymerization reaction between the polydimethylsiloxane and the polyvinyl acetate;

[0043] The polymerization product in the reactor is put into isopropanol to obtain the raw rubber material.

[0044] In the present invention, the molecular weight of the polydimethylsiloxane ranges from 1000 to 10000, and can be 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 1000, or any value or range between 1000 and 10000.

[0045] The molecular weight ratio of the polyvinyl acetate to the polydimethylsiloxane is in the range of 0.1:1 to 0.5:1, and can be 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, or any value or range between 0.1:1 and 0.5:1.

[0046] The polydimethylsiloxane and the polyvinyl acetate are put into a reaction kettle for mixing, and then the temperature in the reaction kettle is maintained at a set temperature range, the set temperature range is 25 degrees Celsius to 100 degrees Celsius, and can be 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, or any value or any range between 25 degrees Celsius and 100 degrees Celsius.

[0047] Within the above-mentioned set temperature range, the raw materials undergo polymerization reaction, and the polymerization reaction time ranges from 20 hours to 30 hours, and can be 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, or any value or range between 20 hours and 30 hours.

[0048] In some preferred embodiments of the present invention, when the raw materials are mixed, an ultrasonic vibrator is used to vibrate and mix the materials in the reactor to promote the intermolecular polymerization of the polydimethylsiloxane and the polyvinyl acetate. Further preferably, the ultrasonic vibrator uses a frequency of 10 5 Hz ultra-high frequency ultrasonic vibrator.

[0049] After the polymerization reaction, the polymerization product in the reactor is put into isopropanol for degumming to remove unreacted raw materials and solvents to ensure the physical and chemical properties of the product, thereby obtaining the raw rubber material.

[0050] Among them, the specific process of the polymerization reaction includes:

[0051] After PDMS and PVAC are mixed, the polymerization reaction site is the hydrocarbon site in the PDMS repeating unit, and the PDMS hydrocarbon bond breaking H + After that, the carbon-carbon double bond C2H3 of the PVAC structure with the carboxylic acid group removed + bond to obtain an intermediate product.

[0052] Then, CH3 + Neutral hydrogen ion H + Desorption, forming free bond CH2 2+ and with another dehydrogenated ion H + The hydrocarbon group of the intermediate product has a carbon-carbon single bond.

[0053] Finally, the hydrogen-rich environment provides strong reduction reaction conditions, reducing carbon-carbon double bonds to carbon-carbon single bonds and forming polymer crosslinks.

[0054] The chemical reaction formula is as follows:

[0055] 0. (C4H6O2) n →nC2H3 + +nCH3COO - ;

[0056] 1. C3H9Si(C2H6SiO2) n C3H9Si+nC2H3 + →C3H9Si(C2H5SiO2C2H3) n C3H9Si+nH+ ;

[0057] 2. C3H9Si(C2H5SiO2C2H3) n C3H9Si→C3H9Si(C2H5SiO2C2H2) n C3H9Si+nH + ;

[0058] 3. C3H9Si(C2H5SiO2C2H2) n C3H9Si+C3H9Si(C2H5SiO2) n C3H9Si→C3H9Si(C2H5SiO2) n C3H9Si(C2H2) n C3H9Si(C2H5SiO2) n C3H9Si;

[0059] 4. C3H9Si(C2H5SiO2) n C3H9Si(C2H2) n C3H9Si(C2H5SiO2) n C3H9Si+2nH + →C3H9Si(C2H5SiO2C2H6) n C3H9Si.

[0060] The overall reaction formula of the polymerization reaction is:

[0061] C3H9Si(C2H6SiO2) n C3H9Si+(C4H6O2) n →

[0062] C3H9Si(C2H5SiO2C2H6) n C3H9Si+CH3COOH

[0063] The present invention uses polyvinyl acetate as a modifier to modify polydimethylsiloxane to enhance the toughness of the modified polydimethylsiloxane. The present invention can increase the lateral ductility of polydimethylsiloxane by lateral modification of PDMS with PVAC, and finally make the material have good hardness and meet the flatness requirements of the final product.

[0064] The obtained raw rubber material has a transparent appearance and good fluidity, and is the basic material for producing mixed silicone rubber.

[0065] After the raw rubber material is obtained, the raw rubber material is mixed and stirred with a compounding agent to obtain a silicone rubber material through kneading.

[0066] The present invention has no special restrictions on the type of the compounding agent, and any compounding agent known to those skilled in the art can be used. Preferably, the compounding agent includes at least one of an accelerator, a filler, and an antioxidant.

[0067] In some specific embodiments of the present invention, based on the amount of raw rubber material, the compounding agent includes: 0.5wt% to 1.5wt% of accelerator; 10wt% to 30wt% of filler; and 1wt% to 3wt% of antioxidant.

