CN114888306A - Selective laser melting partition lapping optimization scanning method and system - Google Patents
Selective laser melting partition lapping optimization scanning method and system Download PDFInfo
- Publication number
- CN114888306A CN114888306A CN202210515536.1A CN202210515536A CN114888306A CN 114888306 A CN114888306 A CN 114888306A CN 202210515536 A CN202210515536 A CN 202210515536A CN 114888306 A CN114888306 A CN 114888306A
- Authority
- CN
- China
- Prior art keywords
- scanning
- abnormal temperature
- temperature
- value
- temperature value
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
- B22F10/30—Process control
- B22F10/36—Process control of energy beam parameters
- B22F10/366—Scanning parameters, e.g. hatch distance or scanning strategy
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
- B22F10/20—Direct sintering or melting
- B22F10/28—Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
- B22F10/80—Data acquisition or data processing
- B22F10/85—Data acquisition or data processing for controlling or regulating additive manufacturing processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F12/00—Apparatus or devices specially adapted for additive manufacturing; Auxiliary means for additive manufacturing; Combinations of additive manufacturing apparatus or devices with other processing apparatus or devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F12/00—Apparatus or devices specially adapted for additive manufacturing; Auxiliary means for additive manufacturing; Combinations of additive manufacturing apparatus or devices with other processing apparatus or devices
- B22F12/90—Means for process control, e.g. cameras or sensors
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y10/00—Processes of additive manufacturing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y30/00—Apparatus for additive manufacturing; Details thereof or accessories therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y50/00—Data acquisition or data processing for additive manufacturing
- B33Y50/02—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
Abstract
The invention discloses a selective laser melting subarea lap joint optimization scanning method and a selective laser melting subarea lap joint optimization scanning system, which belong to the technical field of selective laser melting, wherein the method analyzes the temperature distribution of a scanned current layer in real time and collects abnormal temperature values of subarea lap joint areas; if the abnormal temperature value is lower, increasing the lap joint length of the next layer; if the abnormal temperature value is higher, firstly analyzing the width of the zone overlapping area with the higher temperature, reducing the scanning laser power of the next layer at the position of the zone overlapping area within a preset first threshold value, and reducing the overlapping length of the next layer at the position of the zone overlapping area above the preset first threshold value while reducing the laser power; and further combining a feedback regulation mechanism to continuously optimize the parameters of the next layer of the zone overlap scanning. According to the invention, the parameters of the zone lapping scanning are continuously optimized based on temperature feedback to eliminate the abnormal temperature, so that the lapping quality is improved, and the generation of local defects is avoided.
Description
Technical Field
The invention belongs to the technical field of selective laser melting, and particularly relates to a selective laser melting subarea overlapping optimization scanning method and system.
Background
In a Selective Laser Melting (SLM) technique, a part model is first sliced in layers, and then a filling path is calculated according to the profile of the layered slice by using a suitable scan path planning strategy. And the laser scans along a preset filling path to rapidly melt the metal powder in the corresponding area, and then the metal powder is solidified and formed. The manufacturing of the three-dimensional solid part can be realized by continuously superposing in a layer-by-layer scanning forming mode. The technology has the remarkable advantages of high forming efficiency, high material utilization rate, no limitation of part shapes and the like, and is particularly suitable for producing complex parts.
When a selective laser melting technology is adopted to manufacture complex parts, the parts are required to be processed in a partitioned mode, so that the problems of residual stress concentration, powder under-melting and the like caused by overlong scanning lines are avoided. When the partition scanning strategy is adopted, the slice outline of the current layer of the part is divided into a plurality of small partitions, and filling paths in the partitions are sequentially scanned according to a specific sequence, so that filling scanning in the whole outline is completed. In order to ensure that the sub-areas are connected tightly and avoid the occurrence of phenomena such as pores, a certain overlap area is often needed between the sub-areas. However, since the overlapped region is simultaneously scanned and heated by the filling scan line of the adjacent sub-region, the temperature distribution of the region will be greatly different from the rest of the region, which will cause the overlapped region to be more prone to defects and the mechanical properties to be reduced.
Patent CN109047759A discloses a laser scanning method for improving interlayer strength and reducing warpage, in which similar problems are pointed out, and it is proposed that at least a part of the scanning path between each subarea is connected end to end with the scanning path of a part of the adjacent subarea, so as to enhance the interconnectivity between subareas and further improve the forming strength. However, this method only addresses this problem and does not specify how to perform end-to-end connections to achieve the best results. Patent CN113385690A proposes a scan path design method based on a laser melting technique for selective area exposure of metal surface, which indicates that the overlap ratio between the subareas should be 10% -20%, so as to ensure the bonding strength between the subareas, but does not discuss in detail how to adjust this ratio. Patent CN114012107A proposes a multi-laser lapping method for 3D printing equipment, which proposes different lapping modes between partitions, such as hinge type, handle type, mortise and tenon type, dovetail type or deformation tai chi type, and indicates that a lapping region of 0.05-0.2 mm should exist between adjacent partitions. The methods all provide that a certain overlap area should exist between the subareas and respective overlap schemes are provided, but the schemes all need to be judged by operators according to own experience and set in advance. However, in the selective laser melting process, due to the complexity of the manufacturing process, the quality of the lap joints between the sub-regions is often closely related to the scanning condition and the contour shape of the current layer, and the fuzzy and inflexible way set in advance by manual judgment cannot ensure the quality of the lap joints in the whole forming process.
