Ultrasonic removal methods of three-dimensionally printed parts

An imaging device includes an ejector head configured to eject a material, a platen having a first surface configured to receive material ejected by the ejector head and support an object formed with the ejected material, a vibrator configured to vibrate, and a controller operatively connected to the vibrator. The controller is configured to operate the vibrator to vibrate and loosen material adhering to the first surface of the platen to enable the object to be removed from the platen.

TECHNICAL FIELD

The system and method disclosed in this document relate to printers that produce three-dimensional objects and, more particularly, to systems and methods that remove three-dimensionally printed parts from such printers.

BACKGROUND

Digital three-dimensional manufacturing, also known as digital additive manufacturing, is a process of making a three-dimensional solid object of virtually any shape from a digital model. Three-dimensional printing is an additive process in which one or more printheads eject successive layers of material on a substrate in different shapes. Three-dimensional printing is distinguishable from traditional object-forming techniques, which mostly rely on the removal of material from a work piece by a subtractive process, such as cutting or drilling.

Once a part has been formed by a three-dimensional printing system on a surface of a planar support member of a three-dimensional printing system, the part is often difficult to remove. The difficulty arises because a layer of support material can hold the printed part securely to the planar support member. Often times, attempts to manually remove the printed part results in damage to the part due to the strong hold of the layer of support layer between the surface of the planar support member and the printed part. Particularly thin or weaker portions of the printed part are especially vulnerable to such damage during removal. Therefore, a method for removing a printed part from a planar support member of a three-dimensional printing system that preserves the structural integrity of the printed part would be beneficial.

SUMMARY

A three-dimensional object printer facilitates the removal of parts from a platen with little or no damage to the parts. The printer includes an ejector head configured to eject a material, a platen having a first surface configured to receive material ejected by the ejector head and support an object formed with the ejected material, a vibrator configured to vibrate, and a controller operatively connected to the vibrator, the controller being configured to operate the vibrator to vibrate and loosen material adhering to the first surface of the platen to enable the object to be removed from the platen.

A method for operating a three-dimensional printer facilitates the removal of parts from a platen with little or no damage to the parts. The method includes operating an ejector head with a controller to eject a material onto a first surface of a platen to form an object, and operating a vibrator with the controller to vibrate and loosen material adhering to the first surface of the platen to enable the object to be removed from the platen.

DETAILED DESCRIPTION

For a general understanding of the present embodiments, reference is made to the drawings. In the drawings, like reference numerals have been used throughout to designate like elements.

FIG. 6shows a configuration of components in a printer100, which produces a three-dimensional object or part10. As used in this document, the term “three dimensional printer” refers to any device that ejects material with reference to image data of an object to form a three dimensional object. The printer100includes a support material reservoir14, a building material reservoir18, a pair of ejector heads22,26, a planar support member34, actuators42, and a controller46. Conduit50connects ejector head22to support material reservoir14and conduit54connects ejector head26to building material reservoir18. Both ejector heads are operated by the controller46with reference to three-dimensional image data in a memory operatively connected to the controller to eject the support and building materials supplied to each respective ejector head towards an upper surface35of the planar support member34. The building material forms the structure of the part10being produced, while the support structure58formed by the support material enables the building material to maintain its shape while the material solidifies as the part is being constructed.

The controller46is also operatively connected to at least one and possibly more actuators42to control movement of the planar support member34, and the ejector heads22,26relative to one another. That is, one or more actuators can be operatively connected to the structure supporting the ejector heads to move the ejector heads in a process direction and a cross-process direction with reference to the surface of the planar support member. Alternatively, one or more actuators can be operatively connected to the planar support member34to move the surface on which the part is being produced in the process and cross-process directions in the plane of the planar support member34. As used herein, the term “process direction” refers to movement along one axis in the surface of the planar support member34and “cross-process direction” refers to movement along an axis in the planar support member surface that is orthogonal to the process direction axis in that surface. These directions are denoted with the letters “P” and “C-P” inFIG. 6. The ejector heads22,26also move in a direction that is orthogonal to the planar support member34. This direction is called the vertical direction in this document, and is denoted with the letter “V” inFIG. 6. Movement in the vertical direction is achieved with one or more actuators operatively connected to the planar support member34, by one or more actuators operatively connected to the ejector heads22,26, or by one or more actuators operatively connected to both the planar support member34and the ejector heads22,26. These actuators in these various configurations are operatively connected to the controller46, which operates the actuators to move the planar support member34, the ejector heads22,26, or both in the vertical direction.

