Minimum lubricating and grinding method for high-aluminum-silicon mobile phone cover plate glass

Abstract

The invention belongs to the technical field of grinding machining, and discloses a high-aluminum-silicon mobile phone cover plate glass minimum quantity lubrication grinding method which combines minimum quantity lubrication cooling and traditional cutting fluid cooling, when the grinding speed is 25-35 m / s, the minimum quantity lubrication cooling mode is adopted, edge breakage in the grinding process can be effectively restrained, and the grinding quality is improved. The low roughness can be obtained by increasing the spraying pressure within a certain range, and when the grinding speed is larger than 35 m / s, due to the fact that the pressure of trace lubricating oil mist is not enough to enable most of oil mist to enter a grinding area, and the cooling performance of trace lubricating oil is lower than that of cutting fluid, a cutting fluid cooling mode is adopted; the method is beneficial to improving the processing quality of the high-alumina-silica glass, is beneficial to improving the grinding yield, and is suitable for grinding the high-alumina-silica glass.

Description

Technical Field

[0001] The invention relates to the technical field of grinding processing, and in particular to a micro-lubrication grinding method for a high-aluminum-silicon mobile phone cover glass. Background Art

[0002] Curved mobile phones and other smart device screens need to be made of high-aluminum silicate glass. The manufacturing process includes a series of preparation processes, and grinding is one of them. High-aluminum silicate glass has high hardness and brittleness, which makes it easy to crack and collapse during the grinding process, affecting the processing quality and efficiency. Traditional grinding tools and processes have certain limitations when processing high-aluminum silicate glass, such as high grinding force, high temperature, low processing efficiency, etc., and a large amount of cutting fluid is used to lubricate and cool the workpiece, which has a great impact on the environment and the health of operators.

[0003] Minimum quantity lubrication usually refers to the mixing of compressed gas (air, nitrogen, carbon dioxide, etc.) with a very small amount of lubricating oil to form a micron-sized droplet oil mist, which is sprayed at high speed to the cutting area or kinematic pair through a nozzle, thereby effectively cooling and lubricating the cutting area or kinematic pair. In the existing technology, the research on minimum quantity lubrication grinding is mostly applied to high-temperature alloys, while there are few studies on grinding non-metallic materials such as ceramics, alumina-silicon glass, etc.

[0004] Therefore, the present invention proposes a micro-lubrication grinding method for high-aluminum-silicon mobile phone cover glass, which combines micro-lubrication with traditional cutting fluid pouring cooling to improve the processing quality of high-aluminum-silicon glass and improve the grinding yield. Summary of the invention

[0005] The present invention aims to provide a method for micro-lubrication grinding of high-aluminum-silicon mobile phone cover glass, so as to improve the processing quality of high-aluminum-silicon glass and increase the yield rate of grinding.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The technical solution provided by the present invention is:

[0008] A method for micro-lubrication grinding of high-aluminum-silicon mobile phone cover glass comprises the following steps:

[0009] S1. Clamp the high-alumina-silicon glass to be processed on the machine tool;

[0010] S2, clamp the tool and determine the processing origin;

[0011] S3. Adjust the distance between the low-temperature nozzle and the cutting edge of the tool. The distance between the low-temperature nozzle and the cutting edge of the tool is 7-10 mm.

[0012] S4, setting the cooling and lubrication parameters of the micro-lubrication cooling system, turning on the micro-lubrication cooling system, and allowing the nozzle to spray micro-lubrication oil mist onto the high-aluminum silicate glass;

[0013] S5, setting the corresponding grinding speed, and then starting the processing machine to perform preliminary grinding on the high-aluminum-silicon glass;

[0014] S6, after the preliminary grinding in step S5 is completed, the grinding speed is increased and the cutting fluid cooling method is used to complete the processing;

[0015] In step S4, the cooling lubrication parameters are set to a micro-lubrication oil injection rate of 40 ml / h and a spray pressure of 0.4-0.5 MPa;

[0016] In step S5, the corresponding grinding processing parameter is set to a grinding speed of 25-35 m / s;

[0017] In step S6, the grinding speed is increased to greater than 35 m / s.

[0018] Further, in step S4, the lubricating medium in the minimal lubrication system is lubricating oil or a mixture of lubricating oil and water.

