Module for multi-material printing using selective laser melting

Abstract

This utility model relates to the production of multi-material products, specifically to a device for printing multi-material parts using selective laser melting. The module for multi-material printing using selective laser melting additive manufacturing technology incorporates a number of solutions aimed at reducing powder material consumption during printing and the time required to change materials during the printing process. The advantage of this utility model is the ability to form a multi-material part using the SLM method in a single process cycle. The module dispenses material in small portions, reducing material loss during the printing process. This reduces the number of production steps, increases productivity, and simplifies the production of multi-material parts.

Description

[0001] The utility model relates to the field of obtaining articles from several powder materials by the additive manufacturing method, and in particular by the selective laser melting (SLM) method by dosing a second powder material into specified areas of a layer during the construction of the article.

[0002] The manufacture of parts from multiple powder materials is fraught with technological difficulties due to the limitations of the equipment used in production. Scientific and engineering communities are currently focusing their efforts on optimizing the process of producing parts from multiple powder materials with a combination of properties suitable for long-term use.

[0003] The requirements placed on products during their use have led to research and development in the field of producing products with a range of properties by combining dissimilar powder materials in a single production cycle. To realize this potential, a technology developed thanks to the ability to create products with complex geometries while minimizing manufacturing steps is being used.

[0004] Selective laser melting (SLM) is a technology used to manufacture parts from multiple powder materials. This technology allows for the production of parts with complex configurations from multiple powder materials.

[0005] The production of products from multiple powder materials faces a number of limitations associated with the complexity of applying two or more powder materials to the corresponding areas of the layer when constructing products using the SLM method.

[0006] Existing research and patent publications describe a number of solutions aimed at producing products from several powder materials by improving the technology or introducing design solutions into the equipment for their production.

[0007] A device for applying multiple powder materials in a single layer using selective laser melting is described in application CN119407207. A key feature of this technical solution is that the device for applying multiple powder materials uses an electrostatic field to precisely control the deposition process. By controlling the electric field parameters (voltage, frequency, on / off time), the system can select the powder material, control the amount and speed of deposition, and create gradients.

[0008] The disadvantages of the presented invention include low accuracy of boundaries and the impossibility of creating sharp transitions, the complexity and unreliability of the mechanical system.

[0009] The main components of the system are powder cylinders, screen units, and electrode control units. Powder bins are used to store various powder materials. Screen units are designed to sift powder material directly into specific areas of the platform. Electrode control units are designed to generate and control the electric field for capturing, transferring, and applying the material.

[0010] The design operates by using a central control system that activates an electric drive and moves the selected container along rail guides precisely above the desired screen unit and electrode area. However, the use of screen units complicates the selection of powder materials. This complex mechanical system with numerous moving parts increases the overall size of the system. Limited flexibility and speed of powder material switching are also a drawback of this invention.

[0011] Application CN119387610 for a multi-material printer for additive manufacturing of metal parts was submitted by the UNIVERSITY OF SCIENCE & TECHNOLOGY BEIJING. The equipment presented in this application is equipped with a galvanometer scanner located above the forming cylinder, which houses the substrate. The device enables the production of complex metal parts from various powder materials, which is particularly useful for creating parts with combined properties.

[0012] The design of the multifunctional metal additive 3D printing printer is a complex system with clearly organized relationships between components, ensuring precise layer-by-layer formation of parts from various metal powder materials.

[0013] The central element of the system is the forming cylinder, around which all other components are organized. Within it is the build platform, connected to a piston mechanism that ensures its height positioning in single-layer increments. Above the forming cylinder is a galvanometric scanner, functionally linked to the control system and synchronized with the powder feed mechanisms.

[0014] A cylinder containing the first powder material is located on one side, and a cylinder containing the second powder material is located on the opposite side. Both cylinders are equipped with piston mechanisms for the measured supply of powder material and are connected to the forming cylinder via connecting plates, ensuring a smooth transition of the powder material between zones.

[0015] The key coordinating element of the system is the distribution plate, whose position is controlled via a control rod and a linkage system from a articulated motor. This plate defines the application zones of different powder materials within a single layer.

