APPARATUS AND METHOD FOR SUPPORT REMOVAL
An apparatus and method for removing support material from a part formed by three-dimensional (3D) printing. The support removal machine contains a tank for submersion of a 3D printed part into a liquid mass. The liquid mass circulates in the tank in a controlled manner such that submerged parts remain centrally suspended in the tank, regardless of the material, density and geometry comprising the part. The part circulates and rotates in conjunction with the rotational flow of the liquid mass for uniform exposure to means of support removal. During rotation, the part may be subjected to multiple means of agitation that include heat, chemical and ultrasonic, in order to optimize energy use and maximize efficiency of the removal of support material.
This application claims the benefits of U.S. provisional application No. 62/344,122, filed Jun. 1, 2016 and entitled SUPPORT REMOVAL APPARATUS, which provisional application is incorporated by reference herein in its entirety.
TECHNICAL FIELDThe present disclosure pertains generally to an apparatus and method for removing support material from a part formed by three-dimensional printing.
BACKGROUNDVarious systems exist for removing support material from a 3D printed part. These systems often relate to methods for agitating a 3D printed part in a liquid media designed to erode support material surrounding the part. Additional known methods of support removal for three dimensional objects include raising and lowering temperature in a support removal tank to melt the support material, where the support material has a lower melting point than the part. Known systems may utilize a single tank into which the raw part is submerged, or they may include multiple tanks having different properties, including differing temperature or liquids.
U.S. Pat. No. 8,636,850 to Narovlyansky discloses a method for removing the support structures from 3D objects using a liquid jet. The '850 process generally involves inserting two or more objects made by solid freeform fabrication into a cell having an inlet to receive a high-pressure liquid jet located at a top side of the cell and a plurality of draining perforations at the circumferential wall of the cell.
U.S. Pat. No. 8,459,280 to Swanson discloses a support structure removal system comprising a reservoir tank and base unit. The vessel comprises a vessel body, a porous floor configured to retain a 3D part, and an impeller rotatably mounted below the porous floor. The impeller is rotated under magnetic force to agitate the solution around the part. Further, the tank may have a means for adjusting pH and temperature to promote support removal.
U.S. Pat. No. 7,546,841 to Tafoya discloses a device for support removal using liquid agitation and heat in a tank. Communication between a thermocouple in the tank and a microprocessor monitors the temperature in the tank and adjusts conditions accordingly.
The above systems often require manual adjustment throughout the process to adjust for various parts. The above systems may be optimally designed for certain types of parts, and may work well for parts of known and tested sizes, shapes and materials. However, when new types of parts are introduced to the system, much adjustment in setting parameters such as heat, pH, and time is required on the part of the operator to optimize efficient use of energy and time.
Therefore, the drawbacks of the current support removal systems include a lack of efficiency when used for a wide variety of parts. Further, movement of the center of mass of the part throughout the tank increases inefficiency and provides an opportunity for delicate parts to collide with the walls of the tank or components of the machine. Such collisions may cause the part to fracture, and also increase inefficiency through uncontrolled movement within the tank.
Efficient support removal for a wide variety of materials and part shapes and sizes requires a system that is responsive to changes in the part and the working environment surrounding the part. Further, a system is desired that can measure the parameters of the part, either directly or indirectly, and adjust automatically to unique properties of each part. Therefore, a need exists for a support removal machine that can efficiently handle the wide and expanding variety of part types encountered in the fast-growing field of three dimensional printing.
SUMMARYIn the present disclosure, a solution to the problems of existing support removal devices is provided through a machine design that maximizes energy efficiency. The present disclosure describes a support removal machine that responds automatically to changing conditions within a tank and structural changes in the part while maintaining the part in optimal location within the tank for support removal. The continuous regulation of part motion and tank parameters, through a novel combination of liquid flow, heat, ultrasonic radiation, and measurement capabilities, maximizes the use of energy and minimizes damage to the part.
