Powder for additive manufacturing, additive manufacturing method and laser metal powder bed

Abstract

The invention provides powder for additive manufacturing, which comprises metal powder and a bonding agent, the bonding agent is a flexible bonding agent, the bonding agent is a non-white paste lipid substance, and the bonding agent and the metal powder are mixed in proportion so that the metal powder is bonded by the bonding agent; the temperature of the metal powder melted by the laser at high temperature is T0, the boiling point of the adhesive is T1, and T1 is smaller than or equal to T0, so that the adhesive is vaporized in the melting process of the metal powder, the metal particles are bonded by the adhesive, higher binding force exists between the powder particles, the capability of resisting to being blown away by airflow in a wind field is higher, pollution caused by flying dust powder is reduced, and the service life of the metal powder is prolonged. The metal powder bed can be provided with a draught fan with large wind power to blow splashing particles and smoke away from the printing area, the quality of the generated metal film belt can be improved, and the thickness of the metal film belt is more uniform.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a powder for additive manufacturing, an additive manufacturing method and a laser metal powder bed. Background Art

[0002] Additive manufacturing is a manufacturing method that directly shapes parts from the bottom up by accumulating materials layer by layer. Laser additive manufacturing technology mainly includes powder bed melting, which refers to laser selective melting. Metal powder interacts with high-energy laser beams to melt and deposit. It uses a motion platform based on a manipulator or machine tool to deposit at a suitable speed, layer by layer, to form parts and structures.

[0003] The laser metal powder bed includes a powder spreading device, which has a great influence on the quality of metal powder laying. The quality of powder spreading directly affects the density and surface roughness of rapid prototyping metal parts. When the powder spreading plane is uneven, it will cause different laser focusing effects at different positions of the powder bed, and the powder melting effects will be different, which will cause the LPBF scanning forming surface to also be uneven, and ultimately cause the density and surface quality of the formed parts to be seriously reduced; uneven powder spreading will also cause the laser melting powder to have a convex or concave forming surface, resulting in a more uneven powder spreading effect next time; powder spreading will change the loose density of the powder, and the loose density will affect the shrinkage of the laser melted powder and the stability of the laser-material interaction. Therefore, the effect of the powder spreading device has a great influence on the metal forming effect.

[0004] In the prior art, a powder spreading device uses a scraper to scrape the powder. The scraped powder layer is not dense enough after laying, the filling amount of metal powder is insufficient, the thickness of the laid metal layer is small, and the gaps between the powders are large, which affects the forming height of the material.

[0005] In addition, the existing metal powder bed uses a fan to blow the flying particles and smoke away from the printing area. When the wind speed is high, it is easy to cause dust to affect the printing quality. When the wind speed is low, it is difficult to blow away the flying particles and smoke. The laid metal powder cannot meet the technical requirements of being blown at high wind speed without causing dust. Summary of the invention

[0006] The purpose of the present invention is to provide a powder for additive manufacturing, an additive manufacturing method and a laser metal powder bed, so as to solve the technical problems existing in the prior art that the thickness of the laid metal layer is small, the gaps between the powders are large, and the laid metal powder cannot meet the requirements of being blown by high wind speed without raising dust.

[0007] The present invention provides a powder for additive manufacturing, comprising: metal powder; an adhesive, which is a flexible adhesive, the adhesive is a non-white paste-like lipid substance, the adhesive and the metal powder are mixed in proportion so that the metal powder is bonded by the adhesive; the temperature at which the metal powder is melted by a laser at high temperature is T0, the boiling point of the adhesive is T1, T1≤T0, so that the adhesive is vaporized during the melting process of the metal powder.

[0008] Furthermore, the adhesive is a paste-like lipid substance or solder paste to which high-temperature-resistant melanin is added, and the solder paste is a paste-like substance including solder powder.

[0009] Furthermore, the material of the metal powder is aluminum and / or copper.

[0010] Further, it is characterized by comprising:

[0011] A forming table, wherein a powder spreading part is provided on the forming table;

[0012] Laser emitting section, where the laser is projected from above the molding table to the powder spreading section;

[0013] A feeding section, which is arranged above the forming table and has a feeding port;

[0014] A roller wheel is arranged below the feeding part and is used to crush the powder thrown out of the feeding part;

[0015] A roller support portion connected to the roller;

[0016] A first driving mechanism is connected to the roller to drive the roller to roll;

[0017] A second driving mechanism is connected to the roller support portion to drive the roller to move left and right;

[0018] A controller electrically connected to the laser emitting unit, the first driving mechanism and the second driving mechanism;

[0019] There are at least two rollers, which are arranged opposite to each other and rotate in opposite directions. When the rollers move to the bottom of the feeding part, the feeding port faces the gap between the two rollers, so that the powder fed from the feeding port is rolled by the two rollers to form a film belt.

