Device for producing a dental splint

Abstract

A device for producing a dental splint is described, comprising a computing unit (1), a thermoforming station (2) for a film on a denture model (3), and a laser cutting system (4) for cutting out the dental splint from the film. In order to configure a device of the type depicted at the outset in such a way as to enable a manufacturing process of dental splints which is as fully automated and rapid as possible, wherein, in particular, the space requirement of the required devices is minimized and complicated robotics systems for transporting the dental splints are intended to be dispensed with, it is proposed that a plurality of workstations are provided which comprise at least one 3D printer (5) for producing the denture model (3) on a workpiece carrier (10), the thermoforming station (2), a severing device (6) for severing the thermoformed film from the denture model (3), and the laser cutting system (4), wherein the workstations are arranged along a transport system (7) which comprises a guide (8) and a transport means (9) which is arranged movably along the guide (8) for loading and unloading the workstations with the workpiece carrier (10).

Description

[0001] Device for producing a dental splint

[0002] Technical area

[0003] The invention relates to a device for producing a dental splint comprising a computing unit, a thermoforming station for a film on a denture model and a laser cutting system for cutting the dental splint from the film, wherein several work stations are provided which comprise at least one 3D printer for producing the denture model on a workpiece carrier, the thermoforming station, a separating device for separating the thermoformed film from the denture model and the laser cutting system.

[0004] State of the art

[0005] To produce a dental splint to correct malocclusion, a series of temporally and spatially separated work steps are necessary. After recording the actual position of the teeth using an imaging technique, a specialist must determine a target position. Subsequently, several 3D dental models are created, starting from the actual position, in which the tooth position is gradually changed until the target position is reached. These models serve as molds for the thermoforming of thermoplastic films, which must be removed from the mold, cut to size, and deburred so that the patient can use these processed films as a dental splint. In the prior art, it is therefore known to arrange several workstations that can carry out individual work steps automatically in a production line and to feed the intermediate products one after the other to the workstations.A disadvantage of the current technology, however, is that some work steps, particularly the production of denture models using hardening resins or plaster, are very time-consuming, and the denture molds and foils must be frequently moved between workstations during production, making time- and labor-saving automation of the manufacturing process difficult. In particular, the transport and positioning of the aligners requires complex robotic arms and conveyor belts, which is why automated production of aligners requires a large amount of space.

[0006] To minimize movement between workstations, devices have already been disclosed that perform multiple work steps at the same location. EP2101674B1, for example, shows a device in which foils removed from the denture model are stored on a movable platform, where they can be automatically processed based on CAD templates using movable thermoforming tools and cut by a laser. Furthermore, devices for 3D printing denture models exist that feature a ball milling cutter for trimming the foil. However, these also only perform two work steps, which does not allow for automated production.

[0007] Description of the invention

[0008] The invention is therefore based on the object of enabling a manufacturing process for dental splints that is as fully automated and fast as possible, whereby in particular the space requirement of the required devices is to be minimized and complicated robotic systems for transporting the dental splints are to be dispensed with.

