Online quality monitoring method for SLM forming process of engine wheel rotating part

Abstract

The invention discloses an engine wheel rotating part SLM forming process quality online monitoring method. The method comprises the following steps that S1, a part forming process is simulated; s2, importing data; s3, selective laser melting forming and online regulation and control; and S4, taking the workpiece and carrying out post-treatment. Accurate monitoring of a temperature field is completed by dividing monitoring point positions of a forming surface according to the resolution of a monitoring instrument, multiple signal collectors are arranged to mutually verify and correct monitoring data to improve the monitoring precision, and the online monitoring process is simplified by evaluating and correcting the process stability in real time by means of a database obtained through simulation. Closed-loop full-process monitoring of a monitoring scheme of interference factors in the whole forming process is completed, and online monitoring of the quality of the SLM forming process of the engine wheel rotating part is achieved.

Description

Technical Field

[0001] The invention belongs to the application field of laser selective melting forming process, and in particular relates to an online monitoring method for process quality of an engine wheel rotating part when the engine wheel rotating part is formed by using the laser selective melting forming process. Background Art

[0002] The rotating parts of the engine wheels are the core and key parts of the engine. Because they work in the harsh environment of high temperature, high pressure and high speed, they are generally made of difficult-to-process materials such as high-temperature alloys and titanium alloys, and have extremely high requirements for dimensional accuracy, surface quality and mechanical properties. Such parts are usually produced by combining traditional casting, forging, welding or powder metallurgy with machining processes. However, in recent years, with the continuous increase in model production tasks and the gradual improvement of iterative efficiency requirements, the contradiction between the performance and demand of traditional manufacturing processes in terms of response speed, production cycle, complexity realization and cost control has become increasingly severe. People have gradually turned their attention to the laser selective melting forming process, which has obvious advantages in solving the above problems.

[0003] Selective laser melting (SLM) is an emerging manufacturing process that is suitable for the formation of digital complex components, flexible and rapid development, and high material utilization. It has emerged in solving the bottleneck problem of engine wheel rotating parts manufacturing. However, since the selective laser melting process involves multi-physical field coupling, the stability of this coupling is easily destroyed even under slight disturbances, which in turn introduces defects in the disturbed forming area, and ultimately leads to quality problems such as dimensional accuracy, internal defects, and surface roughness of the formed parts; at the same time, the existing selective laser melting forming process either has no full-process monitoring measures and cannot effectively evaluate the overall quality, or has insufficient monitoring data accuracy and cannot accurately diagnose process problems, or has problems such as too large data volume and low processing efficiency and cannot be used for real-time correction of the forming process. As a result, the quality of the wheel rotating parts formed by selective laser melting must be judged by additional detection means after the forming is completed, and this judgment has a lag in the problems caused by the forming process, and it is extremely difficult to repair the forming problems afterwards, not to mention that some problems cannot be repaired or are not allowed to be repaired at all, which leads to serious quality problems. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to provide an online monitoring method for the quality of the forming process of the laser selective melting forming process of engine wheel rotating parts, to improve the monitoring measures of the whole process of the forming process, to improve the accuracy of the monitoring data, to reasonably simplify the amount of data, and to solve the problems of the existing laser selective melting forming process that cannot effectively evaluate the overall quality, cannot accurately diagnose process problems, and cannot correct the forming process in real time. The present invention has broad application prospects in the application field of the laser selective melting forming process.

