Method for processing a large-diameter semi-circular inner cavity

Abstract

The application relates to the field of mechanical processing, and discloses a processing method for a large-diameter semicircular inner cavity, which comprises the following steps: first step: positioning and installing a machine shell on a gantry bore milling processing table, the machine shell is provided with bearing positions and sealing positions at two ends, a dial gauge is used to correct the two ends of the machine shell through the bearing positions at two sides, the central axis of the machine shell is made parallel to the X axis of a machine tool, and the machine shell is pressed tightly after the central surface of the machine shell is leveled; second step: fixing at least one process block at the inner cavity processing position corresponding to the middle surface of the machine shell; third step: after the X, Y and Z zero point positions of the machine shell are determined, a three-flank milling cutter is used to coarsely process the inner cavity of the machine shell; fourth step: assembling a boring cutter row, adjusting the length of the cutter row, installing the cutter row on a milling shaft, and performing tool setting; fifth step: performing semi-precision boring processing after setting cutting parameters; sixth step: setting precision boring cutting parameters to process the inner cavity; and seventh step: performing precision boring by fine adjustment of the boring cutter row. The application provides a processing method for a large-diameter inner cavity with high processing precision.

Description

Technical Field

[0001] This invention relates to the field of machining, and specifically to a method for machining a large-diameter semi-circular inner cavity. Background Technology

[0002] The boiler gas compressor is a crucial component of the combined alkali process system. The compressor casing is a horizontally split structure. Due to the corrosive nature of the working medium within the compressor casing, the inner cavity is typically made of stainless steel, with some sections having a large diameter exceeding 2000 mm. In contrast, conventional compressor casings are made of ordinary carbon steel, with a maximum diameter of 1300 mm. Furthermore, the machining precision requirements for this compressor inner cavity are high; failure to meet these precision requirements could lead to damage to internal components during compressor operation. Therefore, conventional machining methods are insufficient for processing these large-diameter semi-circular inner cavities. Consequently, there is an urgent need for a machining method capable of cutting large-diameter semi-circular inner cavities from stainless steel. Summary of the Invention

[0003] The present invention aims to provide a machining method for a large-diameter semi-circular inner cavity, so as to provide a machining method for a large-diameter inner cavity with high machining accuracy.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a method for processing a large-diameter semi-circular inner cavity, comprising the following steps:

[0005] Step 1: Position and install the machine housing on the gantry milling machine table. The machine housing has bearing positions and sealing positions at both ends. Use a dial indicator to calibrate the two ends of the machine housing through the bearing positions on both sides to make the central axis of the machine housing parallel to the X-axis of the machine tool. After leveling the center surface of the machine housing, press the machine housing tightly.

[0006] Step 2: Fix at least one process block at the inner cavity machining location corresponding to the split surface in the housing, and measure the width and side coordinates of the process block. The process block is machined together with the semi-circular inner cavity.

[0007] Step 3: After determining the X, Y, and Z zero points of the housing, use a three-sided milling cutter to rough machine the inner cavity of the housing, removing most of the excess material and leaving a 0.5mm boring machining allowance;

[0008] Step 4: Assemble the boring bar set, adjust the length of the bar set, and install the bar set on the milling spindle; adjust the position of the boring bar set and perform tool setting;

[0009] Step 5: After setting the cutting parameters, perform semi-finish boring, leaving a 0.15mm finish boring allowance. After machining, use a dial indicator to collect the coordinate values ​​of the lowest point of the sealing position and the lowest point of the inner cavity, calculate the difference, and determine whether the machined inner cavity and the sealing position meet the concentricity requirements. If they do not meet the requirements, repeat steps 4 and 5.

[0010] Step 6: Set the fine boring cutting parameters to machine the inner cavity, leaving a fine boring allowance of 0.05mm. Use a micrometer to measure the process block to determine whether the machined diameter of the inner cavity meets the tolerance.

[0011] Step 7: Based on the measurement results, fine-tune the boring bar rack for precision boring until the machined diameter meets the accuracy requirements.

