CN106041080B - Dusty material laser sintering (SLS) device - Google Patents

Abstract

The invention relates to a powder material laser sintering forming device, which belongs to the technical field of 3D printing additive manufacturing, and provides a powder material laser sintering forming device with simple operation, high powder spreading efficiency, good powder spreading effect and wide application range. The technical solution is that hydraulic cylinders are installed in the collecting cylinder, forming cylinder and powder supply cylinder, and the pushing baffle is arranged on the hydraulic cylinder, the powder spreading slide rail is set in the middle of the forming cavity, and the roller frame is slidably installed on the powder spreading On the slide rail, the powder spreading roller is installed on the roller frame, the roller frame screw is arranged on the roller frame, the preheating guide rail is arranged on the upper part of the forming cavity, the preheating shell is slidably installed on the preheating guide rail, and the preheating shell is set There is a preheating rod, an infrared thermometer is installed outside the preheating shell, a laser scanning system is installed on the top of the molding cavity, and an intake and exhaust device is installed on the side wall of the molding cavity; the invention is widely used in laser sintering of powder materials.

Description

Powder material laser sintering forming device

technical field

The invention relates to a powder material laser sintering forming device, which belongs to the technical field of 3D printing additive manufacturing.

Background technique

In recent years, 3D printing technology has set off a 3D printing boom in academia and industry with its unique advantages. 3D printing is based on the three-dimensional model, using polymer plastics, photosensitive resin, metal powder, film-coated powder and other materials as raw materials, and realizes the manufacture of three-dimensional models through the principle of layer-by-layer superposition of materials, integrating CAD, mechanical automation and other technologies , has the characteristics of rapidity, high flexibility, and high efficiency, and is especially suitable for manufacturing complex structural models in small batches. Its products have been used in automobile manufacturing, aerospace and other fields.

Selective laser sintering (SLS) technology is a kind of 3D printing technology. SLS uses laser to selectively sinter solid powder in layers, and makes the sintered solidified layers superimposed to form parts of the required shape.

The whole process is as follows: when working, the powder cylinder piston (powder feeding piston) rises, and the powder spreading roller evenly spreads a layer of powder on the forming cylinder, and the computer controls the two-dimensional scanning trajectory of the laser beam according to the prototype slice model. The solid powder material is selectively sintered to form a layer of the part. After one layer is sintered, the piston of the forming cylinder is lowered by one layer thickness, and the powder spreading system spreads new powder, and the laser beam is controlled to scan and sinter the new layer. This cycle goes on and on, layer by layer, until the three-dimensional parts are formed. The outstanding advantage of SLS forming is that it uses a wide range of forming materials. At present, the materials that can be successfully processed by SLS include paraffin, polymer, metal, ceramic powder, etc. and their composite powder materials. Due to the variety of SLS forming materials, material saving, excellent performance of formed parts, and SLS forming without support, the application of SLS is becoming more and more extensive.

At present, in the SLS forming process, there are still the following problems to be solved: ① It is difficult to monitor the powder quality. The quality of powder spreading has an important influence on the quality of formed parts. When powder spreading is uneven, it is easy to cause internal defects of formed parts, thereby reducing product quality and even waste products.

② It is difficult to monitor whether the warping deformation of the formed part occurs during the forming process. During the forming process, when the part warps and deforms, if it cannot be found in time and the process parameters are adjusted in time, the degree of deformation will become more and more serious, resulting in forming failure .

③ The preheating of the formed powder is uneven and the accuracy of the preheating temperature is low. There are two main heat sources for the preheating of the powder during the powder spreading process. preheating. Due to the different sizes of the molded parts, the temperature distribution in different parts is different, and the preheating of the laid powder is not uniform. At the same time, it is difficult for the preheating system to compensate for the uneven preheating caused by the formed part itself to the laid powder, which eventually leads to uneven preheating of the formed powder and insufficient preheating temperature control accuracy, which affects the quality of the formed part, and even makes it difficult to form .