Hydraulic pressure oscillates and suspends a 3D printed part while interrogating with ultrasonic frequencies. A key functional feature of the present disclosure is the ability to maintain the position of the part in a generally central location in the tank. This is accomplished through the use of manifolds positioned at specific locations throughout the tank to create a rotational liquid flow that creates liquid current that sinks parts that would otherwise float and floats parts that would otherwise sink. Under these rotational flow conditions, parts are centrally located submerged in the tank and rotate along with the flow of the liquid. In one embodiment, one or more manifolds may be located at the bottom of the tank along with one on the weir wall. The locations of the pump connected to the manifolds allows for the use of commercially available pumps, rather than custom built pumps, because the manifolds were designed around the pumps.
Rotation of the part within the liquid mass creates friction between the materials in the liquid mass and the part, thereby causing support removal. Support removal is enhanced by ultrasonic transducers placed tangentially in the tank to the rotating object. The ultrasonic generators create heat within the designated liquid mass within the tank, which enhances support removal, while also causing cavitation through direct interaction with the rotating part. The part generally circulates around a central point in a tank, and the part itself rotates. The motion of the part in the tank creates a controlled agitation. As the part spins and circulates within the mass, each aspect of the part is exposed to the ultrasonic waves, thereby creating a synergistic effect in support removal through the circulatory and rotational effects of part motion and the ultrasonic enhancement of support destruction.
The ultrasonic interrogation of the part creates heat and cavitation in a generally uniform manner across the part. However, a heating unit in the tank is also used to generate heat for support removal. The heating unit and the ultrasonic generator operate in harmony, such that when the ultrasonic generator needs to be dialed down, the heater can compensate by maintaining the heat of the mass at an optimal level. An advantage of using ultrasonic radiation resulting cavitation of the liquid mass, which a heater and pump will not create. Overuse of an ultrasonic device can degrade the liquid mass such that the fluid becomes exhausted. The part material is energy sensitive to deformation or delaminating so the constant optimization of energy use with regard to an ultrasonic component is important.
The use of an ultrasonic transducer has dual effects, such that the ultrasonic transducer may be considered more of a mixing component for the liquid mass rather than a heater. While heating with an ultrasonic transducer may require more energy than the use of a standard heating unit, the ultrasonic transducer has multiple effects due to the particular effect of ultrasonic radiation on the parts. While regulating the work that the ultrasonic transducer is doing, the device is characterizing. Ultrasonic radiation affects the surface of the part microscopically by causing vibration, thus, the work being done by the ultrasonic generator goes beyond heat alone, and creates a synergistic effect on support removal, causing the removal of support material in less time.
Another important feature of the support removal machine of the present disclosure is the inclusion of two linked tanks, an output, or part-containing tank, and an input tank. The liquid mass, which may be a detergent, flows from the bottom of the input tank through a manifold into the output tank, generating a pressure and rotational flow within the output tank. Importantly, there is no suction means to withdraw fluid from the output tank during operation. Fluid from the output tank continually flows from the output tank back into the input tank over a weir at the top of the outflow tank.
Therefore, the liquid level of the input tank is below that of the output tank, allowing the liquid mass to be discharged from the output tank over barrier between the output tank and the input tank, thereby forming a weir. The weir provides both oxygenation and cooling to the liquid mass; essential functions in maintaining optimal conditions for support removal. The wall separating the two tanks that allow formation of the weir is important because it allows for simultaneous oxygenation and temperature reductions, without the inclusion of additional costly or energy consuming features to regulate these parameters. The liquid mass and the weir cascade rely on the properties of each to maintain a proper balance of oxygenation, pH and evaporation. The machine and liquid mass have been thoroughly tested to optimize the interaction between the weir and the liquid mass.
Through use of the machine, the liquid mass is consumed, and is eventually required to be replaced. Throughout use, however, the level of liquid mass in the output tank is maintained, and kept full. As the liquid mass is consumed, the liquid level of the inflow tank decreases. Once the level decreases to a certain point, a liquid level sensor in the inflow tank is triggered, signaling the operator to replenish the liquid mass. Unlike other support removal machines and systems, the support removal machine of the present disclosure does not require the user to empty and refill the tank, rather, the conditions of the liquid mass are calibrated such that refilling the inflow tank when the level is decreased to a set point is sufficient to maintain operation of the system virtually indefinitely.
