Method for improving milling machining precision of barrel type part mounting seat

Abstract

The application provides a method for improving milling machining precision of a cylinder part mounting seat, and the steps are as follows: measuring the center size of the mounting seat surface by a relative measurement method; machining all other mounting seats to qualified sizes; replacing a tool; finishing the mounting seat with a flatness of 0.01mm; machining a threaded hole, milling the threaded hole by a spiral milling method, and the cutting depth of the inner layer is 0.4mm; and using a chamfering tool to chamfer the threaded hole. Since the mounting seat is a non-symmetrical structure, no measuring tool or standard part can measure the center size of the mounting seat surface, and the center size of the mounting seat surface is measured by the relative measurement method. By adjusting the machining sequence, the distribution of the allowance, the tool selection and the adjustment of the cutting amount, the part machining size meets the design drawing requirements. The application has the following advantages: effectively preventing the quality fluctuation of products, preventing the generation of quality out-of-tolerance sheets, canceling the bench work flat grinding process, and improving the part machining efficiency.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, and in particular to a method for improving the milling accuracy of mounting bases for cylindrical parts. Background Technology

[0002] A certain cylindrical part, a large thin-walled welded part, has a diameter of over 1200mm and a height of over 1400mm. The dimension from the surface of the mounting base to the center cannot be directly measured and is usually ensured by CNC equipment. There is a stepped mounting base with dimensions of 200mm x 180mm. The flatness of the mounting base is 0.01mm, and the parallelism of the two stepped surfaces is 0.01mm. During the development process, these dimensional tolerances posed a great challenge to the machining. In the early stage, the flatness requirement of the outer surface was ensured by surface grinding, but the parallelism of the inner surface exceeded the tolerance. By adjusting the machining sequence, changing the cutting tools, and adjusting the machining parameters, the above practical problems were solved. Summary of the Invention

[0003] The purpose of this invention is to solve problems such as out-of-tolerance dimensions of the mounting base surface to the center and the flatness and parallelism of the mounting base plane in cylindrical parts. This invention provides a method for improving the milling accuracy of mounting bases for cylindrical parts.

[0004] This invention provides a method for improving the milling accuracy of mounting bases for cylindrical parts, characterized by the following steps:

[0005] 1. Measure the distance from the surface of the mounting base to the center using a relative measurement method.

[0006] Using a ceramic standard ball, the standard ceramic ball is made coaxial with the rotation center of the part. The distance from the surface of the mounting base to the center is measured using a dial indicator on a machine tool.

[0007] The processing equipment involves measuring the actual dimensions of a square worktable or the outer circle of a circular worktable, then using a dial indicator to measure the dimensions from the surface of the mounting base to the center.

[0008] 2. Machin all other mounting brackets to the required dimensions.

[0009] The mounting base with a flatness of 0.01mm has undergone semi-finishing.

[0010] A 0.2mm allowance is left for planes A and B in terms of their planar dimensions;

[0011] Leave a 0.2mm allowance for inner contour 4 and inner contour 2 5;

[0012] III. Replacing the cutting tool

[0013] Replace with a 3-flute tool;

[0014] Use uncoated cutting tools;

[0015] Use non-dulled cutting tools;

[0016] The radius of the tool to be replaced should be smaller than the transition radius of inner contour 14 and inner contour 25.

[0017] IV. Mounting base with a precision-machined flatness of 0.01mm

[0018] Machining inner contour 1 (4) and inner contour 2 (5) to the acceptable dimensions;

[0019] Chamfer inner contour 1 4, inner contour 2 5, at this time the chamfer size is nominal size + 0.2mm;

[0020] Machining plane A: the first cut reaches a depth of 0.1mm, the second cut reaches a depth of 0.05mm, leaving a 0.05mm allowance;

[0021] Machining plane B, the first cut depth is 0.1mm, the second cut depth is 0.05mm, leaving a 0.05mm allowance. When machining plane B, the tool compensation is increased by 0.03mm to ensure that the tool side edge does not cut the inner contour 5 during the machining process.

[0022] Plane B is machined using a reverse milling toolpath, and the flatness of plane B is within 0.006.

[0023] After plane B is machined to a satisfactory condition, plane A is machined using a reverse milling toolpath until plane A is machined to a satisfactory condition.

[0024] V. Machining Threaded Holes 1

[0025] The threaded hole 1 was milled using a helical milling method, with an inner cutting depth of 0.4 mm.

[0026] Use a chamfering tool to chamfer the threaded hole 1.

[0027] Because the mounting base has an asymmetrical structure, and there are no measuring tools or standard parts available to measure the dimension from the surface of the mounting base to its center, a relative measurement method is used to measure this dimension. By adjusting the machining sequence, the allocation of allowances, the selection of tools, and the adjustment of cutting parameters, the machined dimensions of the part are made to meet the requirements of the design drawings.

[0028] Compared with the prior art, the advantages of this invention are:

[0029] The method for improving the milling accuracy of cylindrical parts mounting bases described in this invention can effectively prevent product quality fluctuations, eliminate the generation of out-of-tolerance quality reports, eliminate the need for benchwork surface grinding, and improve parts processing efficiency. Attached Figure Description

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0031] Figure 1 This is a schematic diagram of the mounting bracket.