④ The gas protection system in the forming cavity has uneven air intake. During the forming process, some powders need to be protected by gas to prevent oxidation. However, during the SLS forming process, if the protective gas distribution in the forming cavity is uneven, the formed parts will be oxidized, thus Affect the quality of formed parts.

⑤Due to the above problems, it is difficult for one device to form different powders. For example, nylon has very strict requirements on the precision of powder preheating temperature control, so a high-precision preheating system is required; some powder forming processes require gas protection to prevent the oxidation of formed parts, and a gas protection system needs to be installed. The currently developed SLS forming equipment is mainly aimed at specific forming powders, and it is difficult to meet various powder forming requirements.

Contents of the invention

In order to solve the technical problems existing in the prior art, the present invention provides a powder material laser sintering forming device with simple operation, high powder spreading efficiency, good powder spreading effect and wide application range.

In order to achieve the above purpose, the technical solution adopted in the present invention is a powder material laser sintering forming device, which includes a forming cavity, and the lower part of the forming cavity is provided with a collection cylinder, a forming cylinder and a powder supply cylinder, and the forming cylinder is located in the set Between the material cylinder and the powder supply cylinder, a hydraulic cylinder is arranged in the material collecting cylinder, the forming cylinder and the powder supply cylinder, and the piston rod of the hydraulic cylinder is provided with a pushing baffle, and the middle part of the forming cavity There is a powder spreading slide rail, and the roller frame is slidably installed on the powder spreading slide rail. The powder spreading roller is installed on the roller frame, and a roller driving motor is arranged on one side of the powder spreading roller. The roller frame is also provided with a roller A rack screw, the end of the drum rack screw is provided with a drum rack driving motor, the upper part of the molding cavity is provided with a preheating guide rail, and the preheating shell is slidably installed on the preheating guide rail through a preheating bracket. A preheating rod is arranged inside the preheating casing, an infrared thermometer is arranged outside the preheating casing, and a reflector is arranged on the inner wall of the preheating casing, a laser scanning system is arranged on the top of the molding cavity, and a laser scanning system is installed on the top of the molding cavity. The side wall is provided with an intake and exhaust device, and the hydraulic oil cylinder, the roller frame drive motor, the preheating rod, the infrared thermometer and the laser scanning system are all connected with the main control system.

Preferably, the air intake and exhaust device mainly consists of a plurality of air intake hoods and exhaust devices arranged on the side wall of the molding cavity. The circulation device is connected, the oxygen sensor is installed on the inner wall of the molding cavity, and the intake air circulation device and the oxygen sensor are connected with the main control system.

Preferably, the powder spreading drum is provided with a powder spreading heating rod and a powder spreading temperature measuring couple, and the two sides of the drum frame are respectively provided with an infrared emitting device and an infrared receiving device, and the powder spreading heating rod, powder spreading temperature measuring The galvanic couple, the infrared emitting device and the infrared receiving device are all connected with the main control system.

Preferably, the powder supply cylinder is mainly composed of four shrouds and a frame, and the four shrouds are connected end to end and fixed inside the frame in turn, and the outer wall of the shroud is provided with ear seats, and the ear seats are fixed on the frame by bolts, The coaming is a hollow structure, and a powder supply heating device is arranged inside the coaming, and the powder supply heating device is connected with the main control system.

Preferably, the enclosure is made of aluminum alloy.

Preferably, an image acquisition device is provided on the top of the molding cavity, supplementary lights are provided on both sides of the molding cavity, and both the image acquisition device and the supplementary light are connected to the main control system.

Preferably, a lens shield is provided on the outside of the image acquisition device.

Preferably, the image acquisition device is a high-resolution industrial CCD camera, and the supplementary light is an LED light.

Compared with the prior art, the present invention has the following technical effects: the present invention can monitor the quality of powder spreading and whether warping and deformation of formed parts occur, and can give an alarm to resurface forming powder or adjust process parameters; Uniform preheating improves the powder preheating efficiency; the protective gas in the forming cavity can be uniformly entered into the forming cavity, and can be evenly distributed in the forming cavity, avoiding the oxidation of the formed parts during the forming process; it can improve the quality of the formed parts and the production Efficiency is of great significance to the development of SLS forming technology; and it has a wide range of applications, and can process materials such as wax powder, polystyrene powder, nylon powder, coated ceramic powder, coated metal powder, coated sand, polycarbonate powder, etc. of laser sintering.