[0012] The beneficial effects of this plan are:

[0013] 1. High machining accuracy. This technical solution utilizes a phased process of roughing, semi-finish boring, and finish boring to gradually remove excess material, reducing the load on the machine housing during machining. Simultaneously, a certain boring allowance is retained for fine machining. This phased machining method helps control the machining process, improving accuracy and stability. By using measuring tools such as dial indicators and feeler gauges, and finely adjusting the position of the boring bar, precise measurement and adjustment of the machining diameter and concentricity can be achieved, ensuring that the machining results meet accuracy requirements and avoiding dimensional deviations or concentricity issues in the machined product. Through a series of clamping, alignment, tool setting, trial cutting, and measurement processes, the machine housing manufacturing ensures that it meets the unit's design performance requirements.

[0014] 2. Since this technical method involves machining a large-diameter inner cavity, and the assembled housing is composed of two housings, a very large inside micrometer would be required to accurately measure the inner cavity diameter. These inside micrometers are quite expensive. Therefore, this solution fixes a process block at the machining location of the inner cavity on one side of the split surface and records its coordinates. The process block is machined together with the semi-circular inner cavity. When the inner cavity diameter needs to be measured, the remaining length at the bottom of the process block is measured using a micrometer. The length of the process block that has been removed is calculated, and this, combined with the original coordinates of the side of the process block, allows for a quick calculation of the inner cavity diameter. Using this method, after each cut, only the width of the process block needs to be measured with a micrometer to calculate the machined diameter of the inner cavity. This is much faster than the traditional method of using an inside micrometer to check the inner diameter. Since multiple measurements of the machining allowance and inner diameter are often required during the cutting process, measuring the process block significantly improves the machining efficiency of the housing and reduces costs.

[0015] Preferably, as an improvement, the boring bar in the fourth step includes a bar, a boring bar, and two extension blocks. The two ends of the bar have U-shaped grooves that are slidably connected to the extension blocks. The end of the U-shaped groove near the middle of the bar is arc-shaped. The extension blocks are detachably connected to the bar. The end of the extension blocks away from the bar is provided with a tool holder for mounting the boring bar.

[0016] The beneficial effects are as follows: The tool post has U-shaped grooves at both ends, with the end near the center being arc-shaped, making the middle of the tool post thicker. The arc-shaped connection also provides reinforced support for the extension blocks on both sides. Simultaneously, the U-shaped grooves at both ends slide against the extension blocks, and the side walls of the U-shaped grooves provide limiting and support for the extension blocks. This prevents the boring tool from shifting or tilting due to cutting obstruction during high-speed rotation of the tool post, thus avoiding a reduction in machining quality. The above design provides better sliding connection and positioning, ensuring the stability and accuracy of the tool post and extension blocks. It also improves the tensile strength of the tool post, making it less prone to deformation, giving it excellent vibration resistance and high torque. Due to the U-shaped groove design, even if the tool post extends too far, it is less likely to cause precision loss in the machine tool spindle due to leverage. The tool post and extension blocks are detachably connected, allowing for easy replacement or adjustment of the extension blocks to adapt to the machining needs of internal cavities of different sizes and shapes.

[0017] Preferably, as an improvement, the bottom array of the U-shaped chute has several threaded holes, and the extension block and the cutter bar are detachably connected by bolts.

[0018] The beneficial effects are as follows: Through the above settings and the array of threaded holes, users can easily adjust the length of the tool rack. The internal structure of the machine housing is complex, and the dimensions at different positions need to be changed frequently. With the above settings, the length of the tool rack can be adjusted by simply adjusting the position of the bolts. This allows the tool rack to adapt to the machining needs of large-diameter semi-circular inner cavities of different sizes, improving the flexibility and adaptability of machining, without having to replace the entire tool rack, thus improving machining efficiency.

[0019] Preferably, as an improvement, the tool setting position in the fourth step is at the two symmetrical ends on the dividing surface of the inner cavity and a point on the bottom surface.

[0020] The beneficial effects are as follows: Selecting the two symmetrical ends on the inner cavity split surface as the tool setting positions, and adjusting and setting the tool at the symmetrical positions can reduce deviations and imbalances during the machining process, improve the symmetry and consistency of the machining, ensure that the rotation center of the boring tool plate coincides with the rotation center of the machine housing, and facilitate the operator to adjust and set the tool, thereby improving the efficiency and accuracy of your operation.

