Closed impeller artificial teaching automatic welding process

Abstract

The application relates to a closed impeller artificial teaching automatic welding process, and relates to the technical field of impeller manufacturing, which comprises the following steps: controlling the spot welding quality and assembly gap of blades and a wheel disc and a wheel cover, setting a zero point, adjusting the zero point of a robot and a positioner to an initial setting position, adjusting the welding position of a welding gun and an impeller weld, artificially teaching collision and searching, respectively teaching and searching four welding beads of the same blade and the wheel cover and the wheel disc, setting welding process parameters according to the actual situation of the assembly gap, respectively setting the single-blade welding process to all other blades, adopting a cross-over symmetrical welding method, and checking and cleaning after welding. The application has the advantages that the problems of easy welding deviation and welding penetration of single-radian welding beads and double-radian welding beads are solved.

Description

Technical Field

[0001] This application relates to the field of impeller manufacturing technology, and in particular to a closed impeller manual teaching automatic welding process. Background Technology

[0002] The closed impeller is the most important rotor component of a centrifugal compressor. Centrifugal compressors are characterized by low energy consumption, high stability, no pollution, and easy fully automatic control. They are widely used in industries such as petroleum, chemical, metallurgy, food, waste heat recovery, and environmental protection. The compressor drives the impeller to rotate at high speed, with an operating speed of over 3000 rpm, which increases the speed of the gas being drawn in, thereby increasing its kinetic and static pressure energy simultaneously. This static pressure energy is further increased in the subsequent diffuser and exhaust casing to achieve the purpose of increasing the temperature and pressure of the compressed medium.

[0003] Closed impellers are a type of semi-closed impeller. Due to limited welding space during the manufacturing process, the welding of closed impellers is often more difficult. Closed impellers are generally composed of a disc, a cover, and blades. The profiles of the cover and blades vary depending on the impeller model. Covers are generally divided into flat cover, conical cover, and arc cover; blades are divided into airfoil type, flat type, and arc type. Various cover types and blades form impellers with different structural forms, which makes it very easy to generate large assembly gaps during the manufacturing process.

[0004] Currently, automatic welding is effective for welding workpieces with regular bevels and assembly gaps of less than 2mm. However, when applied to welding closed impellers, it is prone to defects such as weld deviation, weld penetration, undercut, and porosity. In addition, there are many types and structures of closed impellers, and automatic welding is not very adaptable to welding closed impellers. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this application provides a closed impeller manual teaching automatic welding process.

[0006] The technical solution for a closed impeller manual-taught automatic welding process provided in this application is as follows:

[0007] A closed impeller manual-taught automatic welding process includes the following steps:

[0008] S1. Control the spot welding quality of blades to the wheel disk and wheel cover. The assembly gap between blades and wheel disk is less than 1mm, the assembly gap between blades and flat wheel cover and conical wheel cover is less than 2mm, and the assembly gap between blades and arc-shaped wheel cover is less than 5mm.

[0009] S2. Set the zero point. Adjust the robot and positioner zero points to the initial position. Install the impeller and impeller positioning fixture onto the positioner. Ensure that the gap between the outer circle of the center hole fixture and the inner hole of the impeller hub or the center process hole of the impeller is controlled between 0.04-0.06mm. In the impeller outlet direction, one of the blades and the outer circle forming end point of the disc must coincide with one of the cross zero-position lines of the positioner.

[0010] S3. Adjust the positioner and robot to enter the impeller flow channel from the impeller inlet and outlet directions respectively, and adjust the welding position of the welding torch and the impeller weld to the ship-shaped welding position.

[0011] S4. Manual teaching collision positioning, adopting different positioning methods for different types of weld beads;

[0012] S41. Straight weld bead positioning method: locate the Z-axis (wheel disc and wheel cover side) and X-axis (blade side). The collision point should be 30-50mm away from the weld bead. Locate three positions, each approximately one-third the length of the blade. The tip of the welding wire should be perpendicular to the collision position.

