A laser coaxial wire-based additive manufacturing device and method based on split beam heating

Abstract

The application discloses a kind of laser coaxial fuse additive devices and methods based on spectroscopy heating, it is related to laser additive technical field.The application adopts spectroscopy lens and divides annular laser into two annular lasers inside and outside, annular laser beam in inside is used for preheating of welding wire, annular laser beam in outside is used for additive, simultaneously, two laser beams can adjust energy ratio of additive process in real time.The device of the application includes beam shaping mirror group, laser, wire feeding mechanism, laser spectroscopy component, energy distribution system, laser head shell.Beam shaping mirror group is used to change the beam shape of laser beam, and the energy distribution system can change the rotation angle of the spectroscopy lens, thereby changing the distribution ratio of laser energy.The laser coaxial fuse additive device of the application preheats the welding wire, improves the additive speed on the basis of ensuring the molding of additive part, and improves the additive efficiency.

Description

TECHNICAL FIELD

[0001] The application relates to a laser coaxial wire-based additive device and method based on light-splitting heating, and belongs to the technical field of laser additive manufacturing. BACKGROUND

[0002] Additive manufacturing technology, also known as 3D printing technology, has attracted extensive attention of many scholars in recent years. Among many additive manufacturing methods, laser additive manufacturing is a relatively advanced manufacturing method for preparing metal components with excellent performance, and has been widely used in the fields of aerospace, automobiles, military equipment, medical treatment and the like. Laser coaxial wire-based additive technology adopts a ring-shaped light spot, and the wire is located inside the light spot, thereby reducing the directional limitation of the additive scanning path and improving the process stability and flexibility.

[0003] During laser coaxial wire-based additive manufacturing, the peak energy of the laser is relatively high, so that the temperature gradient of the molten pool is relatively large, columnar crystals are easily formed, and the anisotropy of the additive organization is increased. Moreover, since the temperature of the wire is relatively low, the wire needs to be completely melted after entering the molten pool to ensure good forming quality, and the additive efficiency is reduced. The emergence of hot-wire laser additive manufacturing reduces the peak energy of the laser to a certain extent, and improves the additive efficiency. However, the current hot-wire laser additive manufacturing generally adopts an external current mode, which increases the complexity of the process. In order to solve the problems of high peak energy during laser coaxial wire-based additive manufacturing and complex hot-wire additive process, it is urgent to invent a laser coaxial wire-based additive device and method based on light-splitting heating, which preheats the wire by using laser light splitting, reduces the peak temperature of the laser during additive manufacturing, and improves the additive efficiency. SUMMARY

[0004] The purpose of the application is to preheat the wire by using laser light splitting, and to propose a laser coaxial wire-based additive device and method based on light-splitting heating, which divides the laser beam into two laser beams, and respectively uses the two laser beams for wire preheating and additive manufacturing, accurately controls the wire preheating temperature and the peak temperature of the additive laser, and finally obtains well-formed additive organization and improves the additive efficiency.

[0005] To achieve this purpose, the application adopts the following technical solutions:

[0006] A laser coaxial wire-based additive device based on light-splitting heating, characterized in that the device comprises a beam shaping mirror group, a laser, a wire feeding mechanism, a laser light splitting component, an energy distribution system and a laser head shell.

[0007] Optionally, the energy distribution system comprises a computer, a light splitting lens, and a heat-insulating temperature measuring nozzle. The light splitting lens can reflect and transmit laser. The computer can adjust the rotation angle of the light splitting lens to change the proportion of laser reflection and transmission, thereby adjusting the power of the heating laser beam and changing the preheating temperature of the welding wire. After heating, the welding wire enters the heat-insulating temperature measuring nozzle. The heat-insulating temperature measuring nozzle can prevent the high-temperature welding wire from contacting the additive beam focusing lens, thereby avoiding damage to the lens. At the same time, the heat-insulating temperature measuring nozzle can measure the temperature of the welding wire and feed back the temperature information to the computer. The computer can issue instructions to adjust the angle of the light splitting lens in real time, so that the welding wire maintains a constant temperature.