[0019] Further, in step S4, the cooling gas in the minimal lubrication system is supercritical carbon dioxide gas or cryogenic liquid nitrogen gas.

[0020] Furthermore, in step S5, the rotation speed of the spindle is reasonably increased while maintaining a consistent feed speed.

[0021] The beneficial effects of the technical solution are as follows: the technical solution performs grinding in stages according to the grinding speed, each grinding corresponds to a different grinding speed, and at different grinding speeds, the most suitable grinding cooling method is selected, thereby improving the lubrication and cooling performance during the grinding process, which can effectively reduce the cutting force and friction coefficient, further reduce the grinding force, have a better glass edge morphology, and effectively inhibit the occurrence of edge chipping during the grinding process. Suitable grinding cooling methods are selected for both grindings, which can effectively reduce the roughness of the glass surface, thereby improving the processing quality of high-alumina silicon glass, and improving the grinding yield rate, while also reducing the use of cutting fluid and reducing the impact on the environment and human body. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the test system of the present invention;

[0023] Figure 2 This is a roughness result diagram at different grinding speeds of the present invention;

[0024] Figure 3 This is a relationship diagram between the micro-lubrication spray pressure and the grinding surface roughness of the present invention;

[0025] Figure 4 It is a schematic diagram of the direction of grinding force components in the grinding force analysis test;

[0026] Figure 5 Schematic diagram of grinding force with minimal lubrication and cutting fluid cooling;

[0027] Figure 6 The morphology of the glass edge of test numbers 3 and 12, where a is the glass edge of the minimal lubrication cooling method; b is the glass edge of the cutting fluid cooling method;

[0028] Figure 7 The glass edge breakage at different grinding speeds. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0030] A method for micro-lubrication grinding of high-aluminum-silicon mobile phone cover glass comprises the following steps:

[0031] S1. Clamp the high-alumina-silicon glass to be processed on the machine tool;

[0032] S2, clamp the tool and determine the processing origin;

[0033] S3. Adjust the distance between the low-temperature nozzle and the cutting edge of the tool. The distance between the low-temperature nozzle and the cutting edge of the tool is 7-10 mm.

[0034] S4, setting the cooling and lubrication parameters of the micro-lubrication cooling system, turning on the micro-lubrication cooling system, and making the nozzle spray micro-lubricating oil mist onto the high-alumina silicon glass, the lubricating medium in the micro-lubrication system is lubricating oil or a mixture of lubricating oil and water, and the cooling gas in the micro-lubrication system is supercritical carbon dioxide gas or cryogenic liquid nitrogen gas;

[0035] S5, setting the corresponding grinding speed, and then starting the processing machine to perform preliminary grinding on the high-aluminum-silicon glass;

[0036] S6, after the preliminary grinding in step S5 is completed, the grinding speed is increased, and the cutting fluid cooling method is used to complete the processing. At the same time, the spindle speed can be reasonably increased while keeping the feed speed consistent;

[0037] In step S4, the cooling lubrication parameters are set to a micro-lubrication oil injection rate of 40 ml / h and a spray pressure of 0.4-0.5 MPa;

[0038] In step S5, the corresponding grinding processing parameters are set to a grinding speed of 25-35 m / s;

[0039] In step S6, the grinding speed is increased to greater than 35 m / s.

[0040] In order to verify the rationality of the above method, the following experiments are carried out:

[0041] 1. Test Materials

[0042] The experimental material is high alumina silicate glass (145mm×72mm×6mm), and its physical properties are shown in Table 1.

[0043] Table 1 Physical properties of high alumina silicate glass

[0044]

[0045] 2. Test process

[0046] The grinding test was carried out on a JTDM-540 high-speed drilling and tapping center machine. The micro-lubrication system model is KS-2102, the micro-lubricating oil model is KS-1108, and the test system is as follows Figure 1 The grinding was carried out using 150#-D6, 400#-D6 and 800#-D6 diamond grinding heads respectively.

[0047] The test adopts side grinding, and the parameters are as follows: a e =0.05mm, a p =0.03mm, f = 0.625mm / r; where a e is the cutting width, a p is the cutting depth, f is the feed per tooth, the micro-lubrication injection volume is 40mL / h, the cutting fluid pouring pressure is 2MPa, and the test plan is shown in Table 2.