[0016] The doctor blade system is organized as follows: the first doctor blade moves along rails along the first powder cylinder, while the second doctor blade has its own drive system and bracket. Their movement is synchronized with the operation of the powder cylinder pistons.

[0017] The lifting connecting plate with a drive mechanism plays a special role, ensuring a continuous support surface when transitioning between different materials. When raised, it fills the gap between the second connecting plate and the guide rails, and when lowered, it allows the first squeegee to pass freely.

[0018] All components operate in a strict sequence: first, the articulated motor, via linkages and a control rod, positions the distributor plate parallel to the platform. Its thickness is equal to the layer thickness. The distributor plate covers part of the platform. The lifting coupling plate lowers, opening a passage for the first doctor blade. Then, a piston in the first powder cylinder lifts the powder to the layer height. The first doctor blade moves from the first powder cylinder to the build chamber, trimming off excess and evenly distributing the powder only in the area not covered by the distributor plate—that is, in the area of ​​the future part. A galvanometric scanner then melts the applied powder according to the layer data for the base material. Then, the articulated motor moves the distributor plate to a vertical position, and the adhering base material powder is scraped off.The lifting coupling plate rises to level the surface and fill the gap between the guide rails and the coupling plate, preparing the way for the second doctor blade. The piston in the second powder cylinder lifts its powder, and the second doctor blade begins its movement from the second powder cylinder to the build chamber. Since the spreader plate is now vertical, the doctor blade deposits powder over the entire platform surface, including the area where the base material was just printed and the vacated space where the spreader plate previously stood. A galvanometric scanner melts the powder only in the desired areas. The build platform then lowers by the thickness of one layer, and the cycle repeats.

[0019] While it is possible to produce a part from multiple powder materials in a single layer using SLM, this solution requires a complex control system for multiple powder cylinders. Other disadvantages of this solution include low distribution accuracy and high powder loss due to the fact that a significant portion of the powder remains in the cylinders.

[0020] A device that best characterizes the state of the art for producing parts from multiple powder materials using additive manufacturing is selected as a prototype and presented in patent CN115430847 for a device for applying multiple powder materials of any shape onto the same layer using additive manufacturing, filed by HUAZHONG UNIVERSITY OF SCIENCE & TECHNOLOGY. The operating principle of this device is based on the coordination of movements, contour formation, and switching of powder materials.

[0021] The main components of each unit are several powder bins connected to rotating vertical scrapers in the internal cavity, as well as a reservoir for collecting excess powder, located on rail guides.

[0022] The ends of the telescopic extension plate are secured to adjacent scrapers to prevent powder from falling between the scraper sets due to expansion or contraction as the scrapers move. A buffer plate with multiple openings is located under the excess powder collection tank. The opening and closing of these openings is controlled by a staggered arrangement of multiple buffer plates. The flow of powder from the hopper is regulated by a shut-off valve.

[0023] The solution under consideration has several significant drawbacks, such as reduced accuracy and mixing at the interface between powder materials. Powder from one hopper may slightly spill or mix with another at the point of contact, creating a transition region with uncertain properties. Other disadvantages of this device include its complex mechanical system and high powder consumption. This device is limited in the amount of materials it can handle in a single pass. Although the device has several units, within a single pass, the outer units are limited. To form sections of different materials alternating along the direction of travel (X-axis), a reverse idle stroke and switching of the units is required, which reduces the speed.

[0024] The technical objective of the proposed utility model is to develop a device for manufacturing a product from several powder materials using the selective laser melting method, capable of dosing a second powder material into a specified area, hereinafter referred to as a module.

[0025] The key to the module is the use of piezoelectric elements and ultrasound to dispense the second powder material. It also features hardware and software communication with the SLM system. The combination of these two components makes it possible to create structures or reinforced zones without completely replacing the powder material. The multi-material printing module as a whole enables the formation of parts from several powder materials in a single process cycle with clear interfaces between powder materials or predetermined gradient transitions, minimizing mixing zones and the consumption of expensive powder materials.

