Patent Description:
There is a need to verify material properties of each additively built article. Traditionally, there is a long lead time between the time of growing the plate of parts and when traditional material testing can be completed on test bars from that plate. This requires increased effort and cost be added to the parts before even knowing if the material properties are ultimately acceptable.

The current method for verifying material properties of additively manufactured articles is to complete tensile testing. Test bars are built with each build. Tensile testing cannot be completed until the test bars have been removed from the plate and machined to the proper dimensions for testing. This requires the build plate to go through all of the required post processing before the testing is completed. By the time the testing is completed a new build has started and much value has been added to the parts.

Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved verification methods and devices to verify material properties earlier in the process. The present disclosure provides a solution for this need. <CIT> relates to methods and systems for screening of material properties in additively manufactured specimens.

The claimed invention is defined in the independent method claim <NUM> and device claim <NUM>. Further embodiments are defined by dependent claims.

Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, an illustrative view of an embodiment of a machine in accordance with the disclosure is shown in <FIG> and is designated generally by reference character <NUM>. Other embodiments and/or aspects of this disclosure are shown in <FIG>.

In accordance with at least one aspect of this disclosure, referring to <FIG>, a torsion testing machine <NUM> for additively manufactured (e.g., selective laser sintered) test articles (e.g., as shown in Figs. <NUM>-<NUM> built) can include at least one build plate holder <NUM> configured to allow insertion of and retention of a build plate <NUM> therein. The build plate holder <NUM> can include any suitable fastener(s) to retain the build plate <NUM> therein (e.g., clamps 101a or one or more screws configured to interface with existing screw holes in the build plate <NUM>). In certain embodiments, the build plate holder <NUM> can include a slot configured to receive the build plate <NUM> such that it that retains the build plate <NUM> with or without one or more fasteners.

The machine <NUM> can include at least one torsion motor <NUM> (e.g., and electric motor) and at least one torsion shaft <NUM> configured to operatively connect to the torsion motor <NUM>. The at least one torsion shaft <NUM> can be configured to mate with at least one test article (e.g., test article <NUM>) built on and attached to the build plate <NUM> when the build plate <NUM> is in the build plate holder <NUM>.

The at least one torsion motor <NUM> can be configured to apply a torsion to the at least one test article <NUM> through the torsion shaft <NUM> while the build plate <NUM> is retained in the build plate holder <NUM>. The machine <NUM> can include at least one torque sensor <NUM> operatively connected to the torque motor <NUM> to determine a torque applied by the torsion motor <NUM> to the test article <NUM>. The torque sensor <NUM> may be wireless and configured to communicate with a data acquisition system (e.g., as described below). Any suitable torque sensor <NUM> as appreciated by those having ordinary skill in the art is contemplated herein.

In certain embodiments, the machine <NUM> can include at least one strain gauge (not specifically shown) operatively connected to the at least one torque motor <NUM> to determine a twist on the torsion shaft <NUM> and/or the test article <NUM>. For example, the strain gauge can be attached to the shaft between the torque motor and the test article <NUM>. The strain gauge can be integrated into the torque sensor <NUM>, and/or can be wireless, for example.

In certain embodiments, the machine <NUM> can include at least one motor sensor (not shown), e.g., within the motor, configured to measure a position of the torsion motor <NUM>. The motor <NUM> can be configured to sense position as appreciated by those having ordinary skill in the art. In certain embodiments, the machine <NUM> can include a data acquisition system <NUM> operatively connected to the torque sensor <NUM> and the strain gauge, for example, and configured to compare the torque and the twist to known data to determine a condition of the test article <NUM> and/or other articles built on the build plate <NUM>. The data acquisition system <NUM> can also be configured to control the motor <NUM> and/or any other suitable portions of the machine <NUM> (e.g., a mechanized positioning system). The data acquisition system <NUM> can include any suitable computer hardware and/or software.

The torsion motor <NUM> (and/or the build plate holder <NUM>) can be mounted to a movable assembly <NUM> to allow the torsion motor <NUM> to be repositioned relative to the build plate holder <NUM> to allow the shaft <NUM> to mate with a test article <NUM> located, e.g., in a plurality of discreet positions or located in any position on the build plate. The moveable assembly <NUM> can include an adjustable rail system <NUM> allowing the motor <NUM> (e.g., and anything attached thereto such as the torque sensor <NUM>) to slide on one or more rails 115a. The machine <NUM> can include one or more quick release clamps 115b to selectively lock the motor <NUM> to the one or more rails 115a. While the motor <NUM> is shown moveable, it is contemplated that, either additionally or alternatively, the build plate holder <NUM> and/or the build plate <NUM> can be moveable relative to the motor <NUM> in any suitable manner to allow connection of the shaft <NUM> and the test article <NUM>. While embodiments are shown having motion available in <NUM> dimensions, it is contemplated that the moveable assembly <NUM> can be configured to move in any suitable number of dimensions (e.g., in the additional 3rd up down dimension).