[0068] Specifically, the amount of the promoter is 0.5wt% to 1.5wt%, which can be 0.5wt%, 1wt%, 1.5wt%, or any value between 0.5wt% and 1.5wt%. The promoter is preferably a BPO promoter, which functions to promote the dissociation of PVAC.

[0069] The amount of the filler is 10wt% to 30wt%, which can be 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, or any value between 10wt% and 30wt%. The filler is selected from carbon black, and its performance is to improve the wear resistance of rubber;

[0070] The dosage of the antioxidant is 1wt% to 3wt%, and can be 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, or any value between 1wt% and 3wt%. The antioxidant is selected from the antioxidant with model number 4010NA, and its function is to prevent the aging of rubber caused by factors such as oxidation and heat during use.

[0071] In the present invention, the raw rubber and the compounding agent are mixed by kneading, and then placed in a rubber mixer and mechanically stirred to uniformly disperse the compounding agent in the raw rubber.

[0072] Next, the silicone rubber material obtained after kneading is weighed and sheared to obtain a sealing rubber strip. Specifically, the rubber sheet removed after kneading is sheared into a rubber material that is easy to process.

[0073] Then, the obtained sealing rubber strip is heated and molded to obtain a sealing ring blank. In some specific embodiments of the present invention, the rubber material is placed in a mold and heated and molded with the help of a formed male and female mold. In the present invention, the thickness of the silicone rubber sealing ring blank ranges from 0.2 mm to 0.4 mm, and can be 0.2, 0.25, 0.3, 0.35, 0.4, or the thickness of the sealing ring blank ranges from 0.2 mm to 0.4 mm. Any value or any range.

[0074] Finally, the sealing ring blank is deburred to obtain a sealing ring. In some specific embodiments of the present invention, the formed sealing ring is placed on a trimming machine to remove excess burrs.

[0075] In the present invention, the silicone rubber sealing ring structure is prepared by an integrated plastic forming technology, and then vacuum pumping can achieve better sealing conditions.

[0076] The present invention also provides a silicone rubber sealing ring prepared by the above preparation method, wherein the silicone rubber sealing ring comprises: 31% to 32% of carbon element, 30% to 35% of oxygen element, 26% to 30% of silicon element, 6% to 8% of hydrogen element and the remainder of other elements.

[0077] In the present invention, the thickness of the silicone rubber sealing ring is 0.2 mm to 0.4 mm, and can be 0.2, 0.25, 0.3, 0.35, 0.4, or the thickness of the sealing ring blank is any value or range between 0.2 mm and 0.4 mm. In some specific embodiments of the present invention, the thickness of the silicone rubber sealing ring is 0.3 mm.

[0078] Among them, the silicone rubber sealing ring is only 0.05 to 0.15 mm higher than the fixture panel, so the sealing ring has extremely high requirements for accuracy and physical properties. The silicone rubber sealing ring prepared by the present invention has no Z-axis gravity, and has good oil resistance, water absorption resistance, wear resistance, acid and alkali resistance, pressure resistance, deformation resistance and tensile strength. Therefore, the silicone rubber sealing ring provided by the present invention can achieve repeated extrusion times and the recovery rate of the sealing ring after extrusion is high.

[0079] The silicone rubber sealing ring provided by the present invention can achieve sealing effect in the processing of thin products made of different metal materials in special structure processing such as electronic appliances, automobile parts, and mobile phone manufacturing. It forms a Z downward pulling force by vacuum suction to fix the product to prevent abnormal movement during processing and cause processing abnormalities.

[0080] In some specific embodiments of the present invention, the present invention provides a vacuum adsorption fixture for CNC machining, the vacuum adsorption fixture comprising:

[0081] A jig loading plate (1) is provided with a workpiece placement groove, and a sealing ring receiving groove (2) is provided at the bottom of the workpiece placement groove (3) for cooperating with a vacuum generating assembly;

[0082] A silicone rubber sealing ring (4), arranged in the sealing ring receiving groove (2);

[0083] The vacuum generating assembly comprises a suction head (5); the suction head is connected to the workpiece (6), the surface of the fixture loading plate and the space formed by the part of the sealing ring higher than the fixture panel through an air channel (7).

[0084] See also Figure 2 , Figure 2 This is a schematic diagram of the structure of a vacuum adsorption fixture for CNC machining provided by the present invention. Figure 2 In the figure, 1- jig loading plate, 2- sealing ring receiving groove, 3- workpiece placing groove, 4- silicone rubber sealing ring, 5- suction head, 6- workpiece, 7- airway.