[0013] S42. Single-arc weld bead positioning method: locate three positions. Use the vertical positioning method for the arc start position and the middle point position. When locating the X-axis (blade side) for the arc end position, the welding wire tip is tilted at 45° to the blade, and the collision point is 30-50mm away from the weld bead.

[0014] S43, Double-arc weld bead positioning method, namely the arc starting position, the highest position of blade arc, the arc ending position, the midpoint between the arc starting position and the highest position of arc, and the midpoint between the arc ending position and the highest position of arc. The arc starting position is 20mm-30mm away from the blade tip, and the arc ending position is 20mm-30mm away from the other end of the blade. The arc starting position, the highest position of arc, the midpoint between the arc starting position and the highest position of arc, and the midpoint between the arc ending position and the highest position of arc all adopt the vertical positioning method. When locating the X-axis (blade side) and Z-axis (wheel cover side) at the arc ending position, the welding wire tip is tilted at 45° to both the blade and the wheel cover, and the collision point is 30-50mm away from the weld bead.

[0015] S5. Perform teaching and positioning for the four weld lines of the same blade, wheel cover, and wheel disc respectively;

[0016] S51. The weld bead between the blade and the non-working side of the wheel disk is welded in the direction from the inlet end to the outlet end.

[0017] S52. Locate the weld bead on the working surface side of the blade and wheel cover, with the welding direction from the outlet end to the inlet end;

[0018] S53. The weld bead between the blade and the working surface of the wheel disc is welded in the direction from the outlet end to the inlet end.

[0019] S54. The weld bead between the blade and the non-working side of the wheel cover is welded in the direction from the inlet end to the outlet end.

[0020] S6. Perform trial runs on the four welds of the same weld in the order of S4 to correct singularities.

[0021] S7. Set welding parameters. Set welding process parameters according to the actual assembly gap. When the bevel gap is greater than 2mm, use root pass welding or oscillating arc welding. For double arc welds, root pass welding must be performed.

[0022] S8. Set the welding process settings for a single blade to all other blades, and use the cross-shaped symmetrical welding method. After each weld is completed, add a cleaning torch and wire cutting command.

[0023] S9. After welding is completed, inspect and clean the impeller and remove the impeller fixing fixture together. Before welding the impeller, the plane of the impeller fixing fixture must be leveled before installing the new impeller.

[0024] Furthermore, in step S1, the length of a single spot weld is required to be less than 20mm.

[0025] Furthermore, in step S1, the distance between the nearest weld seam to the blade inlet / outlet end face is between 20mm and 50mm.

[0026] Furthermore, in step S2, the flatness of the impeller positioning fixture plane must be checked to be <1 / 1000 before installation.

[0027] Furthermore, in step S7, when performing double-arc weld root pass welding, the root pass should not have ridges, and the two sides of the weld pass should be smooth.

[0028] Furthermore, in step S7, when the bevel assembly gap is 0-2mm, and the weld leg size is less than 8mm, single-pass welding is performed without root pass or arc welding. The welding current is set to 200-240A and the arc voltage is set to 22-26V. When the weld leg size is between 8-12mm, root pass welding is required. The welding current for the root pass is set to 100-140A and the arc voltage is set to 16-20V. The current for the cover pass is set to 220-260A and the arc voltage is set to 24-30V.

[0029] Furthermore, in step S7, when the bevel assembly gap is between 2-3mm, a root pass weld is set with a welding current of 100A-140A and an arc voltage of 16-20V, without oscillating arc welding. The cover pass weld current is set according to the required weld leg size.

[0030] Furthermore, in step S7, when the bevel gap is between 3-5mm, a root pass is set and oscillating arc welding is performed. The oscillating arc welding parameters are set to Weave sine (2.0Hz, 1.8mm, 0.05s, 0.05s).