Turning toFIG. 1, a part60is formed on the upper surface35of the planar support member34by operation of the ejector heads22,26(FIG. 6). Removal of such a part can be difficult because the structure58(FIG. 6) can include a support layer59(FIG. 1), which is made of support material that adheres the part to the upper surface35of the planar support member34. To facilitate removal, the printing system further includes a vibrator, such as the vibrator110, which is configured to vibrate and loosen the printed part from the planar support member.

The vibrator110includes a vibrating element112configured to vibrate, and a contact element114operatively connected to the vibrating element112that engages a lower surface37of the planar support member34as shown inFIG. 1. The actuators42are operatively connected to the vibrator110to move the vibrator in a vertical direction V, a process direction P, and/or a cross-process direction C-P (FIG. 6) with reference to the planar support member34under control of the controller46. Alternatively, the controller46is configured to operate the actuators42to move either or both of the vibrator110and the planar support member34with respect to each other in the vertical, process, and cross-process directions. The controller46is also operatively connected to the vibrating element112. The controller46is configured to operate the vibrating element112to produce vibration selectively and is further configured to vary the intensity of the vibration produced by the vibrating element112. Varying the intensity should be understood to mean that one or both of the frequency and the magnitude of the vibration is varied, or the length of time that the vibrator is controlled to vibrate a particular area is varied. A higher intensity is associated with a higher frequency or magnitude or both, or a relatively higher length of time that an area is subject to vibration, while a lower intensity is associated with a lower frequency or magnitude or both, or a relatively lesser length of time that an area is subject to vibration. The vibrating element112in some embodiments is an ultrasonic transducer configured to vibrate at high frequency. In other embodiments, the vibrating element is configured to vibrate at another desired frequency, or multiple frequencies, and with any desired vibrating magnitude or magnitudes that result in any desired vibration intensity.

In operation, the controller46operates the vibrating element112of the vibrator110to produce vibrations, and the actuators42to move the vibrator110with the contact head114of the vibrator110engaging the lower surface35of the planar support member34as shown inFIG. 1. The vibrations produced by element112are transferred by the contact head114to the planar support member34. In the embodiment shown, the contact head114transfers vibrations in a direction perpendicular to the lower surface35of the planar support member. However, the contact head114can be configured to contact the support member at any desired angle in order to transfer vibrations at any corresponding desired angle with respect to the planar support member. The vibrations in the planar support member34loosen or break the bond between the support layer59and the part60or between the part60and the planar support member34to enable the part to be readily removed without damaging the part60. The vibrator can be controlled to move in the process direction P and the cross process direction C-P (FIG. 6) in some predetermined pattern while remaining in contact with the lower surface37. For example, the vibrator110can be controlled with reference to image data of the part in order to vibrate portions of the lower surface37corresponding to the printed part. The vibrator110can be moved to vibrate the lower surface37along the entire or partial length of the object and along the entire or partial width of the object, or to vibrate the lower surface37at any location on the lower surface37below a portion of the printed part that assists in part removal.