[0005] The technical solution of the present invention is:

[0006] The present invention provides a method for online monitoring of the quality of a forming process of a laser selective melting forming process of an engine wheel rotating part, comprising:

[0007] S1. Simulate the part forming process: simulate the part model with the process plan, and obtain the target signal normal window database of the part under the stable processing state, wherein the target signal normal window database includes the powder surface information of each layer position, the overall temperature field of the forming surface at each processing point, and the part cross-section information;

[0008] S2. Data import: import the part model of the process plan and the target signal normal window database obtained in step S1 into the forming equipment, and the forming equipment divides the entire monitoring area into several corresponding points according to the resolution of the monitoring instrument to realize the monitoring of the temperature field in the forming surface;

[0009] S3. Laser selective melting forming and online control: During the forming process, the powder surface of the powder spreading process, the temperature field and splashing of the scanning process, the part section after scanning, and the position information of each section in the current surface and Z-axis direction are monitored. The stability of the process is judged based on whether the monitoring data is consistent with the corresponding data in the normal window database of the target signal. If the system predicts that it will be unstable, the corresponding feedback adjustment is immediately carried out to avoid quality problems;

[0010] S4. Take out the parts and carry out post-processing. After forming is completed, take out the parts from the forming equipment and carry out subsequent processing.

[0011] Furthermore, the powder surface information refers to the uniformity, flatness and position accuracy of the powder surface. The overall temperature field of the forming surface at each processing point refers to the set of normal temperature ranges within the entire forming surface and the points within the resolution of the monitoring instrument at the current light spot location. The cross-sectional information of each layer of parts refers to the cross-sectional geometry and three-dimensional position information of each layer after processing.

[0012] Furthermore, the forming equipment used in step S2 can adjust the overall temperature field and the temperature field of local points in the forming surface, and the accuracy of the instrument for heating the local points in the forming surface is not less than the resolution of the temperature field monitoring instrument selected by the equipment. For example, the overall temperature field is adjusted by heating the cabin, and the local points in the forming surface are heated by a dedicated heating laser.

[0013] Furthermore, each monitoring instrument of the forming equipment used in step S2 has multiple channels in its corresponding responsible area, and each channel is distributed in a symmetrical relationship with the corresponding channel in the responsible monitoring area.

[0014] Furthermore, the accuracy of the device for adjusting the temperature field at a local point on the forming surface needs to be adjusted to the accuracy corresponding to the detection instrument. For example, when a special heating laser is used to heat a local point on the forming surface, the laser spot used needs to be adjusted to a size consistent with the resolution of the monitoring instrument.

[0015] Furthermore, the wind speed of the fan of the equipment used in S2 can be adjusted steplessly at any time according to the splashing situation.

[0016] Furthermore, during the laser scanning process, the wind speed is regulated in real time according to the spatter situation, the energy density is regulated according to the molten pool temperature, and the overall temperature field and local point temperature are regulated according to the temperature gradient; after the scanning is completed, the part cross-sectional geometry and the feature position information on the current plane are monitored, and when deviations occur, incremental and de-quantified scanning operations are promptly organized in the current layer, or the deviations are corrected by adjusting the scanning process of the next layer; during the Z-axis movement, the position of the next formed section in the height direction of the part is monitored and adjusted in real time.

[0017] Furthermore, the taking out and post-processing are specifically: taking out the parts from the forming equipment after the forming is completed, then performing heat treatment to eliminate part of the thermal stress, and then performing wire cutting to remove the substrate and process support. The parts in the present invention refer to engine wheel rotating parts.

[0018] The beneficial effects of the present invention compared with the prior art are:

[0019] (1) The online monitoring method for the forming process quality of the laser selective melting forming process of the engine wheel rotating parts of the present invention monitors and adjusts the whole process from powder spreading to Z-axis movement after the laser scanning in steps and in real time, and can timely discover and correct the instability of multi-physical field coupling in the whole forming process, and suppress the occurrence and development of quality problems such as dimensional accuracy, internal defects and surface roughness;

[0020] (2) The online monitoring method for the quality of the laser selective melting forming process of the engine wheel rotating parts of the present invention sets up multiple signal collectors to independently obtain the target signal of the monitoring area, and uses the data of each signal collector to verify and correct each other, thereby improving the accuracy of the collected data;

[0021] (3) The method for online monitoring the quality of the forming process of the laser selective melting forming process of the engine wheel rotating parts of the present invention proposes dividing the entire forming surface into corresponding points according to the resolution of the monitoring instrument, and independently monitoring and adjusting each point, thereby improving the monitoring accuracy and the simplicity of implementation;