[0020] Furthermore, the rollers also include at least one elastic roller, which is arranged below the two opposite rollers and above the forming table, and the elastic roller rolls the film strip on the forming table.

[0021] Furthermore, the laser metal powder bed includes a powder spreading moving part, which is connected to the second driving mechanism and moves left and right at a speed V1; the second driving mechanism drives the roller supporting part to move left and right at a speed V2, V1=V2.

[0022] Furthermore, the first driving mechanism drives the roller to rotate at a linear velocity V3, V1=V2=V3; the laser metal powder bed includes a powder spreading moving part, which is connected to the second driving mechanism and moves left and right at a speed V1, and the elastic roller has a rotation linear velocity V4, V1=V4.

[0023] Furthermore, the laser metal powder bed also includes a third driving mechanism, a rotating wheel is provided at the feeding port, the rotating wheel rotates to open or close the feeding port, and the rotating wheel is connected to the third driving mechanism;

[0024] The third driving mechanism is electrically connected to the controller, and the controller is configured to: when receiving a quantitative feeding or timed feeding instruction issued by the user, the third driving mechanism drives the rotating wheel to rotate to open or close the feeding port.

[0025] Furthermore, the powder spreading moving part includes a guide rail, and the guide rail and the roller supporting part are slidably connected to enable the roller supporting part to move left and right along the guide rail.

[0026] The present application provides an additive manufacturing method, comprising the following steps:

[0027] S1, mixing metal powder and binder to form a pile;

[0028] S2, putting the pile into the feeding part;

[0029] S3, align the feeding port with the position between the two opposite rollers, open the feeding port, and allow the pile to flow from the feeding port to between the two rollers;

[0030] S4, two opposite rollers roll and press the pile to form a film strip of equal thickness;

[0031] S5, the powder spreading moving part moves, and the elastic roller rolls the film tape again, so that the film tape is spread on the powder spreading part;

[0032] S6, the laser emitting part aims at the powder spreading part and emits the laser;

[0033] The process from S3 to S6 is continuously repeated until the film strips are stacked layer by layer from bottom to top until the target part is constructed.

[0034] The technical solution of the present invention has at least the following technical effects:

[0035] The present invention provides a powder for additive manufacturing, including metal powder and adhesive, wherein the adhesive is a flexible adhesive, which is a non-white paste-like lipid substance, and the adhesive and the metal powder are mixed in proportion so that the metal powder is bonded by the adhesive; the temperature at which the metal powder is melted by a laser at high temperature is T0, and the boiling point of the adhesive is T1, T1≤T0, so that the adhesive vaporizes during the melting process of the metal powder, and the metal particles are bonded by the adhesive, and the powder particles have a higher bonding force, and the ability to resist being blown away by wind field airflow is stronger, thereby reducing the pollution of dust powder, and the metal powder bed can be equipped with a fan with a larger wind force to blow the flying particles and smoke away from the printing area, which can improve the quality of the generated metal film belt, so that the thickness of the metal film belt is more uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A schematic diagram of a film strip formed by mixing metal powder and a binder provided in an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of a laser metal powder bed provided by an embodiment of the present invention;

[0039] Figure 3 A partial schematic diagram of a laser metal powder bed provided in an embodiment of the present invention;

[0040] Icons: 1. Powder spreading moving part; 11. Guide rail; 2. Powder crushing mechanism; 21. Roller; 22. Elastic roller; 3. Feeding part; 4. Laser emitting part; 5. Forming table; 61. Metal powder; 62. Adhesive. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0043] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0044] In the present invention, unless otherwise clearly specified and limited, a first feature being above or below a second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them. Moreover, a first feature being above, above, and above a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being below, below, and below a second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0045] The laser metal powder bed includes a powder spreading device, which has a great influence on the quality of the laying of the metal powder 61. The quality of the powder spreading directly affects the density and surface roughness of the rapid prototyping metal parts. In the prior art, the powder spreading device uses a scraper to scrape the powder, and the scraped powder layer is not dense enough after laying, the filling amount of the metal powder 61 is not enough, the thickness of the laid metal layer is small, and the gaps between the powders are large, which affects the forming height of the material.

