Apparatus and method for producing additively manufactured metal matrix composites and articles of manufacture thereof

Abstract

To provide a method, product, apparatus and manufactured article for applying composite-based additive manufacturing (CBAM) to produce an object with metal and with a metal-fiber mixture or composite.SOLUTION: The approach works by the steps of: slicing a 3D model; selectively printing fluid over a sheet of base material for each layer based on a model; overflowing fluid to which powdery metal adheres onto a base in a printed area; clamping and aligning a stack of covering sheets; heating the stacked sheet to melt the powdery metal and fuse a layer of the base; and removing excess powder and an unfused portion of the base.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This application claims the benefit of U.S. Provisional Application No. 62 / 256,436, filed November 17, 2015. This application is a continuation of the following applications (including drawings thereof): U.S. Application No. 61 / 528,537, International Application No. PCT / US12 / 52946, U.S. Application No. 13 / 582,939, European Application No. 20120828967, U.S. Application No. 61 / 769,724, International Application No. PCT / US14 / 18806, U.S. Application No. 14 / 835,685 No. 14 / 835,690, U.S. Application No. 14 / 835,697, U.S. Application No. 14 / 703,372, U.S. Application No. 62 / 243,590, U.S. Application No. 61 / 773,810, U.S. Application No. 14 / 199,603, U.S. Application No. 61 / 914,613, and U.S. Application No. 14 / 566,661 are incorporated by reference.

[0002] The present invention relates generally to three-dimensional fabrication. [Background technology]

[0003] No. WO 2014 / 134224A2 (corresponding to International Application No. PCT / US14 / 18806), entitled "Method and Apparatus for Three-Dimensional Composites" (which corresponds to U.S. Application Nos. 61 / 528, 537, International Application No. PCT / US12 / 52946, U.S. Application No. 13 / 582,939, European Application No. 20120828967, U.S. Application No. 61 / 769,724, U.S. Application No. 14 / 835, No. 685, U.S. Application No. 14 / 835,690, U.S. Application No. 14 / 835,697, U.S. Application No. 14 / 703,372, U.S. Application No. 62 / 243,590) describe "additive" methods and apparatus for producing three-dimensional objects, called "composite-based additive manufacturing" or CBAM, which generally use a substrate, typically a fibrous substrate and a polymer, to produce the three-dimensional object. The present invention refers to WO 2014 / 134224 A2, which describes the application of the technology described in the WO publication with metals. Summary of the Invention

[0004] The CBAM method described in WO 2014 / 134224 A2 expands the range of materials that can be used in 3D printing to create three-dimensional objects. Until recently, research into this technology has focused on using various substrates, including carbon fibers, polymer-based materials, and natural fibers, among others, with various polymers as binders. The application describes the use of CBAM methods and apparatus to produce objects in metals and in metal fiber hybrids or composites. The application also describes articles of manufacture thereof.

[0005] This approach has many advantages, including the ability to produce complex geometries over traditional methods such as milling or casting, improved material properties over traditional metals, faster production speeds, elimination of complex fixtures, complex tool paths and tool changes, and, in the case of casting, the elimination of the need for patterns and tooling. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 illustrates a metal piece made by the method described in the present application. [Diagram 2] 1 is a flow chart illustrating the steps for generating a 3D metal object according to the teachings of the present invention. [Diagram 3] FIG. 1 illustrates an apparatus used to selectively deposit liquid (to which powder adheres) in an exemplary implementation of the present invention. [Figure 4] FIG. 2 depicts a high-level block diagram of a processor in an exemplary implementation of the invention. [Diagram 5] 1 shows a compaction apparatus in which multiple substrate tiles (layers) are placed and then stacked one on top of the other in the compaction apparatus. The tiles are aligned by inserting alignment pins of the compaction apparatus into alignment holes in each tile. [Figure 6] FIG. 1 shows the compression device after the substrate layers with all the "slices" of the ring torus have been inserted inside. Springs within the compression device press the substrate layers together. [Figure 7] FIG. 1 is a block diagram illustrating a processor that controls multiple components of an apparatus for fabricating a 3D object. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Technology Output A metal piece 100 made by the method described in this application is shown in Figure 1. The method for making the metal piece is described in detail below.

[0008] Technical Description FIG. 2 is a flow chart illustrating the steps for generating a 3D metal object according to the teachings of the present invention.

