A system and method for controlling the placement of a dental mold 3D printing tray

Abstract

This invention discloses a system and method for controlling the placement of a 3D printing tray for dental models, belonging to the field of dental instrument manufacturing technology. The system includes a deviation detection device, a force application device, and a control device. The deviation detection device detects a deviation at a first position on the printing platform; the force application device applies a control force to a second position on the tray corresponding to the first position; and the control device controls the sequence and magnitude of the control force applied by the force application device to the second position on the tray based on the deviation value at the first position. The method is implemented based on the corresponding system. The control device of this invention controls how the force application device applies control force to the tray based on the deviation value of the printing platform detected by the deviation detection device, thereby reducing the instantaneous impact of the tray on the printing platform. This ensures that after the tray is installed on the printing platform, the deviation of the printing platform is within the required range, guaranteeing the quality of the dental model printing.

Description

Technical Field

[0001] This invention belongs to the field of dental instrument manufacturing technology, specifically relating to a system and method for controlling the placement of a 3D printed dental model tray. Background Technology

[0002] Invisible aligners are increasingly accepted by patients due to their ease of removal, comfort, and aesthetic appeal. The manufacturing process involves first creating a physical dental model (jaw model, tooth model) using 3D printing technology based on a digital model of the jaw. Then, a polymer material film is thermoformed onto the physical dental model to form a shell-like invisible aligner containing the shape of teeth. Finally, through processes such as cutting, polishing, cleaning, sterilization, and packaging, the final invisible aligner is formed and ready for the patient to wear. Because invisible aligners require high manufacturing precision, the level of precision directly determines the orthodontic effect and can even lead to medical accidents. The quality of the dental model directly determines the quality of the aligner. If the jaw model is substandard, it cannot be used in subsequent processes. The quality of the dental model is primarily affected by the 3D printing process. Currently, dental models are mainly made of resin material, printed layer by layer.

[0003] Currently, 3D printers used for printing dental models typically print the model directly onto the printer's printing platform. After printing, a tool is used to remove the finished model before printing the next one. However, the limited operating space of the printer restricts the operator's movements. Secondly, manually removing the model can easily damage the product and is very inefficient, especially for products like dental models that require high precision and are produced in large batches.

[0004] To address the aforementioned issues, existing 3D printing technologies propose placing a tray (or base plate, carrier plate, etc.) on a printing platform, and then printing the product onto the tray. Before printing begins, the tray is placed on the printing platform, and the product is then printed on the platform. After printing, the product is attached to the tray. At this point, the tray is removed from the printing platform, and the entire tray, along with the product, is taken outside the printer. The product is then removed from the outside of the printer. When the tray with the product attached is removed, a new tray can be installed for printing.

[0005] For example, when printing dental molds, because dental molds are small in size, multiple dental molds can be printed on one tray. After printing is completed, the tray is removed, the dental mold is removed from the outside of the printer, and a new tray is installed to continue printing.

[0006] When placing the tray on the printing platform, it needs to be locked in place. In existing technologies, magnetic attraction is often used for quick and easy fixing and disassembly, with magnets used to attach the tray to the printing platform. However, for existing 3D printers that print dental molds, each layer needs to be smoothed with a scraper before printing the next layer. During this smoothing operation, the tangential force is significant, requiring the tray to withstand it. Magnetic attraction alone may not provide sufficient tangential force, causing the tray to shift during smoothing. Therefore, those skilled in the art utilize positioning pins to fix the tray in place. These pins also serve a positioning function. When installing the tray, the pins are used for positioning, and then the magnetic attraction is used to hold it in place.

[0007] For printers that print dental models, or many 3D printers, the printing platform can be raised and lowered; its structural principle is similar. Figure 1 As shown, the lifting mechanisms 2 are all located on one side of the printing platform 1, while the other side is suspended, similar to a cantilever structure.

[0008] Because dental molds require large-scale production in each batch, relying solely on manual operation is inefficient. Therefore, those skilled in the art have designed automated production lines that utilize robotic arms for pallet loading and unloading. When loading pallets, the robotic arm grasps the pallet, moves it above the printing platform, aligns it with the positioning pins, and then lowers the pallet. However, the positioning...