[0046] In addition, the existing laser metal powder bed uses a fan to blow the flying particles and smoke away from the printing area. When the wind speed is high, it is easy to cause dust to affect the printing quality, and it is difficult to blow away the flying particles and smoke at a low wind speed. The laid metal powder 61 cannot meet the technical requirements of being blown at high wind speed without causing dust.

[0047] The present application provides a powder for additive manufacturing, the powder comprising metal powder 61 and adhesive 62 . The adhesive 62 is a flexible adhesive 62 . The adhesive 62 and the metal powder 61 are mixed in proportion so that the metal powder 61 is bonded by the adhesive 62 .

[0048] In the prior art, the powder used for additive manufacturing is metal powder 61. Since the metal powder 61 is a small particle powder with large gaps between the powder particles, when the wind is strong, the metal particles are easily blown away, causing dust to affect the printing quality. The difference between the technical solution of the present application and the prior art is that a binder 62 is added to the powder.

[0049] The metal particles are bonded together by the adhesive 62, and there is a higher bonding force between the powder particles, and the ability to resist being blown away by the wind field airflow is stronger, which reduces the pollution of dust powder on the one hand; on the other hand, since the probability of dust is reduced, the laser metal powder bed can be equipped with a fan with a larger wind force to blow the flying particles and smoke away from the printing area, which can improve the quality of the generated metal; in addition, since the bonding force of the powder particle support is higher and it resists being blown away by the wind field airflow, it has a stronger ability to resist being blown away by the wind field airflow, and a metal film strip with a more uniform layer thickness can be obtained, and the product quality is higher, thereby improving the forming stability.

[0050] The adhesive 62 can improve the laser energy absorption rate of the metal film strip, increase the laser energy utilization rate, and reduce diffuse reflection. The energy absorption of the metal powder 61 laser in the molten area increases with the increase of the melting degree. When the material is solid, the laser absorption rate is about 5-7%; the liquid absorption rate is 25-35%; in the keyhole state, it can reach more than 90%. When the laser is irradiated on the film strip, the diffuse reflection generated by the film strip will not be completely directly reflected. A part of the laser is refracted multiple times in the film strip, which makes the film strip produce a preheating effect, thereby improving the laser utilization rate. Therefore, the technical solution of adding an adhesive 62 to the metal powder 61 in the present application is a great improvement over the prior art.

[0051] In some embodiments of the present application, the temperature at which the metal powder 61 is melted by the laser at high temperature is T0, and the boiling point of the adhesive 62 is T1, T1≤T0, so that the adhesive 62 is vaporized during the melting process of the metal powder 61, and the probability of the adhesive 62 remaining in the melted technical powder is small. The adhesive 62 is made of a substance that does not react with the metal powder 61, which can reduce the impact of the adhesive 62 on the produced metal parts.

[0052] It can be arranged that the adhesive 62 having solubility is selected so that the bonding effect between the adhesive 62 and the metal powder 61 can be better.

[0053] In some embodiments of the present application, the hardness of the metal powder is lower than HB280, so that the metal powder can be rolled by a roller to form smaller powder particles and the probability of damage to the metal powder caused by long-term rolling of the roller is reduced.

[0054] In some embodiments of the present application, the material of the metal powder is aluminum and / or copper. The aluminum powder or copper powder is combined with an adhesive and rolled to form a metal film strip. The aluminum powder or copper powder in the metal film strip is rolled into smaller particles. The metal film strips are stacked layer by layer from bottom to top until the target part is constructed to form an aluminum part or a copper part. The demand for aluminum parts or copper parts is large. The laser metal powder bed of the present application can produce high-quality aluminum parts and copper parts, and has a wide range of applications.

[0055] In some embodiments of the present application, the adhesive is a paste-like lipid substance to which high-temperature resistant melanin is added. The high-temperature resistant melanin will not decompose or react with the metal powder when irradiated by laser, so that the chemical properties of the generated film strip are stable. On the other hand, the high-temperature resistant melanin can improve the laser absorption rate and diffuse reflection ability of the metal film strip, so as to make the laser heating of the film strip more efficient and improve the utilization rate of the laser.

