A high surface quality laser additive and subtractive forming apparatus and method

Abstract

The application discloses a kind of high surface quality laser additive and subtractive forming device and method, belong to laser additive manufacturing field including: continuous laser, for melting powder and formed entity realizes additive manufacturing;Pulse laser, for removing additive manufacturing parts slag, side powder adhesion or will be additive manufacturing parts nearby powder displacement;Beam time-sharing admission mechanism, for permitting continuous laser and pulse laser to carry out additive / subtractive machining;Galvanometer and optical path system, for expanding beam, collimation, deflection, focusing continuous laser and pulse laser according to the set path processing;Beam spatial position detection module, for realizing the high-precision coincidence of continuous laser and pulse laser in spatial position.The application adopts scanning galvanometer and F-theta mirror to solve the problem of part side powder adhesion in existing laser additive manufacturing, avoids the motion precision difference problem caused by multiple scanning galvanometers, effectively improves the surface quality and dimensional accuracy of laser additive manufacturing parts, meets the industrial application demand.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of laser additive manufacturing, and more particularly, relates to a high-surface-quality laser additive and subtractive forming device and method. BACKGROUND

[0002] Additive manufacturing technology is a new manufacturing technology based on the idea of discrete accumulation, which forms complex parts by layer-by-layer deposition of materials. Laser selective melting forming (or laser powder bed melting forming) is the most critical laser additive manufacturing technology, which is gradually applied in various industrial fields such as aerospace, automobile industry, shipbuilding, mold, power electronics, etc. due to its high forming precision, no need for mold, short production cycle, etc. The technology uses a focused continuous laser beam to melt a loose powder bed to form a molten pool, which forms a molten channel after cooling, and the parts are formed by layer-by-layer accumulation, but the size of the laser spot during the forming process is not the same, and the adhesion and slag of the side surface powder will lead to poor quality of the side surface of the laser selective melting forming (or laser powder bed melting forming) parts, so that parts with internal surfaces, especially internal channels, must be post-processed to meet the needs of industrial applications.

[0003] In view of the problem of powder adhesion and slag on the side surface of laser selective melting forming (or laser powder bed melting forming) parts, the current post-processing methods generally include sandblasting, mechanical subtractive machining and abrasive flow. Sandblasting and mechanical subtractive machining can effectively remove the powder adhesion and slag on the outer surface of the parts, but they cannot be used for the inner surface of the parts. Although abrasive flow can treat the inner surface of the parts to some extent, it cannot be used for internal non-conducting structures. Therefore, there is an urgent need for a method to optimize the surface quality of the parts in situ during laser selective melting forming (or laser powder bed melting forming). The current related published patents use a method of installing a mechanical subtractive machining device in a traditional laser selective melting forming (or laser powder bed melting forming) equipment, such as patent numbers CN104493491A, CN106273440A and CN113967737A, etc. However, this method greatly changes the current industrialized SLM equipment, the equipment is complex, the cost is extremely high, and the introduction of machining leads to low overall processing efficiency.

[0004] Pulsed laser, especially ultra-short pulsed laser, has extremely high peak power due to its extremely short pulse width, which instantaneously vaporizes and removes the material. Therefore, the present application introduces pulsed laser into the traditional laser selective melting forming (or laser powder bed melting forming) equipment to optimize the surface quality of the parts in situ.

[0005] Patents CN104923786A, CN205660160U, CN113977087A, CN111992712A, CN111992879A, CN212598870U, CN114535621A disclose a scheme of a double optical path system, which introduces two laser beams into the shaping area through two sets of beam expansion collimating mirrors, scanning galvanometers and F-theta field lenses. Due to the existence of two sets of scanning galvanometers and F-theta focusing lenses, the device cost is high, the coincidence degree of the two laser beams in spatial position is difficult to adjust, and the motion precision is poor.

