Patent Description:
Depowdering LPBF parts is a rate limiting part of the additive manufacturing process. Traditional commercial products and solutions fall short when applied to intricate parts. It remains important to have multiple tool options for depowdering to suit more and more geometries. Some of the traditional tools are effective, but there is an ongoing need for improvement and diversity of tools for depowdering additive manufactured parts.

The conventional techniques have been considered satisfactory for their intended purpose. However, there is an ever present need for improved systems and methods for enhanced depowdering. This disclosure provides a solution for this need. <CIT> relates to an additive manufacturing apparatus and a system for depowdering according to the preamble of claim <NUM>. <CIT> relates to a powder removal mechanism.

A system for depowdering additively manufactured parts is provided in claim <NUM> and includes a deflection plate, a hammer device mounted to a first side of the deflection plate, and a mounting plate operatively connected to a second side of the deflection plate relative to the hammer device, the mounting plate being configured for rotation relative to the deflection plate.

An ultrasonic transducer system can be mounted to the mounting plate for inducing ultrasonic vibrations into the mounting plate. The ultrasonic transducer system can include at least one ultrasonic transducer ring mount mounted to the mounting plate. Each ring mount can include a receptacle for mounting a respective ultrasonic transducer thereto. The ultrasonic transducers can be of an electrically insulative material and can be hardened against explosion for safe use with explosive powder. The at least one ultrasonic transducer ring mounts can be a pair of ultrasonic transducer ring mounts. A first ultrasonic transducer having a first frequency can be mounted to a first one of the ultrasonic transducer ring mounts, and a second ultrasonic transducer having a second frequency can be mounted to a second one of the ultrasonic transducer ring mounts. The first frequency of the first ultrasonic transducer can be different than the second frequency of the second ultrasonic transducer.

An arm can connect between an arm actuator and the deflection plate such that the arm actuator is configured to rotate the arm and deflection plate through <NUM>° of rotation back and forth about an arm axis defined along the arm. A plate actuator can be connected to the deflection plate and to the mounting plate for actuating rotation of the mounting plate relative to the deflection plate within a plane parallel to a plane defined by the second surface of the deflection plate. The plate actuator can be configured to rotate the mounting plate through <NUM>° of rotation back and forth about a plate axis perpendicular to the second surface of the deflection plate.

The mounting plate can include an inner hub and an outer rim connected to one another by a plurality of radial spokes. The rim of the mounting plate can include a plurality of sets of fastener holes configured to receive fasteners of a variety of different build plate configurations. The mounting plate can include a lip, wherein only the lip of the mounting plate contacts the deflection plate. A retention plate can be mounted to the deflection plate with a portion of the mounting plate between the deflection plate and retention plate.

A controller is operatively connected to control movement of the mounting plate, and actuation of the hammer device and transducer system. The controller includes machine-readable instructions configured to cause the controller to rotate a build plate fixed to the mounting plate through yaw, pitch, and roll angles and to remove powder while doing so by controlling the hammer device to vibrate the build plate. The machine-readable instructions can include instructions to rotate a two axis system of actuators to rotate the mounting plate through yaw, pitch, and roll. The controller can be connected to the ultrasonic transducer system such that the machine-readable instructions can include instructions to drive ultrasonic vibrations from the ultrasonic transducer system into the build plate. The machine readable instructions can include instructions to sweep the ultrasonic transducer system through a range of resonant frequencies.

A build plate having an additively manufactured build can be mounted to the mounting plate with a plurality of fasteners. The fasteners can engage the mounting plate in part through a respective die spring for each fastener.

These and other features of the systems and methods of the subject disclosure will become more readily apparent to those skilled in the art from the following detailed description taken in conjunction with the drawings.

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, a partial view of an embodiment of a system in accordance with the disclosure is shown in <FIG> and is designated generally by reference character <NUM>. Other embodiments of systems in accordance with the disclosure, or aspects thereof, are provided in <FIG>, as will be described. The systems and methods described herein can be used to depowder additively manufactured parts.

After parts are additively manufactured, for example using a laser powder bed fusion method, or other powder sintering method, excess powder must be removed from the parts. To do so efficiently and safely, especially from internal features, can require applying directional and/or rotational forces to the additively manufactured parts. A system <NUM> for depowdering additively such manufactured parts <NUM> can include a build plate <NUM> mounted to a first side <NUM> of a mounting plate <NUM> with a plurality of fasteners <NUM> (e.g. bolts). The fasteners <NUM> can engage the mounting plate <NUM> in part through a respective die spring <NUM> for each fastener <NUM>. Using die-springs <NUM> under heads of the fasteners <NUM> protects the fasteners <NUM> and allows for resonant bounce between build plate <NUM> and mounting plate <NUM>.

The mounting plate <NUM> can include an inner hub <NUM> and an outer rim <NUM> connected to one another by a plurality of radial spokes <NUM>. The spokes <NUM> allow for more deflection than would otherwise be possible with a solid mounting plate <NUM>, and ultimately for improved resonance through the build plate <NUM> and par <NUM> for improved powder removal. The rim <NUM> of the mounting plate <NUM> can include a plurality of sets of fastener holes <NUM> configured to receive fasteners <NUM> of a variety of different build plate configurations. For example, the fastener holes <NUM> can be indexed (e.g. using lettering and/or numbering system) to correspond to known build plate configurations to assist in mounting and remounting the build plate <NUM> during cleaning. This can be beneficial if the system <NUM> is being implemented as a retrofit, for example.