[0056] Specifically, the appearance of the high temperature resistant melanin is black powder. Pigment melanin can be selected, and the crystal form is spinel type, and the CAS number is: 68186-91-4. The pigment melanin is crushed into melanin powder with smaller particle size, which can improve the laser absorption rate and diffuse reflection ability of the metal film tape.

[0057] In other embodiments of the present application, the adhesive is a solder paste used for welding the same materials. The solder paste is a paste mixture formed by mixing solder powder, flux, and other surfactants, thixotropic agents, etc. The solder paste has the property of high temperature resistance. When the laser irradiates the metal film tape, the solder paste will not decompose or react chemically with the metal powder, and can improve the laser absorption rate and diffuse reflection ability of the metal film tape.

[0058] Reference Figure 1-Figure 3 The present application also provides a laser metal powder bed, which uses mixed metal powder 61 and adhesive 62 powder as raw materials. The laser metal powder bed includes a forming table 5, a laser emitting unit 4, a feeding unit 3, a roller 21, a roller 21 support unit, a first driving mechanism, a second driving mechanism and a controller.

[0059] The forming table 5 is provided with a powder spreading part, which can be set as a powder spreading trough, and the powder is spread in the powder spreading trough. The laser emitting part 4 is located above the powder spreading table, and the laser is projected from the upper part of the forming table 5 to the top of the powder spreading part to locally melt the metal particles. The feeding part 3 is arranged above the forming table 5, and has a feeding port, and the powder mixed with the metal powder 61 and the adhesive 62 is thrown out from the feeding port.

[0060] The roller 21 is disposed below the feeding part 3 and is used for crushing the powder fed from the feeding part 3 . The roller 21 support part is connected to the roller 21 and is used for supporting the axial center of the roller 21 to drive the roller 21 to move.

[0061] The first driving mechanism is connected to the roller 21 to drive the roller 21 to roll around the axis. The second driving mechanism is connected to the supporting portion of the roller 21 to drive the roller 21 to move left and right.

[0062] The controller is electrically connected to the laser emitting unit 4, the first drive mechanism and the second drive mechanism. The first drive mechanism and the second drive mechanism can be configured as motors, one motor drives the roller 21 to rotate, and the other motor drives the roller 21 to move left and right. Both motors are connected to the controller and receive signals from the controller.

[0063] There are at least two rollers 21, which are arranged opposite to each other and rotate in opposite directions, with a very small gap between the two rollers. When the rollers 21 move to the bottom of the feeding part 3, the feeding port is facing the gap between the two rollers 21 to feed the powder, so that the powder fed from the feeding port is rolled by the two rollers 21 rotating relative to each other to form a film strip.

[0064] In the prior art, a scraper is mostly used to scrape powder. The present application uses a roller 21 to crush the powder, which has a stronger crushing effect than the scraper. Since the metal powder 61 with a flexible adhesive 62 is thrown out from the feeding port, rather than the loose powder layer scraped out by the scraper, the roller 21 is used to roll the powder. On the one hand, the roller 21 can prefabricate the powder into a thin film powder belt structure of equal thickness. Since the powder is rolled and squeezed between the two rollers 21, the distance between the metal particles is smaller, the pressed metal film belt is denser, and the thickness of the metal film belt is more uniform. Even if large particles exceeding the powder spreading thickness appear, they can be pressed into a smaller set thickness by the roller 21, so that larger particles of powder can be used in the printing process of smaller layer thickness, which can reduce the cost of powder use and has a higher fault tolerance rate. The uniform thickness of the film belt will make the powder spreading effect more reliable, and the probability of dust when blown by the wind will be further reduced, and the working environment will be better. On the other hand, the roller 21 is ultra-finely ground, and since the powder contains adhesive 62, it is not easy to remain on the roller 21, which reduces the probability of powder adhesion between the rollers 21, and has a higher utilization rate of raw materials, which is a great improvement over the existing technology.

[0065] In some embodiments of the present application, the roller 21 further includes at least one elastic roller 22 , which is disposed below two opposite rollers 21 and above the forming table 5 , and the elastic roller 22 rolls the film strip on the forming table 5 .

[0066] The powder is first rolled by two opposing rollers 21, and then moves downward to between the elastic rolling roller and the powder spreading moving part 1. When the rolled film tape is extruded downward to the height of the bottom of the elastic rolling roller, under the rolling of the elastic rolling roller, the film tape is evenly covered on the substrate plane of the powder spreading part of the forming table 5, so that the thickness of the laid film tape is more uniform, thereby making the laser focusing more accurate, the energy absorption more stable, and able to withstand higher wind speeds in the wind field.