[0031] Furthermore, after the weld is completed and cooled to below 50°C in step S9, the impeller and tooling can be disassembled, and the positioner can be lifted and disassembled after being adjusted to the zero position.

[0032] In summary, this application includes at least one of the following beneficial technical effects:

[0033] This invention employs different positioning methods for different weld bead types, solving the problems of easy weld misalignment and weld burn-through in single-arc and double-arc weld beads;

[0034] This invention solves the welding problems of large impeller bevel assembly gap and natural bevel by using a combination of root pass welding and oscillating arc welding.

[0035] This invention sets different welding process parameters for different weld bead types and assembly gaps, solving the problems of defects such as weld ridges and undercut.

[0036] This invention is applicable to the automatic welding of closed impellers of different models, provided that the operating space is met, and is even more suitable for the automatic welding of open impellers. Attached Figure Description

[0037] Figure 1 This is a structural schematic diagram of a closed impeller manual teaching automatic welding process in an embodiment of this application.

[0038] Figure 2 for Figure 1 Internal sectional view.

[0039] Figure 3 for Figure 2 The AA-direction sectional view is used to illustrate a single-arc weld bead.

[0040] Figure 4 for Figure 2 The BB-direction sectional view used to illustrate the double-curvature weld bead.

[0041] Explanation of reference numerals in the attached diagram: 1. Wheel cover; 2. Wheel disc; 3. Blade; 4. Double-curved weld bead; 5. Single-curved weld bead. Detailed Implementation

[0042] To illustrate in detail the technical solutions adopted by the present invention to achieve the intended technical objectives, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Furthermore, the technical means or technical features in the embodiments of the present invention can be replaced without creative effort. The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0043] like Figures 1 to 4 As shown, the present invention provides a closed impeller manual teaching automatic welding process, characterized by comprising the following steps:

[0044] S1. Control the spot welding quality of blade 3 with wheel disk 2 and wheel cover 1. The assembly gap between blade 3 and wheel disk 2 is less than 1mm. In this embodiment, the assembly gap between blade 3 and flat wheel cover and conical wheel cover is less than 2mm. The assembly gap between blade 3 and arc-shaped wheel cover is less than 5mm.

[0045] In step S1 above, the length of a single spot weld must be less than 20mm. Spot welding is not allowed on the inlet and outlet end faces of blade 3. The distance from the nearest spot weld to the inlet and outlet end faces of blade 3 must be no less than 20mm and no more than 50mm. The non-working surface weld between blade 3 and wheel cover 1 must not be beveled due to the presence of a natural bevel.

[0046] S2. Set the zero point. Adjust the robot and positioner zero points to the initial position. Install the impeller and impeller positioning fixture onto the positioner. The impeller consists of a wheel disk 2, a wheel cover 1, and several blades 3. Ensure that the outer circle of the center hole fixture and the inner hole of the impeller hub or the center process hole of the impeller are controlled within 0.04-0.06mm. In the impeller outlet direction, one of the blades 3 and the outer circle forming end point of the wheel disk 2 must coincide with one of the cross zero-position lines of the positioner.

[0047] In step S2 above, the impeller positioning fixture must ensure the fit between the fixture plane and the positioner mounting surface to facilitate disassembly after welding. The fitting surface of the fixture must be machined to a smooth finish with a roughness of Ra12.5. The roughness requirement for the center hole positioning fixture is Ra6.3. Before hoisting the impeller onto the positioner, the positioner must be adjusted to the horizontal zero limit position. During hoisting, it should hang naturally and should not be fitted using hot fitting. The above-mentioned center positioning fixture is made of 45# material. The flatness of the impeller positioning fixture plane must be checked to be <1 / 1000 before installation.

[0048] S3. Adjust the positioner and robot to enter the impeller flow channel from the impeller inlet and outlet directions respectively, and adjust the welding position of the welding torch and the impeller weld to the ship-shaped welding position.