[0026] The technical result of this utility model is improved dosing accuracy. Using a nozzle system to feed a second powder material ensures powder material is dispensed into specified areas of each layer with improved accuracy. Unlike the traditional method of switching between powder cylinders, this approach minimizes mixing zones of powder materials at boundaries and creates microstructures with clear or defined gradient transitions. Using this module, microscopic portions are dispensed, significantly reducing powder material consumption and resulting in substantial savings, especially when working with expensive powder alloys.

[0027] The drawing attached to the description shows:

[0028] Fig. 1 - device for printing from several powder materials using the selective laser melting method (module).

[0029] The multi-material printing module includes a hopper for the second powder material - 1, a vibrating powder material dispenser - 2, a dosing nozzle - 3, a motor - 4, rail guides - 5 and carriages on which the module is installed - 6, a microcontroller control unit - 7.

[0030] The module is a compact, stand-alone unit mounted on the frame of a selective laser melting (SLM) system parallel to the main recoating unit. The module is designed for precise and localized dispensing of a second or more powder materials during 3D printing.

[0031] The recoating hopper of the selective laser melting system is used for the first powder material. The hopper (1) of the module is designed for loading the second powder material and is a sealed cylindrical or prismatic container, permanently attached together with the vibrating feeder (2) on carriages (6). The hopper is designed to store a reserve of the second powder material. The vibrating feeder (2) is configured for high-frequency vibration for portioned dosing of powder material directly into a specified zone of the layer. A motor (4) and a microcontroller control unit (7) are mounted on the external side of the vibrating feeder (2), configured to control the motor (4), piezoelectric elements, and the elements of the module as a whole. The microcontroller control unit programmatically sets the dosing accuracy of the powder material.The vibratory feeder (2) is a chamber or channel designed to receive a portion of powder material from the hopper and transport it. Piezoelectric elements located on the exterior or interior of the vibratory feeder convert electrical signals into high-frequency mechanical vibrations. The piezoelectric elements generate vibrations in the vibratory feeder (2), which is the central component of the module. After feeding the second portion of powder material, the vibratory feeder switches off, preventing further powder feed.

[0032] The motor (4) is connected to a drive mechanism that moves the module along the rails. An electric motor can be used as the drive mechanism. The module is also equipped with a microcontroller control unit (7), which is connected to the motor (4) to control the movement of the hopper (1). The motor (4) and the microcontroller control unit (7) can be secured to the dispenser by welding, screwing, adhesive, or other means.

[0033] The dosing nozzle (3) is located at the bottom of the vibratory feeder (2) in a corresponding opening made on the bottom of the vibratory feeder. It is a tapered, round end into which the powder material from the vibratory feeder (2) enters and forms a thin stream of powder material on the surface of the powder bed, ensuring high precision of its delivery to the powder bed. The dosing nozzle (3) is a design element that can be replaced with a nozzle of a different size or opening shape, taking into account the granulometric composition of the supplied powder material. The dosing nozzle (3) is the final element that transmits ultrasonic vibrations from the piezoelectric elements of the vibratory feeder (2) to the powder material.

[0034] The module is mounted on its own rigid rail guides (5), which are installed on the recoater of the SLP unit. Movement along the X-axis is ensured by the standard movement of the recoater along its own rail guides. Movement along the Y-axis is performed by the rail guides (5) included in the module design, which provide a fixed trajectory of movement of the entire module, positioning it parallel to the main recoater. The rail guides allow the nozzle to be positioned at any point in the plane of the working field. When static, the module is in the initial or working position, installed with the possibility of movement along the rail guides (5) due to the tongue-and-groove connection between the rail guides (5) and the carriages (6), on which the vibratory dispenser (2) of the powder material and the hopper (1) are installed. The vibratory dispenser (2) and the hopper (1) are inseparably connected to the carriages (6).The module can be mounted on the SLP frame in dual or multiple configurations with independent control, allowing for a wider range of powder material types. The number of modules is limited by the SLP frame's dimensions.