[0067] In some embodiments of the present application, the laser metal powder bed includes a powder spreading movable part 1, which is connected to a second driving mechanism and moves left and right at a speed V1; the second driving mechanism drives the roller 21 support part to move left and right at a speed V2, V1=V2, so that the roller 21 support part drives the roller 21 and the powder spreading movable part 1 to move at the same speed, so that the thickness of the laid film tape is more uniform.

[0068] In some embodiments of the present application, the first driving mechanism drives the roller 21 to rotate at a linear speed V3, V1 = V2 = V3, so that the film strips rolled by the two opposite rollers 21 can be laid exactly in the powder laying groove.

[0069] It can be arranged that the rotational linear velocity V4 of the elastic roller 22 is the same as the velocity of the powder spreading moving part 1V1, so that the film strip rolled by the elastic roller 22 can be laid just in the powder spreading groove, and the powder spreading effect is better.

[0070] In some embodiments of the present application, the powder spreading moving part 1, the feeding part 3, the roller 21 and the roller 21 supporting part are detachably connected into one device, which is convenient for user operation and reduces the number of operating methods.

[0071] In some embodiments of the present application, the two opposite rollers 21 and the motor are driven by a transmission wheel, referring to Figure 3 The roller 21 used for crushing the powder is directly or indirectly transmitted to the two transmission wheels. This transmission method can effectively reduce the shear force on the roller 21, so that the probability of the roller 21 being crushed when subjected to the crushing pressure is low, thereby reducing the probability of the laser metal powder bed using maintenance parts for a long time.

[0072] It can be arranged that the two rollers 21 are symmetrically arranged so that the rolling forces exerted on the two rollers are more symmetrical and can offset part of the forces of each other.

[0073] In some embodiments of the present application, the laser metal powder bed further includes a third drive mechanism, a rotating wheel is provided at the feeding port, the rotating wheel rotates to open or close the feeding port, and the rotating wheel is connected to the third drive mechanism. Optionally, the third drive mechanism is a motor.

[0074] The third drive mechanism is electrically connected to the controller, and the controller is configured to: when receiving a quantitative feeding or timed feeding instruction issued by the user, send a signal to the third drive mechanism to drive the wheel to rotate to open or close the feeding port, thereby meeting the user's set timed quantitative feeding requirements of powder, and can be better used in the printing process to print finer film strips.

[0075] Optionally, the third driving mechanism can drive the feeding part 3 to move left and right and forward and backward. The controller is configured to: receive a position instruction issued by the user, send a signal to the third driving mechanism to drive the feeding part 3 to move to a specified position, and realize the feeding of powder at a predetermined position.

[0076] In some embodiments of the present application, the powder spreading movable part 1 includes a guide rail 11, and the guide rail 11 and the roller 21 support part are slidably connected to enable the roller 21 support part to move left and right along the guide rail 11, limiting the moving path of the roller 21 so that the moving position of the roller 21 is fixed, thereby enabling better coordination between the roller 21 and the powder spreading movable part 1, so that the film tape after being rolled by the roller 21 can be placed at the vertex to enhance the printing effect.

[0077] The following is a detailed description of the additive manufacturing method using the laser metal powder bed laser metal powder bed of the present application:

[0078] S1, mixing metal powder 61 and flexible adhesive 62 in a certain proportion, stirring evenly to form a pile;

[0079] S2, putting the pile into the feeding part 3;

[0080] S3, align the feeding port of the feeding part 3 with the position between the two opposite rollers 21, open the feeding port, and allow the pile to flow from the feeding port to between the two rollers 21;

[0081] S4, two opposite rollers 21 roll and press the piled materials to form a film strip of equal thickness;

[0082] S5, the powder spreading moving part 1 moves, the elastic roller 22 rolls the film strip again, and the film strip is laid in the powder spreading groove of the forming table 5;

[0083] S6, the laser emitting unit 4 aims at the powder spreading slot to emit laser to melt the metal powder 61, if there is unmelted metal powder 61, jump to S7 or S8; if all the metal powder 61 is melted, jump to S3;

[0084] S7, taking out the independent pieces formed by the unmelted powder;

[0085] S8, removing the unmelted powder by ultrasonic vibration of the solvent.

[0086] The controller in the present application may include one or more of the following components: a memory, a processor, and one or more applications, wherein the one or more applications may be stored in the memory and configured to be executed by one or more processors, and the one or more programs are configured to execute the method described in the aforementioned method embodiment.

[0087] The memory may include a random access memory (RAM) or a read-only memory (ROM). The memory may be used to store instructions, programs, codes, code sets or instruction sets. The memory may include a program storage area and a data storage area. The processor may include one or more processing cores. The processor uses various interfaces and lines to connect various parts within the entire electronic device. Professional and technical personnel may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some or all of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A powder for additive manufacturing, characterized in that: include: Metal powder; An adhesive, which is a flexible adhesive, and is a non-white paste-like lipid substance, wherein the adhesive and the metal powder are mixed in proportion so that the metal powder is bonded by the adhesive; The temperature at which the metal powder is melted by the laser is T0, and the boiling point of the adhesive is T1, where T1≤T0, so that the adhesive vaporizes during the melting process of the metal powder.

2. The powder for additive manufacturing according to claim 1, characterized in that The adhesive is a paste-like lipid substance or solder paste added with high-temperature resistant melanin, and the solder paste is a paste-like substance including solder powder.

3. The powder for additive manufacturing according to claim 1 or 2, characterized in that: The material of the metal powder is aluminum and / or copper.

4. A laser metal powder bed, wherein the laser metal powder bed uses the powder according to claim 1, characterized in that: include: A forming table, wherein a powder spreading part is provided on the forming table; A laser emitting unit, which projects laser light from above the molding table to the powder spreading unit; A feeding section, which is arranged above the forming table and has a feeding port; A roller wheel is arranged below the feeding part and is used for rolling the powder thrown out by the feeding part; A roller support portion connected to the roller; A first driving mechanism, connected to the roller to drive the roller to roll; A second driving mechanism, connected to the roller support portion, to drive the roller to move left and right; a controller electrically connected to the laser emitting unit, the first driving mechanism and the second driving mechanism; There are at least two rollers, which are arranged opposite to each other and rotate in opposite directions; When the roller moves to the bottom of the feeding part, the feeding port faces the gap between the two rollers, so that the powder thrown out of the feeding port is rolled by the two rollers to form a film belt.

5. The laser metal powder bed according to claim 4, characterized in that: The rollers also include at least one elastic roller, which is arranged below the two opposite rollers and above the forming table, and the elastic roller rolls the film belt on the forming table.

6. The laser metal powder bed according to claim 4, characterized in that: The laser metal powder bed includes a powder spreading moving part, which is connected to the second driving mechanism and moves left and right at a speed V1; the second driving mechanism drives the roller supporting part to move left and right at a speed V2, V1=V2.

7. The laser metal powder bed according to claim 6, characterized in that: The first driving mechanism drives the roller to rotate at a linear velocity V3, V1=V2=V3; the laser metal powder bed includes a powder spreading moving part, the powder spreading moving part is connected to the second driving mechanism and moves left and right at a speed V1, and the elastic roller has a rotation linear velocity V4, V1=V4.

8. The laser metal powder bed according to claim 4, characterized in that: The laser metal powder bed further comprises a third driving mechanism, a rotating wheel is provided at the feeding port, the rotating wheel rotates to open or close the feeding port, and the rotating wheel is connected to the third driving mechanism; The third driving mechanism is electrically connected to the controller, and the controller is configured to: when receiving a quantitative feeding or timed feeding instruction issued by a user, the third driving mechanism drives the rotating wheel to rotate to open or close the feeding port.

9. The laser metal powder bed according to claim 6, characterized in that: The powder spreading moving part comprises a guide rail, and the guide rail is slidably connected to the roller supporting part so that the roller supporting part moves left and right along the guide rail.

10. An additive manufacturing method for manufacturing the film strip according to claim 3, characterized in that: The following steps are involved: S1, mixing metal powder and binder to form a pile; S2, placing the pile of materials into the feeding part; S3, aligning the feeding port with the position between the two opposite rollers, opening the feeding port, and allowing the pile to flow from the feeding port to between the two rollers; S4, the two opposite rollers roll and press the piled materials relative to each other to form the film strips of equal thickness; S5, the powder spreading moving part moves, and the elastic roller rolls the film strip again, so that the film strip is spread on the powder spreading part; S6, the laser emitting unit aims at the powder spreading unit and emits a laser; The process between S3 to S6 is continuously repeated until the film strips are stacked layer by layer from bottom to top until the target part is constructed.

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