Therefore, how to improve the quality of the lap joint to avoid the generation of local defects becomes a technical problem in the field.
Disclosure of Invention
Aiming at the defects or the improvement requirements of the prior art, the invention provides a selective laser melting zone lapping optimization scanning method and a selective laser melting zone lapping optimization scanning system, and aims to flexibly adjust the lapping length and the laser power of the next zone lapping zone in real time according to the deviation condition of the abnormal temperature value of the zone lapping zone obtained after the current layer is scanned, thereby eliminating the abnormal temperature of the zone lapping zone, improving the lapping quality and avoiding the generation of local defects, thereby solving the technical problem of low lapping quality caused by the fact that the zone lapping mode in the existing selective laser melting forming depends on manual judgment and advanced rigid setting.
In order to achieve the above object, according to one aspect of the present invention, the following technical solutions are provided:
a selective laser melting partition lapping optimization scanning method comprises the following steps:
(S1) acquiring abnormal temperature values of the zone overlapping areas in the current layer from the temperature distribution scanned on the current layer; the abnormal temperature value is a temperature value outside a preset reference temperature range, if the abnormal temperature value is lower than the minimum value in the preset reference temperature range, the abnormal temperature value is lower, otherwise, the abnormal temperature value is higher;
(S2) if the abnormal temperature value is lower, increasing the lap length of the next layer of the zone corresponding to the lower abnormal temperature value in the path planning; if the abnormal temperature value is higher, judging whether the width of a subarea overlapping area corresponding to the higher abnormal temperature value is larger than a preset first threshold value or not, if not, reducing the laser power of the next layer scanning the subarea overlapping area in the path planning, and if so, reducing the laser power of the next layer scanning the subarea overlapping area in the path planning and simultaneously reducing the overlapping length of the next layer of the subarea overlapping area;
(S3) acquiring the temperature distribution after the next layer of scanning in real time, judging whether abnormal temperature values still exist in the overlapping area of each subarea, and if so, repeatedly executing the steps (S2) - (S3) until the abnormal temperature values disappear.
Preferably, the step (S1) is specifically performed by: the method comprises the steps of counting peak temperatures appearing at each point in the scanning process of the current layer in real time, taking the average value of the peak temperatures appearing at each point as a temperature reference value, regarding an interval within +/-10% of the temperature reference value as a normal interval, namely the preset reference temperature range, and regarding a temperature value exceeding the normal interval as an abnormal temperature value.
Preferably, in step (S2), the method for reducing the laser power at the overlap region of the next layer scanned by the partition in the path planning includes: and aiming at each scanning line, when the tail end is scanned, the laser power is reduced so as to ensure that the energy received by the subarea overlapping area corresponding to the higher abnormal temperature value is reduced.
Preferably, when the steps (S2) - (S3) are repeatedly executed, the optimization amplitude is gradually adjusted by adopting a gradient descending method until the abnormal temperature value disappears; the optimized amplitude refers to the amplitude of increasing the lap joint length or reducing the lap joint length and reducing the laser power.
Preferably, in step (S1), a peak temperature distribution map after the current layer is scanned is generated according to the peak temperature appearing at each point; setting a temperature contour line on the peak temperature distribution diagram according to the interval of the temperature reference value +/-10%; and judging whether the abnormal temperature value exists in the zone overlapping area or not by combining the temperature contour lines.
Preferably, the method for acquiring the temperature distribution after the current layer is scanned includes: and acquiring the temperature distribution of the current layer after laser scanning in the selective laser melting process in a thermal infrared imager monitoring mode.
According to another aspect of the invention, the following technical scheme is also provided:
a selective laser melting zoned lap optimization scanning system, comprising:
the temperature monitoring module is used for acquiring the temperature distribution of the scanned current layer in real time and acquiring abnormal temperature values of the overlapped areas of the subareas in the current layer; the abnormal temperature value is a temperature value outside a preset reference temperature range, if the abnormal temperature value is lower than the minimum value in the preset reference temperature range, the abnormal temperature value is lower, otherwise, the abnormal temperature value is higher;
the local variable power module is used for increasing the lap joint length of the next layer of the subarea lap joint area corresponding to the lower abnormal temperature value in the path planning if the abnormal temperature value is lower; if the abnormal temperature value is higher, judging whether the width of a subarea overlapping area corresponding to the higher abnormal temperature value is larger than a preset first threshold value or not, if not, reducing the laser power of the next layer scanning the subarea overlapping area in the path planning, and if so, reducing the laser power of the next layer scanning the subarea overlapping area in the path planning and simultaneously reducing the overlapping length of the next layer of the subarea overlapping area;
and the information feedback module is used for acquiring the temperature distribution after the next layer of scanning in real time, judging whether abnormal temperature values still exist in the overlapping area of each subarea, and if so, repeatedly calling the temperature monitoring module and the local variable power module until the abnormal temperature values disappear.