Description of drawings

Fig. 1 is a structural schematic diagram 1 of the present invention.

Fig. 2 is a schematic diagram of the second structure of the present invention.

Fig. 3 is a first schematic diagram of the structure of the intake and exhaust device in the present invention.

Fig. 4 is the second structural schematic diagram of the intake and exhaust device in the present invention.

Fig. 5 is a structural schematic diagram of the powder supply cylinder in the present invention.

Fig. 6 is a structural schematic diagram of the enclosure of the present invention.

Fig. 7 is a structural schematic diagram of the preheating shell in the present invention.

Fig. 8 is a structural schematic diagram of the roller stand in the present invention.

Fig. 9 is a schematic structural view of the powder spreading roller in the present invention.

detailed description

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

As shown in Fig. 1 and Fig. 7 to Fig. 9, the powder material laser sintering forming device includes a forming cavity 5, and the lower part of the forming cavity 5 is provided with a collection cylinder 15, a forming cylinder 14 and a powder supply cylinder 10, and the forming cylinder 14 is located at Between the collection cylinder 15 and the powder supply cylinder 10, the collection cylinder 15, the molding cylinder 14 and the powder supply cylinder 10 are all provided with a hydraulic cylinder 13, and the piston rod of the hydraulic cylinder 13 is provided with a pushing baffle 11, and the molding cavity The middle part of the body 5 is provided with a powder spreading slide rail 19, and the roller frame 20 is slidably installed on the powder spreading slide rail 19, and the powder spreading roller 18 is installed on the roller frame 20, and one side of the powder spreading roller 18 is provided with a roller drive motor 29, The drum frame 20 is also provided with a drum frame screw 17, the end of the drum frame screw 17 is provided with a drum frame drive motor 9, the upper part of the molding cavity 5 is provided with a preheating guide rail 7, and the preheating housing 24 passes through the preheating bracket 25 is slidably installed on the preheating guide rail 7, thereby realizing the movement of the whole preheating device. A preheating rod 37 is arranged inside the preheating casing 7, an infrared thermometer 39 is arranged outside the preheating casing, and a reflector 38 is arranged on the inner wall of the preheating casing 24, and a laser scanning system 1 is arranged on the top of the molding cavity 5 , The side wall of the molding cavity 5 is provided with an intake and exhaust device, and the hydraulic cylinder 13, the roller frame drive motor 9, the preheating rod 37, the infrared thermometer 39 and the laser scanning system 1 are all connected to the main control system 8. An infrared thermometer 39 is installed on the preheating shell 24 to measure the temperature of the laid powder and feed the information back to the main control system, thereby accurately adjusting the preheating temperature. The preheating housing 24 is installed on the preheating support 25, and multi-layer preheating rods 37 are installed inside the preheating housing 24, and each layer is connected into a square by four preheating rods 37. A reflector 38 is installed on the inner wall of the preheating shell 24 for reflecting the heat radiated by the preheating rod 37 to improve heating efficiency. All the above-mentioned devices are connected with the main control system 8 to realize the uniform preheating of the laid powder and ensure the accuracy of the powder preheating temperature.

As shown in Fig. 8 and Fig. 9, a powder spreading heating rod 32 and a powder spreading thermocouple 31 are arranged in the powder spreading drum, and an infrared emitting device 22 and an infrared receiving device 30 are respectively arranged on both sides of the roller frame 20, and the powder spreading The heating rod 32 , powder spreading thermocouple 31 , infrared emitting device 22 and infrared receiving device 30 are all connected with the main control system 8 .

