A method for machining a single-screw compressor rotor using a cradle-type five-axis machining center.

Abstract

A method for machining a single-screw compressor rotor using a cradle-type five-axis machining center is characterized by the following steps: First, a positioning fixture is installed on the five-axis worktable, which can accurately position the rotor's circumferential and Z-axis positions when the rotor is installed in both directions. Second, one end of the rotor is tightly fitted into the positioning fixture, and the five-axis machine tool uses a bar end mill to machine the rotor profile through the side edge of the end mill, with the retraction position being the midpoint of the rotor's Z-axis. Third, after half of the rotor is machined in the Z-axis direction, the rotor is removed from the fixture and reinstalled in the reverse direction, with the other side of the rotor tightly fitted into the positioning fixture. Fourth, the five-axis machine tool uses a bar end mill to machine the other half of the rotor profile through the side edge of the end mill, with the retraction position being the midpoint of the rotor's Z-axis. Finally, after the rotor profile is cut in both directions, it is removed from the machine tool, and the machining is complete. This invention offers fast processing speed, high precision, requires no special equipment, and is low in cost.

Description

Technical Field

[0001] This invention relates to a machining method, and more particularly to a method for machining a single-screw compressor rotor, specifically a method for machining a single-screw compressor rotor using a cradle-type five-axis machining center. Background Technology

[0002] As is well known, a single screw compressor is a type of machine with superior theoretical performance, good force balance, high efficiency, low noise, low vibration, and convenient on-site maintenance.

[0003] Currently, the mainstream profile of single-screw air compressors is a "straight-straight envelope meshing pair". There are two methods for machining the rotor. One method is to design a dedicated rotor machining machine tool and use the contouring method for machining. However, each machine tool has a limited machining size, and multiple dedicated rotor machining machines are needed to cover all products. Moreover, it is difficult to guarantee the repeatability of accuracy. The second method is to use a general-purpose five-axis machine tool with a ball end mill for overall line sweeping machining. This method can cover most products with one five-axis machine tool and has strong versatility. However, the ball end mill line sweeping machining speed is slow and the tool wears quickly, resulting in accuracy loss and low overall efficiency. Summary of the Invention

[0004] The purpose of this invention is to address the problems of high cost and poor repeatability of dedicated machines and low processing efficiency of general-purpose five-axis machine tools in the existing machining of single-screw compressor rotors, and to invent a method for machining single-screw compressor rotors using a cradle-type five-axis machining center that is efficient and low-cost.

[0005] The technical solution of this invention is:

[0006] A method for machining a single-screw compressor rotor using a cradle-type five-axis machining center, characterized by comprising the following steps:

[0007] First, install a tooling with positioning function on the five-axis worktable so that the circumferential position and Z-axis position of the rotor can be accurately positioned when the rotor is installed in the forward or reverse direction.

[0008] Secondly, install one end of the rotor tightly with the positioning fixture. The five-axis machine tool uses a bar end mill to process the rotor profile through the side edge of the bar end mill. The retraction position of the tool is the midpoint of the rotor's Z-axis.

[0009] Third, after half of the rotor is machined in the Z-axis direction, remove the rotor from the fixture, reinstall it in the opposite direction, and install the other side of the rotor in close fit with the positioning fixture.

[0010] Fourth, the five-axis machine tool uses a bar end mill to machine the other half of the rotor profile through the side edge of the bar end mill, and the retraction position of the tool is the midpoint of the rotor's Z-axis.

[0011] Finally, after the rotor profile is cut in both directions, it is removed from the machine tool, and the machining is complete.

[0012] The positioning fixture includes: a fixture base 1, a pull rod 2, a pressure plate 3, and a nut 4. The fixture base 1 is used to connect to the worktable of a cradle-type five-axis machining center. One end of the pull rod 2 is connected to a threaded hole on the fixture base 1, and the other threaded end passes through the center hole of the single-screw compressor rotor 5. The pressure plate 3 presses against the single-screw compressor rotor 5 and is locked with the nut 4. A misalignment pin 6 is installed on the fixture base 1 to prevent the single-screw compressor rotor 5 from being misaligned. One end of the misalignment pin 6 is inserted into the keyway 7 in the center of the single-screw compressor rotor 5. A set of at least two end face positioning pins 8 for positioning the end face of the single-screw compressor rotor 5 when it is installed in the correct orientation and a set of at least two groove wall positioning pins 10 for positioning the end face groove wall 9 when the single-screw compressor rotor 5 is installed in the fixture base 1.

[0013] The tooling base 1 is provided with a boss 11 for inserting into the center hole of the single screw compressor rotor 5, and the anti-mistake pin 6 is installed on the boss 11.

[0014] The beneficial effects of this invention are:

[0015] This invention solves the problem of insufficient swing angle and stroke of the five-axis cradle turntable by using a universal five-axis cradle with rotors installed in both directions.

[0016] The universal cradle five-axis has high torque, and when used with the side edge of a bar end mill, it achieves fast cutting speed and high machining efficiency.