[0021] Preferably, as an improvement, the height of the process block is 40-70mm, and the process block is made of the same material as the housing.

[0022] The beneficial effects are as follows: By setting the material of the process block to be the same as that of the machine housing, they have the same physical properties and coefficient of thermal expansion. During processing, the machine housing and the process block will expand or contract in a similar way due to heat, thereby reducing dimensional changes and deformations caused by material differences. When measuring the process block with a micrometer, the amount of material cut will not differ due to material differences, thus preventing large errors in the micrometer's measurement of the inner diameter. The above setting can improve the measurement accuracy of the inner diameter. The height of the process block is set to 40-70mm, which is relatively small and easier to fix on the center surface of the machine housing. Installation and disassembly are simpler, and the amount of material cut is relatively small, reducing the processing time of the process block. During boring, the edge of the machined area is relatively thin, and due to thermal deformation or machining trajectory, the machined edge may be uneven or deformed, often requiring secondary processing and grinding. The process block in this technical solution is fixed at the corresponding inner cavity machining area, which can effectively avoid the above problems.

[0023] Preferably, as an improvement, in the second step, two process blocks are symmetrically fixed at the inner cavity machining points corresponding to the split surfaces in the housing.

[0024] The beneficial effects are as follows: By symmetrically setting two process blocks, on the one hand, the edge of the split surface of the housing will be smoother after the process blocks are removed, reducing the unevenness of the edge caused by unilateral machining, which helps to improve the sealing performance of the housing after assembly. On the other hand, by measuring the allowance changes of the two process blocks with a micrometer, if the allowance of the two process blocks decreases within the tolerance range, it can be said that the machining center of the boring bar has not shifted to the left or right. This helps to determine the accuracy of machining and monitor the machining quality, ensuring that the machining center is aligned with the center line of the housing, thereby improving the accuracy and stability of machining, and facilitating timely adjustment and correction of machining parameters. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the casing structure of Embodiment 1 of the present invention;

[0026] Figure 2 This is a schematic diagram showing the location of the process block in Embodiment 1 of the present invention;

[0027] Figure 3 This is a schematic diagram of the boring bar structure in Embodiment 1 of the present invention;

[0028] Figure 4 This is a schematic diagram showing the location of the process block in Embodiment 2 of the present invention. Detailed Implementation

[0029] The following detailed description illustrates the specific implementation method:

[0030] The reference numerals in the accompanying drawings include: housing 1, bearing seat 2, process block 3, housing cavity 4, tool rack 5, boring tool 6, extension block 7, U-shaped slide 8, tool holder 9.

[0031] Example 1

[0032] A method for machining a large-diameter semi-circular inner cavity includes the following steps:

[0033] Step 1: [The following text appears to be a separate, unrelated section:] ... Figure 1 The housing 1 shown is positioned and installed on the gantry milling machine table. The housing 1 has bearing positions 2 and sealing positions at both ends. A dial indicator is used to calibrate the two ends of the housing 1 through the bearing positions 2 on both sides to make the central axis of the housing 1 parallel to the X-axis of the machine tool. After leveling the center surface of the housing 1, the housing 1 is pressed to ensure the accuracy of the fixed position of the housing 1.

[0034] Step 2: As Figure 2 As shown, a process block 3 is fixed with bolts at the inner cavity machining point corresponding to the split surface in the housing 1. The height of the process block 3 is 40-70mm (50mm in this embodiment). The width and side coordinates of the process block 3 are measured. The process block 3 is made of the same material as the housing 1. The process block 3 is machined together with the inner cavity 4 of the housing. During the boring process, the edge of the machining point is relatively thin. Due to thermal deformation or unilateral machining, the machining edge may be uneven or deformed, often requiring secondary machining and grinding. The process block 3 in this technical solution is fixedly set at the corresponding inner cavity machining point, which can effectively avoid the above problems.

[0035] Step 3: After determining the X, Y, and Z zero points of housing 1, use a three-sided milling cutter to rough machine the inner cavity 4 of the housing, remove most of the excess material, and leave a 0.5mm boring allowance. Using a three-sided milling cutter results in fast machining speed, which helps to improve machining efficiency.