[0008] Optionally, the light beam shaping mirror group comprises a light beam shaping lens, a light splitting prism, a light beam bending lens, a reflecting lens, a light splitting lens, a flat lens, and a focusing lens. The laser beam is generated by a laser, transmitted by an optical fiber, and emitted by a laser emitting head. The initial unshaped laser beam is a point light source with Gaussian distribution. Then, the laser beam becomes a parallel ring-shaped light after passing through the light beam shaping lens. After passing through the light splitting prism, the laser beam becomes a symmetrically distributed semi-ring-shaped light beam. After being reflected by the light beam bending lens, the semi-ring-shaped light beam reaches the light splitting lens. The laser beam is split into two beams after passing through the light splitting lens. One beam of laser continues to maintain parallel transmission with the welding wire, reaches the light splitting prism, and is re-integrated into a ring-shaped laser beam. Finally, the ring-shaped laser beam converges through the focusing lens and reaches the additive part. The other beam of laser transmits horizontally to the reflecting lens, changes direction to be parallel to the welding wire, and finally converges through the focusing lens to reach the surface of the welding wire and heat the welding wire.

[0009] Optionally, the reflecting lens is located above the flat lens, and the flat lens is mainly used to support the reflecting lens.

[0010] Optionally, the energy distribution system can adjust the output power of the laser in real time during the additive process, and control the wire feeding speed of the wire feeding mechanism.

[0011] Optionally, the laser coaxial wire melting additive method based on light splitting heating comprises the following steps:

[0012] 1. Turn on the wire feeding mechanism, feed the welding wire into the wire feeding mechanism, straighten it through the straightener, and then enter the coaxial wire melting laser head. Stop feeding the wire after the welding wire passes through the heat-insulating temperature measuring nozzle.

[0013] 2. Turn on the energy distribution system, set the additive path, input the brand or composition of the welding wire in the energy distribution system, call the database, and if the selected material is in the database, call the melting point parameters of the material in the database. If the selected material is not in the database, call the melting point parameters of the material with the closest composition in the database. The energy distribution system controls the angle of the reflecting lens according to the material properties to achieve energy matching between the heating beam and the additive beam.

[0014] 3). Turn on the laser, print according to the preset additive path, and the wire feeding mechanism runs synchronously according to the predetermined wire feeding speed; during the printing process, the energy distribution system adjusts the energy distribution of the heating light beam and the additive light beam in real time according to the forming quality of the additive part until the additive is completed.

[0015] Advantages of the present application

[0016] 1. The annular laser beam is split, the energy ratio of the two beams is adjustable in real time, the energy utilization ratio of the additive process is optimized, the internal annular beam is used for heating the wire, and the external annular beam is used for the additive process, and the microstructure of the additive part is improved.

[0017] 2. The addition of hot wire makes the wire melt at a faster speed in the molten pool, improves the additive speed on the basis of ensuring the forming of the additive part, and improves the additive efficiency.

[0018] 3. The device has high intelligence, can adjust the energy ratio of the additive process in real time, and can obtain good additive forming effect. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a whole schematic diagram of a coaxial wire melting device based on split heating;

[0020] Figure 2 It is a schematic diagram of laser spots at different positions;

[0021] In the figure:

[0022] 1-laser emitting head;

[0023] 21-unshaped laser beam, 22-annular beam, 23-semi-annular beam, 24-double semi-annular beam, 25-double annular beam, 26-heating annular beam, 27-additive annular beam;

[0024] 3-laser head shell;

[0025] 41-beam shaping lens, 42-split prism, 43-beam bending lens, 44-reflective lens, 45-split lens, 46-flat lens, 47-split prism, 48-heating beam focusing lens, 49-additive beam focusing lens;

[0026] 5-welding wire;

[0027] 6-heat-insulating temperature measuring nozzle;

[0028] 7-straightener;

[0029] 8-wire feeding mechanism;

[0030] 9-energy distribution system;

[0031] 10-laser;

[0032] 11-additive. DETAILED DESCRIPTION

[0033] The application will be further described below in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the application, and not to limit the application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings, not all the structures.

[0034] In the description of the application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0035] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "under", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0036] In the description of the present embodiment, the terms "up", "down", "right", etc. orientation or position relationship is based on the orientation or position relationship shown in the drawings, only for the convenience of description and simplification of operation, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the application. In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.