[0017] The general-purpose cradle five-axis has good rigidity, and when used with a bar end mill side-edge machining, tool wear is small and machining accuracy is high. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the rotor of the present invention when it is mounted upright.

[0019] Figure 2 This is a schematic diagram of the rotor of the present invention when reversed.

[0020] Figure 3 This is a schematic diagram showing the usage state of the clamp when the rotor of the present invention is mounted correctly.

[0021] Figure 4 This is a schematic diagram showing the usage state of the clamp when the rotor of the present invention is reversed. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] like Figure 1-4 As shown.

[0024] A method for machining a single-screw compressor rotor using a cradle-type five-axis machining center includes the following steps:

[0025] First, install a positioning device, such as a cradle-type five-axis worktable. Figure 3 , 4 The tooling shown can accurately position the rotor's circumferential and Z-axis positions when the rotor is installed in both directions.

[0026] Secondly, install one end of the rotor tightly into the positioning fixture. Using a five-axis machine tool with a bar end mill, machine the rotor profile using the side edge of the end mill. The retraction position is the midpoint of the rotor's Z-axis. Figure 1 As shown;

[0027] Third, after half of the rotor is machined in the Z-axis direction, remove the rotor from the fixture, reinstall it in reverse, and fit the other side of the rotor tightly with the positioning fixture. Figure 2 As shown;

[0028] Fourth, the cradle-type five-axis machine tool uses a bar end mill to machine the other half of the rotor profile through the side edge of the bar end mill, and the retraction position of the tool is the midpoint of the rotor's Z-axis.

[0029] Finally, after the rotor profile is cut in both directions, it is removed from the machine tool, and the machining is complete.

[0030] The positioning fixture used in this invention includes: a fixture base 1, a pull rod 2, a pressure plate 3, and a nut 4. The fixture base 1 is connected to the worktable of a cradle-type five-axis machining center by bolts. One end of the pull rod 2 is connected to a threaded hole on the fixture base 1, and the other threaded end passes through the center hole of the single-screw compressor rotor 5. The pressure plate 3 presses against the single-screw compressor rotor 5 and is locked with the nut 4. A misalignment pin 6 is installed on the fixture base 1 to prevent misalignment of the single-screw compressor rotor 5. One end of the misalignment pin 6 is inserted into the keyway 7 in the center of the single-screw compressor rotor 5. A set of at least two end-face positioning pins 8 for end-face positioning when the single-screw compressor rotor 5 is correctly mounted is installed on the fixture base 1. Figure 3 ) and a set of at least two slot wall positioning pins 10 for positioning the end face slot wall 9 when the single screw compressor rotor 5 is reversed. Figure 4 The tooling base 1 is provided with a boss 11 for inserting into the center hole of the single screw compressor rotor 5, and the anti-misalignment pin 6 is installed on the boss 11.

[0031] All parts not covered in this invention are the same as or can be implemented using existing technologies.

Claims

1. A method for machining a single-screw compressor rotor using a cradle-type five-axis machining center, characterized in that it Includes the following steps: First, install a tooling with positioning function on the five-axis worktable so that the circumferential position and Z-axis position of the rotor can be accurately positioned when the rotor is installed in the forward or reverse direction. Secondly, install one end of the rotor tightly with the positioning fixture. The five-axis machine tool uses a bar end mill to process the rotor profile through the side edge of the bar end mill. The retraction position of the tool is the midpoint of the rotor's Z-axis. Third, after half of the rotor is machined in the Z-axis direction, remove the rotor from the fixture, reinstall it in the opposite direction, and install the other side of the rotor in close fit with the positioning fixture. Fourth, the five-axis machine tool uses a bar end mill to machine the other half of the rotor profile through the side edge of the bar end mill, and the retraction position of the tool is the midpoint of the rotor's Z-axis. Finally, after the rotor profile is cut in both directions, it is removed from the machine tool, and the machining is complete. The tooling with positioning function includes: tooling base (1), pull rod (2), pressure plate (3) and nut (4). The tooling base (1) is used to connect to the worktable of the cradle-type five-axis machining center. One end of the pull rod (2) is connected to the screw hole on the tooling base (1) by thread, and the other threaded end passes through the center hole of the single screw compressor rotor (5). The pressure plate (3) presses against the single screw compressor rotor (5) and is locked with nut (4). A misalignment pin (6) is installed on the tooling base (1) to prevent the single screw compressor rotor (5) from being misaligned. One end of the misalignment pin (6) is inserted into the keyway (7) in the center of the single screw compressor rotor (5). A set of at least two end face positioning pins (8) for positioning the end face when the single screw compressor rotor (5) is installed on the tooling base (1) and a set of at least two slot wall positioning pins (10) for positioning the end face slot wall (9) when the single screw compressor rotor (5) is reversed.

2. The method of claim 1, wherein: The tooling base (1) is provided with a boss (11) for inserting into the center hole of the single screw compressor rotor (5), and the anti-fooling pin (6) is installed on the boss (11).

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