A high-precision sealing seat bottom surface processing method

Abstract

The application discloses a high-precision sealing seat bottom surface processing method, which comprises the following steps: forming an inner hole through turning processing of the sealing seat bottom, and sequentially performing grinding processing and lapping processing on the bottom end face of the inner hole, wherein a lapping tool is used in the lapping processing. In the method, spiral lapping processing is adopted, tool loss is reduced, processing cost is lowered, and reasonable turning, grinding and lapping parameters are selected to ensure the flatness and shape tolerance of the inner hole end face of the sealing seat. Meanwhile, a slot opening type plane lapping device is used for spiral lapping, and reasonable turning, grinding and lapping parameters are selected, so that the flatness of the sealing seat bottom processing surface is controlled within 0.0012 mm, the polishing time is reduced from 40 hours in the prior art to within 2.5 hours, and the production efficiency is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine manufacturing technology, and in particular relates to a high-precision sealing seat bottom surface machining method. Background Technology

[0002] The flatness of the end face of the sealing seat for aero-engines is extremely precise, reaching the level of one ten-thousandth, which is close to the realm of high-precision machining, making it a major challenge in the processing of sealing support components. This flatness is used for graphite seals and directly affects the results of airflow tests for downstream components; therefore, the compliance of this dimension plays a crucial role in the quality of the parts.

[0003] In terms of process design, machining is required first to remove most of the excess material. During machining, the flatness must be controlled within 0.01mm, leaving a 0.01mm allowance for manual grinding. The flatness of the bottom end face of the inner hole must reach 0.0012mm. Due to the special structure of the part, ordinary grinding tools cannot be used; specialized grinding tools must be manufactured. Existing grinding tools are mostly made of ordinary cast iron, which easily produces grinding marks on both the tool and the part, making it impossible to guarantee a flatness of 0.0012mm. Using existing turning and grinding techniques, the flatness can only reach 0.003mm. Therefore, a high-precision machining method for the bottom surface of the sealing seat is needed. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a method for machining the bottom surface of a high-precision sealing seat.

[0005] The present invention is achieved through the following technical solutions.

[0006] The present invention provides a high-precision sealing seat bottom surface processing method, which includes turning the sealing seat bottom to form an inner hole, and sequentially grinding and lapping the bottom end face of the inner hole, wherein a lapping tool is used in the lapping process.

[0007] Preferably, the turning process is performed by wax injection to turn the inner hole, so that the flatness of the bottom end face is within 0.01mm and the roundness of the inner hole is within 0.01mm, and a 0.1mm allowance is left on the bottom end face for subsequent grinding. Before turning, the bottom surface plane of the lower part of the bottom end face is supported.

[0008] Preferably, the sealing seat needs to be aligned before the grinding process, and the steps include:

[0009] A1: First, perform rough alignment of the reference circle. Then, align the inner hole of the bushing by grinding it to a point within 0.02mm. The end face runout of the inner hole should be within 0.02mm.

[0010] A2: Then perform fine alignment of the reference circle, with the inner hole aligned within a range of 0.01mm and the bottom end face of the sealing seat running out within a range of 0.01mm;

[0011] A3: Press the bushing tightly against the bottom of the sealing seat. During the pressing process, use a dial indicator to monitor the sealing seat and observe whether the dial indicator reading changes. When the dial indicator reading changes, it means that the pressing part of the sealing seat has been displaced or deformed. At this time, it is necessary to repeat the alignment steps A1 and A2 and then press it again until the change in the dial indicator reading at the alignment point after pressing is within 0.01mm.

[0012] Preferably, the grinding process includes, in sequence, the steps of rough grinding, fine grinding, and precision grinding of the surface:

[0013] B1: The grinding amount of the rough grinding surface is 0.03mm, the workpiece rotation speed is 10-30 rpm, the grinding wheel linear speed is 10-30m / s, the cutting depth is 0.001-0.02mm / cut, and the feed rate is 80-110mm / min;

[0014] B2: The grinding amount for fine grinding of the surface is 0.02mm, the workpiece rotation speed is 10-30 rpm, the grinding wheel linear speed is 10-30m / s, the cutting depth is 0.001-0.02mm / cut, and the feed rate is 80-110mm / min;

[0015] B3: The grinding amount of the fine grinding surface is 0.01mm, the part rotation speed is 10-30 rpm, the grinding wheel linear speed is 10-30m / s, the cutting depth is 0.001-0.02mm / cut, and the feed rate is 80-110mm / min.