[0049] In step S3 above, it is necessary to ensure that the robot moves smoothly and does not touch the workpiece. The coord linkage command is used to ensure that the relative position of the two is always in the ship-shaped welding position.

[0050] S4. Use the manual teaching method for collision positioning. When positioning, make sure that the end of the welding wire is in the center of the welding gun nozzle. After positioning, adjust the position of the welding wire to the center in time.

[0051] In step S4 above, different positioning methods are used for different types of weld beads:

[0052] S41, Straight Weld Bead: Find the Z-axis (side of wheel 2 and wheel cover 1) and X-axis (side of blade 3). The collision point is 30-50mm away from the weld bead. Find three positions, each position is about one-third of the length of blade 3. The end of the welding wire is perpendicular to the collision position.

[0053] S42, Single-arc weld bead 5: Find three positions. Use the vertical positioning method for the starting position and the middle position. When finding the ending position on the X-axis (side of blade 3), the tip of the welding wire is tilted at 45° to blade 3, and the collision point is 30-50mm away from the weld bead.

[0054] S43, Double-arc weld bead 4: Find five positions, namely the arc starting position, the highest arc position of blade 3, the arc ending position, the midpoint between the arc starting position and the highest arc position, and the midpoint between the arc ending position and the highest arc position; the arc starting position is 20mm-30mm away from the end of blade 3, and the arc ending position is 20mm-30mm away from the other end of blade 3; the arc starting position, the highest arc position, the midpoint between the arc starting position and the highest arc position, and the midpoint between the arc ending position and the highest arc position are all located using the vertical positioning method. When searching the X-axis (side of blade 3) and Z-axis (side of wheel cover 1) for the arc ending position, the tip of the welding wire is tilted at 45° to both blade 3 and wheel cover 1, and the collision point is 30-50mm away from the weld bead.

[0055] In step S4 above, the weld bead type should be confirmed before positioning, and then different positioning methods should be selected. When using the coord linkage command to teach to the ideal position, care should be taken to avoid collision with the impeller.

[0056] S5. Perform teaching and positioning for the four weld lines of the same blade 3, wheel cover 1, and wheel disk 2, respectively. The specific sequence is as follows:

[0057] S51. First, find the weld bead on the non-working side of blade 3 and wheel 2, and the welding direction is from the inlet end to the outlet end.

[0058] S52. Find the weld bead on the working surface side of blade 3 and wheel cover 1, with the welding direction from the outlet end to the inlet end;

[0059] S53, the weld bead between the working surface of the blade 3 and the wheel disk 2 is welded in the direction from the outlet end to the inlet end;

[0060] S54. Finally, find the non-working side weld of blade 3 and wheel cover 1, and weld in the direction from the inlet end to the outlet end.

[0061] In step S5 above, the starting point of the welding direction is the arc starting position mentioned in step S4. After each weld seam is found, a torch cleaning and wire cutting procedure must be added in the middle of the process. The torch cleaning station is set up in the work area and a safety warning sign is set up.

[0062] S6. Perform trial runs on the four welds of the same weld in the order specified in S5, and correct any singularities.

[0063] In step S5 above, when testing the four weld seams of the same blade 3 and wheel cover 1 of the wheel disc 2, it is necessary to carefully observe the movement and posture of the welding torch to ensure that the welding wire is always in the center of the weld seam during the movement, and that the weld seam is in the ship-shaped welding position. If the movement is skewed or a welding dead angle is formed, causing the program to be unable to continue running, the singularity point needs to be corrected.

[0064] S7. Set welding parameters. Set welding process parameters according to the actual assembly gap. When the bevel gap is greater than 2mm, use root pass welding or sway arc welding. For double arc weld 4, root pass welding must be performed. The root pass should not have a ridge angle and the two sides of the weld should be smooth.