Preferred embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein:
In the following description, the various embodiments of the present invention will be described in detail. However, such details are included to facilitate understanding of the invention and to describe exemplary embodiments for implementing the invention. Such details should not be used to limit the invention to the particular embodiments described because other variations and embodiments are possible while staying within the scope of the invention.
Furthermore, although numerous details are set forth in order to provide a thorough understanding of the present invention, it will be apparent to one skilled in the art that these specific details are not required in order to practice the present invention. In other instances details such as, well-known methods, types of data, protocols, procedures, components, networking equipment, processes, interfaces, electrical structures, circuits, etc. are not described in detail, or are shown in block diagram form, in order not to obscure the present invention.
The terms “support”, “support material” and “support structure” as used throughout the specification and claims should be construed in their broadest interpretation to include any material or materials used for provisional support during fabrication of a 3D object and that is not part of the three-dimensional object. The support may include materials that are different than the modeling materials used to fabricate the 3D object or a combination of modeling materials and materials that are different than the modeling materials used to fabricate the 3D object.
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During operation of support removal machine 100, energy of liquid mass 28 may be regulated, and oxygenation, or aeration, of liquid mass 28 may maintain proper chemistry. To avoid introducing additional components to oxygenate (aerate) and decrease temperature when necessary, a weir 20 may exist between output tank 16 and input tank 18. Weir 20 may be comprised of a wall 36, or attenuating wall for its effect on ultrasound, between output tank 16 and input tank 18. The flow of liquid mass 28 from output tank 16 to a lower point in input tank 18 over wall 36 creates a passive system for achieving proper temperature and oxygenation states in the liquid mass. A positive pressure in output tank 16 created by flow into output tank 16 from pump 30 generates an overflow across wall 36 without a need for active suction from output tank 16, thus creating a system that eliminates the potential for damage to part 40 caused by suction from output tank 16. There is a negative pressure in input tank 18 that corresponds to the positive pressure in output tank 16. During operation of support removal machine 100 the liquid mass will naturally evaporate. Liquid level sensor 26 which in some embodiments may be continuous, notifies a user when the liquid mass 28 level needs maintenance. An alternative embodiment may comprise one tank or multiple tanks.
In a preferred embodiment, a feature of the support removal machine 100 of the present disclosure is the inclusion of two linked tanks, output tank 16 and an input tank 18, wherein the output tank 16 contains part 40 and the input tank 18 may contain a conditioned liquid mass 28. In the preferred embodiment, liquid mass 28, which may be a detergent, is pumped through a pump 30 from a lower area of input tank 18 through multiple manifolds 14 into output tank 16, generating a hydraulic pressure and rotational flow within output tank 16. In a preferred embodiment, pump 30 is positioned below input tank 18. The location of pump 30 may be important because, in one embodiment, pump 30 is not self-priming, and therefore, requires liquid mass 28 to be pumped to feed into pump 30 above the pump inlet. Manifolds 14 are positioned to be capable of directing a flow of liquid mass 28 in order to create a circularized flow, or vortex, in output tank 16. This flow allows for uniform exposure of all aspects of the part 40 to means of support removal, including, but not limited to, ultrasound, heat, and chemical treatment. In a preferred embodiment, no means of suction exists for withdrawal of liquid mass 28 from output tank 16 into input tank 18 during operation. Liquid mass 28, in a preferred embodiment, flows over the weir 20 as liquid mass 28 is pumped from input tank 14 to output tank 16. In a preferred embodiment, pump 30 is a magnetically coupled centrifugal pump. Pump 30 may be placed at a location beneath the level of the input tank 18 or output tank 16. In one embodiment, pump 30 has a motor that operates at 50/60 Hz and is not adjusted.
In the preferred embodiment, input tank liquid level 19 is below that of the output tank 16, allowing the liquid mass 28 to be discharged from the output tank 16 over a wall 36 between the output tank 16 and the input tank 18, thereby forming a weir 20. Weir 20 has a wall 36 to separate liquid mass 28 between output tank 16 and input tank 18. The weir 20 should be located just above upper manifold 14, allowing the rotational flow to continue within the output tank 16, while allowing liquid mass 28 to flow over weir 20 in a laminar fashion. In a preferred embodiment, the distance between liquid mass 28 level in the output tank 16 and the liquid level in input tank 18 may be between 2 inches and 12 inches.