[0035] The multi-material printing module is a precision dosing device designed for integration into a standard selective laser melting (SLM) system. The module's operation is based on the synchronized interaction of mechanical, piezoelectric, and software components, controlled by a single microcontroller control unit (7). The interaction process begins with commands from the SLM control program. When the layer construction algorithm requires the application of a second powder material to a specific area, the module receives an activation signal and begins moving by activating the motor (4) along its own rail guides (5). This ensures precise positioning of the dosing nozzle (3) over a specified point on the work platform without interfering with the primary powder application process.After positioning the dosing nozzle (3), the vibrating doser (2) is activated for precise application of the powder material.

[0036] The key element of the dosing system is the vibratory feeder (2), which uses piezoelectric elements. Under the control of a single microcontroller unit (7), high-frequency voltage is applied to these elements, generating ultrasonic vibrations of a precisely defined amplitude and frequency. These vibrations are transmitted to the dosing nozzle (3), creating a vibrational conveying effect for the powder material. The module's design allows for the powder to be fed in measured portions, preventing uncontrolled spillage or the formation of a powder dust cloud. The module doses the material in small portions, reducing losses and thereby saving powder (especially for expensive alloys).

[0037] The dosing accuracy is regulated by three main parameters: the pulse duration of the piezoelectric element activation, its frequency, and the amplitude of its vibrations. This allows not only for precise control of the amount of powder material fed but also for monitoring its packing density, which is critical for forming clear boundaries between dissimilar powder materials or creating predetermined gradient transitions. After feeding the second powder material, the vibratory feeder is turned off, thereby preventing further powder feed. The module, on command from a single microcontroller control unit, returns to its original position or moves to the next dosing point, without interfering with the subsequent stages of the process: layer leveling by the main recoater and subsequent laser fusion. Dosing of the first powder material can be performed sequentially with the feeding of the second powder material using the second module.

[0038] Thus, the interaction of all module components—from receiving control signals and precise positioning to high-frequency vibratory dosing—ensures a seamless process cycle for multi-material SLM. This allows for the flexible and cost-effective introduction of localized zones of a different powder material into the product structure without the need for a complete replacement of the powder mixture in the working chamber, significantly reducing the consumption of expensive powder materials and overall production time.

[0039] The operating principle of the multi-material printing module is confirmed by experimental data obtained during prototype testing. It was found that the use of piezoelectric elements with an ultrasonic vibration frequency in the 20-40 kHz range enables powder material dosing accuracy of up to ±1 mg. The module's positioning speed along the rail guides is 200 mm / s, with a stopping accuracy of ±50 μm. During operation, the module saved up to 35% of powder material compared to the traditional cylinder switching method. The width of the transition zone between dissimilar powder materials did not exceed 50 μm. These parameters demonstrate the technological efficiency and economic feasibility of the proposed solution.

Claims

1. A precision dosing module for a selective laser melting (SLM) device for multi-material printing, configured to be placed on a frame of an SLM installation and comprising a hopper for storing powder material and rail guides, characterized in that it includes a vibratory dispenser combined with the hopper, equipped with piezoelectric elements providing high-frequency vibration, a dosing nozzle located in the lower part of the vibratory dispenser in a corresponding hole made in the bottom of the vibratory dispenser for receiving the dosing nozzle, a motor mounted on the outer part of the vibratory dispenser, connected to a drive mechanism designed to move the module along the rail guides, and a microcontroller control unit, wherein the hopper is combined with the vibratory dispenser with ensuring a continuous transition of the through cavity of the hopper into the cavity of the vibratory dispenser, and the hopper and the vibratory dispenser are permanently fixed on carriages,mounted on rail guides using a tongue and groove connection, ensuring the possibility of moving the module along the rail guides.

2. A module for multi-material printing according to paragraph 1, characterized in that the hopper is made in the form of a cylindrical or prismatic container.

3. A module for multi-material printing according to paragraph 1, characterized in that the microcontroller control unit is designed with the ability to control the motor, piezoelectric elements and the drive mechanism.

4. A module for multi-material printing according to paragraph 1, characterized in that an electric drive is installed as a drive mechanism.

5. A module for multi-material printing according to paragraph 1, characterized in that the dosing nozzle is designed with the possibility of being replaced with a nozzle with a different size or shape of the opening for different granulometric composition of the powder material.

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