A powder spreading thermocouple 31 and a powder spreading heating rod 32 are installed inside the powder spreading drum 18 to measure the temperature and preheat the powder spreading drum, so as to realize the preheating of the formed powder by the powder spreading drum 18 during the powder spreading process . The powder spreading roller 18 is installed on the roller frame 20, and a roller drive motor 29 is provided on one side of the roller frame 20 to be connected with the powder spreading roller 18. The bottom of both sides of the drum frame 20 is provided with a drum frame screw 17, the drum frame screw 17 is connected with the drum frame driving motor 9, and the drum frame driving motor 9 drives the drum frame screw 17 to rotate, thereby driving the drum frame 20 in the powder shop. Movement on track 19. An infrared emitting device 22 and an infrared receiving device 30 are installed on the roller frame 20 at the front end of the powder spreading roller 18 to measure whether the parts are warped or not. When the part is warped and deformed, it will block the infrared rays emitted by the infrared emitting device 22, so that the infrared receiving device 30 cannot receive the infrared signal, and will feed this information back to the main control system 8, thereby reminding the operator to adjust the process parameters.

As shown in Figures 5 and 6, the powder supply cylinder 10 is mainly composed of four enclosures 12 and a frame 34, and the four enclosures 12 are connected end to end and fixed inside the frame 34 in turn, and the outer wall of the enclosure 12 is provided with ear seats 35, The lugs 35 are fixed on the frame 34 by bolts 33. The enclosure 12 is made of aluminum alloy and has a hollow structure. A powder supply heating device 36 is arranged inside the enclosure 12, and the powder supply heating device 36 is connected to the main control system 8. The powder supply heating device 36 preheats the formed powder in the powder supply cylinder. The lower end of the pushing baffle 11 is connected with the piston rod of the hydraulic cylinder 13, and the lifting of the pushing baffle 11 is mainly realized by the main control system 8 to adjust the lifting of the hydraulic cylinder 13. A forming cylinder 14 and a material collecting cylinder 15 are installed near the powder supply cylinder, and the forming cylinder 14 and the material collecting cylinder 15 have the same structure and hydraulic system as the powder supply cylinder.

As shown in Figures 2 to 4, the intake and exhaust device mainly consists of a plurality of intake covers 23 and exhaust devices 16 arranged on the side walls of the molding cavity, and the intake covers 23 and exhaust devices 16 are all passed through the intake duct 26. The exhaust pipe 27 is connected to the gas circulation device 28 , the oxygen sensor 21 is installed on the inner wall of the molding cavity 5 , and the intake air circulation device 28 and the oxygen sensor 21 are connected to the main control system 8 . One end of the air inlet pipe 26 is connected with the forming cavity, and a netted air inlet cover 23 is installed at the outlet of the air inlet pipe 26 for evenly entering the airflow. The other end of the intake pipe 26 is connected with an intake circulation device 28 . Oxygen sensors 21 are installed at different positions in the forming cavity to measure the oxygen content in different positions of the forming cavity, and feed back the oxygen content information to the main control system 8, so as to adjust the inert gas intake through the intake circulation device 28. The exhaust device 16 is installed at the front end of the forming chamber, and the exhaust device 16 is connected with the intake air circulation device 28 through the exhaust pipe 27 to realize the supply and circulation of the protective gas.

In addition, as shown in Figure 1, the top of the molding cavity 5 is also provided with an image acquisition device 2, and the two sides of the molding cavity 5 are provided with supplementary lights 6, the image acquisition device 2 and the supplementary light 6 are connected with the main control system 8 phase connections. A lens protective cover 4 is arranged outside the image acquisition device 2 . The image acquisition device 2 is a high-resolution industrial CCD camera, and the supplementary light 6 is an LED light. A high-resolution industrial CCD camera is installed on the top of the forming cavity, and LED lights are installed on both sides of the top of the forming cavity for light compensation during the photographing process. The lens protective cover 4 is installed on the outermost side of the high-resolution industrial CCD camera to prevent the powder from polluting the lens. The lens protective cover 4 is a fully enclosed structure, and the material is high temperature resistant transparent organic glass. The imaging system takes pictures of the powdered surface and the profile of the sintered layer formed part, and transmits the picture information to the image processing system. After the image processing system receives the picture information taken by the forming system, it analyzes and detects the picture. Detect whether the powder is evenly spread according to the gray scale of the powder, and detect the contour size of the sintered layer formed part according to the image of the formed part, realize graphic measurement of points, lines, circles, arcs, distances, ellipses, angles, etc., and feed back information to the main machine control system 8. Based on the feedback information, the main control system 8 judges whether the powder spreading is uniform, whether the contour size of the formed part of the sintered layer meets the requirements, and judges whether it is necessary to carry out two or more powder spreading, so as to issue instructions to the powder spreading system and the laser sintering forming system to adjust Powder spreading times and laser sintering forming process.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included within the scope of the present invention .