[0009] 1. A CAD model is generated (step 102), which is sliced ​​into layers (step 104) using a slicer program such as Netfabb, described in (see WO 2014 / 134224 A2, paragraph 0055; see also U.S. Patent Application Nos. 61 / 528,537 and 61 / 769,724). Each slice also contains registration holes, which are used to accurately orient each printed layer of the substrate in the finished object (see WO 2014 / 134224 A2, paragraph 00121).

[0010] 2. The output of the slicer, which may be, for example, a bitmap file, is sent to an inkjet printer (step 106). For each layer, the printer selectively prints a fluid onto a sheet of substrate material (step 108) (see WO 2014 / 134224 A2, paragraph 00113). The fluid may be the binder itself in liquid form, or a liquid to which a powder adhesive adheres. The substrate may comprise fiberglass, high temperature fiberglass, boron fiber, or carbon fiber.

[0011] 3. If a powder binder is used, the powder binder is flooded onto the printed substrate (see WO 2014 / 134224 A2, paragraph 0059). The powder adheres to the printed areas. Excess powder is removed either by airflow, vacuum, vibration, or other mechanical means.

[0012] 4. Stack the coated sheets of substrate in a press or clamp (step 110) (see WO 2014 / 134224 A2, paragraph 00124) using registration holes in each layer to align the printed portions of each sheet within the stack (see WO 2014 / 134224 A2, paragraph 00106).

[0013] 5. The assembled sheets are then heated in an oven and optionally compressed to melt the binding material and fuse the layers of the substrate to form the 3D object (step 112) (see WO 2014 / 134224 A2, paragraph 00149).

[0014] 6. The unfused substrate around the 3D object is then removed (step 114), typically using abrasive blasting materials or chemical means (see WO 2014 / 134224 A2, paragraph 0081).

[0015] Issues with using metals in technology It has been discovered that this technique can be used with metals. In one example, the substrate used is a non-woven carbon fiber veil available from Hollingsworth and Vose. Metallized veils can also be used. The veil or substrate is printed on an inkjet printer as described above, for example using a HP45 thermal inkjet head with a solution of mainly deionized water, pyrrolidone and alcohol. The solution may have an evaporation inhibitor including glycol and pyrrolidone. The fluid is printed on the areas of the substrate that will become part of the object, i.e. the printed areas correspond to the layer geometry for the object. This is done for each layer as described in the previous application. Each layer is flooded with a metal powder, for example solder powder. The excess powder is removed by moving parts, vacuum, vibration or compressed air, or a combination of such methods. This results in the selective deposition of the solder powder. One of the problems with using metal powder in this type of process is that the powder oxidizes and when heated to its melting point, the particles of the powder do not fuse together well. There are many solutions to this problem, one solution is to mix the metal powder with a powdered solvent such as rosin, which acts as a reducing agent. A typical solvent to metal powder ratio is about 50 / 50. Another method is to melt the powder in a reducing, vacuum and / or inert atmosphere furnace. In this way, other metals or alloys such as aluminum, steel, stainless steel, copper, brass, and titanium, among others, can be used. Additionally, liquid solvents can be used as printing fluids or in combination with printing fluids by selective deposition methods such as inkjet printing.

[0016] As an example, metal powder can be mixed with a powder solvent before it is deposited on the substrate. Then all layers of the object are printed and stacked in alignment as described in the previous application. They are compressed and heated as described in the previous application. The heating temperature is raised to the melting point of the powder. The layers fuse together to produce a build block. After removing the build block from the compression fixture, it is abrasive blasted and the areas where the powder is not attached, i.e. the parts of the object that were not coated with metal, are abrasive blasted, the uncoated carbon fiber being very brittle. What remains is a three-dimensional carbon fiber metal composite of the part represented by the CAD model.