Preferably, the temperature monitoring module is configured to count peak temperatures occurring at each point in a scanning process of a current layer in real time, use an average value of the peak temperatures occurring at each point as a temperature reference value, regard an interval within ± 10% of the temperature reference value as a normal interval, that is, the preset reference temperature range, and regard a temperature value exceeding the normal interval as an abnormal temperature value.
Preferably, the local variable power module further comprises:
the laser power sub-module is used for reducing the laser power of the next layer scanning the zone lap joint area in the path planning, and the specific method comprises the following steps: and aiming at each scanning line, when the tail end is scanned, the laser power is reduced to ensure that the energy received by the subarea overlapping area corresponding to the higher abnormal temperature value is reduced.
Preferably, when the information feedback module repeatedly calls the temperature monitoring module and the local variable power module, the optimization amplitude is gradually adjusted by adopting a gradient reduction method until the abnormal temperature value disappears; the optimized amplitude refers to the amplitude of increasing the lap joint length or reducing the lap joint length and reducing the laser power.
In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:
1. the selective laser melting subarea overlapping optimization scanning method provided by the invention analyzes the temperature distribution of the scanned current layer in real time, and acquires the abnormal temperature value of the subarea overlapping area; selecting different strategies to adjust the next layer of subarea overlap scanning parameters in real time according to the deviation condition of the abnormal temperature value, and optimizing the laser power and the overlap length; if the abnormal temperature value is lower, which indicates that the zone overlapping area has insufficient overlapping, increasing the overlapping length at the next layer of the zone overlapping area in the path planning; if the abnormal temperature value is higher, firstly analyzing the width of the temperature higher zone overlapping area, adopting different coping strategies for different widths, reducing the scanning laser power of the next layer in the zone overlapping area within a preset first threshold value to reduce the temperature of the next layer, and reducing the overlapping length of the next layer in the zone overlapping area above the preset first threshold value while reducing the laser power; optimizing the laser power and the lap joint length of the temperature abnormal subarea lap joint area during the next layer scanning by the means; and further monitoring whether an abnormal temperature value exists in the actual temperature after the next layer of scanning in real time by combining a feedback regulation mechanism, and continuously optimizing the lapping scanning parameters of the next layer of subarea in the lapping area with abnormal temperature, thereby eliminating the abnormal temperature of the subarea lapping area, improving the lapping quality and avoiding the generation of local defects.
2. The invention provides a specific abnormal temperature value judging method, a next-layer scanning laser power adjusting method and a lap joint length adjusting strategy, wherein in the selective laser melting forming process, the laser scanning parameters and the lap joint length of the next-layer subarea lap joint area are adjusted in real time according to the analysis result of the temperature distribution of the previous layer, the flexibility and the reliability of the method are high, the lap joint quality can be effectively improved, and the generation of local defects is avoided.
3. According to the method, the optimization amplitude is gradually adjusted in the subsequent layer scanning step by adopting a gradient descending method according to the real-time feedback of the temperature distribution after the current layer scanning until the abnormal temperature value disappears; the abnormal temperature of the zone overlapping area can be completely eliminated, the overlapping quality is improved, and the generation of local defects is avoided.
4. The invention only optimizes the lapping area, thus being combined with the prior subarea scanning strategy, multi-laser scanning and other processes and being an optimization supplement to the prior forming process.
Drawings
FIG. 1 is a flow chart of a selective laser melting, zoning, overlapping and optimizing scanning method in a preferred embodiment of the invention;
FIG. 2 is a block diagram of one embodiment of a selective laser melting zoned lap optimization scanning system in accordance with the preferred embodiment of the present invention;
FIG. 3 is an example of an under lap condition in a preferred embodiment of the present invention;
FIG. 4 is an example of an overlap over length in a preferred embodiment of the present invention;
figure 5 is an example of lap power modulation in a preferred embodiment of the invention.