Weir 20 provides both oxygenation and cooling to liquid mass 28, which are essential functions in maintaining optimal conditions for support removal. The cooling effect of weir 20 allows temperature of liquid mass 28 to be controlled with much tighter tolerances, even at low temperature settings. Weir 20 therefore allows the user to process delicate parts 40 that would normally be in danger of being damaged or altered due to temperature overshoot. Wall 36, which separates output tank 16 and input tank 18 to form weir 20 allows for simultaneous oxygenation, or aeration, and temperature reductions without the inclusion of additional costly or energy consuming features to regulate these parameters. Liquid mass 28 and weir 20 create a cascade to regulate oxygenation, pH and evaporation. Parameters of weir 20 have been optimized for efficiency of support removal.
As liquid mass 28 is consumed or exhausted through evaporation, mechanical, or chemical or other means, the consumed portion may require replacement. The level of liquid mass 28 in output tank 16 and input tank 18 is therefore monitored and maintained. As the liquid mass 28 is consumed, the liquid level of the input tank 18 decreases. Once the liquid mass 28 level in input tank 18 decreases to a certain point, a liquid level sensor 26, which may be a continuous liquid level sensor, in input tank 18 is triggered, signaling the operator to replenish or restore liquid mass 28. Unlike other support removal machines and systems, the support removal machine 100 of the present disclosure may not require the user to empty and refill the system completely, rather, the conditions of the liquid mass 28 are calibrated such that refilling the system when the level of liquid mass 28 is decreased to a set point may be sufficient to maintain operation of the system indefinitely.
Support removal machine 100 may respond automatically to changing conditions within output tank 16 and input tank 18, and structural changes in the part 40, while maintaining part 40 in an optimal location within output tank 40 for support removal. The continuous regulation of the position, circulation, and rotation of part 40 occurs in response to output tank 16 parameters, subject to a combination of parameters including liquid mass 28 flow, heat, ultrasound, and measurement capabilities, such that the use of energy in support removal machine 100 is maximized and damage to part 40 is minimized.
The flow of liquid mass 28, generated as liquid mass 28 passes through a set of tank manifolds 14, is generally rotational such that the liquid mass 28 is a vortex and that part 40 does not, due to the rotational flow of liquid mass 28, generally contact the surface of liquid mass 28. The position of manifolds 14 and the direction of the flow of liquid mass 28 generated from manifolds 14 creates a vortex that suspends part 40 between a surface of the liquid mass 28 and a bottom and sides of output tank 16. In an alternative embodiment of the present disclosure, a single tank having a pump may generate flow to effectively rotate part 40 in a single chamber.
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Hydraulic pressure oscillates and suspends a 3D printed part while interrogating with ultrasonic frequencies. A key functional feature of the present disclosure is the ability to maintain the position of the part 40 in a generally central location in output tank 16. Maintaining position of part 40 is accomplished through the use of manifolds 14 positioned at locations throughout tank 40 to create a rotational liquid flow, or vortex, that creates liquid current to sinks a part 40 that would otherwise float and to float a part 40 that would otherwise sink. Under the rotational flow conditions generated by the apparatus and method of the present disclosure, a part 40 is centrally located, submerged in a tank and circulated around a central axis of the tank, along with being rotating around an axis of the part 40. In one embodiment, one or more manifolds may be positioned on the walls of the tank at certain locations along output tank 16 including one position immediately adjacent to weir 20 on wall 36. The location of pump 30, connected to the manifolds 14, allows for the use of commercially available pumps, rather than custom built pumps, because the manifolds were designed around the performance, or operating abilities, of the pumps. However, custom built pumps are contemplated within the present disclosure.