[0037] When the laser coaxial wire is added, the peak energy of the laser is high, so that the temperature gradient of the molten pool is large, which is easy to form columnar crystals, and increases the anisotropy of the additive organization. Not only that, because the wire temperature is low, the wire needs to be completely melted after entering the molten pool to ensure good forming quality, which reduces the efficiency of the additive.

[0038] To address the aforementioned issues, this embodiment provides a laser coaxial filament additive manufacturing device and method based on spectroscopic heating, which can be used in the field of laser additive manufacturing.

[0039] like Figure 1 As shown, the laser coaxial welding wire additive manufacturing device based on beam splitting heating described in this invention includes a beam shaping lens group, a laser, a wire feeding mechanism, a laser beam splitting component, an energy distribution system, and a laser head housing. The energy distribution system includes a computer, a beam splitting lens, and a heat-insulating temperature-sensing nozzle. The beam splitting lens reflects and transmits laser light. By adjusting the rotation angle of the beam splitting lens via computer commands, the ratio of laser reflection to transmission can be changed, thereby adjusting the power of the heating laser beam and altering the preheating temperature of the welding wire. After heating, the welding wire enters the heat-insulating temperature-sensing nozzle, which prevents the high-temperature welding wire from contacting the additive beam focusing lens, thus avoiding lens damage. Simultaneously, the heat-insulating temperature-sensing nozzle measures the temperature of the welding wire and feeds the temperature information back to the computer. The computer issues commands to adjust the angle of the beam splitting lens in real time, maintaining a constant temperature for the welding wire.

[0040] The beam shaping lens assembly includes a beam shaping lens, a beam splitter prism, a beam bending lens, a reflecting lens, a beam splitter lens, a plane lens, and a focusing lens. The laser beam is generated by a laser, transmitted through an optical fiber, and emitted from the laser emitter. It enters the coaxial fused wire laser head. Initially, the unshaped laser beam is a Gaussian-distributed point source. Subsequently, the laser beam passes through the beam shaping lens and becomes a parallel ring beam. After passing through the beam splitter prism, it becomes a symmetrically distributed semi-ring beam. The semi-ring beam is reflected by the beam bending lens and reaches the beam splitter lens. The laser beam is split into two beams after passing through the beam splitter lens. One laser beam continues to propagate parallel to the welding wire through the lens and is reassembled into a ring laser beam after reaching the beam splitter prism. Finally, it is converged by the focusing lens and reaches the additive component. The other laser beam propagates horizontally and reaches the reflecting lens, where its direction changes to be parallel to the welding wire. Finally, it is converged by the focusing lens and reaches the surface of the welding wire, heating the welding wire.

[0041] The reflective lens is located above the plane lens, which is mainly used to support the reflective lens. The energy distribution system can adjust the output power of the laser in real time during the additive manufacturing process, while controlling the wire feeding speed of the wire feeding mechanism.

[0042] The laser coaxial filament additive manufacturing method based on spectroscopic heating includes the following steps:

[0043] (1). Open the wire feeding mechanism and feed the DP800 high-strength steel welding wire with a diameter of 1.0mm into the wire feeder. After being straightened by the straightener, it enters the coaxial fusion laser head. Stop feeding the wire after the welding wire passes through the heat-insulating temperature measuring wire nozzle.

[0044] (2). Open the energy distribution system, import the additive path designed by the layered slicing software into the computer, input the brand of DP800 high-strength steel welding wire in the energy distribution system, call the database, select the laser output power as 2500W according to the composition and attribute of the DP800 high-strength steel welding wire in the database, and the welding wire preheating temperature as 700 DEG C, the energy distribution system automatically calculates the angle of the light splitting lens according to the material attribute in the database and the laser energy and preheating temperature information, so that the welding wire preheating temperature can reach the preset temperature at the beginning of the additive;

[0045] (3). Start the laser, print according to the preset additive path, and the wire feeding mechanism synchronously operates according to the predetermined wire feeding speed; in the printing process, the energy distribution system adjusts the energy distribution of the heating light beam and the additive light beam according to the forming quality of the additive part in real time until the additive is finished.