[0016] Preferably, the grinding wheel used in the grinding process is made of silicon carbide with a particle size of 70-90 mesh.

[0017] Preferably, the grinding process includes, in sequence, the steps of rough grinding of the plane, fine grinding of the plane, and final grinding of the plane:

[0018] C1: The spindle speed of the rough grinding surface grinding machine is 80-120 r / min, and the flatness of the rough grinding surface to the bottom end face is 0.005 mm;

[0019] C2: The spindle speed of the fine grinding surface grinding machine is 170-220 r / min, and the flatness of the fine grinding surface to the bottom end face is 0.003 mm;

[0020] C3: The spindle speed of the precision grinding machine is 380-420 r / min, and the flatness of the precision grinding surface to the bottom end face is 0.0012 mm.

[0021] Preferably, the grinding process is spiral polishing, with the coarse grinding surface using grinding paste M40, the fine grinding surface using grinding paste M20, and the precision grinding surface using grinding paste M10.

[0022] Preferably, during the rough grinding, fine grinding, and precision grinding processes, grinding should be stopped every 3 to 4 minutes, and the grinding surface of the grinding tool should be ground flat on a standard platform until the flatness reaches 0.001 mm before it can be used again.

[0023] Preferably, the grinding tool is in the shape of a hollow cylinder, and a plurality of grooves are provided at one end of the grinding tool.

[0024] Preferably, the grinding tool is made of ductile iron.

[0025] The beneficial effects of this invention are as follows:

[0026] The method of this invention employs spiral grinding, which reduces tool wear and processing costs. By selecting appropriate turning and grinding steps and grinding parameters, the flatness and shape tolerance of the inner hole end face of the sealing seat are guaranteed. At the same time, the spiral grinding is performed using a slotted surface grinding device. By selecting appropriate turning, grinding and polishing parameters, the flatness of the bottom surface of the sealing seat is controlled within 0.0012mm, and the polishing time is reduced from 40 hours in the prior art to less than 2.5 hours, which greatly improves production efficiency. Attached Figure Description

[0027] Figure 1 This is a structural diagram of the machined part of the sealing seat;

[0028] Figure 2 This is the front view of the grinding tool of the present invention;

[0029] Figure 3 This is a top view of the grinding tool of the present invention;

[0030] Figure 4 This is a drawing of the grinding tool of the present invention;

[0031] In the diagram: 1-inner hole, 2-bottom end face, 3-bottom plane, 4-grinding tool, 41-groove, 5-wax filling area. Detailed Implementation

[0032] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0033] Example:

[0034] like Figures 1 to 4As shown, a method for machining the bottom surface of a high-precision sealing seat includes turning the bottom of the sealing seat to form an inner hole 1, and then sequentially grinding and lapping the bottom end face 2 of the inner hole 1, wherein a lapping tool 4 is used in the lapping process. This method is applicable to the machining of sealing seats for aero-engines.

[0035] The turning process employs a wax-filling method to turn the inner hole 1, with the wax-filling area 5 as shown. Figure 1 As shown, the wax injection method is an existing turning process and will not be described in detail here. The turning process ensures that the flatness of the bottom end face 2 is within 0.01mm and removes most of the excess material. The roundness of the inner hole 1 is within 0.01mm, and a 0.1mm allowance is left on the bottom end face 2 for subsequent grinding. Before turning, the bottom surface plane 3 of the bottom end face 2 is supported by a support to increase the rigidity of the sealing seat and prevent bottom surface vibration and tool deflection. Supporting the bottom surface plane 3 can effectively prevent surface finish problems such as bottom surface ripples and vibration marks caused by poor rigidity of the sealing seat, and avoid indirectly affecting the requirement of machining the bottom end face 2 to a flatness of 0.0012.

[0036] First, the inner hole of the sealing seat is roughly aligned to the reference circle, and then the reference circle is finely aligned to eliminate the influence of the flatness and roundness of the sealing seat itself. Grinding machine accuracy is higher than that of lathe, which can meet higher machining accuracy requirements.