The same reference numbers will be used throughout the drawings to refer to the same elements or structures, wherein:
1. a peak temperature profile; 2. a thermal infrared imager; 3. a germanium glass viewing window; 4. a forming surface; 5. a galvanometer and a laser; 6. a laser window; 7. a variable power modulation control card; 8. a galvanometer control card; 9. a laser control interface; 10. an under lap condition example; 11. peak temperature distribution under insufficient overlap; 12. optimizing the path under the condition of insufficient lapping; 13. an example of an overlap over long condition; 14. peak temperature distribution under an excessively long lap joint condition; 15. optimizing the path under the condition of overlong overlap; 16. an example of the condition after the overlap length is optimized; 17. optimizing the lapping length and then carrying out peak temperature distribution; 18. lap power modulation example.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
In the invention, the subarea overlapping is formed by adopting a subarea scanning strategy, a group of parallel lines are adopted in the subareas for filling, a certain overlapping area, namely a subarea overlapping area, exists between different subareas, and the width of the area is recorded as the overlapping length.
The invention provides a selective laser melting partitioned lapping optimization scanning method based on temperature feedback, which is used for analyzing the temperature distribution condition of a lapping area in real time based on a temperature feedback mode, so that the laser power and the lapping length are optimized, the generation of abnormal temperature of the partitioned lapping area is avoided, the lapping quality is improved, and the generation of local defects is avoided.
As shown in fig. 1, an embodiment of the present invention provides a selective laser melting, zoning, overlapping and optimizing scanning method, including the following steps:
(S1) acquiring abnormal temperature values of the subarea overlapping areas in the current layer from the temperature distribution scanned by the current layer; the abnormal temperature value is a temperature value outside a preset reference temperature range, if the abnormal temperature value is lower than the minimum value in the preset reference temperature range, the abnormal temperature value is lower, otherwise, the abnormal temperature value is higher.
In the embodiment, the temperature distribution after laser scanning in the selective laser melting process is obtained in a thermal infrared imager monitoring mode, and abnormal temperature values of the subarea overlapping areas in the path planning are collected. An infrared thermal imager with 60HZ, 640 × 480 resolution and 20-1200 ℃ temperature measurement range is adopted, and paraxial monitoring is carried out on a forming surface through a germanium glass observation window.
When the temperature distribution condition is analyzed, the peak temperature appeared at each point in the scanning area is counted, a peak temperature distribution graph is generated according to the peak temperature, and the average value of the peak temperature is calculated to be used as a temperature reference value. And extracting the contour of the peak temperature distribution diagram through a contour extraction function in an OpenCV (open source library) to extract a temperature value contour line. And regarding an interval within +/-10% of the temperature reference value as a normal interval, namely the preset reference temperature range, and regarding a temperature value exceeding the interval as an abnormal temperature value. And (4) judging whether abnormal temperature values exist in the zone overlapping area or not and judging the specific deviation proportion by combining the temperature value contour lines.
(S2) if the abnormal temperature value is lower, increasing the lap length of the next layer of the zone corresponding to the lower abnormal temperature value in the path planning; if the abnormal temperature value is higher, whether the width of the subarea overlapping area corresponding to the higher abnormal temperature value is larger than a preset first threshold value or not is judged, if not, the laser power of the next layer scanning the subarea overlapping area in the path planning is reduced, if so, the laser power of the next layer scanning the subarea overlapping area in the path planning is reduced, and meanwhile, the overlapping length of the next layer of the subarea overlapping area is reduced.
In this embodiment, the corresponding overlap length and the scanning laser power are adjusted according to the abnormal temperature value in the overlap area, so as to avoid the abnormal temperature value appearing again at the same position during the next scanning. When the abnormal temperature value of the lap joint area is lower, the lap joint length is not enough, so that under-melted areas exist among the subareas, and the lap joint length needs to be increased; when the abnormal temperature value of the overlap joint area is higher, firstly, the width of the abnormal temperature value area is judged, the overlap joint area with the width of 0.05-0.15 mm should exist between adjacent subareas, when the width of the abnormal temperature value area exceeds 0.2 (the preferred value of a preset first threshold value), the overlap joint length needs to be reduced firstly, and then the laser power for scanning the overlap joint area is correspondingly reduced according to the specific value of the abnormal temperature value. The laser power is adjusted by additionally arranging a variable power modulation control card between the vibrating mirror and a laser connecting wire, adjusting a laser power control signal through the control card, and reducing the laser power at the end point when parallel lines filled in a scanning subarea are scanned so as to achieve the effect of reducing the laser power of a scanning lap joint area.
The preset first threshold value can be flexibly set according to the material and experiment requirements.
(S3) acquiring the temperature distribution after the next layer of scanning in real time, judging whether abnormal temperature values still exist in the overlapping area of each subarea, and if so, repeatedly executing the steps (S2) - (S3) until the abnormal temperature values disappear.
In the embodiment, in the subsequent scanning process, the temperature distribution after scanning is obtained again through the thermal infrared imager, whether the local variable power optimization is effective or not is fed back, and abnormal temperature values are avoided through continuous adjustment among all the layers. If abnormal temperature values exist in the lap joint area after the local variable power optimization and the scanning, comparing the area width and the temperature values of the abnormal temperature values before and after the optimization, and continuing the variable power optimization in a gradient descending mode until the abnormal temperature values disappear.