[0006] Patent CN111992877A discloses a double-station laser additive and subtractive composite manufacturing device, which continuously performs laser additive manufacturing and laser subtractive manufacturing in two stations. The optical path system position is unchanged, and the station switching is realized by translating the shaping cylinder. This scheme leads to a doubling of the volume of the conventional laser selective melting forming (or laser powder bed fusion forming) equipment, a significant increase in equipment cost, and low forming efficiency due to the back-and-forth reciprocating shaping cylinder during the forming process. It is also difficult to coincide in spatial position, especially under heavy load.

[0007] Patent CN114535610A discloses a double-beam synchronous laser selective melting forming device and method, which uses a beam combiner to combine Gaussian beams and flat-top beams to improve the efficiency of additive manufacturing. This patent does not involve laser additive and subtractive technology. Similarly, patent CN114643369A discloses a scanning method for double-beam composite additive manufacturing, which also does not involve laser subtractive and high-precision forming. Patent CN115889820A and patent CN110977152A disclose a device for combining two laser beams and an additive manufacturing forming method. The focused spot sizes of the two beams after combining are inconsistent, and this patent does not involve laser additive and subtractive technology. Patent CN115026313A discloses a device and method for adjusting the coincidence of the trajectories of two beams by adjusting the first mirror of the scanning galvanometer. It realizes controllable laser additive processing of two beams in different time periods, but this patent does not involve laser subtractive and other aspects.

[0008] Patent CN110587118A discloses a device for simultaneous / periodic entry of dual-beam laser selective melting equipment for additive / subtractive manufacturing. The device uses a non-conventional small-curvature spherical transmitting mirror and two plane mirrors to realize reflection of two beams on the same straight line. However, the device is not easy to control and cannot guarantee spatial coincidence of the two beams during forming. In addition, the patent does not disclose a related method for laser subtractive manufacturing. Patent CN206326260U discloses a device for laser additive / subtractive manufacturing using infrared and green lasers. The device uses a 45° mirror to transmit 1064 nm infrared laser and reflect 532 nm green laser to realize dual-wavelength laser sharing a set of optical path system for infrared laser additive manufacturing and green laser subtractive manufacturing. However, the patent is mainly used for manufacturing hollow overhanging structures in parts and does not mention laser high-precision additive / subtractive manufacturing. Patent CN110369725A discloses a device and method for laser composite additive / subtractive manufacturing. The device uses continuous / ultrafast laser composite method for laser additive / subtractive manufacturing. However, the patent does not mention beam switching scheme and does not provide a specific structure of continuous laser and ultrafast pulse laser switching device.

[0009] It can be seen that the current solutions for improving surface quality of laser additive manufactured parts mainly include composite mechanical subtractive manufacturing, continuous / ultrafast laser composite scheme, and dual-beam switching scheme using dual optical paths and dual stations. There is no single optical path, continuous / short pulse and ultra-short pulse dual laser composite device and method. SUMMARY

[0010] To overcome the above defects and improve the existing technology, the present application provides a high-surface-quality metal / non-metal laser additive / subtractive forming device and method, which solves the problems of powder adhesion and slagging during laser additive manufacturing, and improves the surface quality of laser additive manufactured parts.

[0011] To achieve the above-mentioned purposes, according to one aspect of the present application, a high-surface-quality laser additive / subtractive forming device is provided, which comprises: a continuous laser, a first beam expander and collimator, a pulsed laser, a second beam expander and collimator, a beam time-sharing access mechanism, a beam spatial position detection module, a scanning galvanometer, and an F-theta lens.

[0012] The continuous laser is installed on the first beam expander collimator through an optical fiber and a QBH interface, the pulsed laser is installed on the second beam expander collimator, the first beam expander collimator and the second beam expander collimator are arranged on a beam time-sharing access mechanism, a beam spatial position detection module is arranged between the beam time-sharing access mechanism and a scanning galvanometer, and an F-theta mirror is arranged below the scanning galvanometer, and the scanning galvanometer and the F-theta mirror are respectively used for deflection and focusing of a laser beam. The beam time-sharing access mechanism comprises a reversing servo motor, a mirror and an integral frame, the mirror and the integral frame are directly installed with the reversing servo motor and are driven through key connection, and are locked through bolts (nails).