[0009] The pin and tray typically use a transition fit. After the tray is placed, there is a certain gap between the tray and the printing platform. To eliminate this gap, a robotic arm is usually used to apply downward pressure to the tray, pressing it directly into place. Alternatively, in cases using magnetic attraction, a strong magnetic force can instantly attach the tray to the printing platform. However, given the structure of the 3D printer described above, when performing these operations, the tray will cause a momentary impact on the printing platform, resulting in a downward deviation. To ensure printing accuracy, this deviation must be controlled within a reasonable range; for example, when printing dental molds, it must be controlled within 30 microns (0.3 mm).

[0010] Furthermore, although printers need to be leveled before printing, this leveling process usually occurs before placing the tray, and even after leveling, it's difficult to achieve absolute levelness; it only controls the deviation within a reasonable range. The act of placing the tray, however, can easily cause the deviation to exceed this reasonable range, resulting in a defective printed dental model. Summary of the Invention

[0011] In order to prevent deviations of the printing platform from exceeding reasonable limits due to the robot's movements or locking forces when placing the printing tray onto the printer's printing platform using a robotic arm, this invention provides a system and method for controlling the placement of a dental mold 3D printing tray, thereby controlling the tray placement process to minimize deviations that could lead to defective printed dental molds.

[0012] In a first aspect, the present invention provides a system for controlling the placement of a dental mold 3D printing tray, comprising:

[0013] A deviation detection device is used to detect the deviation at a first position on the printing platform, where the first position is a position where a positioning pin is provided.

[0014] A force-applying device, the force-applying device being used to apply a control force to a second position on the tray corresponding to the first position;

[0015] A control device that controls the sequence and magnitude of the control force applied by the force-applying device to the second position of the tray based on the deviation value at the first position.

[0016] Furthermore, the printing platform is provided with four positioning pins, positioning the four corners or four sides of the tray, with the first position formed at or near the positioning pins, and the deviation detection device simultaneously detects the deviation at the four positions.

[0017] Furthermore, the control device, based on the deviation value at the first position, controls the sequence in which the force-applying device applies control force to the second position of the tray, including:

[0018] Obtain the deviation values ​​Δx1, Δx2, Δx3, and Δx4 at the four first positions;

[0019] Select the first position corresponding to the smallest deviation value, and use the second position corresponding to that position as the reference.

[0020] According to the benchmark, the force application device first applies a control force to the second position diagonally opposite to the benchmark, then applies a control force to two non-diagonally opposite second positions simultaneously, and finally applies a control force to all four second positions simultaneously.

[0021] Furthermore, the control device controls the magnitude of the control force applied by the force-applying device to the second position of the tray based on the deviation value at the first position, including:

[0022] The smaller the deviation value, the smaller the applied control force. The applied control force must satisfy the following condition: when the control force is applied, the deviation change at the corresponding position is within the required range.

[0023] Furthermore, the force application device includes an electromagnet mounted on the printing platform and a corresponding magnetic component mounted on the tray. The controller controls the current flowing into the electromagnet based on the deviation value at the first position, thereby controlling the magnitude of the control force applied to the tray.

[0024] Furthermore, the deviation detection device is a laser ranging device or a visual ranging device.

[0025] Secondly, the present invention provides a method for controlling the placement of a dental mold 3D printing tray, comprising:

[0026] The deviation detection device detects the deviation at the first position of the printing platform, where the first position is where a positioning pin is set.

[0027] The control device controls the sequence and magnitude of the control force applied by the force-applying device to the second position on the tray corresponding to the first position, based on the deviation value at the first position.

[0028] Furthermore, the printing platform is provided with four positioning pins, forming four first positions, and the corresponding tray has four second positions. The control device controls the order in which the force application device applies control force to the second positions of the tray according to the deviation value at the first position, including:

[0029] Obtain the deviation values ​​Δx1, Δx2, Δx3, and Δx4 at the four first positions;

[0030] Select the first position corresponding to the smallest deviation value, and use the second position corresponding to that position as the reference.

[0031] According to the benchmark, the force application device first applies a control force to the second position diagonally opposite to the benchmark, then applies a control force to two non-diagonally opposite second positions simultaneously, and finally applies a control force to all four second positions simultaneously.

[0032] Furthermore, the control device controls the magnitude of the control force applied by the force-applying device to the second position of the tray based on the deviation value at the first position, including:

[0033] The smaller the deviation value, the smaller the applied control force. The applied control force must satisfy the following condition: when the control force is applied, the deviation change at the corresponding position is within the required range.