[0037] Before the grinding process, the sealing seat needs to be aligned. The steps include:

[0038] A1: First, perform rough alignment of the reference circle. Then, align the point by grinding the inner hole of the bushing to a range of 0.02mm. The runout of the end face of the inner hole 1 should be within a range of 0.02mm.

[0039] A2: Then perform fine alignment of the reference circle. The inner hole 1 is aligned to the point within 0.01mm, and the bottom end face 2 of the sealing seat runs within 0.01mm.

[0040] A3: Tighten the bushing to the bottom of the sealing seat. During the tightening process, use a dial indicator to monitor the sealing seat and observe whether the dial indicator reading changes. When the dial indicator reading changes, it means that the tightened part of the sealing seat has been displaced or deformed. At this time, it is necessary to repeat the alignment steps A1 and A2 (physical compensation, replacement of pressure plate, etc.) and tighten again until the change in the dial indicator reading at the alignment point after tightening is within 0.01mm. This indicates that the error and deformation caused by the installation, alignment and tightening of the sealing seat are small.

[0041] The grinding process includes, in sequence, rough grinding, fine grinding, and finishing grinding of the surface:

[0042] B1: The grinding amount of the rough grinding surface is 0.03mm, the workpiece rotation speed is 20 rpm, the grinding wheel linear speed is 20m / s, the cutting depth is 0.005mm / cut, and the feed rate is 100mm / min;

[0043] B2: The grinding amount for fine grinding of the surface is 0.02mm, the workpiece rotation speed is 20 rpm, the grinding wheel linear speed is 22m / s, the cutting depth is 0.005mm / cut, and the feed rate is 100mm / min;

[0044] B3: The grinding amount of the fine grinding surface is 0.01mm, the part rotation speed is 20 rpm, the grinding wheel linear speed is 24m / s, the cutting depth is 0.005mm / cut, and the feed rate is 100mm / min;

[0045] After fine grinding, check that the flatness of the bottom end face 2 is within 0.007mm before proceeding with further grinding.

[0046] The grinding wheel used in the grinding process is made of silicon carbide, with a grit size of 80 mesh and specifications of 100×50×32mm, 39C60J8VP.

[0047] The grinding abrasive is grinding paste, and the grinding method is spiral polishing to ensure the shape tolerance of the inner hole 1. The grinding process includes the following steps in sequence: rough grinding of the plane, fine grinding of the plane, and final grinding of the plane.

[0048] C1: The rough grinding surface uses M40 grinding paste. The spindle speed of the grinding machine is 100r / min. Grinding must be stopped after every 3 minutes. The grinding surface of the grinding tool 4 can only be used after it is ground flat on a standard platform until the flatness reaches 0.001mm. The flatness of the rough grinding surface to the bottom end face 2 is 0.005mm.

[0049] C2: The fine grinding surface uses grinding paste M20. The spindle speed of the grinding machine is 200r / min. Grinding must be stopped after every 4 minutes. The grinding surface of the grinding tool 4 can only be used after it is ground flat on a standard platform to a flatness of 0.001mm. The fine grinding surface is ground to a flatness of 0.003mm on the bottom end face 2.

[0050] C3: The fine grinding surface uses grinding paste M10. The spindle speed of the grinding machine is 400r / min. Grinding must be stopped after every 3 minutes. The grinding surface of the grinding tool 4 can only be used after it is ground flat on a standard platform to a flatness of 0.001mm. The fine grinding surface is ground to a flatness of 0.0012mm on the bottom end face 2.

[0051] The grinding tool 4 is a hollow cylinder, and eight evenly distributed grooves 41 are provided at one end of the grinding surface of the grinding tool 4, which is conducive to the discharge of waste powder generated during grinding.

[0052] The grinding tool 4 is made of ductile iron. Ductile iron has higher strength and wear resistance than ordinary cast iron. Using this material can avoid grinding marks and ensure that the required flatness is obtained through grinding.

[0053] Example 2:

[0054] A high-precision sealing seat bottom surface machining method, based on Example 1, with the only difference being:

[0055] Grinding processes consist of three steps: rough grinding, fine grinding, and finishing grinding of the surface.

