Screw compressor rotor surface coating thickness control method

Abstract

The invention provides a method for controlling the thickness of a coating on the surface of a rotor of a screw compressor. The method comprises the following steps: (1) coating the surface of the rotor with a coating, wherein the thickness of the coating is greater than the actually required thickness of the coating; 2) recording the coordinate of the X axis when the grinding wheel stops grinding; (3) tool setting is carried out, and the grinding wheel makes contact with a coating on the edge of the to-be-polished molded wire groove; (4) a grinding wheel is driven to grind the molded wire groove to be ground; 5) measuring whether the coating thicknesses of the short side and the long side of the molded line of the molded line groove are correct or not; (6) the C shaft is adjusted to deviate to the side with the thick coating, the C shaft is a moving shaft for controlling the circumferential angle of the grinding wheel and the axis of the rotor, and the steps (3)-(5) are repeated by replacing one molded line groove; (7) the grinding wheel is driven to continuously grind the molded wire groove to be ground; 8) observing whether two sides of the molded line of the molded line groove are exposed; (9) measuring whether the coating thickness difference between the short side and the long side of the molded line of the molded line groove is greater than Xmm or not; and (10) adjusting the shaft C to deviate to one side with thicker coating thickness.

Description

Technical Field

[0001] The invention relates to a method for controlling the thickness of a surface coating on a screw compressor rotor. Background Art

[0002] Oil-free air compressors, with their advantages of oil-free compressed air and low operating costs, are widely used in fields with stringent air quality requirements, such as healthcare, food, and electronics. As a type of oil-free air compressor, screw-type oil-free air compressors require a clean, impurity-free interior of the main unit's compression chamber to ensure the compression of pure, oil-free air. This requires spraying a coating on the rotor surface. To ensure proper performance and prevent jamming, the coating thickness must be uniform and consistent.

[0003] When preparing the rotor surface coating, a fine coating spray method is used to make the coating thickness as thin as possible while meeting the requirements of covering the surface, so as to reduce the degree of uneven coating thickness.

[0004] Disadvantage 1: Since the rotor surface is an irregular curved surface, this solution cannot obtain a coating with stable film thickness;

[0005] Disadvantage 2: The film thickness cannot be stably controlled, so the coated rotors need to be used in groups and pairs, which requires considerable manpower and time.

[0006] Disadvantage 3: Even if the rotors are used in pairs, it is difficult to achieve the meshing clearance requirements designed for the rotors. In order to avoid adverse conditions such as jamming or high temperature, the rotor clearance is usually adjusted to a larger value, resulting in low exhaust efficiency and unsatisfactory performance. Summary of the Invention

[0007] The main technical problem to be solved by the present invention is to provide a method for controlling the thickness of the surface coating of a screw compressor rotor, which can ensure that the final coating film thickness meets the requirements of the meshing rotor clearance and takes into account both gas sealing and smooth operation.

[0008] In order to solve the above technical problems, the present invention provides a method for controlling the thickness of a coating on the surface of a screw compressor rotor, comprising the following steps:

[0009] 1) applying a coating on the surface of the rotor, wherein the thickness of the coating is greater than the actual required coating thickness;

[0010] 2) Record the coordinate of the X-axis when the grinding wheel stops grinding, which is recorded as the final grinding coordinate; the X-axis is the motion axis that controls the radial distance between the grinding wheel and the rotor axis;

[0011] 3) Set the tool so that the grinding wheel contacts the coating on the edge of the groove to be ground;

[0012] 4) driving the grinding wheel to grind the wire groove to be ground, and stopping the grinding when the X-axis coordinate is greater than the final grinding coordinate Mmm;

[0013] 5) Measure the coating thickness on the short side and long side of the profile groove to see if it is correct. If so, proceed to step 7. If not, proceed to step 6.

[0014] 6) Adjust the C-axis toward the side with thicker coating thickness. The C-axis refers to the motion axis that controls the circumferential angle between the grinding wheel and the rotor axis. Repeat steps 3-5 for another groove.