[0048] Table 2 Experimental plan

[0049]

[0050]

[0051] To eliminate tool wear errors, a new diamond grinding head was used for each test, and each test was performed three times. The grinding fluid was Fenair E361. The Kistler 9257BA device was used to comprehensively measure the forces in three directions generated during the grinding process. In order to evaluate the quality of the machined surface, a LEXT OLS4000 3D laser confocal microscope was used to finely measure the surface roughness and perform morphological analysis. The roughness test method was to select 5 measuring points on the machined surface, and the average value after removing the maximum and minimum values. The length and width of the chipping edge were the average values ​​of three tests.

[0052] 3. Analysis of test results

[0053] 3.1 Effect of grinding speed on roughness

[0054] like Figure 2 As shown, the diamond grinding head is 400#-D6, the spray pressure used in the micro-lubrication cooling method is 0.4MPa, and the glass surface roughness values ​​obtained by the micro-lubrication method and the traditional cutting fluid cooling method are shown at cutting speeds of 25, 30, 35, 40 and 45m / s respectively.

[0055] from Figure 2 It can be seen that when the grinding speed is 25-35m / s, under the two lubrication methods, as the grinding speed increases, the roughness of the glass surface shows a downward trend, and the difference in roughness between the two is not large, indicating that micro-lubrication can replace cutting fluid cooling. At the same time, according to existing literature, while keeping the feed speed consistent, a reasonable increase in the spindle speed helps the material achieve a more ideal plastic grinding effect. When the grinding speed increases from 35m / s to 45m / s, the glass surface roughness obtained by the traditional cutting fluid cooling method continues to decrease, while the micro-lubrication method begins to rise after reaching a certain optimization point. This is because as the grinding speed increases, on the one hand, the air barrier layer generated by the grinding wheel will hinder the micro-lubricant from entering the grinding area. On the other hand, at higher grinding speeds, the cooling performance of micro-lubrication is limited. Therefore, when the grinding speed is greater than 35m / s, its roughness will increase instead. Therefore, when the grinding speed is greater than 35m / s, the cutting fluid cooling method is selected.

[0056] 3.2 Effect of spray pressure on roughness

[0057] When the micro-lubricating oil spray pressure was 0.20, 0.30, 0.40, 0.50, and 0.60 MPa and the grinding speed was 35 m / s, the relationship between the spray pressure and the roughness of the glass grinding surface was obtained using three diamond grinding heads. Figure 3 shown.

[0058] from Figure 3 It can be seen that when the spray pressure increases within the range of 0.20-0.5MPa, the roughness value of the ground glass surface decreases within a certain range, and the lowest roughness value appears under the condition of 0.4-0.5MPa. When the spray pressure increases within the range of 0.5-0.6MPa, the effect of increasing the spray pressure on improving the roughness is small. Under the condition of a grinding speed of 35m / s, the lowest roughness value can be obtained by using a spray pressure of 0.4-0.5MPa.

[0059] 3.3 Grinding force analysis

[0060] In the grinding force analysis test, the grinding speed is 35m / s, and the spray pressure used in the micro-lubrication cooling method is 0.4MPa. Since there is only the rotation of the grinding head and the horizontal feed movement of the glass workpiece during the grinding process, there is no relative movement of the grinding head axial direction (Fz), and its grinding force component is negligible. Therefore, the test mainly studies and analyzes the tangential grinding force Fx and the normal grinding force Fy. The average value of the stable state in each direction during grinding is taken as the grinding force value in each direction, such as Figure 4 shown.

[0061] The tangential grinding force Fx and normal grinding force Fy of the cutting tool using minimal lubrication and cutting fluid cooling are as follows: Figure 5 shown.

[0062] Depend on Figure 5 It can be seen that the tangential grinding force Fx and the normal grinding force Fy of the micro-lubrication method are reduced by 12-13% compared with the cutting fluid cooling method. This is because the micro-lubrication technology can use a very small amount of lubricant to cool the cutting area during the grinding process, effectively reducing the cutting temperature, thereby reducing the impact of the thermal softening effect. In addition, the lubricant of the micro-lubrication technology can also reduce the cutting force and the friction coefficient, further reducing the grinding force. It further shows that under this grinding condition, the micro-lubrication method has better lubrication and cooling performance.