Compared with the prior art, the invention has the beneficial effects that: by means of temperature feedback, the temperature distribution condition of the lapping area is analyzed in real time, so that the laser power and the lapping length are optimized, the generation of abnormal temperature of the area lapping area is avoided, the lapping quality is improved, and the generation of local defects is avoided. The invention only optimizes the lapping area, thus being combined with the prior subarea scanning strategy, multi-laser scanning and other processes and being an optimization supplement to the prior forming process.
The embodiment of the present invention further provides a selective laser melting, zoning, overlapping and optimizing scanning system, which includes:
the temperature monitoring module is used for collecting abnormal temperature values of the subarea overlapping area in the current layer from the temperature distribution after the current layer is scanned; the abnormal temperature value is a temperature value outside a preset reference temperature range, if the abnormal temperature value is lower than the minimum value in the preset reference temperature range, the abnormal temperature value is lower, otherwise, the abnormal temperature value is higher;
the local variable power module is used for increasing the lap joint length of the zone lap joint area corresponding to the lower abnormal temperature value of the next layer in the path planning if the abnormal temperature value is lower; if the abnormal temperature value is higher, judging whether the width of a subarea overlapping area corresponding to the higher abnormal temperature value is larger than a preset first threshold value or not, if not, reducing the laser power of the next layer scanning the subarea overlapping area in the path planning, and if so, reducing the laser power of the next layer scanning the subarea overlapping area in the path planning and simultaneously reducing the overlapping length of the next layer of the subarea overlapping area;
and the information feedback module is used for acquiring the temperature distribution after the next layer of scanning in real time, judging whether abnormal temperature values still exist in the overlapping area of each subarea, and if so, repeatedly calling the temperature monitoring module and the local variable power module until the abnormal temperature values disappear.
The specific implementation of each module may refer to the description in the method embodiment, and the embodiment of the present invention will not be repeated.
The selective laser melting zoning lap joint optimization scanning method and system provided by the invention are further described in detail in the following with reference to the attached drawings and examples.
Fig. 2 is a schematic view of an experimental platform of the method of the present invention, in the forming process, a vibrating mirror and a laser device in the laser device 5 emit laser, the laser is controlled by the vibrating mirror to move along a scanning path, and the laser is irradiated onto a forming surface 4 through a laser window 6, so that an irradiated area is melted and solidified to form. And the thermal infrared imager 2 collects the temperature distribution on the forming surface 4 through the germanium glass observation window 3, obtains the peak temperature of each point, generates a peak temperature distribution graph 1, and finds the abnormal temperature value distribution condition of the lap joint area by combining the scanning path coordinate information.
Referring to fig. 3 to 5, at this time, there are several possibilities that the monitored abnormal temperature values of the overlapping area are distributed, and if the peak temperature of the overlapping area in the peak temperature distribution condition 11 is significantly lower than that of the surrounding area under the condition of insufficient overlapping, it is indicated that the insufficient overlapping exists here, as shown in the example 10 of the insufficient overlapping condition, because the scanning of the galvanometer has a certain error and the laser power has a certain stable delay when the laser is turned on and off, the scanning lines between the subareas are not completely overlapped together. Under the condition, the connection between the subareas is not tight, the phenomenon of under-fusion is easy to occur in the lap joint area, and pores, cracks and the like are possibly left, so that the forming quality of the part is seriously influenced. The optimization method at this time is to increase the lapping length as shown in the optimized path 12 under the condition of insufficient lapping, so as to ensure the tight combination between the sub-regions and further ensure the forming quality of the parts.
If the peak temperature of the overlap region is significantly higher than the ambient temperature in the peak temperature distribution 14 when the overlap is too long or in the peak temperature distribution 17 after the overlap length is optimized, the width of the overlap region is analyzed. If the overlap region is wider as shown in the peak temperature profile 14 in the case of an excessively long overlap, which indicates that the overlap length is excessively long, as shown in example 13 of the excessively long overlap, the region is prone to thermal stress accumulation and overburning due to a significant difference in thermal history of the overlap region compared to the main region, and the excessively wide overlap region amplifies this problem, and thus needs to be avoided in an effort. The optimization for this is to reduce the overlap length as shown in the optimized path 15 for overlap overlength, so that an excessively wide overlap region is avoided.
However, in the case where the overlap length is optimized reasonably as shown in the case example 16 after the overlap length is optimized, the situation as shown in the case 17 of peak temperature distribution after the overlap length is optimized may still occur, the peak temperature of the overlap area is still significantly higher than the surrounding area, and the specific deviation value is related to the specific length of the corresponding scan line of the overlap area, and the like. This is because the overlap region undergoes two repeated heating events resulting in more energy input than the bulk region. To compensate for this excessive energy input, the optimization is to adjust the power distribution of the scan lines accordingly, as shown in the overlap power modulation example 18. Aiming at each scanning line, when the tail end is scanned, the laser power is properly reduced, so that the energy received by the lap joint area is properly reduced, and the phenomena of overburning and the like in the lap joint area are avoided.