The intensity of the vibrator110is configured to be controlled with reference to image data as the vibrator110is moved in engagement with the planar support member34. For example, with reference toFIG. 2, the vibrator110is controlled to vibrate at a lower intensity at peripheral portions120,121of the printed part60, and a higher intensity at a central or non-peripheral portion122of the part60in order to ensure that the vibration does not damage the peripheral portion of the part60, which may be weaker or at a greater risk of being damaged than a non-peripheral portion. InFIG. 2, an intensity profile130is shown aligned with the part60and planar supporting member34. Vibration intensity is represented on a vertical axis132, and location of the vibrator along the process direction P is represented on the horizontal axis134. As represented by the plot line135, the intensity is varied from an intensity of zero at the point136corresponding to an outer periphery of the part60and is increased as the vibrator is moved in the process direction through the peripheral portion120of the part60until the vibrator reaches the location that corresponds to point138in the profile, which is associated with the non-peripheral portion122. The vibrator110is vibrated at a constant intensity while translating along the lower surface37of the planar support member34corresponding to the non-peripheral portion122until the vibrator reaches the peripheral portion121location that corresponds to point140in the profile. The constant intensity may correspond to a maximum intensity for a particular part, or the maximum intensity for the vibrating element. The reader should understand that the vibration intensity may also be varied while vibrating the non-peripheral portion121. Finally, the vibration intensity is decreased until the vibrator reaches the location on the member that corresponds to the point142in the profile. While the vibration intensity is shown as zero at the outer periphery of the printed part, the reader should understand that a non-zero minimum intensity may also be utilized at the outer periphery.

In another example shown inFIG. 3, a printed part150has a generally triangular shape in which the thickness of the part150varies along the process direction P. The relatively thin portions of the part150are subject to a higher risk of being damaged by vibrations from a vibrator than relatively thicker portions. As the vibrator110is moved in a process direction P, the vibrator110is controlled to vibrate at a relatively lower intensity at the positions along the portion of the lower surface37of the planar support member34corresponding to the relatively thinner or weaker sections of a part150. These portions of the part150could be susceptible to damage at higher intensities that can be used at the relatively thicker or stronger sections of the part150. InFIG. 3, an intensity profile152is shown aligned with the part150and planar supporting member34. The vibration intensity is represented on the vertical axis153, and the location of the vibrator with reference to the object150along the process direction P is represented on the horizontal axis155. As shown by the plot line154, the intensity is varied from an intensity of zero at the position on the member34that corresponds to the point156in the profile. This position corresponds to the thinnest portion of part150. Part150increases in resilience to the vibrations as the vibrator moves in the process direction along the member34because the thickness of the part150also increases until the vibrator reaches the position that corresponds to point158in the profile. At that position, the controller maintains a constant vibration intensity until the vibrator110reaches the position that corresponds to the point160in the profile. The vibration intensity is then decreased from the position corresponding to the point160in the profile until the vibrator reaches the position corresponding to the point162in the profile because the thickness of the part150continually decreases in this area.

Although specific profiles are represented inFIGS. 2-3that may be utilized to prevent damage at the perimeter and/or thinner or weaker sections of the printed part, the reader should understand that any profile can be utilized in order to free the printed part in a damage-free manner. For example, the intensity may be varied linearly, non-linearly, or in a stepped manner at the periphery or in relation to stronger or weaker portions of the printed part. Certain areas may be selectively vibrated, while other areas are not vibrated at all. The printed part at a peripheral portion, non-peripheral portion, relatively thinner or weaker portions, or relatively thicker or stronger portions may be vibrated at any desired intensity. The maximum and minimum intensity utilized for any portion of a printed part may also be selected based on any desired factor in order to ensure that the part may be removed without damage. Any desired profile may be utilized under control of the controller.

Moreover, while the vibrator110of the embodiment ofFIGS. 1-3has been described as engaging the lower surface37of the planar support member34, in other embodiments, the vibrator engages the upper surface35, or one of the side surfaces of the planar support member34. In yet other embodiments, the vibrator is securely attached to the planar support member34. In still other embodiments, the vibrator is positioned inside the planar support member. The vibrator may be moveably or fixedly positioned at any desired location in engagement with the planar support member in order to vibrate the planar support member to loosen the part on the planar support member.