[0013] The continuous laser is used to generate continuous laser, which is collimated and expanded through the first beam expander collimator, and then forms a continuous focused laser beam to the set position of a required machining part through the scanning galvanometer and the F-theta mirror, and is used for laser additive manufacturing to form a dense solid part; the pulsed laser is used to generate pulsed laser, which is collimated and expanded through the second beam expander collimator, and then forms a pulsed focused laser beam to the set position of a required machining part through the scanning galvanometer and the F-theta mirror, and is used for removing the side adhered powder of the continuous laser additive manufacturing part or moving the powder around the part. The beam time-sharing access mechanism is used for allowing the continuous laser and the pulsed laser to enter the scanning galvanometer and the F-theta mirror respectively for laser processing. The scanning galvanometer and the F-theta mirror are respectively used for laser beam deflection and laser beam focusing.

[0014] Preferably, the beam spatial position detection and feedback are composed of a beam position detector, a galvanometer offset control and a reversing servo motor position control program, the beam position detector detects the relative offset position of a light spot, and feeds back to a host computer for adjusting the position of the reversing servo motor and the scanning field offset of the scanning galvanometer, so as to realize high-precision coincidence of the continuous laser and the pulsed laser in space.

[0015] Preferably, the continuous laser and the beam expander collimator system in the continuous laser are single-mode or multi-mode lasers, the power output power range is 100-100000 W, the power density range is 1.0x10 5 -7.5x10 9 W / cm 2 ; the beam expander collimator in the continuous laser and the beam expander collimator system is a parallel beam outputting device on the market which can expand the diameter of a laser beam to 10-30 mm.

[0016] Preferably, the pulsed laser and beam expansion collimation system can be nanosecond (ns), picosecond (ps) or femtosecond (fs) lasers, with an output average power range of 1-5000 W and a pulse width range covering 1 fs-1000 ns; the beam expansion collimation mirror in the pulsed laser and beam expansion collimation system can expand the diameter of the laser beam to 10-30 mm and output a parallel beam.

[0017] Preferably, the reversing servo motor can be a servo or stepper motor with or without a brake.

[0018] According to another aspect of the present application, a high-surface-quality laser additive and subtractive forming method is provided, comprising the following steps:

[0019] S1. The central control system plans the laser additive and subtractive processing path according to the three-dimensional slice model, laser processing parameters and other information input by the user;

[0020] S2. The beam time-sharing access mechanism drives the reversing servo motor to move to the continuous laser working position according to the program setting, and the continuous laser and beam expansion collimation system generates a continuous, expanded and parallel continuous laser beam, which passes through the scanning galvanometer and F-theta lens to form a focused continuous beam to reach the relevant position of the required processing part set by the program, thereby completing the laser selective melting (or laser powder bed fusion forming) additive manufacturing of the current slice layer;

[0021] S3. The beam time-sharing access mechanism drives the reversing servo motor to move to the pulsed laser working position according to the program setting, and the pulsed laser and beam expansion collimation system generates a continuous, expanded and parallel pulsed laser beam, which passes through the scanning galvanometer and F-theta lens to form a focused pulsed beam to reach the relevant position of the required processing part set by the program, thereby completing the laser subtractive manufacturing of the current slice layer and removing the excess and powder on the surface of the laser additive manufactured part in step S2;

[0022] S4. The central control system drives the required processing part to descend by one slice layer thickness and performs powder laying, the beam time-sharing access mechanism drives the reversing servo motor to move to the continuous laser working position according to the program setting, and steps S2, S3 and S4 are repeated until the part forming is completed.

[0023] Preferably, step S3 can be executed again after a certain number of layers according to the actual processing technology, such as every layer, every 1 layer, every 2 layers, …, every n layers, etc.

[0024] Preferably, the pulsed laser should be an ultrashort pulsed laser, including picosecond (ps) and femtosecond (fs) lasers in blue, green and infrared wavebands.