[0015] 7) Drive the grinding wheel to continue grinding the groove to be ground, and stop grinding when the X-axis coordinate is greater than the final grinding coordinate Nmm. <M;

[0016] 8) Observe whether the two sides of the profile groove are exposed. If not, proceed to step 9;

[0017] 9) Measure whether the difference in coating thickness between the short side and the long side of the profile groove is greater than X mm. If so, proceed to step 10; otherwise, proceed to step 11.

[0018] 10) Adjust the C axis toward the side with thicker coating thickness;

[0019] 11) Continue grinding until the X-axis reaches the final grinding coordinate.

[0020] In a preferred embodiment: the coating thickness in step 1 is greater than 0.08 mm.

[0021] In a preferred embodiment, M in step 4 is 0.06 mm, N in step 7 is 0.02 mm, and X in step 9 is 0.015 mm.

[0022] In a preferred embodiment, the adjustment value of the C axis in steps 6 and 10 is calculated by the following formula:

[0023]

[0024] Where C: the value to be adjusted for the C axis, U1: the actual measured film thickness value at point U; U0: the film thickness at point U under the theoretical film thickness profile; R: the actual measured radius distance from point U to the axis center; point U is the position where the change between the theoretical film thickness and the actual film thickness is the smallest, and is also the position on the short side of the profile groove.

[0025] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0026] The present invention provides a method for controlling the thickness of a screw compressor rotor surface coating, which can ensure that the final coating film thickness meets the requirements of the meshing rotor clearance and takes into account both gas sealing and smooth operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A flow chart of a control method according to a preferred embodiment of the present invention;

[0028] Figure 2 Schematic diagram of a medium-sized wire duct in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the technical solutions and features of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, modifications of various equivalent forms of the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0030] The present invention provides a method for controlling the thickness of the surface coating of a screw compressor rotor. In response to the various shortcomings of the existing technology mentioned in the background section, a relatively thick surface coating is first prepared, the film thickness is then measured using a professional instrument, and then the rotor surface coating is thinned using dedicated equipment. This reciprocating operation is repeated so that the final coating film thickness meets the requirements of the meshing rotor clearance, taking into account both gas sealing and smooth operation.

[0031] For this reason, the surface of the profile groove has three lines, namely the contour line of the profile groove itself, the actual film thickness line after applying a relatively thick surface coating, and the theoretical film thickness line under ideal conditions.

[0032] It can be seen that the relationship between the three is:

[0033] (1) The theoretical film thickness line is derived from the contour line of the profile groove itself, which is offset upward. The normal distance between each point and the base contour line is equal. In reality, the film thickness data is equal everywhere during film thickness measurement.

[0034] (2) The actual film thickness line is obtained by translating the theoretical film thickness line along the radial direction for a certain distance. The normal distances between the different points are not the same as those between the base contour line. For example, the distance W at the tooth bottom is the largest, the distance U at the short side and the distance V at the long side are different, and the value change of U at the short side is much smaller than that at the other two places.

[0035] Therefore, the grinding amount of the short side and the long side cannot be the same during the grinding process. The coating thickness of the short side and the long side needs to be measured during the grinding process, and then the direction of the grinding wheel needs to be adjusted.

[0036] Before grinding the coating, first find the position where the theoretical film thickness changes the least (the position where U is located) in the design software. The tangent direction of the profile at this position is roughly parallel to the direction of the grinding wheel feed (the angle is the smallest). Record the size of the radius R at this point for subsequent calculations and positioning of the actual measurement point.

[0037] Based on the above requirements, this embodiment provides a method for controlling the thickness of a screw compressor rotor surface coating, comprising the following steps:

[0038] 1) applying a coating on the surface of the rotor, wherein the thickness of the coating is greater than the actual required coating thickness. In this embodiment, the thickness of the coating is greater than 0.08 mm;

[0039] 2) Record the coordinate of the X-axis when the grinding wheel stops grinding, which is recorded as the final grinding coordinate; the X-axis is the motion axis that controls the radial distance between the grinding wheel and the rotor axis;

[0040] 3) Set the tool so that the grinding wheel contacts the coating on the edge of the groove to be ground;

[0041] 4) Drive the grinding wheel to grind the groove to be ground, and stop grinding when the X-axis coordinate is greater than the final grinding coordinate by 0.06 mm;

[0042] 5) Measure the coating thickness on the short side and long side of the profile groove to see if it is correct. If so, proceed to step 7. If not, proceed to step 6.