In certain embodiments, the machine <NUM> can include a part catching tray <NUM> located under the build plate holder <NUM> for catching fractured test parts and/or any other suitable debris. In certain embodiments, the machine <NUM> can include an enclosure <NUM> enclosing at least the torsion motor <NUM>, the torsion shaft <NUM>, and the build plate holder <NUM>. Any other suitable enclosing structure is contemplated herein. In certain embodiments, the machine <NUM> can be integrated into an additive manufacturing machine, and a separate structure may be unnecessary.

In certain embodiments, referring additionally to <FIG>, the torsion shaft <NUM> can include a lower sleeve socket 107a for receiving a socket head 108a of the test article <NUM>. The torsion shaft <NUM> can be configured to removably connect to a motor shaft <NUM> (which can be any shaft of the motor <NUM> or any shaft connected directly or indirectly thereto, e.g., a torque sensor shaft) such that the torsion shaft <NUM> allows positioning of the build plate <NUM> under the torsion motor <NUM> and to allow the sleeve socket 107a to be slid over the test article <NUM> before and/or after insertion of the build plate <NUM>.

In certain embodiments, the torsion shaft <NUM> can include an upper socket 107b (e.g., as shown in <FIG>, for receiving the motor shaft <NUM>. The upper socket 107b and the motor shaft <NUM> can interface together via a removable connection, for example. The removable connection can be a ball detent, for example (e.g., as in a socket wrench connector, or similar).

In accordance with at least one aspect of this disclosure, embodiments include a system (e.g., a machine <NUM>) that include a torsion applicator (e.g., a torsion motor <NUM> and shaft <NUM>) configured to apply a torque to a test article <NUM> that is additively built on and attached to a build plate <NUM>. The system can include at least one twist sensor (e.g., a strain gauge) and at least one torque sensor (e.g., sensor <NUM> with integrated strain gauge).

The system can include a data acquisition system (e.g., system <NUM> as described above) configured to receive torque data from the at least one torque sensor and/or twist data from the at least one twist sensor. The data acquisition system can be configured to compare the torque data and twist data to known expected data. The data acquisition system can be configured to output a plot of torque versus twist. The plot can be displayed on any suitable display for a user to inspect and/or determine a quality of the test article, and hence one or more articles built on the build plate.

In certain embodiments, the data acquisition system can be configured process the torque data and/or the twist data and to determine a quality of an additively manufactured part (e.g., the test article or another part from the same batch) based on the torque and/or twist data. In view of this disclosure, one having ordinary skill in the art would understand how to empirically develop, without undue experimentation, known data to compare the torque data and twist data against to determine a quality of the additive manufacturing part.

Referring additionally to <FIG>, in accordance with at least one aspect of this disclosure, a method for determining quality of an additively manufactured article or batch thereof can include torsion testing at least one additively manufactured test article that is built on and attached to a build plate while the at least one test article is still attached to the build plate. The method <NUM> can include any other suitable portions, certain examples being described below and/or certain examples being shown in <FIG>. For example, torsion testing can include applying a torque to the test article using a torsion testing machine while the build plate is retained in the torsion testing machine.

The method <NUM> can include removing the build plate from an additive manufacturing machine and inserting the build plate into the torsion testing machine. The method <NUM> can include retaining the build plate in the torsion testing machine.

Referring additionally to <FIG>, the method <NUM> can include additively manufacturing the at least one test article (e.g., test article <NUM>) on the build plate to have a test head (e.g., test head 108a) configured to be torqued by a socket (e.g., lower sleeve socket 107a of torsion shaft <NUM>). The test head (e.g., test head 108a) can include a hex shape, for example, or any other suitable shape.

The at least one test article (e.g., test article <NUM>) can include a narrow body (e.g., body 108b), for example. For example, the at least one test article can be shaped to adhere to the ASTM E8/E8M standard for round tensile testing bars (e.g., the gauge section diameter can be about <NUM>% of the gauge section length). The method <NUM> can include sensing a torque on the at least one test article and/or a twist on the at least one test article to create torque data and/or twist data.

The method <NUM> can include comparing the torque data and/or twist data to known expected data to determine a quality of the at least one test article. For example, if torque vs. twist data is within a suitable predetermined range of values of the expected value, the quality can be determined to be acceptable (e.g., by the data acquisition system and/or by a user). The data acquisition system can provide an indication regarding the quality (e.g., an alarm when quality is unacceptable). In certain embodiments, the method can include plotting and displaying torque versus twist on an electronic display, for example.

Torsion testing can include torsion testing the at least one test article until the at least one test article breaks. The method can include catching debris from the broken test article in a part catching tray.