[0017] FIG. 3 shows an apparatus used to selectively deposit liquid (to which powder adheres) in an exemplary implementation of the invention. Alignment guide pins 501 are inserted into the substrate layer 503 to properly align it. Using a solenoid valve or one or more inkjet heads 505, liquid is selectively dispensed from a liquid reservoir 507 through a nozzle 509 onto the substrate layer 503. The nozzle 509 is raster scanned in a two-dimensional plane 510 parallel to and above the substrate layer 503, so that liquid is selectively deposited at desired x, y coordinates of the substrate layer 503 and not on other areas of the substrate layer 503. To accomplish this raster scanning, a stepper motor 511 actuates two belts (not shown) that move a support member (not shown) on two rails (not shown) along a direction parallel to the x-axis. A second stepper motor (not shown) and a third belt (not shown) are mounted on the support member and are used to move a nozzle support (not shown) in a direction parallel to the y-axis. A nozzle 509 is attached to the nozzle support. The two stepper motors work together to move the nozzle 509 to any desired x, y coordinates above the substrate layer. A page-wide head can also be used. A microprocessor 513 controls the stepper motors and solenoid valves or inkjet heads to control when and where the liquid is dispensed on the substrate layer 503. Instead, rather than raster scanning in a line-by-line pattern, the stepper motor can move a nozzle or nozzles 509 in another two-dimensional pattern in a two-dimensional plane to deposit the liquid at specific x, y coordinates. Not shown in FIG. 2 are devices for heating and pressurizing the multi-layer substrate or for removing excess substrate. In some implementations, the substrate layer is moved to a different position before these steps occur.

[0018] FIG. 4 is a high-level block diagram of a processor in an exemplary implementation of the invention. A CAD model in the form of an STL file of the desired three-dimensional object is created using a remote processor 601. This processor 601 uses software (e.g., Netfabb.RTM.Studio software) to create a machine-specific build file. The machine-specific build file is data-transferred to a second processor 603. Depending on the specific implementation, this second processor controls operations including: (1) an inkjet head or other device that selectively deposits liquid; (2) movement of a vibrating trough (and / or compressed air) that spreads the powder on a substrate and then removes excess powder. Alternatively, the invention may be implemented with other configurations of processors. For example, two or more remote processors and two or more on-board processors may be used, and any of the above tasks may be processed by one or more of these different processors.

[0019] FIG. 5 shows the compression device 803 after multiple substrate layers (eg, 801) have been placed, one on top of the other, in an ordered fashion within it.

[0020] Figure 6 shows the substrate layer being compressed in a compression device 903. Screws 905, 907, 909, 911, plates 913, 915 and spring 917 within the compression device are used to apply pressure.

[0021] FIG. 7 is a high level block diagram of some of the hardware that can be used in the present invention. One or more processors 1301 control the applicator 1303, heating element 1305, actuator 1307, artificial pressure source 1309, and an agitator in liquid reservoir 1311. The applicator 1303 deposits powder in the convex areas of the substrate layer but not in the concave areas. The heating element 1305 converts the powder into a substance that flows and then hardens. The resulting hardened material is arranged in a spatial pattern that permeates the substrate layer. The artificial pressure source 1309 can include a press, clamp, spring, elastic element, or other device to compress the substrate layer. The agitator can be used to agitate the liquid used to remove excess substrate.

Claims

1. 1. A system for generating 3D metal objects, comprising: an inkjet printer configured to print, with a fluid, each layer of the 3D metal object layer file onto a plurality of sheets of a substrate material, each sheet representing the shape of the 3D metal object at a particular layer; at least one powder sheet, the powder metal being configured to selectively adhere to the fluid on each sheet of the substrate material into a shape to be printed; a heating and compression device configured to heat and compress the stack of powder sheets to melt the mixture of powder metals and fuse the layers to generate the 3D metal object, wherein the heating and compression device uses an inert atmosphere; Equipped with the system includes a mixture of powder metal and a reducing agent and is configured to flood at least a portion of the mixture onto each sheet of the substrate material to generate a plurality of powder sheets, the mixture being configured to selectively adhere to the fluid on each powder sheet to form a shape to be printed; the system is configured to remove excess powder from each powder sheet after it has first been printed by the inkjet printer and then flooded with the powder metal and reductant; the system is configured to stack the powder sheets in a preregistered registration after removing the excess powder to form a stack of powder sheets, each sheet of the stack of powder sheets corresponding to a layer of the layer file; the powder metal is solder powder, aluminum, copper, brass, tin, or zinc; The reducing agent is a powder. system.

2. The system of claim 1 , wherein the system is configured to remove unmolten material from the 3D metal object.

3. The system of claim 1 , wherein the system comprises a vibration, airflow, or vacuum means.

4. The system of claim 1 , wherein the heating and compacting device raises the temperature to the melting point of the powdered metal.

5. The system of claim 2 , wherein the system removes unmolten substrate material by air blasting with an abrasive or by chemical removal.

6. The system of claim 1 , wherein the fluid comprises an evaporation inhibitor.

7. The system of claim 6 , wherein the evaporation inhibitor is an alcohol.

8. The system of claim 6 , wherein the evaporation inhibitor is selected from the group consisting of glycols and pyrrolidones.

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