[0034] The system of this invention includes a deviation detection device, a force application device, and a control device. The control device controls how the force application device applies a control force to the tray based on the deviation value of the printing platform detected by the deviation detection device. This reduces the instantaneous impact of the tray on the printing platform, ensuring that the deviation of the printing platform is within the required range after the tray is installed, thereby guaranteeing the quality of the dental model printing. A corresponding method, based on this system, can control the tray placement to prevent the deviation of the printing platform from exceeding the required range, thus ensuring the printing quality of the dental model. Attached Figure Description

[0035] Figure 1 This is a schematic diagram illustrating the placement of a tray on the printing platform in an embodiment of the present invention;

[0036] Figure 2 This is a system block diagram of the system in an embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of the system in an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram showing the position of the positioning pin in an embodiment of the present invention;

[0039] Figure 5 This is a schematic diagram of the position of the positioning pin in an embodiment of the present invention (another method);

[0040] Figure 6 This is a flowchart of the method in an embodiment of the present invention;

[0041] Figure 7 This is a flowchart illustrating the control of the force application sequence in an embodiment of the present invention. Detailed Implementation

[0042] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0043] This invention is applicable to Figure 1The illustrated 3D printer has a lifting mechanism 2 located on one side of the printing platform, with the entire printing platform 1 having a cantilever structure. When this type of 3D printer is used, if the tray 3 is placed on the printing platform 100 by a robotic arm, a downward force must be applied to the tray due to the presence of positioning pins. However, if this force is not properly controlled, the deviation Δx of the printing platform will exceed the required range, resulting in a defective dental mold. Therefore, this invention first provides a system for controlling the placement of the dental mold 3D printing tray, based on... Figure 2 The system includes: a deviation detection device 5, a force application device 6, and a control device 4. The deviation detection device 5 is used to detect the deviation at a first position 9 on the printing platform 1. It should be noted that the first position 9 refers to the location on the printing platform where the positioning pins are set. Since the printing platform has multiple positioning pins, not just one, the first position 9 does not define a single location; its number corresponds to the number of positioning pins. For example, if four positioning pins are set on the printing platform 1 to position the tray, then the first position actually refers to four locations. See [link to documentation]. Figure 4 and Figure 5 Indication.

[0044] The force-applying device 6 is used to apply a control force to the second position 10 on the tray 3, which corresponds to the first position 9. Similar to the first position 9, the second position 10 is not limited to one location, but rather the number of positions is consistent with that of the first positions 9, and they correspond to each other.

[0045] It should be noted that tray 3 is provided with pin holes corresponding to the positioning pins. When the tray is placed on the printing platform, the pin holes correspond to the pins, and the corresponding positions on tray 3 correspond to the first position 9, i.e., the second position 10. Furthermore, the "position" mentioned in this article is not limited to a single point, but rather refers to an area.

[0046] The control device 4 controls the order and magnitude of the control force applied by the force application device 6 to the second position 10 of the tray 3 based on the deviation value at the first position 9.

[0047] In this invention, the control device controls how the force application device applies control force to the tray based on the deviation value of the printing platform detected by the deviation detection device, thereby reducing the instantaneous impact of the tray on the printing platform. This ensures that after the tray is installed on the printing platform, the deviation of the printing platform is within the required range, thus guaranteeing the quality of the dental mold printing.

[0048] In an embodiment of the present invention, four positioning pins are provided on the printing platform 1. These four positioning pins can be used to position the four corners or four sides of the tray, which is rectangular. For example... Figure 4 As shown, four positioning pins are positioned at the four corners of the printing platform, allowing the tray to be positioned using these four corners; for example... Figure 5 As shown, four positioning pins are set at the four edges of the printing platform, so that the tray 3 can be positioned by positioning the four edges of the tray.

[0049] In embodiments of the present invention, the deviation detection device 5 can employ laser ranging or visual ranging. Regardless of whether laser ranging or visual ranging is used, the deviation detection device 5 can be positioned below the printing platform. Figure 3 The specific quantity needs to be set according to the number of positioning pins. For example, in one embodiment, laser ranging is used. The laser ranging device 5 can be a laser rangefinder, which is set below the printing platform 1 and connected to the control device. By measuring the position of the printing platform, the deviation of the printing platform is calculated. The principle of laser ranging is a well-known technology and will not be elaborated on in this article.

[0050] For example, in another embodiment, visual ranging is used. The deviation detection device 5 may include a camera and a projector. The camera projects a signal onto the printing platform, and then the camera captures the signal; or a TOF camera can be used directly. The principle of visual ranging is widely disclosed in the prior art, and will not be elaborated further here. Using conventional visual ranging methods may require a combination of a projector and a camera, which may be inconvenient to install. Therefore, the deviation detection device 5 can use an industrial camera to set a marker point at a first position on the printing platform. By capturing images of the marker point, the positional change of the marker point is calculated, and the deviation of the first position is calculated based on the positional change of the marker point. This type of machine vision method is also widely disclosed in the prior art.