[0025] According to another aspect of the present application, a high-surface-quality metal / non-metal laser additive / subtractive forming method is provided, the method comprising the following steps:

[0026] S1. The central control system plans continuous laser additive processing paths and pulsed laser powder displacement processing paths according to user-input three-dimensional slice models, laser processing parameters, and other information;

[0027] S2. The light beam time-sharing access mechanism drives the reversing servo motor to move to the continuous laser working position according to the program settings, and the continuous laser and the beam expansion and collimation system generate continuous, expanded, and parallel continuous laser beams, which pass through the scanning galvanometer and the F-theta lens to form focused continuous beams to reach the relevant positions of the required parts to be processed as set in the program, thereby completing the filling line scanning processing of the current slice layer of laser selective melting (or laser powder bed fusion forming) additive manufacturing;

[0028] S3. The light beam time-sharing access mechanism drives the reversing servo motor to move to the pulsed laser working position according to the program settings, and the pulsed laser and the beam expansion and collimation system generate continuous, expanded, and parallel pulsed laser beams, which pass through the scanning galvanometer and the F-theta lens to form focused pulsed beams to reach the relevant positions of the required parts to be processed as set in the program, thereby completing the powder displacement near the outer surface of the current slice layer of laser additive manufactured parts, so as to move the un-melted powder away from the surface of the already laser additive manufactured solid parts;

[0029] S4. The light beam time-sharing access mechanism drives the reversing servo motor to move to the continuous laser working position according to the program settings, and the continuous laser and the beam expansion and collimation system generate continuous, expanded, and parallel continuous laser beams, which pass through the scanning galvanometer and the F-theta lens to form focused continuous beams to reach the relevant positions of the required parts to be processed as set in the program, thereby completing the contour line scanning processing of the current slice layer of laser selective melting (or laser powder bed fusion forming) additive manufacturing. Since the powder has been removed in step S3 during contour scanning, the powder adhesion during continuous laser scanning contour can be effectively avoided, and the powder adhesion caused by continuous laser processing of the filling line will also be eliminated under the action of surface tension and melt wetting;

[0030] S5. The central control system drives the required parts to be processed to descend by one slice layer thickness and performs powder laying, and repeats steps S2, S3, S4, and S5 until the part forming is completed.

[0031] Preferably, step S3 can be executed again after a certain number of layers according to the actual processing technology, such as every layer, every 1 layer, every 2 layers, …, every n layers, etc.

[0032] Preferably, the pulsed laser can be an ultrafast pulsed laser, including picosecond (ps) and femtosecond (fs) lasers in blue, green and infrared wave bands; or the pulsed laser can also be a short pulsed laser, including nanosecond (ns) lasers in blue, green and infrared wave bands.

[0033] Overall, compared with the prior art, the above technical solutions conceived by the present application have the following beneficial effects:

[0034] 1. The present application removes the adhesion of powder and slag on the surface of the part during the laser additive manufacturing process by continuous laser additive and pulsed laser subtractive, effectively improving the surface quality and precision of the laser additive formed part;

[0035] 2. The present application adopts a single optical path design, time-sharing access to two lasers, and realizes effective coupling of functionality and low cost;

[0036] 3. The present application uses a spot position detector combined with a reversing servo motor and a scanning galvanometer offset control program to effectively ensure the spatial coincidence precision of the two beams during the forming process, ensuring the stability of laser additive and subtractive forming and the surface quality and precision of the formed part;

[0037] 4. The forming method provided by the present application can use ultra-short pulsed laser for laser subtractive to obtain ultra-high laser additive manufacturing part surface quality and precision, or can use ns short pulsed laser to realize low-cost laser additive manufacturing part surface quality improvement. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a structural schematic diagram of an embodiment of the present application, which is in a continuous laser working position.

[0039] Figure 2 is a structural schematic diagram of an embodiment of the present application, which is in a pulsed laser working position.

[0040] Figure 3 is an embodiment method of an embodiment of the present application, which improves the surface quality and precision of the laser selective melting formed (or laser powder bed fusion formed) part based on the pulsed laser direct vaporization effect.

[0041] Figure 4 is another embodiment method of an embodiment of the present application, which promotes powder displacement based on the pulsed laser induced shock wave, forms an erosion area between the powder and the laser selective melting formed (or laser powder bed fusion formed) part, and thereby improves the surface quality and precision of the laser selective melting formed (or laser powder bed fusion formed) part.