[0056] B1: The grinding amount of the rough grinding surface is 0.03mm, the workpiece rotation speed is 30 rpm, the grinding wheel linear speed is 30m / s, the cutting depth is 0.02mm / cut, and the feed rate is 110mm / min;

[0057] B2: The grinding amount for fine grinding of the surface is 0.02mm, the workpiece rotation speed is 30 rpm, the grinding wheel linear speed is 30m / s, the cutting depth is 0.02mm / cut, and the feed rate is 110mm / min;

[0058] B3: The grinding amount of the fine grinding surface is 0.01mm, the part rotation speed is 30 rpm, the grinding wheel linear speed is 30m / s, the cutting depth is 0.02mm / cut, and the feed rate is 110mm / min;

[0059] After fine grinding, check that the flatness of the bottom end face 2 is within 0.007mm before proceeding with further grinding.

[0060] The grinding wheel used in the grinding process is made of silicon carbide with a grit size of 90 mesh.

[0061] The grinding abrasive is grinding paste, and the grinding method is spiral polishing. The shape tolerance of the inner hole 1 is guaranteed. The grinding process includes the following steps: rough grinding, fine grinding, and final grinding of the surface.

[0062] C1: The rough grinding surface uses M40 grinding paste. The spindle speed of the grinding machine is 120r / min. Grinding must be stopped after every 4 minutes. The grinding surface of the grinding tool 4 can only be used after it is ground flat on a standard platform until the flatness reaches 0.001mm. The flatness of the rough grinding surface to the bottom end face 2 is 0.005mm.

[0063] C2: The fine grinding surface uses grinding paste M20. The spindle speed of the grinding machine is 220r / min. Grinding must be stopped after every 4 minutes. The grinding surface of the grinding tool 4 can only be used after it is ground flat on a standard platform until the flatness reaches 0.001mm. The fine grinding surface is ground until the flatness of the bottom end face 2 is 0.003mm.

[0064] C3: The fine grinding surface uses grinding paste M10. The spindle speed of the grinding machine is 420r / min. Grinding must be stopped after every 4 minutes. The grinding surface of the grinding tool 4 can only be used after it is ground flat on a standard platform to a flatness of 0.001mm. The fine grinding surface is ground to a flatness of 0.0012mm on the bottom end face 2.

[0065] Example 3:

[0066] A high-precision sealing seat bottom surface machining method, based on Example 1, with the only difference being:

[0067] Grinding processes consist of three steps: rough grinding, fine grinding, and finishing grinding of the surface.

[0068] B1: The grinding amount of the rough grinding surface is 0.03mm, the workpiece rotation speed is 10 rpm, the grinding wheel linear speed is 10m / s, the cutting depth is 0.001mm / cut, and the feed rate is 80mm / min;

[0069] B2: The grinding amount for fine grinding of the surface is 0.02mm, the workpiece rotation speed is 10 rpm, the grinding wheel linear speed is 10m / s, the cutting depth is 0.001mm / cut, and the feed rate is 80mm / min;

[0070] B3: The grinding amount of the fine grinding surface is 0.01mm, the part rotation speed is 10 rpm, the grinding wheel linear speed is 10m / s, the cutting depth is 0.001mm / cut, and the feed rate is 80mm / min;

[0071] After fine grinding, check that the flatness of the bottom end face 2 is within 0.007mm before proceeding with further grinding.

[0072] The grinding wheel used in the grinding process is made of silicon carbide with a grit size of 70 mesh.

[0073] The grinding abrasive is grinding paste, and the grinding method is spiral polishing. The shape tolerance of the inner hole 1 is guaranteed. The grinding process includes the following steps: rough grinding, fine grinding, and final grinding of the surface.

[0074] C1: The rough grinding surface uses M40 grinding paste. The spindle speed of the grinding machine is 80 r / min. Grinding must be stopped after every 3 minutes. The grinding surface of the grinding tool 4 can only be used after it is ground flat on a standard platform until the flatness reaches 0.001 mm. The flatness of the rough grinding surface to the bottom end face 2 is 0.005 mm.

[0075] C2: The fine grinding surface uses grinding paste M20. The spindle speed of the grinding machine is 170r / min. Grinding must be stopped after every 3 minutes. The grinding surface of the grinding tool 4 can only be used after it is ground flat on a standard platform to a flatness of 0.001mm. The fine grinding surface is ground to a flatness of 0.003mm on the bottom end face 2.