[0051] In an embodiment of the present invention, four positioning pins are provided. The control device controls the sequence of applying control force to the second position of the tray by the force-applying device according to the deviation value at the first position, including the following steps, see reference. Figure 7 :

[0052] Step S201: Obtain the deviation values ​​Δx1, Δx2, Δx3, and Δx4 at the four first positions;

[0053] Step S202: Select the first position corresponding to the smallest deviation value, and use the second position corresponding to that position as...

[0054] Based on;

[0055] Step S203: According to the reference, the force application device first applies a control force to the second position diagonally opposite to the reference, then applies a control force to two non-diagonally opposite second positions simultaneously, and finally applies a control force to all four second positions simultaneously.

[0056] By following the steps described above, the force on the entire pallet can be distributed more evenly. For example, combining... Figure 4 or Figure 5 As shown, for the first position, the deviation value at position ① is Δx1, the deviation value at position ② is Δx2, the deviation value at position ③ is Δx3, and the deviation value at position ④ is Δx4. Assuming that the value of Δx1 is the smallest, then for the second position, position ① is selected as the reference. After the reference is determined, for the second position, firstly, a control force is applied to position ③, which is diagonally opposite to position ①. After applying the control force to position ③, control forces are simultaneously applied to the two non-diagonally opposite positions of position ①, positions ② and ④. Finally, control forces are simultaneously applied to positions ①, ②, ③, and ④.

[0057] In special cases, such as when the values ​​of Δx1, Δx2, Δx3, and Δx4 are the same, any position can be randomly selected as the reference, and then the control force can be applied according to the above procedure.

[0058] Furthermore, in this embodiment of the invention, the control device 4 controls the magnitude of the control force applied to the tray by the force application device based on the deviation value at the first position. This includes: the smaller the deviation value, the smaller the applied control force; and the applied control force satisfies the condition that the deviation change at the corresponding position is within the required range when the control force is applied. For example, if Δx2 is less than the value of Δx3, then the control force applied at position ② is less than the control force applied at position ③. When applying the control force, the deviation at each position is detected in real time by the deviation detection device to ensure that the deviation change at the corresponding position is within the required range during the application of the control force.

[0059] Furthermore, in embodiments of the present invention, reference is made to... Figure 3 The force application device 6 includes an electromagnet 7 mounted on the printing platform 1 and a corresponding magnetic component 8 mounted on the tray. The electromagnet 7 is connected to the control device 4. The control device 4 controls the current flowing into the electromagnet according to the deviation value at the first position, thereby controlling the magnitude of the control force applied to the tray.

[0060] It should be noted that when setting up the electromagnet, since it is not convenient to directly and completely align the electromagnet with the position of the locating pin, the electromagnet should be placed close to the locating pin. Therefore, as mentioned earlier, the first position is not a point but an area. Thus, the first position 9 can be formed at or near the locating pin. Correspondingly, the second position 10 can also be formed at or near the pin hole.

[0061] In other embodiments, the force-applying device can also be a contact mounted on the robot arm. For example, a dedicated force-applying device can be designed, which may include multiple contacts, each of which can be controlled individually. When the robot arm places the tray on the printing platform, the contacts can be aligned with the positioning pins. When applying control force to the tray, each contact is individually controlled to apply pressure to the tray.

[0062] In an embodiment of the present invention, when the force-applying device is an electromagnet structure, the electromagnet is controlled by a control device. The control device can control the magnitude of the current flowing into the electromagnet, thereby controlling the magnitude of the electromagnet's magnetic force.

[0063] In an embodiment of the present invention, the control device 4 may be a PLC, an industrial computer, etc., connected to the force application device 6 and the deviation detection device 4, receiving data from the deviation detection device 4, processing it, and then sending a control signal to the force application device 6 according to the processing result.

[0064] Secondly, in embodiments of the present invention, a method for controlling the placement of a dental mold 3D printing tray is provided, combined with Figure 6 As shown, the method includes the following steps:

[0065] Step S10: The deviation detection device detects the deviation at the first position of the printing platform; the main terms used have been described in detail in the previous description of the system, and will not be repeated here.