Rotation of part 40 within the liquid mass 28 creates friction between the materials in the liquid mass 28 and the part 40, resulting in support removal. In one embodiment, support removal is enhanced by ultrasonic transducers 22 placed tangentially in output tank 16 with respect to rotating part 40. Ultrasonic generator 42 creates heat in liquid mass 28 within output tank 16, which causes support removal through multiple direct and indirect means, while also causing cavitation through direct interaction with the rotating part 40. As the part 40 spins within the liquid mass 28, each aspect of part 40 is exposed to ultrasound, thereby creating a synergistic effect in support removal through rotational effects in liquid mass 28 and the ultrasonic enhancement of support removal.
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The ultrasonic interrogation of part 40 creates heat and cavitation in a generally uniform manner across the part as it rotates and circulates through output tank 16, exposing each surface of part 40 to the ultrasound. Additionally, a heating unit may also be used to generate heat for enhancing support removal. The heating unit and the ultrasonic generator 70 may operate in harmony, such that when the ultrasonic generator 70 needs to be dialed down, the heating unit can compensate by maintaining the heat of the mass at an optimal level. A heating unit may be positioned wherein said heating means comprises a heating element having an internal end positioned internally in the output chamber 16 to engage the liquid mass and an external end communicatively coupled to said microprocessor for controlling heat input to the liquid mass contained within the output chamber 16. An advantage provided by the use of ultrasound is the creation of cavitation of liquid mass 28, which a heater and pump 30 may not do. Overuse of the ultrasonic transducer 22 may degrade the liquid mass 28 such that liquid mass 28 becomes exhausted. The part 40 material may be energy sensitive to deforming or delaminating such that constant optimization of energy within the system is important.
The use of an ultrasonic transducer 22 has dual effects, such that the ultrasonic transducer 22 may be considered a mixing component for liquid mass 28 rather than an just a heater. While heating with an ultrasonic transducer 22 may require more energy than the use of a standard heating unit, the ultrasonic transducer 22 has multiple effects. Ultrasound affects the surface of part 40 microscopically by causing vibration, thus, the work being done by ultrasonic transducer 22 extends beyond heating alone, thus creating a synergistic effect for support removal, and increasing efficiency of the process.
It is obvious that the components comprising the support removal apparatus may be fabricated from a variety of materials, providing such selection or use of materials possess the capacity to withstand premature corrosion given the presence and use of an alkaline aqueous cleaning solution, notably falling within a variety of pH ranges. The tank can be made of 304 and/or 316 SS or any steel alloy with better corrosion resistance than 316 SS. Accordingly, it is most desirable, and therefore preferred, to construct the output tank and input tank work surface, top and nozzle heads from stainless steel; pipe and fittings from a polymeric material such as polyamide (PA) or acrylonitrile-butadiene-styrene (ABS); and cabinet and storage cabinet from a lower grade stainless steel. It is noted herein that the retention tank, nozzle head, work surface, and integral work platform may be alternatively fabricated from materials to lessen the overall weight of the support removal apparatus yet maintaining sufficient resistance to corrosion, such as polypropylene, polyoxymethylene, polyphenylene, ABS, or PA. Similarly, the pump, thermocouple, heating element 38, and level indicator, particularly exposed operable components of each, are fabricated from a high grade stainless steel or coated with an impervious, corrosive-resistant material such as epoxy.
Although the disclosure has been described with reference to certain preferred embodiments, it will be appreciated by those skilled in the art that modifications and variations may be made without departing from the spirit and scope of the disclosure. It should be understood that applicant does not intend to be limited to the particular details described above and illustrated in the accompanying drawings.
Claims
1. A method of removing support structure material, comprising:
- providing a part-containing tank;
- filling the part-containing tank with a liquid mass;
- generating a vortex in the liquid mass contained in the part-containing tank;
- placing a part in the part-containing tank;
- suspending the part in the liquid mass within the vortex; and
- removing support material from the part.
2. The method of claim 1, wherein the part-containing tank has a first side, a second side and a bottom surface; wherein the first side is opposite the second side; wherein a first manifold is positioned at a top portion of the first side and is configured to direct a downward flow of liquid mass along the first side; wherein a second manifold is proximal to a junction between the first side and the bottom surface and is configured to direct a lateral flow of liquid mass along the bottom surface toward the second side.