[0043] 6) Adjust the C-axis toward the side with thicker coating thickness. The C-axis refers to the motion axis that controls the circumferential angle between the grinding wheel and the rotor axis. Repeat steps 3-5 for another groove.

[0044] 7) Drive the grinding wheel to continue grinding the groove to be ground, and stop grinding when the X-axis coordinate is greater than the final grinding coordinate by 0.02 mm;

[0045] 8) Observe whether the two sides of the profile groove are exposed. If not, proceed to step 9;

[0046] 9) Measure whether the difference in coating thickness between the short side and the long side of the profile groove is greater than 0.015 mm. If so, proceed to step 10; otherwise, proceed to step 11.

[0047] 10) Adjust the C axis toward the side with thicker coating thickness;

[0048] 11) Continue grinding until the X-axis reaches the final grinding coordinate.

[0049] The C-axis adjustment values ​​in steps 6 and 10 are calculated using the following formula:

[0050]

[0051] Where C: the value to be adjusted for the C axis, U1: the actual measured film thickness value at point U; U0: the film thickness at point U under the theoretical film thickness profile; R: the actual measured radius distance from point U to the axis center; point U is the position where the change between the theoretical film thickness and the actual film thickness is the smallest, and is also the position on the short side of the profile groove.

[0052] The above is only a specific embodiment of the present invention, but the design concept of the present invention is not limited to this. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A method for controlling the thickness of the coating on the surface of a screw compressor rotor, characterized in that The steps include: 1) applying a coating on the surface of the rotor, wherein the thickness of the coating is greater than the actual required coating thickness; 2) Record the coordinate of the X-axis when the grinding wheel stops grinding, which is recorded as the final grinding coordinate; the X-axis is the motion axis that controls the radial distance between the grinding wheel and the rotor axis; 3) Set the tool so that the grinding wheel contacts the coating on the edge of the groove to be ground; 4) driving the grinding wheel to grind the wire groove to be ground, and stopping the grinding when the X-axis coordinate is greater than the final grinding coordinate Mmm; 5) Measure the coating thickness on the short side and long side of the profile groove to see if it is correct. If so, proceed to step 7. If not, proceed to step 6. 6) Adjust the C-axis toward the side with thicker coating thickness. The C-axis refers to the motion axis that controls the circumferential angle between the grinding wheel and the rotor axis. Repeat steps 3-5 for another groove. 7) Drive the grinding wheel to continue grinding the groove to be ground, and stop grinding when the X-axis coordinate is greater than the final grinding coordinate Nmm. <M; 8) Observe whether the two sides of the profile groove are exposed. If not, proceed to step 9; 9) Measure whether the difference in coating thickness between the short side and the long side of the profile groove is greater than X mm. If so, proceed to step 10; otherwise, proceed to step 11. 10) Adjust the C axis toward the side with thicker coating thickness; 11) Continue grinding until the X-axis reaches the final grinding coordinate.

2. The method for controlling the thickness of a screw compressor rotor surface coating according to claim 1, wherein: The coating thickness in step 1 is greater than 0.08 mm.

3. The method for controlling the thickness of a screw compressor rotor surface coating according to claim 1, wherein: In step 4, M is 0.06 mm, in step 7, N is 0.02 mm, and in step 9, X is 0.015 mm.

4. The method for controlling the thickness of a screw compressor rotor surface coating according to claim 1, wherein: The C-axis adjustment values ​​in steps 6 and 10 are calculated using the following formula: Where C: the value to be adjusted for the C axis, U1: the actual measured film thickness value at point U; U0: the film thickness at point U under the theoretical film thickness profile; R: the actual measured radius distance from point U to the axis center; Among them, point U is the position where the change between theoretical film thickness and actual film thickness is the smallest, and it is also the position on the short side of the profile groove.

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