[0022] (4) The method for online monitoring of the quality of the forming process of the laser selective melting forming process of the engine wheel rotating parts of the present invention corresponds the control of the overall temperature field during the forming process to the monitoring of the overall temperature field of the forming surface at each processing point, simplifies the monitoring process, reduces the amount of data, and improves the feedback adjustment response efficiency, thereby realizing online adjustment of the laser scanning process;

[0023] (5) The method for online monitoring the forming process quality of the laser selective melting forming process of the engine wheel rotating parts of the present invention establishes a target signal normal window database through the target part forming simulation, compares the relationship between the measured signal and the normal window in real time during the forming process, and corrects abnormal conditions that may cause quality problems online, ensuring the quality of the parts without subsequent testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the division of monitoring points in the forming area that a temperature field monitoring device is responsible for. DETAILED DESCRIPTION

[0025] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0026] The technical solution provided by the present invention is as follows:

[0027] A method for online monitoring of the quality of an engine wheel rotating part during SLM forming process comprises the following steps:

[0028] S1. Part forming process simulation: Import the part model with the process plan into the simulation software, input the physical information such as equipment, substrate, parts and processing parameters, obtain the powder surface of each layer of the part under the stable processing state, the overall temperature field of the forming surface at each processing point and the part cross-section information, and form a target signal normal window database;

[0029] Simulation software refers to temperature field simulation software, such as Simufact additive software.

[0030] Among them, powder surface information refers to the uniformity, flatness and position accuracy of the powder surface; the overall temperature field of the forming surface at each processing point refers to the collection of normal temperature ranges at the location of the current light spot, within the entire forming surface, and within the resolution of the monitoring instrument; the cross-sectional information of each layer of parts refers to the cross-sectional geometry and three-dimensional position information after the processing of each layer is completed.

[0031] S2. Data import: import the part model of the process plan and the target signal normal window database obtained in step S1 into the forming equipment. The forming equipment divides the entire monitoring area into several corresponding points according to the resolution of the monitoring instrument to realize the monitoring of the temperature field in the forming surface. Figure 1The figure shows a schematic diagram of the division of monitoring points in the forming area that a temperature field monitoring device is responsible for.

[0032] The forming equipment has the function of adjusting the overall temperature field and the temperature field of local points in the forming surface, and the accuracy of the instrument for heating local points in the forming surface is not lower than the resolution of the temperature field monitoring instrument selected by the equipment; the wind speed of the fan selected by the forming equipment can be adjusted steplessly, and the wind speed can be adjusted spontaneously at any time according to the splashing situation; at the same time, each monitoring instrument of the forming equipment used has multiple channels in its corresponding responsible area, and each channel is symmetrical with the corresponding channel in the responsible monitoring area. For example, a certain instrument is responsible for monitoring area A and area B, and three channels of the instrument are arranged in area A and area B, namely A-1, A-2, A-3, B-1, B-2, and B-3. Then, each channel is symmetrical with the corresponding channel in the responsible monitoring area, that is, A-1 is symmetrically distributed with B-1, A-2 is symmetrically distributed with B-2, and A-3 is symmetrically distributed with B-3.

[0033] S3. Laser selective melting forming and online control.

[0034] After all indicators of the equipment meet the forming requirements, forming begins. During the forming process, the entire process from powder spreading to the end of laser scanning is monitored, and the forming process is adjusted in real time based on the relationship between the monitoring data and the corresponding data in the target signal normal window database. In the powder spreading process, timely instructions are given on whether to continue the next step or spread the powder again based on the powder surface monitoring situation; in the laser scanning process, the wind speed is adjusted in real time based on the spatter situation, the energy density is adjusted based on the molten pool temperature, and the overall temperature field and local point temperature are adjusted based on the temperature gradient; after the scanning, the geometric shape of the part section and the position information of each feature on the current plane are monitored, and when deviations occur, the incremental and de-quantified scanning operations are organized in the current layer in a timely manner, or the deviations are corrected by adjusting the scanning process of the next layer; during the Z-axis movement, the position of the next forming section in the height direction of the part is monitored and adjusted in real time.