[0036] Step 4: Assembly Figure 3The boring bar rack shown includes a rack 5, boring bars 6, and two extension blocks 7. The rack 5 has U-shaped grooves 8 at both ends for sliding connection of the extension blocks 7. The extension blocks 7 are detachably connected to the rack 5. Each extension block 7 has a tool holder 9 for mounting the boring bar 6 at its end furthest from the rack 5. The U-shaped grooves 8 at both ends of the rack 5, with the end near the middle being arc-shaped, make the middle of the rack 5 thicker. The arc-shaped connection also provides a reinforced connection for supporting the extension blocks 7 on both sides. The extension blocks 7 at both ends are slidably positioned within the U-shaped grooves 8. The side walls of the U-shaped grooves 8 provide limiting and support for the extension blocks 7, ensuring proper positioning of the rack 5 during high-speed rotation. During operation, the boring bar 6 is less likely to deviate or skew due to cutting obstruction, thus reducing machining quality. The above-mentioned design provides better sliding connection and positioning, ensuring the stability and accuracy of the tool rack 5 and the extension block 7. At the same time, it improves the tensile strength of the tool rack 5, making it less prone to deformation and giving it excellent shock resistance and high torque. Due to the U-shaped groove design, even if the tool rack 5 extends too far, it is less likely to cause a loss of machine tool spindle accuracy due to the lever principle. The bottom of the U-shaped groove 8 has several threaded holes, and the extension block 7 is detachably connected to the tool rack 5 by bolts, allowing the tool rack 5 to adapt to the machining needs of large-diameter semi-circular inner cavities of different sizes, improving machining flexibility and adaptability.

[0037] Adjust the length of tool rack 5 and install it on the milling spindle of the gantry milling machine; adjust the position of the boring tool rack by feeling the gauge and perform tool setting. Select the two symmetrical ends on the inner cavity split surface as the tool setting position, which can reduce deviation and imbalance during the machining process and improve the symmetry and consistency of the machining.

[0038] Step 5: After setting the cutting parameters, perform semi-finish boring, leaving a 0.15mm finish boring allowance. After machining, use a dial indicator to collect the coordinate values ​​of the lowest point of the sealing position and the lowest point of the inner cavity, calculate the difference, and determine whether the machined inner cavity and the sealing position meet the concentricity requirements. If they do not meet the requirements, repeat steps 4 and 5.

[0039] Step 6: Set the precision boring cutting parameters to machine the inner cavity, leaving a precision boring allowance of 0.05mm. Use a micrometer to measure the process block 3 to determine whether the machined diameter of the inner cavity meets the tolerance. The assembled device is composed of two housings 1 assembled and fixed. If you want to accurately measure the diameter of the inner cavity, you need a very large inside micrometer, which is relatively expensive. Therefore, in this solution, a process block 3 is fixed at the inner cavity machining location on one side of the split surface, and the coordinate value of the process block 3 is recorded. The process block 3 is machined together with the semi-circular inner cavity. When it is necessary to measure the inner diameter... When determining the diameter of the cavity, a micrometer is used to measure the remaining length at the bottom of process block 3. The length of process block 3 that has been cut off is calculated, and the original coordinate value of the side of process block 3 is added to quickly calculate the diameter of the inner cavity. In this way, after each cut, only the width of process block 3 needs to be measured with a micrometer to calculate the machining diameter of the inner cavity. Compared with the traditional method of using an inside micrometer to detect the inner diameter, it is faster. Since the machining allowance and inner diameter often need to be measured multiple times during the cutting process, measuring process block 3 can greatly improve the machining efficiency of housing 1 and reduce the cost.

[0040] Step 7: Based on the measurement results, fine-tune the boring bar rack for precision boring until the machined diameter meets the accuracy requirements.

[0041] This technical solution uses a phased process of roughing, semi-finish boring, and finish boring to help gradually remove excess material, reduce the load on the machine housing 1 during machining, and at the same time retain a certain boring allowance for fine machining. This phased machining method helps to control the machining process and improve the accuracy and stability of machining.

[0042] Example 2

[0043] Example 2 Figure 4 As shown, the difference between Example 2 and Example 1 is that in the second step, two process blocks 3 are symmetrically fixed at the inner cavity machining area corresponding to the split surface of the housing 1, and in the sixth step, a micrometer is used to measure the inner cavity machining diameter of the two process blocks 3 to determine whether it meets the tolerance and whether it is symmetrical. If it does not meet the tolerance, the position of the milling shaft is finely adjusted, and the fourth step is repeated to use a feeler gauge for tool setting.