The adjustment of the laser power at the end of the scanning line is realized by modifying the laser control interface 9. In a traditional mode, the galvanometer control card 8 is connected with the galvanometer and the laser 5, and transmits signals through the laser control interface 9, wherein the signals mainly comprise laser light-emitting enable signals, laser state signals, external power given analog quantity, power indication and the like, the external power given analog quantity corresponds to the port No. 22, and the numerical value of the analog quantity influences the light-emitting power of the laser. Therefore, the invention adds the variable power modulation control card 7 between the galvanometer control card 8 and the galvanometer and laser 5, modifies the laser power control signal of each scanning line according to the lapping power modulation result shown as lapping power modulation example 18, and changes the voltage analog quantity of the No. 22 port according to the specific time sequence control, thereby realizing the effect of power modulation.
In practical applications, the optimization of the overlap region is not successful at one time, for example, in the case of under-overlap condition 10, the case of over-overlap may occur after the overlap length is increased, and similarly, in the case of over-overlap condition 13, the case of under-overlap may occur after the overlap length is decreased, even if the overlap length is reasonable and the size of the overlap region is proper in the case of under-overlap condition 16 after the overlap length is optimized, the peak temperature of the region still has an abnormal value, and the laser power needs to be continuously adjusted to minimize the abnormal value. Therefore, after the optimization strategy is executed once, the thermal infrared imager 2 is required to monitor the forming surface 4 again to judge whether the optimized forming surface has the expected effect. And comparing the difference between the expected change amplitude and the actual change amplitude, and gradually adjusting the optimized amplitude by adopting a gradient descending strategy until the ideal effect is approached.
According to the embodiment of the invention, the temperature monitoring module acquires the temperature distribution after laser scanning in the selective laser melting process in a thermal infrared imager monitoring mode, and acquires the abnormal temperature value of the subarea overlapping area in the path planning. The local variable power module adjusts the corresponding overlapping length and the scanning laser power aiming at the temperature value abnormity of the area, thereby avoiding the repeated abnormal temperature value of the overlapping of the areas during the subsequent scanning. The information feedback module is used for acquiring the temperature distribution after scanning again through the thermal infrared imager in the subsequent scanning process, feeding back whether the local variable power optimization is effective or not, and realizing dynamic balance through continuous adjustment among all layers so as to avoid the occurrence of abnormal temperature values. The method and the system can avoid the generation of abnormal temperature in the zone overlapping area, improve the overlapping quality and avoid the generation of local defects.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. A selective laser melting partition lapping optimization scanning method is characterized by comprising the following steps:
(S1) acquiring abnormal temperature values of the subarea overlapping area in the current layer from the temperature distribution after the current layer is scanned; the abnormal temperature value is a temperature value outside a preset reference temperature range, if the abnormal temperature value is lower than the minimum value in the preset reference temperature range, the abnormal temperature value is lower, otherwise, the abnormal temperature value is higher;
(S2) if the abnormal temperature value is lower, increasing the lap length of the next layer of the zone corresponding to the lower abnormal temperature value in the path planning; if the abnormal temperature value is higher, judging whether the width of a subarea overlapping area corresponding to the higher abnormal temperature value is larger than a preset first threshold value or not, if not, reducing the laser power of the next layer scanning the subarea overlapping area in the path planning, and if so, reducing the laser power of the next layer scanning the subarea overlapping area in the path planning and simultaneously reducing the overlapping length of the next layer of the subarea overlapping area;
(S3) acquiring the temperature distribution after the next layer of scanning in real time, judging whether abnormal temperature values still exist in the overlapping area of each subarea, and if so, repeatedly executing the steps (S2) - (S3) until the abnormal temperature values disappear.
2. The selective laser melting, zoning and overlapping optimization scanning method of claim 1, wherein the step (S1) is specifically performed by: the method comprises the steps of counting peak temperatures appearing at each point in the scanning process of the current layer in real time, taking the average value of the peak temperatures appearing at each point as a temperature reference value, regarding an interval within +/-10% of the temperature reference value as a normal interval, namely the preset reference temperature range, and regarding a temperature value exceeding the normal interval as an abnormal temperature value.
3. The method for optimizing scanning of selective laser melting overlap as claimed in claim 1 or 2, wherein in step (S2), the method for reducing the laser power at the overlap region scanned by the next layer in the path plan comprises: and aiming at each scanning line, when the tail end is scanned, the laser power is reduced so as to ensure that the energy received by the subarea overlapping area corresponding to the higher abnormal temperature value is reduced.