[0042] The same reference signs are used throughout the drawings to represent the same elements or structures. 1, continuous laser, 2, first beam expander collimator, 3, pulsed laser, 4, second beam expander collimator, 5, beam time-sharing admission mechanism, 6, beam spatial position detection module, 7, F-theta lens, 8, scanning galvanometer, 9, focused continuous light beam, 10, focused pulsed light beam, 11, required machining parts. DETAILED DESCRIPTION

[0043] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0044] As Figure 1 and Figure 2An example of the present application proposes a high-surface-quality metal / non-metal laser additive / subtractive forming device, comprising: a continuous laser 1, a first beam expansion collimator 2, a pulsed laser 3, a second beam expansion collimator 4, a beam time-sharing access mechanism 5, a beam spatial position detection module 6, an F-theta mirror 7, and a scanning galvanometer 8. The continuous laser 1 is mounted on the first beam expansion collimator 2 through an optical fiber and a QBH interface, and the pulsed laser 3 is mounted on the second beam expansion collimator 4 in the same way. The beam spatial position detection module 6 is arranged between the beam time-sharing access mechanism 5 and the scanning galvanometer 8, and the F-theta mirror 7 is arranged below the scanning galvanometer 8. The beam time-sharing access mechanism 5 comprises a reversing servo motor, a mirror, and a whole frame, the mirror and the whole frame are directly mounted with the reversing servo motor, and are driven through key connection and locked through bolts (nails). The continuous laser 1 is used to generate continuous laser, which is collimated and expanded through the first beam expansion collimator 2, and then forms a continuous focusing continuous beam 9 through the scanning galvanometer 8 and the F-theta mirror 7 to reach the set position of the required machining part 11, which is used for metal / non-metal laser additive manufacturing to form a dense solid part; the pulsed laser 3 is used to generate pulsed laser, which is collimated and expanded through the second beam expansion collimator 4, and then forms a focused pulsed beam 10 through the scanning galvanometer 8 and the F-theta mirror 7 to reach the set position of the required machining part 11, which is used to remove the side adhered powder of the continuous laser additive manufacturing part or to displace the powder around the part. The beam time-sharing access mechanism 5 is used to allow the continuous laser and the pulsed laser to enter the scanning galvanometer 8 and the F-theta mirror 7 respectively for laser processing. The scanning galvanometer 8 and the F-theta mirror 7 are respectively used for laser beam deflection and laser beam focusing. The beam spatial position detection module 6 is composed of a beam position detector, a galvanometer offset control, and a reversing servo motor position control program. The beam position detector detects the relative offset position of the light spot, which is fed back to the host computer for adjusting the position of the reversing servo motor and the scanning field offset of the scanning galvanometer 8, so as to realize the spatial coincidence of the continuous laser and the pulsed laser with high surface quality.

[0045] As further illustrated in Figure 1 and Figure 2 , the continuous laser 1 is a single-mode or multi-mode laser, with a power output power range of 100-100000 W and a power density range of 1.0x10 5 -7.5x10 9 W / cm 2The first beam expander collimator 2 is a product on the market that can expand the laser beam diameter to 20-30 mm and output parallel light beams. The pulse laser 3 can be a nanosecond (ns), picosecond (ps), or femtosecond (fs) laser, with an output power range of 1-1000 W and a pulse width range covering 1 fs-1000 ns. The second beam expander collimator 4 is a product on the market that can expand the laser beam diameter to 20-30 mm and output parallel light beams. The reversing servo motor can be a servo or stepper motor with or without a brake.