Claims (8)

1. Powder material laser sintering forming device, including a forming cavity, characterized in that: the lower part of the forming cavity is provided with a collection cylinder, a forming cylinder and a powder supply cylinder, and the forming cylinder is located between the collection cylinder and the powder supply cylinder Between, the collection cylinder, the forming cylinder and the powder supply cylinder are all equipped with a hydraulic cylinder, the piston rod of the hydraulic cylinder is provided with a pushing baffle, and the middle of the forming cavity is provided with a powder spreading slide rail, The roller frame is slidably installed on the powder spreading slide rail, and the powder spreading roller is installed on the roller frame, and a roller driving motor is arranged on one side of the powder spreading roller, and a roller frame lead screw is also arranged on the roller frame, and the roller The end of the frame screw is provided with a roller frame drive motor, and the upper part of the molding cavity is provided with a preheating guide rail, and the preheating shell is slidably installed on the preheating guide rail through the preheating bracket, and the preheating shell is provided with a preheating Hot rod, an infrared thermometer is installed outside the preheating shell, and the inner wall of the preheating shell is provided with a reflector, the top of the forming cavity is equipped with a laser scanning system, and the side wall of the forming cavity is provided with an intake and exhaust device, the hydraulic oil cylinder, the roller frame driving motor, the preheating rod, the infrared thermometer and the laser scanning system are all connected with the main control system. 2. The powder material laser sintering forming device according to claim 1, characterized in that: the intake and exhaust device mainly consists of a plurality of intake hoods and exhaust devices arranged on the side wall of the molding cavity, the intake and exhaust The gas hood and the exhaust device are connected to the gas circulation device through the air intake pipe and the exhaust pipe, and the oxygen sensor is installed on the inner wall of the molding cavity, and the air intake circulation device and the oxygen sensor are connected to the main control system. 3. The powder material laser sintering forming device according to claim 1, characterized in that: the powder spreading drum is provided with a powder spreading heating rod and a powder spreading thermocouple, and the two sides of the roller frame are respectively equipped with infrared emission device and infrared receiving device, the powder spreading heating rod, powder spreading thermocouple, infrared emitting device and infrared receiving device are all connected with the main control system. 4. The powder material laser sintering forming device according to claim 1, characterized in that: the powder supply cylinder is mainly composed of four enclosures and a frame, and the four enclosures are connected end to end and fixed inside the frame in turn, and the enclosure The outer wall of the plate is provided with lug seats, which are fixed on the frame by bolts, the enclosure is a hollow structure, and a powder supply heating device is arranged inside the enclosure, and the powder supply heating device is connected with the main control system. 5. The powder material laser sintering forming device according to claim 4, characterized in that: the enclosure is made of aluminum alloy. 6. The powder material laser sintering forming device according to claim 1, characterized in that: the top of the forming cavity is also provided with an image acquisition device, and both sides of the forming cavity are provided with fill lights, and the Both the image acquisition device and the fill light are connected with the main control system. 7. The powder material laser sintering forming device according to claim 6, characterized in that: a lens protective cover is arranged outside the image acquisition device. 8. The powder material laser sintering forming device according to claim 6 or 7, characterized in that: the image acquisition device is a high-resolution industrial CCD camera, and the supplementary light is an LED light.