[0066] Step S20: The control device controls the order and magnitude of the control force applied by the force application device to the second position on the tray corresponding to the first position, based on the deviation value at the first position.

[0067] In an embodiment of the present invention, four positioning pins are provided on the printing platform to form four first positions, and the corresponding tray has four second positions. The control device controls the order in which the force-applying device applies control force to the second positions of the tray according to the deviation value at the first position, including the following steps, see reference. Figure 7 :

[0068] Step S201: Obtain the deviation values ​​Δx1, Δx2, Δx3, and Δx4 at the four first positions;

[0069] Step S202: Select the first position corresponding to the smallest deviation value, and use the second position corresponding to that position as the reference;

[0070] Step S203: According to the reference, the force application device first applies a control force to the second position diagonally opposite to the reference, then applies a control force to two non-diagonally opposite second positions simultaneously, and finally applies a control force to all four second positions simultaneously.

[0071] In an embodiment of the present invention, the control device controls the magnitude of the control force applied by the force application device to the second position of the tray according to the deviation value at the first position, including: the smaller the deviation value, the smaller the applied control force, and the applied control force satisfies: when the control force is applied, the deviation change at the corresponding position is within the required range.

[0072] For a more detailed implementation of the method proposed in this invention, please refer to the description of the system, which will not be elaborated further here.

[0073] This invention provides a system and method for controlling the placement of a dental mold 3D printing tray, thereby controlling the process of placing the tray on the printing platform, reducing the instantaneous impact of the tray on the printing platform during placement, ensuring that the printing platform does not exceed the required deviation range, and thus guaranteeing the printing quality of the dental mold.

[0074] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A system for controlling placement of a dental model 3D printing tray, the system comprising: include: A deviation detection device is used to detect the deviation at a first position on the printing platform, where the first position is a position where a positioning pin is provided. The printing platform is provided with four positioning pins, which are located at the four corners or four sides of the positioning tray. The first position is formed at or near the positioning pins, and the deviation detection device detects the deviation at the four positions simultaneously. A force-applying device, the force-applying device being used to apply a control force to a second position on the tray corresponding to the first position; A control device that controls the sequence and magnitude of the control force applied by the force-applying device to the second position of the tray based on the deviation value at the first position; The control device, based on the deviation value at the first position, controls the sequence of the control force applied by the force-applying device to the second position of the tray, including: Obtain the deviation values ​​Δx1, Δx2, Δx3, and Δx4 at the four first positions; Select the first position corresponding to the smallest deviation value, and use the second position corresponding to that position as the reference. According to the benchmark, the force application device first applies a control force to the second position diagonally opposite to the benchmark, then applies a control force to two non-diagonally opposite second positions simultaneously, and finally applies a control force to all four second positions simultaneously. The control device controls the magnitude of the control force applied by the force-applying device to the second position of the tray based on the deviation value at the first position, including: The smaller the deviation value, the smaller the applied control force. The applied control force must satisfy the following condition: when the control force is applied, the deviation change at the corresponding position is within the required range.

2. The system of claim 1, wherein, The force-applying device includes an electromagnet mounted on the printing platform and a corresponding magnetic component mounted on the tray. The control device controls the current flowing into the electromagnet based on the deviation value at the first position, thereby controlling the magnitude of the control force applied to the tray.

3. The system of claim 1, wherein, The deviation detection device is either laser ranging or visual ranging.

4. A method of controlling placement of a dental model 3D printing tray, characterized by, include: The deviation detection device detects the deviation at the first position of the printing platform, where the first position is where a positioning pin is set. The control device controls the order and magnitude of the control force applied by the force application device to the second position on the tray corresponding to the first position, based on the deviation value at the first position; The printing platform is equipped with four positioning pins, forming four first positions. The corresponding tray has four second positions. The control device controls the sequence of the control force applied by the force application device to the second positions of the tray according to the deviation value at the first position, including: Obtain the deviation values ​​Δx1, Δx2, Δx3, and Δx4 at the four first positions; Select the first position corresponding to the smallest deviation value, and use the second position corresponding to that position as the reference. According to the benchmark, the force application device first applies a control force to the second position diagonally opposite to the benchmark, then applies a control force to two non-diagonally opposite second positions simultaneously, and finally applies a control force to all four second positions simultaneously. The control device controls the magnitude of the control force applied by the force-applying device to the second position of the tray based on the deviation value at the first position, including: The smaller the deviation value, the smaller the applied control force. The applied control force must satisfy the following condition: when the control force is applied, the deviation change at the corresponding position is within the required range.

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