4. The selective laser melting zoning lap joint optimization scanning method of claim 1 or 2, wherein the steps (S2) - (S3) are repeated by gradually adjusting the optimization amplitude by using a gradient descending method until the abnormal temperature value disappears; the optimized amplitude refers to the amplitude of increasing the lap joint length or reducing the lap joint length and reducing the laser power.
5. The selective laser melting, zoning and overlapping optimization scanning method according to claim 2, wherein in the step (S1), a peak temperature distribution map after the current layer is scanned is generated according to the peak temperature appearing at each point; setting a temperature contour line on the peak temperature distribution diagram according to the interval of the temperature reference value +/-10%; and judging whether the abnormal temperature value exists in the zone overlapping area or not by combining the temperature contour lines.
6. The selective laser melting partition lapping optimization scanning method of claim 1 or 2, wherein the method for obtaining the temperature distribution after the current layer scanning comprises: and acquiring the temperature distribution of the current layer after laser scanning in the selective laser melting process in a thermal infrared imager monitoring mode.
7. A selective laser melting zoned lap optimized scanning system, comprising:
the temperature monitoring module is used for collecting abnormal temperature values of the zone overlapping areas in the current layer from the temperature distribution scanned on the current layer; the abnormal temperature value is a temperature value outside a preset reference temperature range, if the abnormal temperature value is lower than the minimum value in the preset reference temperature range, the abnormal temperature value is lower, otherwise, the abnormal temperature value is higher;
the local variable power module is used for increasing the lap joint length of the zone lap joint area corresponding to the lower abnormal temperature value of the next layer in the path planning if the abnormal temperature value is lower; if the abnormal temperature value is higher, judging whether the width of a subarea overlapping area corresponding to the higher abnormal temperature value is larger than a preset first threshold value or not, if not, reducing the laser power of the next layer scanning the subarea overlapping area in the path planning, and if so, reducing the laser power of the next layer scanning the subarea overlapping area in the path planning and simultaneously reducing the overlapping length of the next layer of the subarea overlapping area;
and the information feedback module is used for acquiring the temperature distribution after the next layer of scanning in real time, judging whether abnormal temperature values still exist in the overlapping area of each subarea, and if so, repeatedly calling the temperature monitoring module and the local variable power module until the abnormal temperature values disappear.
8. The system according to claim 7, wherein the temperature monitoring module is configured to count peak temperatures occurring at each point in a scanning process of a current layer in real time, take an average value of the peak temperatures occurring at each point as a temperature reference value, regard an interval within ± 10% of the temperature reference value as a normal interval, i.e., the preset reference temperature range, and regard a temperature value exceeding the normal interval as an abnormal temperature value.
9. The selective laser melting zoned lap optimization scanning system of claim 7 or 8, wherein the locally variable power module further comprises:
the laser power sub-module is used for reducing the laser power of the next layer scanning the zone lap joint area in the path planning, and the specific method comprises the following steps: and aiming at each scanning line, when the tail end is scanned, the laser power is reduced so as to ensure that the energy received by the subarea overlapping area corresponding to the higher abnormal temperature value is reduced.
10. The selective laser melting zoning lap joint optimization scanning system according to claim 7 or 8, wherein when the information feedback module repeatedly calls the temperature monitoring module and the local variable power module, the optimization amplitude is gradually adjusted by adopting a gradient descending method until the abnormal temperature value disappears; the optimized amplitude refers to the amplitude of increasing the lap joint length or reducing the lap joint length and reducing the laser power.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210515536.1A CN114888306B (en) | 2022-05-11 | 2022-05-11 | Selective laser melting partition lapping optimization scanning method and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210515536.1A CN114888306B (en) | 2022-05-11 | 2022-05-11 | Selective laser melting partition lapping optimization scanning method and system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114888306A true CN114888306A (en) | 2022-08-12 |
| CN114888306B CN114888306B (en) | 2023-03-28 |
Family
ID=82721384
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210515536.1A Active CN114888306B (en) | 2022-05-11 | 2022-05-11 | Selective laser melting partition lapping optimization scanning method and system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114888306B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117428210A (en) * | 2023-12-20 | 2024-01-23 | 中国商用飞机有限责任公司 | Multi-laser selective fusion lapping method |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030059334A1 (en) * | 2000-02-19 | 2003-03-27 | Jialin Shen | Device and process for sintering a powder with a laser beam |