[0044] After the above settings: on the one hand, the edge of the split surface of the housing 1 will be smoother after the process block 3 is removed, reducing the unevenness of the edge caused by unilateral processing, which helps to improve the sealing performance of the housing 1 after assembly. On the other hand, by measuring the allowance changes of the two process blocks 3 with a micrometer, if the allowance of the two process blocks 3 is reduced within the tolerance range, it can be said that the machining center of the boring bar has not shifted to the left or right. This helps to determine the accuracy of the machining and monitor the machining quality, ensuring that the machining center is aligned with the center line of the housing 1, thereby improving the machining accuracy and stability, and facilitating timely adjustment and correction of machining parameters.

[0045] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for machining a large-diameter semi-circular inner cavity, characterized in that: Includes the following steps: Step 1: Position and install the machine housing on the gantry milling machine table. The machine housing has bearing positions and sealing positions at both ends. Use a dial indicator to calibrate the two ends of the machine housing through the bearing positions on both sides to make the central axis of the machine housing parallel to the X-axis of the machine tool. After leveling the split surface of the machine housing, press the machine housing tightly. Step 2: Fix the process block at the semi-circular inner cavity machining location corresponding to the split surface in the housing, and measure the width and side coordinates of the process block. The process block and the semi-circular inner cavity are machined together. Step 3: After determining the X, Y, and Z zero points of the housing, use a three-sided milling cutter to rough machine the semi-circular inner cavity of the housing, removing most of the excess material and leaving a 0.5mm boring machining allowance; Step 4: Assemble the boring bar set, adjust the length of the bar set, and install the bar set on the milling spindle; adjust the position of the boring bar set and perform tool setting; Step 5: After setting the cutting parameters, perform semi-finish boring, leaving a 0.15mm finish boring allowance. After machining, use a dial indicator to collect the coordinate values ​​of the lowest point of the sealing position and the lowest point of the semi-circular inner cavity, calculate the difference, and determine whether the machined semi-circular inner cavity and the sealing position meet the concentricity requirements. If they do not meet the requirements, repeat steps 4 and 5. Step 6: Set the fine boring cutting parameters to machine the semi-circular inner cavity, leaving a fine boring allowance of 0.05mm. Use a micrometer to measure the process block to determine whether the machining diameter of the semi-circular inner cavity meets the tolerance. Step 7: Based on the measurement results, fine-tune the boring bar rack for precision boring until the machined diameter meets the accuracy requirements; In the second step, two process blocks are symmetrically fixed at the semi-circular inner cavity machining points corresponding to the split surfaces in the housing. Use a micrometer to measure the allowance changes of the two process blocks respectively. If the allowance of the two process blocks decreases within the tolerance range, it can be concluded that the machining center of the boring bar has not shifted to the left or right. After each cut is completed, the machining diameter of the semi-circular inner cavity can be calculated by measuring the remaining width at the bottom and the coordinate values ​​of the side of the process block with a micrometer.

2. The method for machining a large-diameter semi-circular inner cavity according to claim 1, characterized in that: The fourth step involves a boring bar set consisting of a bar set, a boring bar, and two extension blocks. The bar set has U-shaped grooves at both ends that slide with the extension blocks. The end of the U-shaped groove near the middle of the bar set is arc-shaped. The extension blocks are detachably connected to the bar set. The end of the extension blocks away from the bar set is provided with a tool holder for mounting the boring bar.

3. The method for machining a large-diameter semi-circular inner cavity according to claim 2, characterized in that: The bottom of the U-shaped chute has several threaded holes, and the extension block and the cutter bar can be detachably connected by bolts.

4. The method for machining a large-diameter semi-circular inner cavity according to claim 3, characterized in that: The fourth step involves setting the tool at the symmetrical ends on the midpoint of the semi-circular inner cavity and at a point on the bottom surface.

5. The method for machining a large-diameter semi-circular inner cavity according to claim 4, characterized in that: The height of the process block is 40-70mm, and the process block is made of the same material as the casing.

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