[0085] Preferably, the diameter of the silicone rubber sealing ring (4) is 0.05 mm to 0.15 mm greater than the groove depth of the sealing ring accommodating groove (2), and can be 0.05, 0.07, 0.09, 0.1, 0.11, 0.13, 0.15, or any value or range between 0.05 mm and 0.15 mm.

[0086] In the present invention, the silicone rubber sealing ring is used for CNC negative pressure vacuum adsorption on the surface of the fixture to fix and process the workpiece.

[0087] Specifically, the silicone rubber sealing ring (4) is first fixed to the sealing ring receiving groove (2) of the jig loading plate (1). The jig loading plate described in the present invention is made of high-strength material, and the size of the sealing ring receiving groove matches the specification of the sealing ring. After the sealing ring is fixed, the exposed portion of the sealing ring is 0.05 mm to 0.15 mm higher than the jig panel.

[0088] Then, the vacuum suction head (5) is connected to the air channel (7) on the jig loading plate (1), and the workpiece (6) to be processed is placed on the workpiece placement groove (3) on the jig loading plate (1).

[0089] Next, the vacuum device is turned on, and the vacuum generator uses negative pressure to evacuate the workpiece to a vacuum environment. The vacuum generator evacuates the air in the fixture through the suction head (5) and the airway (7), so that the workpiece, the surface of the fixture loading plate and the exposed part of the sealing ring above the fixture panel form a vacuum state, and form a low pressure or vacuum environment below -70KPa. The vacuum generator suction method is combined with the sealing ring to form a vacuum between the workpiece and the fixture, so that the workpiece is tightly attached to the fixture panel.

[0090] See also Figure 3 , Figure 3 The AA section view of the jig after the sealing ring and the workpiece are assembled. Figure 3 In the figure, 1- jig loading plate, 4- silicone rubber sealing ring, 5- suction head, 6- workpiece, 7- airway.

[0091] By extracting the vacuum, the sealing ring is squeezed and deformed, and the workpiece and the sealing ring / fixture panel fit tightly together to produce a vacuum state and form a Z downward pulling force. The negative pressure is used to suck the workpiece and CNC process it.

[0092] The sealing ring provided by the present invention can tightly connect the workpiece to be processed with the jig, play a sealing role between the workpiece and the jig, form a Z downward pulling force by vacuum suction, fix the product to prevent abnormal movement during processing. The sealing ring provided by the present invention has excellent material ductility, can effectively follow the shape when the negative pressure sucks the workpiece, and provide lateral friction to achieve the best vacuum effect.

[0093] The thickness of the sealing ring provided by the present invention is only 0.2-0.4 mm, and due to the complex structure of the workpiece, it needs to be processed by a CNC machine. The sealing ring prepared by the present invention has excellent oxidation resistance, oil resistance, corrosion resistance, wear resistance, water absorption resistance, and low hardness, and has a soft and high imitation effect, which can improve the processing accuracy and vacuum absorption performance of the product.

[0094] In order to further understand the present invention, the preparation method of the silicone rubber sealing ring provided by the present invention and the vacuum adsorption fixture for CNC processing are described below in combination with the embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0095] Example

[0096] Polydimethylsiloxane and polyvinyl acetate were put into a reactor, and the temperature in the reactor was maintained at a set temperature range. 5 Hz ultra-high frequency ultrasonic vibrator to vibrate and mix the materials in the reactor, so as to promote the polymerization reaction of the polydimethylsiloxane and the polyvinyl acetate for 24 hours;

[0097] After the polymerization reaction, the polymerization product in the reactor is added into isopropanol to remove the glue.

[0098] After obtaining the raw rubber material, the raw rubber material is mixed and stirred with a compounding agent to obtain a silicone rubber material by kneading. Based on the amount of the raw rubber material, the compounding agent includes 1.0wt% of a BPO accelerator, 20wt% of a carbon black filler, and 2wt% of an antioxidant of model 4010NA.

[0099] Next, the silicone rubber material obtained after kneading is weighed and sheared to obtain a sealing rubber strip. Specifically, the rubber sheet removed after kneading is sheared into a rubber material that is easy to process.

[0100] Then, the obtained sealing rubber strip is heated and molded to obtain a sealing ring blank with a thickness of 0.3 mm. The rubber material is placed in the mold with the help of the formed male and female molds and heated and molded.

[0101] Finally, place the formed sealing ring on a trimming machine to remove excess hair.

[0102] The specific parameters of the raw materials for preparing Examples 1 to 9 are shown in Table 1, and the performance of the prepared sealing rings was measured, and the results are shown in Table 1.

[0103] Among them, the hardness test method is the Shore hardness measurement method;

[0104] The test method for tensile strength is tensile strength test;

[0105] The test method for failure elongation is tensile strength test;

[0106] The test method for product processing flatness is the four-point probe test method.