[0065] In step S7 above, the following principles should be followed when setting parameters:

[0066] S71. When the bevel assembly gap is 0-2mm, single-pass welding is required for weld leg size below 8mm, without root pass or arc welding. The welding current is set to 200-240A and the arc voltage is set to 22-26V. When the weld leg size is between 8-12mm, root pass welding is required. The welding current for the root pass is set to 100-140A and the arc voltage is set to 16-20V. The current for the cover pass is set to 220-60A and the arc voltage is set to 24-30V.

[0067] S72. When the bevel assembly gap is between 2-3mm, set the root pass weld with a welding current of 100A-140A and an arc voltage of 16-20V, without oscillating arc welding. The cover pass weld current is set according to the required weld leg size.

[0068] S73. When the bevel gap is between 3-5mm, set the bottom layer weld and perform oscillating arc welding. The oscillating arc welding parameters are set to Weave sine (2.0Hz, 1.8mm, 0.05s, 0.05s).

[0069] S74. In addition to following the principles described in S71-S73 above, double-arc weld 4 must be used for root pass welding. Whether to use oscillating arc welding depends on the bevel gap.

[0070] S8. Set the welding process settings for the single blade 3 to all other blades 3 respectively, and use the cross-shaped symmetrical welding method. After each weld is completed, add a cleaning gun and wire cutting procedure.

[0071] In step S8 above, all blade 3 welds must be set in the following order: first weld all blade 3 welds to the non-working surface of the wheel disk 2, then weld all blade 3 welds to the working surface of the wheel cover 1, then weld all blade 3 welds to the working surface of the wheel disk 2, and finally weld the blade 3 welds to the non-working surface of the wheel cover 1.

[0072] S9. After welding is completed, inspect and clean the impeller and remove the impeller fixing fixture together. Before welding the impeller, the plane of the impeller fixing fixture must be leveled before installing the new impeller.

[0073] In step S9 above, all welds of the impeller must be cleaned and inspected before disassembling the impeller fixing fixture. During cleaning, a pneumatic chisel is used to vibrate and remove spatter to reduce welding stress. After the last weld has cooled to below 50°C, the impeller and fixture can be disassembled. The positioner is then adjusted to the zero position and lifted off the ground.