[0046] In another embodiment of the present application, as shown in Figure 3 , a high-surface-quality additive and subtractive forming method using a continuous laser for additive and combining an ultrashort pulse laser for layer-by-layer subtractive is proposed, comprising the following steps:

[0047] S1. The central control system plans the laser additive and subtractive processing path according to the three-dimensional slice model, laser processing parameters, and other information input by the user;

[0048] S2. The beam time-sharing admission mechanism 5 drives the reversing servo motor to move to the continuous laser working position as shown in Figure 1 , and the continuous laser 1 and the first beam expander collimator 2 generate a continuous, expanded, and parallel continuous laser beam, which passes through the scanning galvanometer 8 and the F-theta lens 7 to form a focused continuous laser beam 9 to the relevant position of the required machining part 11 set by the program, completing the metal / non-metal laser selective melting (or laser powder bed fusion forming) additive manufacturing of the current slice layer;

[0049] S3. The beam time-sharing admission mechanism 5 drives the reversing servo motor to move to the pulse laser working position as shown in Figure 2 , and the pulse laser 3 and the second beam expander collimator 4 generate a continuous, expanded, and parallel pulse laser beam, which passes through the scanning galvanometer 8 and the F-theta lens 7 to form a focused pulse laser beam 10 to the relevant position of the required machining part 11 set by the program, completing the laser subtractive manufacturing of the current slice layer, removing the excess and powder on the surface of the laser additive manufacturing part in step S2;

[0050] S4. The central control system drives the required machining part 11 to descend by one slice layer thickness and performs powder laying, and the beam time-sharing admission mechanism 5 drives the reversing servo motor to move to the continuous laser working position as shown in Figure 1 , and repeats steps S2, S3, and S4 until the part forming is completed.

[0051] In another embodiment of the present application, as shown in Figure 3 , a high-surface-quality additive and subtractive forming method using a continuous laser for additive and combining an ultrashort pulse laser for interval 5-layer subtractive is proposed, comprising the following steps:

[0052] S1. The central control system plans the laser additive and subtractive machining path according to the three-dimensional slice model input by the user, laser processing parameters and other information;

[0053] S2. The beam time-sharing access mechanism 5 drives the reversing servo motor to move to the continuous laser working position as shown in Figure 1 , and the continuous laser 1 and the first beam expander and collimator 2 generate a continuous, expanded and parallel continuous laser beam, which passes through the scanning galvanometer 8 and the F-theta lens 7 to form a focused continuous laser beam 9 to reach the relevant position of the required machining part 11 set by the program, completing the laser selective melting (or laser powder bed fusion forming) additive manufacturing of the current slice layer. The central control system drives the required machining part 11 to descend by one slice layer thickness and performs powder laying, and the step S2 is repeated until the two-layer laser additive manufacturing is completed.

[0054] S3. The beam time-sharing access mechanism 5 drives the reversing servo motor to move to the pulsed laser working position as shown in Figure 2 , and the pulsed laser 3 and the second beam expander and collimator 4 generate a continuous, expanded and parallel pulsed laser beam, which passes through the scanning galvanometer 8 and the F-theta lens 7 to form a focused pulsed laser beam 10 to reach the relevant position of the required machining part 11 set by the program, completing the laser subtractive manufacturing of the current slice layer, removing the excess and powder on the surface of the laser additive manufacturing part in step S2;

[0055] S4. The central control system drives the required machining part 11 to descend by one slice layer thickness and performs powder laying, and the beam time-sharing access mechanism 5 drives the reversing servo motor to move to the continuous laser working position as shown in Figure 1 , and the steps S2, S3 and S4 are repeated until the part forming is completed.

[0056] In another embodiment of the application, as shown in Figure 4 , a high-surface-quality additive and subtractive forming method using a continuous laser for additive manufacturing and combining a short-pulse or ultrashort-pulse laser (nanosecond, picosecond or femtosecond pulse laser) for layer-by-layer machining is proposed, which comprises the following steps:

[0057] S1. The central control system plans the continuous laser additive machining path and the pulsed laser powder displacement machining path according to the three-dimensional slice model input by the user, laser processing parameters and other information;

[0058] S2. The beam time-sharing access mechanism 5 drives the reversing servo motor to move to the continuous laser working position as shown in Figure 1As shown in the continuous laser working position, the continuous laser 1 and the first beam expander and collimator 2 generate continuous, expanded and parallel continuous laser beams, which pass through the scanning galvanometer 8 and the F-theta lens 7 to form a focused continuous laser beam 9 to reach the relevant position of the required machining part 11 set by the program, and complete the filling line scanning processing of the current slice layer of the laser selective melting (or laser powder bed fusion forming) additive manufacturing;