| CN105618740A (en) * | 2016-01-07 | 2016-06-01 | 西安理工大学 | Online detecting and eliminating device and method for melt channel material defects in laser metal forming |
| CN110681869A (en) * | 2019-10-15 | 2020-01-14 | 上海交通大学 | Method for preparing high-strength and high-toughness magnesium rare earth alloy by selective laser melting additive manufacturing technology |
| CN111974990A (en) * | 2019-05-24 | 2020-11-24 | 天津大学 | Method for repairing defects of overlapping positions of adjacent subareas formed by selective laser melting |
| WO2021004185A1 (en) * | 2019-07-09 | 2021-01-14 | 南京中科煜宸激光技术有限公司 | Method for gradient regulation and control of technological parameter in additive manufacturing process |
| CN113145860A (en) * | 2021-04-13 | 2021-07-23 | 长安大学 | Method, system, equipment and storage medium for manufacturing and preparing parts in additive manufacturing mode |
| CN113500213A (en) * | 2021-06-15 | 2021-10-15 | 南京航空航天大学 | Method and device for reducing internal pore defects of selective laser melting formed part |
| CN113579253A (en) * | 2021-07-19 | 2021-11-02 | 华中科技大学 | Method and device for online monitoring of additive manufacturing multi-scale temperature field |
-
2022
- 2022-05-11 CN CN202210515536.1A patent/CN114888306B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030059334A1 (en) * | 2000-02-19 | 2003-03-27 | Jialin Shen | Device and process for sintering a powder with a laser beam |
| CN105618740A (en) * | 2016-01-07 | 2016-06-01 | 西安理工大学 | Online detecting and eliminating device and method for melt channel material defects in laser metal forming |
| CN111974990A (en) * | 2019-05-24 | 2020-11-24 | 天津大学 | Method for repairing defects of overlapping positions of adjacent subareas formed by selective laser melting |
| WO2021004185A1 (en) * | 2019-07-09 | 2021-01-14 | 南京中科煜宸激光技术有限公司 | Method for gradient regulation and control of technological parameter in additive manufacturing process |
| CN110681869A (en) * | 2019-10-15 | 2020-01-14 | 上海交通大学 | Method for preparing high-strength and high-toughness magnesium rare earth alloy by selective laser melting additive manufacturing technology |
| CN113145860A (en) * | 2021-04-13 | 2021-07-23 | 长安大学 | Method, system, equipment and storage medium for manufacturing and preparing parts in additive manufacturing mode |
| CN113500213A (en) * | 2021-06-15 | 2021-10-15 | 南京航空航天大学 | Method and device for reducing internal pore defects of selective laser melting formed part |
| CN113579253A (en) * | 2021-07-19 | 2021-11-02 | 华中科技大学 | Method and device for online monitoring of additive manufacturing multi-scale temperature field |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117428210A (en) * | 2023-12-20 | 2024-01-23 | 中国商用飞机有限责任公司 | Multi-laser selective fusion lapping method |
| CN117428210B (en) * | 2023-12-20 | 2024-03-08 | 中国商用飞机有限责任公司 | Multi-laser selective fusion lapping method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114888306B (en) | 2023-03-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11192296B2 (en) | Additive manufacturing process distortion management | |
| US11161177B2 (en) | Method and apparatus for detecting defects in freeform fabrication | |
| US10682716B2 (en) | Method for rapidly forming a part using combination of arc deposition and laser shock forging and device implementing same | |
| EP1549454B1 (en) | Multi-layer dmd process with part-geometry independant real time closed loop weld pool temperature control system | |
| CN114888306B (en) | Selective laser melting partition lapping optimization scanning method and system | |
| US9272369B2 (en) | Method for automated superalloy laser cladding with 3D imaging weld path control | |
| CN203843168U (en) | Equipment for high-energy-beam additive manufacturing large-size metal parts | |
| CN105828984A (en) | Method for producing a three-dimensional component | |
| CN106735210A (en) | A kind of control system and control method for powder feeding formula increasing material manufacturing equipment | |
| CN111037062A (en) | Adaptive control and automatic visual inspection method for GTAW weld forming | |
| CN109262110B (en) | Metal electric arc additive manufacturing method | |
| US20190030791A1 (en) | Generative Manufacturing of Components with a Heatable Building Platform and Apparatus for Implementing this Method | |
| EP3756859A1 (en) | System for manufacturing additive manufactured object and method for manufacturing additive manufactured object | |
| CN113385690A (en) | Scanning path design method based on metal surface exposure selective laser melting technology | |
| CN112017186A (en) | Material increase and residual height prediction method based on molten pool image and depth residual error network | |
| CN113042886A (en) | Variable-gap pre-scanning laser self-melting and wire-filling interactive welding method | |
| CN116213932A (en) | Automatic production device for set top box and control method thereof | |
| US20180304406A1 (en) | Melting beam surface processing in additive manufacturing | |
| EP3608085A1 (en) | Method for operating an apparatus for additively manufacturing three-dimensional objects | |
| CN107297897B (en) | A kind of equipment and temperature field adjusting method of Layered manufacturing three-dimension object | |
| EP4140741A1 (en) | Method for prefabricating poor fusion defects by controlling lmd process | |
| CN105268972A (en) | Method for manufacturing three-dimensional object | |
| CN107717255A (en) | A kind of manufacture method of fire grate bar | |
| JP2019142101A (en) | Shaping device | |
| CN116174907A (en) | Method and equipment for controlling penetration of lap joint weld of composite welding |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |