CN106738908A - A kind of quick many sintering increasing material manufacturing device and method - Google Patents

Abstract

The invention discloses rapid multi-sintering additive manufacturing equipment and a method. The equipment includes a powder bed subsystem, a surface sintering subsystem and a wire sintering subsystem installed on a frame; the method includes the following steps: 1. The molding area, that is, the sintering area, is divided into a surface sintering area and a wire sintering area surrounded by the surface sintering area. 2. A thermal radiation source is set above the powder bed; 3. A layer of molding powder is laid on the powder bed; 4. The powder is formed on this layer 5. Change the absorption rate of the part area of the working layer forming powder for the radiation of the heat radiation source; 6. Lay another layer of forming powder on the powder bed to form the working layer forming powder; 7. Forming on this layer Sinter the sintering area of the molding line on the powder, 8. Change the absorption rate of the molding powder in the working layer; 9. Repeat steps 6 to 8 until the entire molding process is completed. The invention has the advantages of combining surface sintering and wire sintering, increasing the forming speed and ensuring the forming precision.

Description

A rapid multi-sintering additive manufacturing equipment and method

technical field

The invention relates to a rapid multi-sintering additive manufacturing equipment and method, which belongs to the additive manufacturing technology, and particularly belongs to the technical field of additive manufacturing based on powder sintering.

Background technique

At present, additive manufacturing technology has been widely used in industrial production after decades of development. Among them, the selective laser sintering (SLS) technology sinters the powder together by laser scanning to form the required parts. It has a wide range of application materials, high molding precision, and good mechanical properties of the parts, so it is getting more and more in the field of industrial applications. Many applications to make functional parts.

US patent US 4863538 A discloses a method and apparatus for manufacturing components by selective sintering. The equipment includes a computer-controlled laser to direct laser energy onto the powder to create a sintered agglomerate. For each cross section, the target of the laser beam is scanned over the powder bed and the powder within the boundaries of the cross section is sintered. By applying subsequent layers of powder and performing the described scan sintering until a complete part is formed. The SLS molding method of this technology is because one or several laser lines scan the molding powder to increase its temperature to achieve the purpose of sintering. This scanning method has a slow molding speed, which limits the application range of this technology.

For example, the patent with publication number CN106322983A discloses a denture soft alloy sintering furnace, which relates to the field of high-temperature sintering equipment. A soft alloy sintering furnace for dentures is composed of five parts: an annular furnace heating system, a gas supply system, a sintering tray set system, a loading table lifting system, and a man-machine control system. The sintering tray set system adopts a protective atmosphere circulation system composed of one large and one small high-temperature ceramic sintering trays. The gas supplied by the gas supply system is protective gas, and the protective gas is argon. The loading table lifting system It is an electric power lifting system, the gas supply system is equipped with a flow meter, and the gas supply system is connected by a gas pipe and a sintering disc set system.

For example, the patent publication number CN106310540A discloses a beam shaper for neutron capture therapy, including a beam entrance, a target, a retarder adjacent to the target, a reflector surrounded by the retarder, The thermal neutron absorber adjacent to the retarder, the radiation shield and the beam exit arranged in the beam shaping body, the target material undergoes a nuclear reaction with the proton beam incident from the beam entrance to generate neutrons, and the neutrons are formed to define a The neutron beam of the main axis, the retarder decelerates the neutrons generated from the target to the epithermal neutron energy region, and the material of the retarder is composed of at least one of LiF, Li2CO3, Al2O3, AlF3, CaF2 or MgF2 It is made of powder sintering equipment through the powder sintering process from powder or powder compact into a block. The reflector guides the neutrons off the main axis back to the main axis to improve the intensity of the epithermal neutron beam. The thermal neutron absorber is used Thermal neutrons are absorbed to avoid excessive doses to superficial normal tissues during treatment, and radiation shielding is used to shield leaked neutrons and photons to reduce normal tissue doses in non-irradiated areas.

For example, the patent publication number CN205881682U discloses a process ring applied to a ring ferrite core. The process ring as a whole has a circular structure, the upper and lower surfaces of the process ring are flat, and there are more than two vents on the lower surface; the vents are grooves arranged on the lower surface of the ferrite core process ring, and the grooves are connected. The inner and outer sides of the process ring; the groove is an arc-shaped structure, the depth of the groove is not higher than 1/2 of the width of the side of the process ring, and the width of the groove is not higher than the length of the radius of the inner surface of the process ring. The utility model has novel structure and simple and reasonable design. By setting vents on the process ring through the inner and outer sides of the process ring, the air flow provided by the sintering equipment can enter from the lower part of the cylinder through the four vents, and then be discharged from the upper part to form an air flow cycle. For example, the patent with the publication number CN205860766U discloses a zirconia sintering furnace, which consists of five parts: an annular furnace heating system, a sintering furnace body, a sintering tray, a loading table lifting system, and a man-machine control system. The man-machine control system adopts touch screen PID+PLC control system, the heating curve can be displayed dynamically in real time, the sintering process curve can be edited and pre-stored, the sintering data can be saved automatically, and it is equipped with USB interface, which can be remotely controlled with PC. The system adopts an automatic lifting structure, the sintering tray adopts a stackable structure, and the annular furnace heating system adopts a ring arrangement structure of heating elements.

To sum up, the disadvantage of the traditional existing technology is that the traditional SLS/SLM molding method is one or several laser line scanning molding, and the molding speed is slow; the powder-based 3DP additive manufacturing technology is powder-oriented Spray glue, its initial molding strength is not high, the subsequent processing is complicated, and it is difficult to form functional parts.

Contents of the invention

The object of the present invention is to provide a rapid multi-sintering additive manufacturing equipment and method capable of overcoming the above-mentioned technical problems. The invention overcomes the deficiencies of the traditional technology, and proposes a Fast Multi-Sintering additive manufacturing method and equipment for realizing the Fast Multi-Sintering additive manufacturing method. The invention also improves the molding while maintaining the SLS/SLM molding accuracy. speed.

The rapid multi-sintering additive manufacturing equipment of the present invention is composed of a powder bed subsystem, a surface sintering subsystem and a wire sintering subsystem installed on a frame; the powder bed subsystem includes a vertical lifting molding platform, a powder conveying device and a powder laying device, the powder conveying device transports the molding powder to the powder laying device, and the powder laying device accumulates the molding powder above the molding platform to form a powder bed, and the surface of the powder bed contains sintered and solidified sintered area, the sintering area is composed of a surface sintering area and a wire sintering area surrounded by a surface sintering area; the surface sintering subsystem includes a heat radiation source and a surface sintering initiation device; The radiation absorption rate of the molding powder for the thermal radiation source, so that the molding powder in the surface sintering area causes its temperature to rise by absorbing the radiation of the thermal radiation source to achieve sintering; the wire sintering subsystem includes a wire sintering energy source, A laser scanning device and a focusing device; the focusing device focuses the radiation of the wire sintering energy source on the upper surface of the powder bed, and the laser scanning device scans the wire sintering area so that the formed powder in this area passes through Absorption of radiation from a line sintering energy source causes its temperature to rise to sintering.

Surface sintering is carried out in a two-dimensional plane, and the sintering speed is fast, but due to the power limitation of the thermal radiation source and the range of change rate of the radiation absorption rate of the molding powder to the thermal radiation source, the surface sintered area and the non-sintered The temperature difference in the area is small, especially the temperature gradient in the transition part from the sintered area to the non-sintered area is relatively mild, and the accuracy of the surface sintering profile is often not high. The non-sintered area refers to the part outside the sintered area.

In order to overcome the problem of low surface sintering profile accuracy, the wire sintering area is surrounded outside the surface sintering area, and the wire sintering subsystem focuses on the wire sintering energy source in the sintering area of the powder bed to achieve higher sintering power density and higher sintering profile accuracy , However, because of the line scanning, the speed of wire sintering is relatively low.

The surface sintering initiation device includes a liquid numerical control spray head installed on a horizontal movement device, and the liquid numerical control spray head sprays radiation absorbing agent to the surface sintering area and changes the radiation absorption rate of the area to the thermal radiation source.

The surface sintering initiating device includes an initiating light projection device and the molding powder contains a photosensitive material, and the initiating light projection device projects the initiating light onto the surface sintering region to change the absorption spectrum of the photosensitive material of the molding powder , thereby changing its absorptivity to the radiation of the thermal radiation source, and causing the temperature of the molded powder in the surface sintering region to increase to achieve sintering.

The wire sintering energy source is laser. The molding powder is nylon powder. Since the basic structure of the powder 3D printer is already a standard configuration and is a well-known technology, so there is no explanation.

The rapid multi-sintering additive manufacturing method of the present invention comprises the following steps:

1. Divide the molding area of each layer, that is, the sintering area, into a surface sintering area and a wire sintering area surrounded by the surface sintering area. The line sintering area includes the outer contour of the molding area, and can also include an internal connection rib structure planned according to a certain filling ratio, and the certain filling ratio is specifically a filling ratio greater than 0 and less than 50%; the surface sintering area is the rest of the internal Closed plane space. Laser sintering in the line sintering area can improve the precision; the surface sintering area can be sintered by radiation irradiation, which is beneficial to improve the molding speed.

2. A thermal radiation source is set above the powder bed;

3. Lay a layer of molding powder on the powder bed to form a working layer of molding powder;

4. Forming said line sintering region on the layer of forming powder by focusing and scanning radiation sintering of a line sintering energy source;

5. Change the absorption rate of the heat radiation source radiation in some areas of the forming powder of the working layer, so that the surface sintering area will absorb more radiation from the heat radiation source and cause its temperature to rise and cause sintering; on the one hand, changing the absorption rate of the heat source radiation has A variety of methods, including but not limited to spraying heat source radiation absorbers, change the absorption spectrum of the photosensitive material in the molding powder by inducing light; on the other hand, changing the heat source radiation absorption rate can be positive or negative, for example, it can make the sintered area The radiation absorption rate increases, and the radiation absorption rate of the non-sintered area can also be reduced;

6. Lay another layer of molding powder on the powder bed to form a working layer of molding powder;

7. Forming said wire sintered area by focusing and scanning radiation sintering of a wire sintering energy source on this layer of molding powder and bonding it with the sintered part of the previous layer;

8. Change the absorption rate of the heat radiation source radiation in the part area of the molding powder in the working layer, so that the surface sintered area will absorb more radiation from the heat radiation source, causing its temperature to rise and cause sintering, and combine with the sintered part of the previous layer together;

9. Repeat steps 6 to 8 until the entire molding process is completed.

In addition, for the suspended area, the sintered area of the working layer corresponds to the overlapping part of the previous layer as the non-sintered area, and the wire sintering method is used to improve the molding accuracy.

The advantage of the invention is that surface sintering and wire sintering are combined, the forming speed is greatly improved and the forming precision is guaranteed at the same time.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the rapid multi-sintering additive manufacturing equipment of the present invention;

Fig. 2 is a structural representation of the horizontal motion device of the present invention;

Fig. 3 is a structural schematic diagram of a molded part processed by the present invention.

In the figure, 1-frame, 2-laser scanning device, 3-liquid numerical control nozzle, 4-horizontal movement device, 5-radiation absorber, 6-molding powder, 7-thermal radiation source, 8-powder storage chamber, 9 -Powder molding chamber, 10-Powder pushing platform, 11-Forming platform, 12-Powder laying device, 13-Surface sintering area, 14-Line sintering area, 15-Inkjet subsystem lateral guide, 16-Inkjet subsystem lateral Slider, 17-longitudinal guide rail of inkjet subsystem, 18-longitudinal slider of inkjet subsystem, 19-backbone outline in forming area, 20-backbone connecting rib in forming area.

detailed description

Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. The basic structure of powder additive manufacturing equipment, powder handling, powder storage, powder delivery, powder laying, and the model slices involved in the additive manufacturing method to generate the molding area of each layer and the principle of layered construction are well-known technologies and will not be repeated here. .

As shown in FIG. 1 , the rapid multi-sintering additive manufacturing equipment of the present invention is composed of a powder bed subsystem, a laser scanning subsystem, an inkjet printing subsystem and a thermal radiation source 7 installed on a frame 1 .

The powder bed subsystem includes a vertical lifting molding platform 11, a powder conveying device and a powder laying device 12; the powder conveying device is composed of a powder storage chamber 8 and a powder pushing platform 10; the powder pushing platform 10 is a part of the powder conveying device part. The powder laying device accumulates the molding powder 6 above the molding platform 11 to form a powder bed, that is, the powder bed is composed of the molding powder 6 between the powder molding cavity 9 and the molding platform 11; A sintered region that undergoes sintering and solidification is included, the sintered region is composed of a surface sintered region and a wire sintered region surrounding the surface sintered region.

The surface sintering subsystem includes a heat radiation source 7 and a surface sintering initiation device; the surface sintering initiation device can change the radiation absorption rate of the molding powder in the surface sintering area to the heat radiation source, thereby making the forming of the surface sintering area The powder absorbs the radiation from the thermal radiation source to cause its temperature to rise to achieve sintering; for example, the surface sintering inducing device is an inkjet printing subsystem, and the ink ejected by it can change the radiation absorption rate of the formed powder for the thermal radiation source The inkjet printing subsystem includes an infusion device, a nozzle maintenance device, a horizontal movement device 4 and a liquid digital control nozzle 3 installed on the horizontal movement device 4 .

The laser scanning subsystem includes a laser (not shown in the figure), a laser scanning device 2 and a focusing device (not shown in the figure) as a wire sintering subsystem; the focusing device focuses the radiation of the wire sintering energy source on the The upper surface of the powder bed is scanned by the laser scanning device 2 in the wire sintering area, so that the formed powder in this area absorbs the radiation of the wire sintering energy source and causes its temperature to rise to achieve sintering. Fig. 2 is a schematic structural diagram of the numerical control nozzle of the surface sintering initiation device.

The horizontal motion device as shown in Figure 2 includes two inkjet subsystem transverse guide rails 15 installed on the frame 1, and two inkjet subsystems that can slide on the inkjet subsystem transverse guide rails 15 respectively. System horizontal slider 16, between the two inkjet subsystem horizontal sliders 16, an inkjet subsystem longitudinal guide rail 17 is installed, and the inkjet subsystem longitudinal slider 18 is on the inkjet subsystem longitudinal guide rail 17 longitudinal movement. Therefore, the vertical slider 18 of the inkjet subsystem can move horizontally in the area defined by the lateral guide rail 15 of the inkjet subsystem and the longitudinal guide rail 17 of the inkjet subsystem. In addition, a liquid numerically controlled nozzle 3 is installed on the longitudinal slider 18 of the inkjet subsystem, and the liquid numerically controlled nozzle 3 can also be placed in the area defined by the horizontal guide rail 15 of the inkjet subsystem and the longitudinal guide rail 17 of the inkjet subsystem. Horizontal movement inside, and the area defined by the horizontal guide rail 15 of the inkjet subsystem and the longitudinal guide rail 17 of the inkjet subsystem will cover the area of the molding platform 11 in the powder molding chamber 9 to complete the set inkjet operation.

The radiation of the thermal radiation source 7 is infrared, especially near infrared, and the radiation of the thermal radiation source 7 also includes visible light components; the selection of the thermal radiation source 7 includes but is not limited to ceramic infrared sources, halogen lamps, and carbon fiber infrared sources. It should be based on the absorptivity of the molding powder to heat radiation and the absorptivity of heat radiation after being sintered by the surface.

As shown in Figure 3, the wire sintered area of the molding area includes at least the outer contour of the molding area, and at the same time, in order to increase the mechanical strength of the molding part and reduce the deformation during the molding process, the wire sintering area of the molding area can also include the internal rib structure.

The wire sintered area and the surface sintered area of the profiled area can partially overlap. The overlapping regions undergo both wire and face sintering operations. The first way of overlapping is edge overlapping where the wire sintering area and the surface sintering area meet, and the area of the edge overlapping part is usually no more than two-thirds of the area of the wire sintering area. The advantages of the edge overlap are: on the one hand, it increases the bonding strength between the wire sintering area and the surface sintering area; Improve reliability. The second overlapping method is that part of the line sintering area forms a network structure and passes through and covers part of the surface sintering area to form overlapping overlap, which can also be regarded as the case where part of the rib structure overlaps with the surface sintering area. The overlapped part of the cover is usually subjected to wire sintering operation first, and then surface sintering operation, the purpose of which is to reduce the warping and shrinkage deformation of the surface sintering area by reducing the local area of the surface sintering area and providing an adhesion structure in the surface sintering area .

In addition, the forming sequence of the line sintering area and the surface sintering area in the forming area can be exchanged and crossed, that is, the line sintering area is formed first and then the surface sintering area is formed, or the surface sintering area is formed first and then the line sintering area is formed, or crossed. Carry out, for example, form the ribs of the backbone first, then form the sintered area of the surface, and finally form the outer contour of the backbone. Because it involves radiation absorption and sintering of the heat radiation source 7 by the molding powder, the sintering temperature of the molding powder used is generally selected below 600 degrees, including low melting point alloys and polymer materials, such as nylon powder.

The rapid multi-sintering additive manufacturing method of the present invention comprises the following steps:

1. Divide the molding area of each layer, that is, the sintering area, into a surface sintering area and a wire sintering area surrounded by the surface sintering area. The wire sintering area includes the outer contour 19 of the molding area, and can also include an internal connection rib structure 20 planned according to a certain filling ratio, and the certain filling ratio is specifically a filling ratio greater than 0 and less than 50%; as shown in FIG. 3 ; The surface sintering area is the remaining internal closed planar space. Laser sintering in the line sintering area can improve the precision; the surface sintering area can be sintered by radiation irradiation, which is beneficial to improve the molding speed.

2. A thermal radiation source is set above the powder bed;

3. Lay a layer of molding powder on the powder bed to form a working layer of molding powder;

4. Forming said line sintering region on the layer of forming powder by focusing and scanning radiation sintering of a line sintering energy source;

5. Change the absorption rate of the heat radiation source radiation in some areas of the forming powder of the working layer, so that the surface sintering area will absorb more radiation from the heat radiation source and cause its temperature to rise and cause sintering; on the one hand, changing the absorption rate of the heat source radiation has A variety of methods, including but not limited to spraying heat source radiation absorbers, change the absorption spectrum of the photosensitive material in the molding powder by inducing light; on the other hand, changing the heat source radiation absorption rate can be positive or negative, for example, it can make the sintered area The radiation absorption rate increases, and the radiation absorption rate of the non-sintered area can also be reduced;

6. Lay another layer of molding powder on the powder bed to form a working layer of molding powder;

7. Forming said wire sintered area by focusing and scanning radiation sintering of a wire sintering energy source on this layer of molding powder and bonding it with the sintered part of the previous layer;

8. Change the absorption rate of the heat radiation source radiation in the part area of the molding powder in the working layer, so that the surface sintered area will absorb more radiation from the heat radiation source, causing its temperature to rise and cause sintering, and combine with the sintered part of the previous layer together;

9. Repeat steps 6 to 8 until the entire molding process is completed.

In addition, for the suspended area, the sintered area of the working layer corresponds to the overlapping part of the previous layer as the non-sintered area, and the wire sintering method is used to improve the molding accuracy.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the disclosure of the present invention are all It should be covered within the protection scope of the claims of the present invention.