[0076] C3: The fine grinding surface uses grinding paste M10. The spindle speed of the grinding machine is 380r / min. Grinding must be stopped after every 3 minutes. The grinding surface of the grinding tool 4 can only be used after it is ground flat on a standard platform to a flatness of 0.001mm. The flatness of the fine grinding surface is reduced to 0.0012mm at the bottom end face 2.

Claims

1. A method for machining the bottom surface of a high-precision sealing seat, characterized in that: The process includes turning the bottom of the sealing seat to form an inner hole (1), and grinding and lapping the bottom end face (2) of the inner hole (1) in sequence, wherein a lapping tool (4) is used in the lapping process. The turning process is performed by waxing the inner hole (1) so that the flatness of the bottom end face (2) is within 0.01mm and the roundness of the inner hole (1) is within 0.01mm. A 0.1mm allowance is left on the bottom end face (2) for subsequent grinding. Before turning, the bottom surface plane (3) of the bottom end face (2) is supported. Before the grinding process, the sealing seat needs to be aligned. The steps include: A1: First, perform rough alignment of the reference circle. Then, use the inner hole of the bushing to perform point alignment within 0.02mm. The end face runout of the inner hole (1) is within 0.02mm. A2: Then perform fine alignment of the reference circle. The inner hole (1) is aligned to the point within 0.01mm. The bottom end face (2) of the sealing seat runs within 0.01mm. A3: Press the bushing tightly against the bottom of the sealing seat. During the pressing process, use a dial indicator to monitor the sealing seat and observe whether the dial indicator reading changes. When the dial indicator reading changes, it means that the pressing part of the sealing seat has been displaced or deformed. At this time, it is necessary to repeat the alignment steps A1 and A2 and then press it again until the change in the dial indicator reading at the alignment point after pressing is within 0.01mm. The grinding process includes, in sequence, the rough grinding surface, the fine grinding surface, and the precision grinding surface: B1: The grinding amount of the rough grinding surface is 0.03mm, the workpiece rotation speed is 10-30 rpm, the grinding wheel linear speed is 10-30m / s, the cutting depth is 0.001-0.02mm / cut, and the feed rate is 80-110mm / min; B2: The grinding amount for fine grinding of the surface is 0.02mm, the workpiece rotation speed is 10-30 rpm, the grinding wheel linear speed is 10-30m / s, the cutting depth is 0.001-0.02mm / cut, and the feed rate is 80-110mm / min; B3: The grinding amount of the fine grinding surface is 0.01mm, the part rotation speed is 10-30 rpm, the grinding wheel linear speed is 10-30m / s, the cutting depth is 0.001-0.02mm / cut, and the feed rate is 80-110mm / min; The grinding process includes, in sequence, the rough grinding of the surface, the fine grinding of the surface, and the final grinding of the surface: C1: The spindle speed of the rough grinding surface grinding machine is 80-120 r / min, and the flatness of the rough grinding surface to the bottom end face (2) is 0.005 mm; C2: The spindle speed of the fine grinding surface grinding machine is 170-220 r / min, and the flatness of the fine grinding surface to the bottom end face (2) is 0.003 mm; C3: The spindle speed of the precision grinding machine tool is 380-420 r / min, and the flatness of the precision grinding plane to the bottom end face (2) is 0.0012 mm; During the rough grinding, fine grinding and precision grinding processes, grinding must be stopped every 3 to 4 minutes. The grinding surface of the grinding tool (4) can only be used after it has been ground flat on a standard platform to a flatness of 0.001 mm. The grinding tool (4) is a hollow cylinder, and a number of grooves (41) are provided at one end of the grinding tool (4).

2. The method for machining the bottom surface of a high-precision sealing seat as described in claim 1, characterized in that: The grinding wheel used in the grinding process is made of silicon carbide with a grit size of 70-90 mesh.

3. The method for machining the bottom surface of a high-precision sealing seat as described in claim 1, characterized in that: The grinding process is spiral polishing. The coarse grinding surface uses grinding paste M40, the fine grinding surface uses grinding paste M20, and the precision grinding surface uses grinding paste M10.

4. The method for machining the bottom surface of a high-precision sealing seat as described in claim 1, characterized in that: The grinding tool (4) is made of ductile iron.

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