[0046] Obviously, the above-mentioned embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. For those skilled in the art, according to the idea of the present application, the specific embodiments and application range can be changed, and the content of the specification should not be understood as limiting the present application. Any modification, equivalent replacement and improvement within the spirit and principle of the present application should be included in the protection scope of the claims of the present application.

Claims

1. A laser coaxial filament additive manufacturing device based on spectroscopic heating, characterized in that, Includes a beam shaping mirror assembly, a laser (10), a wire feeding mechanism (8), a laser beam splitting component, an energy distribution system (9), and a laser head housing (3); The energy distribution system (9) includes a computer, a beam splitter (45), and a heat-insulating temperature measuring nozzle (6). The beam splitter (45) can reflect and transmit laser light. By adjusting the rotation angle of the beam splitter (45) through computer commands, the ratio of laser reflection and transmission can be changed, thereby adjusting the power of the heating laser beam and changing the preheating temperature of the welding wire (5). After heating, the welding wire (5) enters the heat-insulating temperature measuring nozzle (6). The heat-insulating temperature measuring nozzle (6) can prevent the high-temperature welding wire (5) from contacting the additive beam focusing lens (49) to avoid damage to the lens. At the same time, the heat-insulating temperature measuring nozzle (6) can measure the temperature of the welding wire (5) and feed the temperature information back to the computer. The computer issues commands to adjust the angle of the beam splitter (45) in real time to keep the welding wire (5) at a constant temperature. The beam shaping lens assembly includes beam shaping lenses (41, 46), beam splitting prisms (42, 47), beam bending mirrors (3), reflecting mirrors (44), beam splitting lenses (45), plane lenses (46), and focusing lenses (48, 49). The laser beam is generated by a laser (10), transmitted through an optical fiber, emitted by a laser transmitter (1), and enters a coaxial fused-wire laser head. The initial unshaped laser beam (21) is a Gaussian-distributed point source. Subsequently, the laser beam becomes a parallel ring light after passing through the beam shaping lens (41), and then becomes a symmetrically distributed beam after passing through the beam splitting prism (42). The semi-circular laser beam is reflected by the beam bending lens (43) and then reaches the beam splitting lens (45). After passing through the beam splitting lens (45), the laser beam is split into two beams. One laser beam continues to be transmitted through the lens in a direction parallel to the welding wire (5) and reaches the beam splitting prism (47) where it is reassembled into a circular laser beam. Finally, it is converged by the focusing lens (49) and reaches the additive part (11). The other laser beam is transmitted horizontally and reaches the reflecting lens (44), where its direction changes to be parallel to the welding wire (5). Finally, it is converged by the focusing lens (48) and reaches the surface of the welding wire (5) and heats the welding wire (5).

2. The laser coaxial filament additive manufacturing device based on spectroscopic heating as described in claim 1, characterized in that: The reflective lens (44) is located above the plane lens (46), which is mainly used to support the reflective lens (44).

3. The laser coaxial filament additive manufacturing device based on spectroscopic heating as described in claim 1, characterized in that: The energy distribution system (9) can adjust the output power of the laser (10) in real time during the additive manufacturing process, while controlling the wire feeding speed of the wire feeding mechanism (8).

4. The additive manufacturing method using the laser coaxial fuse additive manufacturing device based on spectroscopic heating as described in claim 1, characterized in that, Includes the following steps: 1). Open the wire feeding mechanism (8), feed the welding wire (5) into the wire feeder, straighten it through the straightener (7) and enter the coaxial welding wire laser head. Stop feeding the wire after the welding wire passes through the heat-insulating temperature measuring wire nozzle (6); 2) Open the energy distribution system (9), set the additive path, input the grade or composition of the welding wire in the energy distribution system (9), call the database, if the selected material is in the database, call the melting point parameter of the material in the database; if the selected material is not in the database, call the melting point parameter of the material with the closest composition in the database; the energy distribution system (9) controls the angle of the reflective lens (44) according to the material properties to realize the energy ratio of the heating beam and the additive beam; 3). Turn on the laser (10) and print according to the preset additive path. The filament feeding mechanism (8) runs synchronously according to the predetermined filament feeding speed. During the printing process, the energy distribution system (9) adjusts the energy distribution between the heating beam and the additive beam in real time according to the forming quality of the additive part (11) until the additive process ends.

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