Torsion testing the at least one additively manufactured test article (e.g., test article <NUM>) can be performed while the build plate is still in an additive manufacturing machine. Torsion testing the at least one additively manufactured test article can be performed prior to completion of additive manufacture of the additively manufactured article or batch thereof in the additive manufacturing machine.

In accordance with at least one aspect of this disclosure, referring to <FIG>, and <FIG>, a method can include additively manufacturing a test article <NUM> on a build plate <NUM> to include a test head 108a shaped to be torqued by a socket. Additively manufacturing the test article <NUM> can include forming a base 108c of the test article <NUM> to adhere to the build plate <NUM> such that the base of the test article <NUM> remains attached to the build plate <NUM> throughout torsion testing.

Additively manufacturing the test article can include forming a narrow body 108b attached to the head 108a and the base 108c such that the narrow body 108b fails before the base 108c detaches from the build plate <NUM>. Additively manufacturing the test article <NUM> can include forming the base 108c to have a wide area (e.g., at least as wide as the head 108a) contacting the build plate <NUM> to enhance adherence to the build plate <NUM>.

The wide area base 108c can include a disc shape contacting the build plate <NUM>, for example, or any other suitable shape. Forming the test head 108a can include forming a hex head configured to be torqued by a standard socket wrench, for example, or any other suitable shape.

Embodiments include a torque testing machine that can allow for a new method (embodiments disclosed herein) of quality testing to be used. The torsion sample can be built and tested on the plate. Embodiments allow for proper testing inputs of strain rate along with proper measurement of the outputs of torque and strain. Embodiments of a torsion testing machine also allow for the variation in torque sample location on the plate. Embodiments reduced lead time from growth of a plate of parts to verification of material properties of the grown parts. Embodiments enable an accurate and controlled testing environment with accurate and recordable data output, for example.

Embodiments include a torsion sample (e.g., a test article <NUM>) and testing method (e.g., method <NUM>) that can be completed on the build plate, e.g., right after powder removal. The torsion sample can be grown on the plate in such a way that one or more embodiments of a torsion testing machine (e.g., embodiments disclosed herein) can be used to test the material. Embodiments utilize a test method and specimen that can be completed directly on the plate prior to all post processing of the plate other than powder removal, which can allows the material properties to be verified prior to adding effort and cost into the post processing of the plate.

For example, in certain embodiments, a short sample can be grown directly on the plate, already to the dimensions needed for torsion testing (e.g., a test article with a hex head which can fit within a testing machine as described above). Adjustable systems as described hereinabove can allow for gauge section diameter (e.g., diameter of the torsion shaft <NUM>) and/or height (e.g., of the torsion shaft) to be adjusted as needed.

Embodiments allow immediate feedback on potential machine failure to reduce exposure to in process parts which can speed up the manufacturing process by eliminating process steps needed for tensile testing, for example. The removed portion of the test article can be utilized for other material verification needs, i.e. hardness, surface roughness, porosity, grain size, chemistry, etc..

Certain embodiments of a torsion testing machine can include a frame (e.g., extruded t-slot aluminum rails), a build plated mount (which can be fixed or moveable, and may be configured to handle various plate sizes), a torque sensor with wireless strain gauge, displacement and/or torque controlled motor on adjustable rails, a data acquisition system with the ability to transfer data, an HMI visual control system with preset programs to control input variables, a part catcher, and the ability to output a Torque-Twist diagram which can allow the verification of material properties via ASTM E143-<NUM> methods.

The motor and torque sensor can be mounted to the adjustable rail system which can be configured to allow the motor and sensor to be moved forward and backward, as well as left to right, for example. This can give embodiments of the machine the capability to test a torque specimen at any location on the build plate. Quick release clamps can be used to lock the motor and sensor in place once lined up with a sample, and also to lock the plate in place to the build plate mount when connected to the torque tester. Certain embodiments of the data acquisition system can collect the torque-twist data and can give the operator a quick pass/fail check as well as output the data for further use. Embodiments can include a safety enclosure to meet safety requirements, and/or a full interlock system on a door of the enclosure.

Aspects of the this disclosure may be described above with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of this disclosure. It will be understood that each block of any flowchart illustrations and/or block diagrams, and combinations of blocks in any flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in any flowchart and/or block diagram block or blocks.

Any suitable combination(s) of any disclosed embodiments and/or any suitable portion(s) thereof are contemplated herein as appreciated by those having ordinary skill in the art.

Claim 1:
A method for determining quality of an additively manufactured article or batch thereof, comprising:
torsion testing at least one additively manufactured test article that is built on and attached to a build plate (<NUM>) while the at least one test article is still attached to the build plate (<NUM>);
additively manufacturing the at least one test article on the build plate (<NUM>) to have a test head configured to be torqued by a socket; and
wherein additively manufacturing the test article includes forming a base of the test article to adhere to the build plate (<NUM>) such that the base of the test article remains attached to the build plate (<NUM>) throughout torsion testing.