3. The method of claim 2, wherein the part-containing tank has a third manifold proximal to a junction between the second side and the bottom surface and is configured to direct an upward flow of liquid mass along the second side.
4. The method of claim 3, wherein each manifold directs a flow of liquid mass under equal pressure.
5. The method of claim 3, wherein each manifold has an orifice; wherein each orifice has an orifice diameter; wherein each orifice diameter is capable of being changed to produce an optimal flow of liquid mass for maintaining a part in proper position within the part-containing tank.
6. The method of claim 1, further comprising providing a part-containing tank in fluid communication with an input tank while leaving a build material undisturbed.
7. The method of claim 6, further comprising filling the input tank and part-containing tank with a liquid mass, wherein the level of liquid mass in the input tank is lower than the level of liquid mass in the part-containing tank.
8. The method of claim 7, further comprising pumping the liquid mass from the input tank into the part-containing tank through a plurality of manifolds.
9. The method of claim 8, further comprising discharging the liquid mass from the part-containing tank to the input tank at an upper portion of the output tank;
10. The method of claim 1, further comprising dropping the liquid mass from the part-containing tank into the input tank.
11. The method of claim 1, further comprising pumping the liquid mass into the part-containing tank through a plurality of manifolds positioned symmetrically in order to generate a vortex within the liquid mass.
12. The method of claim 1, wherein each nozzle in the tank directs flow generally within a same plane.
13. A method of removing support structure material, comprising:
- providing an output tank in fluid communication with an input tank;
- filling the input tank and output tank with a liquid mass, wherein the level of liquid mass in the input tank is lower than the level of liquid mass in the output tank;
- pumping the liquid mass from the input tank into the output tank through at least one manifold;
- forming a vortex in the liquid mass contained in the output tank;
- discharging the liquid mass from the outlet tank to the input tank at an upper portion of the output tank;
- dropping the liquid mass from the output tank into the input tank;
- placing a part in the output tank;
- suspending the part in the output tank below the surface of the liquid mass within the vortex;
- rotating the part in the output tank with hydraulic pressure;
- and removing support material from the part.
14. The method of claim 13, further comprising interrogating the part with ultrasound.
15. The method of claim 13, further comprising oxygenating the liquid mass during transfer from the output tank to the input tank.
16. The method of claim 13, further comprising cooling the liquid mass during transfer from the output tank to the input tank.
17. A support structure removal apparatus, comprising:
- an output tank having walls and a base collectively forming an output tank chamber for containing a liquid mass and a part;
- an input tank having walls and a base collectively forming an input tank chamber; wherein the output tank chamber and the input tank chamber are in liquid communication;
- a pump for causing liquid to flow from the input tank to the output tank;
- manifolds for producing rotational flow in the output tank;
- a weir between the output tank and the input tank, wherein the level of liquid mass is in the input tank is higher than the level of the liquid mass in the input tank;
- an ultrasonic motor in the output tank to provide tangential ultrasonic radiation to the part.
18. The support structure removal apparatus of claim 18, further comprising a level indicator positioned internally in said input chamber at a predetermined distance above said agitating means for transmitting level measurements of the aqueous cleaning solution present in said interior chamber to said microprocessor.
19. The support structure removal apparatus of claim 18, wherein the pump is attached to intake and outlet piping passing through intake and outlet apertures wherein the intake aperture is in a wall of the input tank, and the outlet aperture is in a wall of the output tank, wherein the outlet piping has one end attached to outlet side of a pump and a manifold.
20. The support structure removal apparatus of claim 18, further comprising a basket positioned within the output chamber, having perforated walls to permit passage of the liquid mass and inhibiting the passage of parts, and a parts opening extending through one of its perforated walls to permit access to an interior portion thereof, said basket further comprising an overall geometric configuration substantially capable of fitting through the confines of an opening for positioning within the output chamber.
Type: Application
Filed: Jun 1, 2017
Publication Date: Dec 7, 2017
Inventor: Daniel Joshua Hutchinson (Orchard Park, NY)
Application Number: 15/611,435