[0074] As can be seen from the above embodiments, the method of the present invention can solve the problems of easy welding deviation and weld penetration of single-arc weld pass 5 and double-arc weld pass 4. It can also solve the welding problems of large impeller bevel assembly gap and natural bevel by using a combination of root pass welding and swing arc welding. Moreover, the present invention is applicable to automatic welding of different models of closed impellers under the premise of meeting the operating space requirements, and is more suitable for automatic welding of open impellers.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A closed impeller manual-taught automatic welding process, characterized in that, Includes the following steps: S1. Control the spot welding quality of blade (3) with wheel (2) and wheel cover (1). The assembly gap between blade (3) and wheel (2) is less than 1mm. The assembly gap between blade (3) and flat wheel cover and conical wheel cover is less than 2mm. The assembly gap between blade (3) and arc wheel cover is less than 5mm. S2. Set the zero point and adjust the robot and positioner zero point to the initial position. Install the impeller and impeller positioning fixture onto the positioner. Ensure that the gap between the outer circle of the center hole fixture and the inner hole of the impeller hub is controlled between 0.04-0.06mm. The outer circle forming end point of one blade (3) and the wheel (2) in the impeller outlet direction must coincide with one of the lines of the positioner cross zero position line. S3. Adjust the positioner and robot to enter the impeller flow channel from the impeller inlet and outlet directions respectively, and adjust the welding position of the welding torch and the impeller weld to the ship-shaped welding position. S4. Manual teaching collision positioning, adopting different positioning methods for different types of weld beads; S41, straight weld bead positioning method: locate the wheel disc (2), wheel cover (1) side, and blade (3) side. The collision point is 30-50mm away from the weld bead. Find three positions, each position is one-third of the blade (3) length away, and the welding wire tip is perpendicular to the collision position. S42, Single arc weld (5) positioning method: find three positions. The starting position and the middle point position adopt the vertical positioning method. When finding the end position, the welding wire tip is tilted at 45° to the blade (3) side and the collision point is 30-50mm away from the weld. S43, the double arc weld (4) positioning method, namely the arc starting position, the highest arc position of the blade (3), the arc ending position, the midpoint between the arc starting position and the highest arc position, and the midpoint between the arc ending position and the highest arc position. The arc starting position is 20mm-30mm away from the end of the blade (3), and the arc ending position is 20mm-30mm away from the other end of the blade (3). The arc starting position, the highest arc position, the midpoint between the arc starting position and the highest arc position, and the midpoint between the arc ending position and the highest arc position are all located using the vertical positioning method. When the arc ending position is located on the side of the blade (3) and the side of the wheel cover (1), the tip of the welding wire is tilted at 45° to both the blade (3) and the wheel cover (1), and the collision point is 30-50mm away from the weld. S5. Perform teaching and positioning on the four weld lines of the same blade (3), wheel cover (1), and wheel disk (2); S51, the non-working side weld of the blade (3) and the wheel (2) is in the direction from the inlet end to the outlet end; S52, the weld bead on the working surface of the blade (3) and the wheel cover (1) is welded in the direction from the outlet end to the inlet end; S53, the weld bead on the working surface of the blade (3) and the wheel (2) is welded in the direction from the outlet end to the inlet end; S54, the non-working side weld of the blade (3) and the wheel cover (1) is in the direction from the inlet end to the outlet end; S6. Perform trial runs on the four weld seams of the same blade (3) in the order of S5 to correct singularities. S7. Set welding parameters. Set welding process parameters according to the actual situation of assembly gap. When the bevel gap is greater than 2mm, take root welding or swing arc welding. For double arc weld (4), root welding must be performed. S8. Set the welding process of a single blade (3) onto all other blades (3) respectively, and use the cross-shaped symmetrical welding method. After each weld is completed, add a cleaning gun and wire cutting instruction. S9. After welding is completed, inspect and clean the impeller and remove the impeller fixing fixture together. Before welding the impeller, the plane of the impeller fixing fixture must be leveled before installing the new impeller.

2. The closed impeller manual teaching automatic welding process according to claim 1, characterized in that: In step S1, the length of a single spot weld is less than 20mm.

3. The closed impeller manual teaching automatic welding process according to claim 1, characterized in that: In step S1, the distance between the nearest point of the solid weld seam at the inlet and outlet end face of the blade (3) is 20mm-50mm.

4. The closed impeller manual teaching automatic welding process according to claim 1, characterized in that: When performing the double-arc weld (4) in step S7, the bottom weld should not have a ridge angle, and the two sides of the weld should be smooth.

5. The closed impeller manual teaching automatic welding process according to claim 1, characterized in that: In step S7, when the bevel assembly gap is between 0-2mm and the weld leg size is less than 8mm, single-pass welding is used, without the need for root pass welding and arc welding. The welding current is set to 200-240A and the arc voltage is set to 22-26V. When the weld leg size is between 8-12mm, root pass welding is required. The welding current for the root pass is set to 100-140A and the arc voltage is set to 16-20V. The current for the cover pass is set to 220-260A and the arc voltage is set to 24-30V.

6. The closed impeller manual teaching automatic welding process according to claim 1, characterized in that: In step S7, when the bevel assembly gap is greater than 2mm and less than or equal to 3mm, a root pass is set, with the welding current set to 100A-140A and the arc voltage set to 16-20V.

7. The closed impeller manual teaching automatic welding process according to claim 1, characterized in that: In step S7, when the bevel gap is greater than 3mm and less than or equal to 5mm, a root pass is set and oscillating arc welding is performed.

8. The closed impeller manual teaching automatic welding process according to claim 1, characterized in that: In step S9, after the weld has cooled to below 50°C, the impeller and tooling are disassembled, and the positioner is adjusted to zero before being lifted and disassembled.

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