[0035] S4. Remove parts and perform post-processing: After forming is completed, remove the parts from the forming equipment, then perform heat treatment to eliminate some thermal stress, then perform wire cutting to remove the substrate, and manually remove process supports and other operations.

[0036] Example 1: Online quality monitoring of SLM forming process of a GH4169 high-temperature alloy centrifugal wheel

[0037] (1) Part forming process simulation: The part model of the GH4169 high-temperature alloy centrifugal wheel process solution was imported into the Simufact additive software, and the physical information such as equipment, substrate, part and processing parameters were input to obtain the powder surface of each layer of the part under the stable processing state, the overall temperature field of the forming surface at each processing point and the part cross-section information.

[0038] (2) Data import: The part model of the GH4169 high-temperature alloy centrifugal wheel process solution and the target signal normal window database obtained in step S1 are imported into the forming equipment.

[0039] (3) Laser selective melting forming and online control: After all indicators of the equipment meet the forming requirements, the GH4169 high-temperature alloy centrifugal wheel is formed. During the forming process, the entire process from powder spreading to the end of laser scanning is monitored, and the forming process is adjusted in real time based on the relationship between the monitoring data and the corresponding data in the target signal normal window database. In the powder spreading process, timely instructions are given on whether to continue the next step or spread the powder again based on the powder surface monitoring situation; in the laser scanning process, the wind speed is adjusted in real time based on the spatter situation, the energy density is adjusted based on the molten pool temperature, and the overall temperature field and local point temperature are adjusted based on the temperature gradient; after the scanning, the geometric shape of the part section and the position information of each feature on the current plane are monitored, and when deviations occur, the incremental and de-quantified scanning operations are timely organized in the current layer, or the deviations are corrected by adjusting the scanning process of the next layer; during the Z-axis movement, the position of the next forming section in the height direction of the part is monitored and adjusted in real time.

[0040] (4) Removing the parts and performing post-processing: After forming, the GH4169 high-temperature alloy centrifugal wheel is removed from the forming equipment, and then heat treated to eliminate some thermal stress, wire cutting is performed to remove the substrate, and process support is manually removed.

[0041] Example 2: Online quality monitoring of the SLM forming process of a TC4 titanium alloy primary pump impeller

[0042] (1) Part forming process simulation: The part model of the TC4 titanium alloy primary pump impeller process solution was imported into the Simufact additive software, and the physical information such as equipment, substrate, part and processing parameters were input to obtain the powder surface of each layer of the part under the stable processing state, the overall temperature field of the forming surface at each processing point and the part cross-section information.

[0043] (2) Data import: The part model of the TC4 titanium alloy primary pump impeller process solution and the target signal normal window database obtained in step S1 are imported into the forming equipment.

[0044] (3) Laser selective melting forming and online control: After all indicators of the equipment meet the forming requirements, the TC4 titanium alloy first-stage pump impeller is formed. During the forming process, the entire process from powder spreading to the end of laser scanning is monitored, and the forming process is adjusted in real time based on the relationship between the monitoring data and the corresponding data in the target signal normal window database. In the powder spreading process, timely instructions are given on whether to continue the next step or spread the powder again based on the powder surface monitoring situation; in the laser scanning process, the wind speed is adjusted in real time based on the spatter situation, the energy density is adjusted based on the molten pool temperature, and the overall temperature field and local point temperature are adjusted based on the temperature gradient; after the scanning, the geometric shape of the part section and the position information of each feature on the current plane are monitored, and when deviations occur, the incremental and de-quantified scanning operations are timely organized in the current layer, or the deviations are corrected by adjusting the scanning process of the next layer; during the Z-axis movement, the position of the next forming section in the height direction of the part is monitored and adjusted in real time.