[0059] S3. The beam time-sharing access mechanism 5 drives the reversing servo motor to move to the position as shown in the continuous laser working position according to the program setting, Figure 2 As shown in the pulse laser working position, the pulse laser 3 and the first beam expander and collimator 4 generate continuous, expanded and parallel pulse laser beams, which pass through the scanning galvanometer 8 and the F-theta lens 7 to form a focused pulse laser beam 10 to reach the relevant position of the required machining part 11 set by the program, and complete the powder displacement near the outer surface of the laser additive manufacturing part of the current slice layer, so as to move the unmelted powder away from the surface of the solid part which has been laser additive manufactured;

[0060] S4. The beam time-sharing access mechanism 5 drives the reversing servo motor to move to the position as shown in the continuous laser working position according to the program setting, Figure 1 As shown in the continuous laser working position, the continuous laser 1 and the first beam expander and collimator 2 generate continuous, expanded and parallel continuous laser beams, which pass through the scanning galvanometer 8 and the F-theta lens 7 to form a focused continuous laser beam 9 to reach the relevant position of the required machining part 11 set by the program, and complete the profile line scanning processing of the current slice layer of the laser selective melting (or laser powder bed fusion forming) additive manufacturing. Since the powder has been removed in step S3 during profile scanning, the powder adhesion during continuous laser scanning profile can be effectively avoided, and the powder adhesion caused by continuous laser processing of the filling line will also be eliminated under the action of surface tension and melt wetting;

[0061] S5. The central control system drives the required machining part 11 to descend by one slice layer thickness and performs powder laying, and repeats steps S2, S3, S4 and S5 until the part forming is completed.

[0062] It is easy for those skilled in the art to understand that the above description is only a preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high surface quality laser additive-subtractive forming apparatus, characterized in that, The application relates to a laser additive manufacturing device and method. The device comprises a continuous laser (1), a first beam expanding collimator (2), a pulse laser (3), a second beam expanding collimator (4), a beam time-sharing access mechanism (5), a beam spatial position detection module (6), an F-theta mirror (7) and a scanning galvanometer (8); the continuous laser (1) is arranged on the first beam expanding collimator (2), the pulse laser (3) is arranged on the second beam expanding collimator (4), the first beam expanding collimator (2) and the second beam expanding collimator (4) are arranged on the beam time-sharing access mechanism (5), the beam spatial position detection module (6) is arranged between the beam time-sharing access mechanism (5) and the scanning galvanometer (8), the F-theta mirror (7) is arranged below the scanning galvanometer (8), and the scanning galvanometer (8) and the F-theta mirror (7) are respectively used for deflecting and focusing a laser beam; The continuous laser generated by the continuous laser (1) is collimated and expanded by the first beam expanding collimator (2) and then sequentially enters the scanning galvanometer (8) and the F-theta mirror (7) to form a continuous focused laser beam to reach a preset position of a part to be machined, so that laser additive manufacturing is carried out; The pulse laser generated by the pulse laser (3) is collimated and expanded by the second beam expanding collimator (4) and then sequentially enters the beam time-sharing access mechanism (5), the beam spatial position detection module (6), the scanning galvanometer (8) and the F-theta mirror (7) to form a pulse focused laser beam to reach the preset position of the part to be machined, so that the side adhered powder of the continuous laser additive manufacturing part is removed or the powder around the part is shifted; The beam time-sharing access mechanism (5) is used for switching a continuous laser working position and a pulse laser switching position; when the continuous laser works, the continuous laser does not act on the reflecting mirror in the beam time-sharing access mechanism (5); when the pulse laser works, the pulse laser is reflected by the reflecting mirror in the beam time-sharing access mechanism (5); the beam time-sharing access mechanism (5) comprises a reversing servo motor and a reflecting mirror, is driven through key connection and is used for moving to the continuous laser working position or the pulse laser working position according to a preset path; The beam spatial position detection module (6) is used for detecting the position of the pulse laser beam in real time and adjusting the scanning field deviation of the scanning galvanometer (8) in real time, so that high spatial coincidence of the continuous laser and the pulse laser is realized; The beam spatial position detection module (6) comprises a beam position detector, a galvanometer offset adjustment unit and a reversing servo motor position adjustment unit; the beam position detector is used for detecting the relative offset position of a light spot; the galvanometer offset adjustment unit and the reversing servo motor position adjustment unit are respectively used for adjusting the position of the beam time-sharing access mechanism (5) and the scanning field deviation of the scanning galvanometer (8), so that high-precision coincidence of the continuous laser and the pulse laser in space is realized.