[0107] Table 1

[0108]

[0109] As shown in Table 1, the PDMS molecular weight is first used as the control variable for the test. The SHA hardness of the MPDMS in Example 1 is 11, and the molding degree is relatively difficult, which means that this molecular weight does not have a high cross-linking density. It is difficult for PVCA to produce a polymerization reaction with PDMS, so it is impossible to form a sealing ring for machine processing.

[0110] When the molecular weight of PDMS is increased to 5000, the molecular weight ratio of PVCA / PDMS is fixed at 0.1:1. As the temperature increases from 25, 60 to 100°C, the SHA hardness first decreases from 37 to 29 and then increases to 42, indicating that PVCA can effectively polymerize with PDMS and soften it at a suitable temperature. However, the failure elongation reaches a peak value of 671% in Example 3 (60°C), but drops to 344% when it is increased to 100°C, indicating that at this temperature, the cross-linking reaction of PDMS itself dominates the hardness and failure elongation. Taking the control variable PVCA / PDMS and the molecular weight of 5000 molecular weight PDMS (Example 6), the values ​​and processing flatness are similar to those in Example 5, indicating that the modification point has reached saturation and there is no obvious benefit.

[0111] The molecular weight of PDMS was 10000 and the molecular weight ratio of PVCA / PDMS was fixed at 0.2:1, and the mechanical properties of the material were tested under different temperature conditions. The results showed that as the temperature increased, the SHA hardness and tensile strength increased, showing a positive correlation. However, the failure elongation decreased, indicating that the overall modification benefit was far less than the cross-linking effect of PDMS itself.

[0112] In summary, under the conditions of PDMS molecular weight 5000, PVCA / PDMS molecular weight ratio 0.2:1, and polymerization temperature 60°C, the product MPDMS has the best processing flatness.

[0113] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a silicone rubber sealing ring, characterized in that: The method comprises: Putting polydimethylsiloxane and polyvinyl acetate into a reaction kettle; The temperature in the reactor is maintained within a set temperature range, and the materials in the reactor are vibrated and mixed using an ultrasonic vibrator to promote a polymerization reaction between the polydimethylsiloxane and the polyvinyl acetate; Putting the polymerization product in the reactor into isopropanol to obtain raw rubber material; The raw rubber material and the compounding agent are mixed and stirred to obtain a silicone rubber material through mixing; A sealing ring is formed based on the silicone rubber material to obtain a sealing ring.

2. The preparation method according to claim 1, characterized in that: The molecular weight ratio of the polyvinyl acetate to the polydimethylsiloxane is in the range of 0.1:1 to 0.5:

1.

3. The preparation method according to claim 1, characterized in that: The molecular weight of the polydimethylsiloxane ranges from 1,000 to 10,000.

4. The preparation method according to claim 1, characterized in that: The set temperature range is 25 degrees Celsius to 100 degrees Celsius; the reaction time of the polymerization reaction ranges from 20 hours to 30 hours.

5. The preparation method according to claim 1, characterized in that: The compounding agent includes at least one of an accelerator, a filler and an antioxidant.

6. The preparation method according to claim 5, characterized in that: Based on the amount of the raw rubber material, the compounding agent includes: 0.5wt% to 1.5wt% of an accelerator; 10wt% to 30wt% of a filler; and 1wt% to 3wt% of an antioxidant.

7. The preparation method according to claim 1, characterized in that: The step of performing a sealing ring molding operation based on the silicone rubber material to obtain the sealing ring includes: Weighing and shearing the silicone rubber material to obtain a sealing strip; The sealing strip is heated and molded to obtain a sealing ring blank; The sealing ring blank is deburred to obtain a sealing ring.

8. The preparation method according to claim 7, characterized in that: The thickness of the sealing ring blank ranges from 0.2 mm to 0.4 mm.

9. A vacuum adsorption fixture for CNC machining, characterized in that: The vacuum adsorption fixture comprises: A fixture loading plate is provided with a workpiece placement groove, and a sealing ring receiving groove is provided at the bottom of the workpiece placement groove for cooperating with the vacuum generating assembly; The silicone rubber sealing ring prepared by the preparation method according to any one of claims 1 to 8, arranged in the sealing ring receiving groove; The vacuum generating assembly comprises a suction head; the suction head is connected to the workpiece, the surface of the fixture loading plate and the space formed by the part of the sealing ring higher than the fixture panel through an air passage.

10. The vacuum adsorption fixture according to claim 9, characterized in that: The diameter of the sealing ring is 0.05 mm to 0.15 mm greater than the depth of the sealing ring accommodating groove.

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