[0045] (4) Removing the parts and performing post-processing: After forming, the TC4 titanium alloy primary pump impeller is removed from the forming equipment, and then heat treated to eliminate some thermal stress, wire cutting is performed to remove the substrate, and process support is manually removed.

[0046] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

[0047] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A method for online monitoring of the quality of the SLM forming process of an engine wheel rotating part, characterized in that: The following steps are involved: S1. Simulate the part forming process: simulate the part model with the process plan, and obtain the target signal normal window database of the part under the stable processing state, wherein the target signal normal window database includes the powder surface information of each layer position, the overall temperature field of the forming surface at each processing point, and the part cross-section information; S2, data import: import the part model of the process plan and the target signal normal window database obtained in step S1 into the forming equipment, and the forming equipment divides the entire monitoring area into a number of corresponding points according to the resolution of the monitoring instrument to realize the monitoring of the temperature field in the forming surface; S3, laser selective melting forming and online control: During the forming process, the powder surface of the powder spreading process, the temperature field and splashing of the scanning process, the part section after scanning, and the position information of each section in the current surface and Z-axis direction are monitored. The stability of the process is judged based on whether the monitoring data is consistent with the corresponding data in the normal window database of the target signal. If the system predicts that it will be unstable, the corresponding feedback adjustment is immediately carried out to avoid quality problems. S4. Pick up the items and perform post-processing.

2. The method for online monitoring quality of the SLM forming process of an engine wheel rotating part according to claim 1, characterized in that: The powder surface information refers to the uniformity, flatness and position accuracy of the powder surface.

3. The method for online monitoring quality of the SLM forming process of an engine wheel rotating part according to claim 1, characterized in that: The overall temperature field of the forming surface at each processing point refers to the set of normal temperature ranges within the entire forming surface and within the resolution of the monitoring instrument at the location of the current light spot.

4. The method for online monitoring quality of the SLM forming process of an engine wheel rotating part according to claim 1, characterized in that: The cross-sectional information of each layer of parts refers to the cross-sectional geometric shape and three-dimensional position information after the processing of each layer is completed.

5. The method for online monitoring quality of the SLM forming process of an engine wheel rotating part according to claim 1, characterized in that: The forming equipment used in step S2 can adjust the overall temperature field and the temperature field of local points in the forming surface, and the accuracy of the instrument for heating the local points in the forming surface is not lower than the resolution of the temperature field monitoring instrument selected by the equipment.

6. The method for online monitoring quality of the SLM forming process of an engine wheel rotating part according to claim 5, characterized in that: Each monitoring instrument of the forming equipment used in step S2 has multiple channels in its corresponding responsible area, and each channel is distributed in a symmetrical relationship with the corresponding channel in the responsible monitoring area.

7. The method for online monitoring quality of the SLM forming process of an engine wheel rotating part according to claim 5, characterized in that: In the forming equipment used in step S2, the wind speed of the fan is selected to be infinitely adjusted according to the splashing situation.

8. The method for online monitoring quality of the SLM forming process of an engine wheel rotating part according to claim 1, characterized in that: During the laser scanning process, the wind speed is regulated in real time according to the spatter situation, the energy density is regulated according to the molten pool temperature, and the overall temperature field and local point temperature are regulated according to the temperature gradient; after the scan, the part cross-sectional geometry and the feature position information on the current plane are monitored, and when deviations occur, incremental and de-quantified scanning operations are promptly organized in the current layer, or the deviations are corrected by adjusting the scanning process of the next layer; during the Z-axis movement, the position of the next formed section in the height direction of the part is monitored and adjusted in real time.

9. The method for online monitoring quality of the SLM forming process of an engine wheel rotating part according to claim 1, characterized in that: The taking out and post-processing are specifically as follows: after the forming is completed, the parts are taken out from the forming equipment, and then heat treated to eliminate part of the thermal stress, and then wire cutting is performed to remove the substrate and process support.

10. The method for online monitoring quality of the SLM forming process of an engine wheel rotating part according to claim 1, characterized in that: The parts are engine wheel rotating parts.

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