A deflection plate <NUM> can be mounted to a second side <NUM> of the mounting plate <NUM> such that the mounting plate <NUM> can rotate to the deflection plate <NUM> about axis R1. A hammer device <NUM> (e.g. a pneumatic hammer) can be mounted to a first side <NUM> of the deflection plate <NUM>, opposite the mounting plate <NUM>. The deflection plate <NUM> can include a lip <NUM> for contacting the mounting plate <NUM> through actuation of the hammer device <NUM>. In this way, only the lip <NUM> of the deflecting plate <NUM> contacts the mounting plate <NUM>. The directional forces from the hammer device <NUM> are applied to the build plate through both the deflection plate <NUM> and the mounting plate <NUM>, so as not to contact or cause damage to the build plate <NUM> or part <NUM>. A retention plate <NUM> can be mounted to the deflection plate <NUM> (e.g. along a chordal major diameter) so that a portion of the mounting plate <NUM> is sandwiched between the deflection plate <NUM> and retention plate <NUM>. The retention plate <NUM> thus provides additional support to the mounting plate <NUM>, for example for heavier build plates <NUM> and/or parts <NUM>.

An arm <NUM> can connect between an arm actuator <NUM> and the deflection plate <NUM> such that the arm actuator <NUM> is configured to rotate the arm <NUM> and deflection plate <NUM> together through <NUM>° of rotation back and forth about an arm axis R2 defined along the length of the arm <NUM>. A plate actuator <NUM> can be connected to the deflection plate <NUM> and to the mounting plate <NUM> for actuating rotation of the mounting plate <NUM> relative to the deflection plate <NUM> within a plane P1 parallel to a plane P2 defined by second side <NUM> of the deflection plate <NUM>. The plate actuator <NUM> can be configured to rotate the mounting plate through <NUM>° of rotation back and forth (e.g. between notches <NUM>) about a plate axis R1 perpendicular to the second side <NUM> of the deflection plate <NUM>, and perpendicular to the arm axis R2. The combined rotation of the arm <NUM> and the mounting plate <NUM> allow for two-axis rotation, changing force origin and resonance signature, provided a more effective powder removal.

An ultrasonic transducer system <NUM> can be mounted to the mounting plate <NUM> for inducing ultrasonic vibrations into the mounting plate <NUM>, for example for multi-stage powder removal techniques and recipes. The ultrasonic transducer system can include at least one ultrasonic transducer ring mount <NUM> mounted to the mounting plate <NUM>. Each ring mount <NUM> can include a receptacle <NUM> for mounting a respective ultrasonic transducer <NUM> thereto. Transducer ring mount <NUM> can allow the ultrasonic vibrations to clean the part <NUM>, but will deflects when the hammer device <NUM> is actuated and applied to the mounting plate, protecting the transducer <NUM>. For example, parametric adjustment of the present embodiment allows for the intended amplitude of energy transfer, while deflecting the hammer forces to reduce unintentional transfer of energy back to transducer component, which can be fragile and sensitive to the forces of the hammer device <NUM>. The ultrasonic transducers <NUM> can be of an electrically insulative material protecting operators and surrounding equipment in event of transducer electrical fault, and can be hardened against explosion for safe use with explosive powder.

The at least one ultrasonic transducer ring mount <NUM> can be a pair of ultrasonic transducer ring mounts 142a,b, for example to mount multiple transducers <NUM> having the same or different frequencies. As shown, a first ultrasonic transducer 146a can be mounted to a first one of the ultrasonic transducer ring mounts 142a, and a second ultrasonic transducer 146b can be mounted to a second one of the ultrasonic transducer ring mounts 142b. The frequencies of the ultrasonic transducers can be the same or different, for example the first transducer 146a can have a frequency of <NUM>, and the second transducer 146b can have a frequency of <NUM> however any suitable transducer frequency can be used.

A controller <NUM> can be operatively connected to the system <NUM> to control movement of the mounting plate <NUM>, and actuation of the hammer device <NUM> and transducer system <NUM>. For example, the controller <NUM> can include machine-readable instructions configured to cause the controller to rotate the build plate through two axes of rotation, including yaw, pitch, and roll angles and to remove powder while doing so by controlling the hammer device to vibrate the build plate. The controller <NUM> can also be connected to the ultrasonic transducer system <NUM> to drive ultrasonic vibrations from the ultrasonic transducer system <NUM> into the build plate <NUM> through the mounting plate <NUM>. The controller <NUM> can control the ultrasonic transducer system <NUM> to sweep through a range of resonant frequencies and amplitudes as needed for cleaning.

Claim 1:
A system for depowdering additively manufactured parts, the system comprising:
a deflection plate (<NUM>);
a hammer device (<NUM>) mounted to a first side (<NUM>) of the deflection plate (<NUM>); and
a mounting plate (<NUM>) operatively connected to a second side of the deflection plate (<NUM>) relative to the hammer device (<NUM>), the mounting plate (<NUM>) being configured for rotation relative to the deflection plate (<NUM>); and characterised by
an ultrasonic transducer system (<NUM>) mounted to the mounting plate (<NUM>) for inducing ultrasonic vibrations into the mounting plate;
a controller (<NUM>) operatively connected to control movement of the mounting plate (<NUM>) and actuation of the hammer device (<NUM>) and ultrasonic transducer system (<NUM>), wherein the controller (<NUM>) includes machine-readable instructions configured to cause the controller to rotate a build plate fixed to the mounting plate through yaw, pitch, and roll angles and to remove powder while doing so by controlling the hammer device and ultrasonic transducer system to vibrate the build plate.