Actuator assemblies for additive manufacturing apparatuses and methods for using the same
An actuator assembly for distributing build material and depositing binder material in an additive manufacturing apparatus may comprise an upper support and a lower support spaced vertically spaced from one another. A recoat head actuator may be coupled to a recoat head and one of the upper support and the lower support. The recoat head actuator may include a recoat motion axis. The recoat head actuator effects bi-directional movement of the recoat head on the recoat motion axis. A print head actuator may be coupled to a print head and the other of the upper support and the lower support. The print head actuator may include a print motion axis. The print head actuator effects bi-directional movement of the print head on the print motion axis. The recoat motion axis and the print motion axis are parallel to one another and spaced apart from one another in the vertical direction.
1 . An actuator assembly for distributing build material and depositing binder material in an additive manufacturing apparatus, the assembly comprising:
an upper support;
a lower support spaced from the upper support in a vertical direction, the upper support and the lower support extending in a horizontal direction;
a recoat head for distributing build material;
a print head for depositing binder material;
a recoat head actuator coupled to the recoat head and one of an upper surface of the upper support and a lower surface of the lower support, the recoat head actuator comprising a recoat motion axis, wherein the recoat head actuator is bi-directionally actuatable along the recoat motion axis thereby effecting bi-directional movement of the recoat head;
a print head actuator coupled to the print head and an other of the upper surface of the upper support and the lower surface of the lower support, the print head actuator comprising a print motion axis, wherein the print head actuator is bi-directionally actuatable along the print motion axis thereby effecting bi-directional movement of the print head, wherein the recoat motion axis and the print motion axis are parallel to one another, extend in the horizontal direction, and spaced apart from one another in the vertical direction;
a control system comprising a processor and a non-transitory memory storing computer readable and executable instructions that, when executed by the processor, cause the processor to:
detect position measurements of the print head and the recoat head;
determine a maximum relative velocity of the print head and the recoat head, the maximum relative velocity equal to a sum of a maximum process velocity of the print head and a maximum process velocity of the recoat head; and
determine a real-time minimum separation distance of a plurality of real-time minimum separation distances between the recoat head and the print head, the real-time minimum separation distance comprising:
a collision distance component corresponding to the position measurements of the print head and the recoat head; and
a velocity-based component corresponding to the maximum relative velocity; and
a working axis proximity sensor communicatively coupled to the control system, the working axis proximity sensor configured to detect a position of at least one of the recoat head and the print head
wherein in response to the control system receiving a signal from the working axis proximity sensor indicating that a distance between the recoat head and the print head is less than the real-time minimum separation distance of the plurality of real-time minimum separation distances, the control system sends a signal to halt a manufacturing process,
wherein the upper support is positioned above a support rail,
wherein the lower support is positioned below the support rail,
wherein the support rail extends along an axis extending in the horizontal direction parallel to the recoat motion axis and the print motion axis.
2 . The assembly of claim 1 , wherein the recoat motion axis and the print motion axis are in a vertical plane.
3 . The assembly of claim 1 , further comprising:
an intermediate support positioned between the upper support and the lower support, the intermediate support extending in the horizontal direction;
a process accessory, the process accessory comprising a sensor, an energy source, an end effector or combinations thereof; and
an accessory actuator coupled to the process accessory and the intermediate support, the accessory actuator comprising an accessory motion axis, wherein the accessory actuator is bi-directionally actuatable along the accessory motion axis thereby effecting bi-directional movement of the process accessory, wherein the recoat motion axis, the print motion axis, and the accessory motion axis are parallel to one another and spaced apart from one another in the vertical direction.
4 . The assembly of claim 1 , wherein:
the recoat head comprises a recoat home position;
the print head comprises a print home position spaced apart from the recoat home position in the horizontal direction; and
the control system is communicatively coupled to the recoat head actuator and the print head actuator, the control system comprising the processor and the non-transitory memory storing the computer readable and executable instructions that, when executed by the processor, cause:
the recoat head actuator to advance the recoat head from the recoat home position towards the print home position at a recoat advance rate;
the recoat head actuator to return the recoat head to the recoat home position at a recoat return rate;
the print head actuator to advance the print head from the print home position of the print head towards the recoat home position at a print advance rate; and
the print head actuator to return the print head to the print home position at a print return rate.
5 . The assembly of claim 4 , wherein the recoat return rate is greater than the recoat advance rate.
6 . The assembly of claim 4 , wherein the print return rate is greater than or equal to the print advance rate.
7 . The assembly of claim 4 , wherein the print return rate is less than or equal to the print advance rate.
8 . The assembly of claim 4 , wherein the recoat advance rate comprises:
an initial recoat advance rate; and
a distribution advance rate, wherein the initial recoat advance rate is greater than the distribution advance rate.
9 . The assembly of claim 4 , wherein the print advance rate comprises:
an initial print advance rate; and
a deposition advance rate, wherein the initial print advance rate is greater than the deposition advance rate.
10 . The assembly of claim 4 , wherein the print return rate comprises:
a deposition return rate; and
a print complete return rate, wherein the print complete return rate is greater than the deposition return rate.
11 . The assembly of claim 4 , wherein the print head is advanced from the print home position towards the recoat home position while the recoat head is returned to the recoat home position.
12 . The assembly of claim 4 , wherein the recoat head is advanced from the recoat home position towards the print home position while the print head is returned to the print home position of the print head.
13 . The assembly of claim 1 , wherein the recoat head comprises at least one of a wiper, a blade, or a roller for distributing build material.
14 . The assembly of claim 1 , wherein the recoat head comprises a leading roller and a trailing roller for distributing build material.
15 . The assembly of claim 14 , wherein the leading roller rotates in a first direction and the trailing roller rotates in a second direction opposite the first direction.
16 . The assembly of claim 1 , wherein the print head is fixed in directions orthogonal to the print motion axis.
17 . The assembly of claim 1 , wherein the upper support is provided on and in direct contact with an upper surface of the support rail, and wherein the lower support is provided on and in direct contact with a lower surface of the support rail.
18 . The assembly of claim 1 , wherein in response to the control system receiving the signal from the working axis proximity sensor indicating that the distance between the recoat head and the print head is less than the real-time minimum separation distance of the plurality of real-time minimum separation distances, the control system sends a signal to adjust a speed of one or more of the recoat head and the print head.
19 . The assembly of claim 1 , wherein in response to the control system receiving the signal from the working axis proximity sensor indicating that the distance between the recoat head and the print head is less than the real-time minimum separation distance of the plurality of real-time minimum separation distances, the control system sends a signal to stop movement of the recoat head and the print head.
20 . The assembly of claim 1 , wherein the print head actuator is capable of a first deceleration rate and the recoat head actuator is capable of a second deceleration rate, wherein the smaller of the first deceleration rate and the second deceleration rate is used to compute the velocity-based component of the real-time minimum separation distance, the velocity-based component added to the collision distance component to determine the real-time minimum separation distance.