[0032] In the figure, 1 is a threaded hole, 2 is plane A with a flatness tolerance of 0.01mm, 3 is plane B with a parallelism tolerance of 0.01mm to plane A, 4 is the inner contour, 5 is the inner contour, and 6 is the inner contour transition R. Detailed Implementation

[0033] The present invention will be further explained below with reference to specific implementation schemes, but it is not limited to the present invention. The structures, proportions, sizes, etc. shown in the accompanying drawings are only used to complement the content disclosed in the specification, so as to enable those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0034] This invention provides a method for improving the milling accuracy of mounting bases for cylindrical parts, characterized by the following steps:

[0035] 1. Measure the distance from the surface of the mounting base to the center using a relative measurement method.

[0036] Using a ceramic standard ball, the standard ceramic ball is made coaxial with the rotation center of the part. The distance from the surface of the mounting base to the center is measured using a dial indicator on a machine tool.

[0037] The processing equipment involves measuring the actual dimensions of a square worktable or the outer circle of a circular worktable, then using a dial indicator to measure the dimensions from the surface of the mounting base to the center.

[0038] 2. Machin all other mounting brackets to the required dimensions.

[0039] The mounting base with a flatness of 0.01mm has undergone semi-finishing.

[0040] A 0.2mm allowance is left for planes A and B in terms of their planar dimensions;

[0041] Leave a 0.2mm allowance for inner contour 4 and inner contour 2 5;

[0042] III. Replacing the cutting tool

[0043] Replace with a 3-flute tool;

[0044] Use uncoated cutting tools;

[0045] Use non-dulled cutting tools;

[0046] The radius of the tool to be replaced should be smaller than the transition radius of inner contour 14 and inner contour 25.

[0047] IV. Mounting base with a precision-machined flatness of 0.01mm

[0048] Machining inner contour 1 (4) and inner contour 2 (5) to the acceptable dimensions;

[0049] Chamfer inner contour 1 4, inner contour 2 5, at this time the chamfer size is nominal size + 0.2mm;

[0050] Machining plane A: the first cut reaches a depth of 0.1mm, the second cut reaches a depth of 0.05mm, leaving a 0.05mm allowance;

[0051] Machining plane B, the first cut depth is 0.1mm, the second cut depth is 0.05mm, leaving a 0.05mm allowance. When machining plane B, the tool compensation is increased by 0.03mm to ensure that the tool side edge does not cut the inner contour 5 during the machining process.

[0052] Plane B is machined using a reverse milling toolpath, and the flatness of plane B is within 0.006.

[0053] After plane B is machined to a satisfactory condition, plane A is machined using a reverse milling toolpath until plane A is machined to a satisfactory condition.

[0054] V. Machining Threaded Holes 1

[0055] The threaded hole 1 was milled using a helical milling method, with an inner cutting depth of 0.4 mm.

[0056] Use a chamfering tool to chamfer the threaded hole 1.

[0057] Because the mounting base has an asymmetrical structure, and there are no measuring tools or standard parts available to measure the dimension from the surface of the mounting base to its center, a relative measurement method is used to measure this dimension. By adjusting the machining sequence, the allocation of allowances, the selection of tools, and the adjustment of cutting parameters, the machined dimensions of the part are made to meet the requirements of the design drawings.

[0058] Matters not covered in this invention are common knowledge.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for improving the milling accuracy of a mounting base for cylindrical parts, characterized in that: The steps are as follows:

1. Measure the distance from the surface of the mounting base to the center using a relative measurement method. Using a ceramic standard ball, the standard ceramic ball is made coaxial with the rotation center of the part. The distance from the surface of the mounting base to the center is measured using a dial indicator on a machine tool. The processing equipment involves measuring the actual dimensions of a square worktable or the outer circle of a circular worktable, then using a dial indicator to measure the dimensions from the surface of the mounting base to the center.

2. Machin all other mounting brackets to the required dimensions. The parallelism between plane B and plane A is 0.01 mm. The mounting base with a flatness of 0.01mm has undergone semi-finishing. A 0.2mm allowance is left for planes A and B in terms of their planar dimensions; Leave a 0.2mm allowance for inner contour one (4) and inner contour two (5); III. Replacing the cutting tool Replace with a 3-flute tool: Use uncoated cutting tools; Use non-dulled cutting tools; The radius of the replacement tool should be smaller than the transition radius of inner contour one (4) and inner contour two (5); IV. Mounting base with a precision-machined flatness of 0.01mm Process inner contour one (4) and inner contour two (5) to the qualified dimensions; Chamfer inner contour one (4) and inner contour two (5), at this time the chamfer size is the nominal size + 0.2mm; Machining plane A: the first cut reaches a depth of 0.1mm, the second cut reaches a depth of 0.05mm, leaving a 0.05mm allowance; When machining plane B, the first cut is 0.1mm deep and the second cut is 0.05mm deep, leaving a 0.05mm allowance. When machining plane B, the tool compensation is increased by 0.03mm to ensure that the side edge of the tool does not cut the inner contour II (5) during the machining process. Plane B is machined using a reverse milling toolpath, and the flatness of plane B is within 0.006mm. After plane B is machined to a satisfactory condition, plane A is machined using a reverse milling toolpath until plane A is machined to a satisfactory condition. V. Machining Threaded Holes (1) The threaded hole (1) was milled using a spiral milling method, with an inner cutting depth of 0.4 mm; Use a chamfering tool to chamfer the threaded hole (1).

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