FIG. 4depicts a vibrator210, similar to the vibrator110, having a vibrating element212configured to vibrate an end214. Vibrator210further includes a blade216secured to the end214. The actuators42are operatively connected to the vibrator210to move the vibrator in a vertical direction V, a process direction P, and a cross-process direction C-P (FIG. 6) with reference to the planar support member34under control of the controller46. Alternatively, the controller46is configured to operate the actuators42to move either or both of the vibrator210and the planar support member34with respect to each other in the vertical, process, and cross-process directions. The controller46is also operatively connected to the vibrating element212. The controller46is configured to operate the vibrating element212to produce vibrations and is further configured to vary the intensity of the vibration produced by the vibrating element212. The vibrating element212in some embodiments is an ultrasonic transducer configured to vibrate at high frequency. In other embodiments, the vibrating element is configured to vibrate at another desired frequency, or multiple frequencies, and with any desired vibrating magnitude or magnitudes that result in any desired vibration intensity.

As shown inFIG. 4, the printed object220includes a support layer222that adheres the part to the upper surface35of the planar support member34. In order to break or loosen the bond without damaging the part220, the vibrator210is configured to vibrate the upper surface of the planar support member35while scraping the interface of the support layer222with the upper surface35of the planar support surface34with the blade216. Specifically, the controller46operates the vibrating element212of the vibrator210to produce vibrations. Vibrations from the vibrating element212are transferred through the end214to the blade216to cause the blade216to vibrate. The vibrations transferred to the blade216from the vibrating element212improve the scraping and cutting ability of the blade216to separate the part from the support member as compared to a non-vibrating blade. The controller46operates the actuators42to move the vibrator210so that the blade216engages the upper surface35of the planar support surface34, as shown inFIG. 5, and moves the vibrator210in the process direction P and the cross process direction C-P (FIG. 6) with reference to a printed object220. As shown inFIG. 5, the actuators42hold the vibrator210at an angle α with respect to the upper surface35causing the blade216to flex thereby forming a bend in the blade216. With the bend developed in the blade216, the angle of attack at which an end218of the blade216contacts the support layer222is reduced, which improves the scrapping and cutting action of the blade while reducing the chance that the part220is damaged because the blade216scrapes and cuts at an angle more closely aligned with the upper surface35of the planar support member34. The vibrating blade216facilitates removal of the part220by scraping the printed part220with the support layer222from the upper surface35and/or cutting through the support layer222. The reader should understand that any desired angle α may be utilized that facilitates removal of a printed part. Moreover, while controlling the actuators to move the vibrator210with a bend developed in the blade216has been described, the vibrator210may be positioned so that the blade bends at any desired angle with respect to the upper surface of the planar support surface, or without a bend at all.

In one embodiment of the apparatus shown inFIG. 5, the controller46operates the actuators42to move the vibrator210at a speed in a range of about 1400 to about 1800 mm/sec and to move the planar support member in direction P at a speed of about 2.54 mm/sec. The vibrator was an acoustic transducer and the blade holder angle α was set at about 37.5 degrees to enable the edge of the blade to engage the interface of the part and the upper surface of the planar support member. This embodiment was effective to loosen the adherence of the build material of the part from the material of the planar support member. A variety of materials were used for the planar support member. In one embodiment, the planar member was made of glass, in another the planar member was steel plate covered with a layer of chromium, and in another the planar member was steel plate covered with a layer of nickel. Effective removal of the part from the planar support member required blade angles of 30 degrees or greater. The frequency of the vibration was held relatively constant at 62.5 KHz, ±2 KHz. The controller46is also configured to operate the vibrating element212at a constant intensity, or to vary the intensity of the vibration produced by the vibrating element212of the vibrator210similarly to the vibrator110already described. The intensity and position of the vibrator210can be controlled with reference to image data, and according to any desired intensity profile.

It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems, applications or methods. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements may be subsequently made by those skilled in the art that are also intended to be encompassed by the following claims.