[0063] 3.4 Morphology analysis

[0064] Figure 6 The glass edge morphology of test numbers 3 and 12. Figure 6 -a is the edge of the glass using the minimal lubrication cooling method, the maximum chipping width is about 106μm, and the edge is generally smooth; Figure 6 -b is the edge of the glass using cutting fluid cooling, with a maximum chipping width of about 143μm and a length of about 350μm. This shows that the minimal lubrication technology has a superior performance over the traditional cutting fluid cooling in the grinding process.

[0065] Minimal lubrication technology can accurately deliver a very small amount of lubricant to the grinding area to achieve efficient cooling and lubrication; this helps to reduce the heat generated during the grinding process and reduce the impact of thermal stress on the glass material, thereby reducing the risk of brittle cracking; at the same time, minimal lubrication technology can reduce the mechanical stress on the glass material, and by reducing cutting force and friction, it helps to reduce brittle cracking caused by stress concentration and significantly reduce surface defects caused by insufficient lubrication.

[0066] Glass edge under different grinding speeds with minimal lubrication cooling Figure 7 shown.

[0067] from Figure 7It can be found that the chipping size in the length direction (feed direction) of the glass is significantly larger than that in the width direction. With the increase of grinding speed, the chipping size shows a trend of first decreasing and then increasing. The chipping size is the smallest at a grinding speed of 35m / s, which is consistent with the test results of the effect of grinding speed on surface roughness. Too high or too low grinding speed is not conducive to the realization of good lubrication effect of minimal lubrication in glass grinding.

[0068] The above experiments prove that it is feasible to apply the micro-lubrication technology to the grinding of high-alumina silicon glass. Under certain circumstances, it can improve the processing quality compared with the cutting fluid cooling method. When the grinding speed is 25-35m / s, the micro-lubrication technology is used for lubrication. Compared with the traditional cutting fluid cooling method, it can further improve the cooling performance, effectively reduce the cutting force and friction coefficient, further reduce the grinding force, and effectively inhibit the occurrence of edge chipping during the grinding process; thereby obtaining a lower roughness; when the grinding speed is greater than 35m / s, the traditional cutting fluid cooling method is used. If the micro-lubrication technology is used, the roughness will increase instead. Therefore, the above conclusions are applied to practical applications to obtain the method of the present invention.

[0069] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the technical solution of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for micro-lubrication grinding of high-aluminum-silicon mobile phone cover glass, characterized in that , including the following steps: S1. Clamp the high-alumina-silicon glass to be processed on the machine tool; S2, clamp the tool and determine the processing origin; S3. Adjust the distance between the low-temperature nozzle and the cutting edge of the tool. The distance between the low-temperature nozzle and the cutting edge of the tool is 7-10 mm. S4, setting the cooling and lubrication parameters of the micro-lubrication cooling system, turning on the micro-lubrication cooling system, and allowing the nozzle to spray micro-lubrication oil mist onto the high-aluminum silicate glass; S5, setting the corresponding grinding speed, and then starting the processing machine to perform preliminary grinding on the high-aluminum-silicon glass; S6, after the preliminary grinding in step S5 is completed, the grinding speed is increased and the cutting fluid cooling method is used to complete the processing; In step S4, the cooling lubrication parameters are set to a micro-lubrication oil injection rate of 40 ml / h and a spray pressure of 0.4-0.5 MPa; In step S5, the corresponding grinding processing parameter is set to a grinding speed of 25-35 m / s; In step S6, the grinding speed is increased to greater than 35 m / s.

2. The method for micro-lubrication grinding of high-aluminum-silicon mobile phone cover glass according to claim 1, characterized in that: In step S4, the lubricating medium in the minimal lubrication system is lubricating oil or a mixture of lubricating oil and water.

3. The method for micro-lubrication grinding of high-aluminum-silicon mobile phone cover glass according to claim 1, characterized in that: In step S4, the cooling gas in the minimal lubrication system is supercritical carbon dioxide gas or cryogenic liquid nitrogen gas.

4. The method for micro-lubrication grinding of high-aluminum-silicon mobile phone cover glass according to claim 1, characterized in that: In step S5, the rotation speed of the spindle is reasonably increased while maintaining a consistent feed speed.

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