Claims (7)

1. it is a kind of quickly to sinter increasing material manufacturing equipment more, it is characterised in that including：Rack-mounted powder machine tool system, face Sintering subsystem and line sintering subsystem；The powder machine tool system include vertical lift shaped platform, powder conveyance device and Powder for molding is delivered to the powder laying apparatus, the powder laying dress by powder laying apparatus, the powder conveyance device Put and the powder for molding is deposited in the shaped platform top composition powder bed, the powder bed upper surface includes and carries out sintering curing Sintering region, the sintering region by face sinter region and be enclosed in face sintering zone it is overseas line sintering region constitute；Institute Stating face sintering subsystem includes infrared source and face sintering initiating device.

2. a kind of much quicker sintering increasing material manufacturing equipment according to claim 1, it is characterised in that the line sinters subsystem System includes line sintering energy source, laser scanning device and focusing arrangement；The focusing arrangement gathers the radiation in line sintering energy source The burnt upper surface in powder bed.

3. a kind of much quicker sintering increasing material manufacturing equipment according to claim 1, it is characterised in that the face sintering triggers Device includes the liquid numerical control nozzle on horizontal movement device, and be sprayed onto for radiation adsorber by the liquid numerical control nozzle The face sinters region.

4. a kind of much quicker sintering increasing material manufacturing equipment according to claim 1, it is characterised in that the face sintering triggers Device includes triggering optical projection device and the powder for molding includes photosensitive material, and the initiation optical projection device will trigger light Project to the face sintering region.

5. a kind of much quicker sintering increasing material manufacturing equipment according to claim 1, it is characterised in that the line sintering energy Source is laser.

6. a kind of much quicker sintering increasing material manufacturing equipment according to claim 1, it is characterised in that the powder for molding is Nylon powder.

7. it is a kind of quickly to sinter increasing material manufacturing device and method, it is characterised in that to comprise the following steps more：

(1) it is, that sintering region is divided into face sintering and region and is enclosed in overseas line sintering zone, face sintering zone by every formable layer region Domain, the line sintering region includes the outline of forming area, additionally it is possible to including the inside planned according to certain filling proportion Dowel structure, certain filling proportion is specially the filling proportion less than 50% more than 0；Face sintering region is in remaining Portion closure plane space, line sintering region can improve precision by laser sintered；Face sinters side of the region by radiation exposure Formula sintering is conducive to improving shaping speed；

(2), powder bed top sets infrared source；

(3) a formable layer powder, is laid on powder bed, working lining powder for molding is formed；

(4), pass through to focus on and line sintering zone described in the radiation sinter molding in scan line sintering energy source on the formable layer powder Domain；

(5), change working lining powder for molding subregion for absorptivity that infrared source radiate so that face sintering region due to The more radiation in absorptive thermal radiation source causes its temperature to raise generation sintering；On the one hand change has to the absorptivity of thermal source radiation Various methods, including sprinkling thermal source radiation adsorber, the absorption spectrum of photosensitive material in powder for molding is changed by triggering light；Separately On the one hand it is that erect image also can be negative-appearing image to change thermal source absorptive rate of radiation, can increase the absorptive rate of radiation in sintering region, also can Reduce the absorptive rate of radiation in non-sintered region；

(6) a formable layer powder, is re-layed on powder bed, working lining powder for molding is formed；

(7), pass through to focus on and line sintering zone described in the radiation sinter molding in scan line sintering energy source on the formable layer powder Domain, and be partially bonded together with the sintering of preceding layer；

(8), change working lining powder for molding subregion for absorptivity that infrared source radiate so that face sintering region due to More the radiation in absorptive thermal radiation source causes its temperature to raise generation sintering, and is combined one with the part of sintering of preceding layer Rise；

(9), repeat step (6) to step (8) until completing whole forming process.