2. A high surface quality laser additive-subtractive forming apparatus according to claim 1, characterized in that, The continuous laser (1) is a single-mode or multi-mode laser, with a power output power range of 100-100000 W and a power density range of 1.0x10 5 -7.5x10 9 W / cm 2 ; the first beam expanding collimating mirror (2) is used for expanding the laser beam diameter to 20-30 mm and outputting parallel light beams.

3. A high surface quality laser additive-subtractive forming apparatus according to claim 1, characterized in that, The pulse laser (3) is a nanosecond (ns), picosecond (ps) or femtosecond (fs) laser, the output power range is 1-1000 W, and the pulse width range covers 1 fs-1000 ns; the second beam expanding collimator (4) is used for expanding the diameter of a laser beam to 20-30 mm and outputting parallel light beams.

4. A forming method based on the laser additive-subtractive forming device of any one of claims 1-3, characterized in that, The pulse laser (3) is a picosecond or femtosecond laser, and the method comprises the following steps: S1. The light beam time-sharing access mechanism (5) moves to the continuous laser working position according to the preset program, the continuous laser (1) generates continuous laser, passes through the first beam expander and collimator (2), then passes through the scanning galvanometer (8) and the F-theta lens (7), forms a focused continuous light beam (9) to the preset position of the required machining part (11) set by the program, and completes the laser additive manufacturing of the current slice layer; S2. The light beam time-sharing access mechanism (5) moves to the pulse laser working position according to the preset program, the pulse laser (3) generates a pulse laser beam, passes through the second beam expander and collimator (4), then passes through the scanning galvanometer (8) and the F-theta lens (7), forms a focused pulse light beam (10) to the preset position of the required machining part (11) set by the program, and completes the laser additive manufacturing of the current slice layer; step S2 is executed according to an interval of n layers, and n is an integer greater than or equal to 1; S3. The required machining part (11) is lowered by one slice layer thickness and powder is laid, and steps S1 and S2 are repeated until the part forming is completed.

5. A method of forming based on the laser additive-subtractive forming device of any one of claims 1-3, characterized in that, The pulse laser is a nanosecond laser, and the method comprises the following steps: S1. The light beam time-sharing access mechanism (5) moves to the continuous laser working position according to the preset program, the continuous laser (1) generates continuous laser, passes through the first beam expander and collimator (2), then passes through the scanning galvanometer (8) and the F-theta lens (7), forms a focused continuous light beam (9) to the preset position of the required machining part (11) set by the program, and completes the laser additive manufacturing of the current slice layer; S2. The light beam time-sharing access mechanism (5) moves to the pulse laser working position according to the preset program, the pulse laser (3) generates a pulse laser beam, passes through the second beam expander and collimator (4), then passes through the scanning galvanometer (8) and the F-theta lens (7), forms a focused pulse light beam (10) to the preset position of the required machining part (11) set by the program, and completes the laser additive manufacturing of the current slice layer; step S2 is executed according to an interval of n layers, and n is an integer greater than or equal to 1; S3. The light beam time-sharing access mechanism (5) moves to the continuous laser working position according to the preset program, the continuous laser (1) generates continuous laser, passes through the first beam expander and collimator (2), then passes through the scanning galvanometer (8) and the F-theta lens (7), forms a focused continuous light beam (9) to the preset position of the required machining part (11) set by the program, and completes the laser additive manufacturing of the current slice layer; S4. The required machining part (11) is lowered by one slice layer thickness and powder is laid, and steps S2, S3 and S4 are repeated until the part forming is completed.

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