[0009] The invention achieves this objective by arranging the workstations along a transport system comprising a vertical linear guide and a transport means, displaceable along the vertical linear guide, for loading and unloading the workstations with the workpiece carrier. Due to their detailed and individual surface texture and their fragile materials, automated transport of denture models and dental splints is typically very complex. Since the 3D printer controlled by the computer unit prints the denture model directly onto the workpiece carrier based on the stored patient data, the transport means on the guide only needs to be designed to accommodate and transport the robust and geometrically simple workpiece carrier, not the delicate denture model.As a result of these measures, the transport device requires only a simple receiving mechanism that allows the workpiece carriers, and optionally the film and the dental splint, to be moved for loading and unloading the workstations. This could, for example, be a shovel with a movable stop. Since the workstations, in which all production steps are carried out, from the manufacture of the denture models to the final processing of the dental splint, are arranged along the transport system, the control of the transport device can be kept simple. Several, preferably all, workstations can be loaded and unloaded via the transport device, which can be moved along the guides of the transport system, whereby the transport device only needs to move along a single axis between the workstations.The transport system transports the workpiece carrier with the denture model and a film from the film storage to the thermoforming station where the film is pulled over the denture model in the usual way. To make loading the thermoforming station and correct positioning of the film easier, a centering or clamping ring can be provided for the film. The thermoformed film is then separated from the denture model by the separating device using methods known from the state of the art. For example, in an optional further step before thermoforming, lubricant can be applied to the denture model and / or the pulled film can be subjected to positive or negative pressure. The separated, thermoformed film is then transported by the transport system to the laser cutting system and cut and trimmed to size to form the dental splint. As a result of these measures, careful positioning of the film orCare must be taken to detect the position of the film by the laser cutting system. However, since the diameter of the film hardly changes even after thermoforming, a stop for the film that is adjusted to the diameter can be provided in the laser cutting system so that the control of the transport system can be kept simple for correct loading of the laser cutting system. The computer unit has an interface for transmitting commands and for transferring data, such as CAD plans of a dental model. Furthermore, additional workstations can be provided for carrying out further work steps. Preferably, the transport means arranged on the guide loads and unloads all workstations by being suitable not only for transporting the workpiece carrier, but also for holding the film or the dental splint made from the film.The device can further comprise a film storage unit, from which a film can be transported to the thermoforming station via the transport system. Furthermore, a removable waste container can be provided, into which denture models and film remnants can be disposed of via the transport system. The space required by the device is reduced by the fact that the guide is a vertically running, straight guide. As a result of these measures, both the maximum distance to be covered between the various workstations and the space required by the device are minimized. This reduces the dimensions of the device not only in terms of area but also in height, which means that the device can also be used in cramped dental practices, for example.

[0010] According to the invention, a toothed splint can be manufactured fully automatically with the device using only the transport means for loading and unloading. However, to achieve this, the transport means must be able to accommodate both the robust workpiece carrier and the more delicate films without damage or defects. However, to keep the transport means as simple as possible and preferably make the device more compact, the transport system can include a second transport means for transporting the film from the cutting device to the laser cutting system. As a result of these measures, the transport means only loads and unloads the workstations that operate on the workpiece carrier, for example, the 3D printer, the thermoforming station, and the cutting device, with the transport of the film being handled by the second transport system.This means that the toothed rail can still be manufactured fully automatically, but the transport system can be kept simple in its design and control, as it only has to transport the robust workpiece carrier. The second transport system can also be arranged so that it can be moved on the guide, but is preferably arranged so that it can be moved on a separate guide. This allows greater design freedom with regard to the spatial arrangement of the workstations, as the travel paths of the second transport means can be designed independently of the first transport means. The second transport system can also comprise a gripper, for example. If the device comprises a film storage area, the second transport means is preferably designed to transport the film from the film storage area to the cutting device and on to the laser cutting system.Furthermore, the second transport means is preferably designed to pick up the dental splint after the last processing step of the last work station and to place it at a location, preferably a removal opening, where the dental splint can be easily picked up by a user.

[0011] Although the workpiece carrier can comprise a variety of holding mechanisms, the workpiece carrier, the film and the drawn film can be picked up, placed down and transported particularly easily if a vacuum system is provided that includes at least one nozzle arranged on a suction plate on the first and / or second transport means. Both the workpiece carrier and the film and the drawn film have sufficiently large and smooth surfaces to which the workpiece carrier, film or drawn film can be sucked onto the suction plate in order to adhere reversibly to the suction plate. The suction plate prevents the film and the drawn film in particular from deforming due to the vacuum and thus becoming loose or damaged. If the suction plate is also arranged on the underside of the transport means, the workpiece carrier, film or drawn film can adhere via its upper side, so that their underside remains free.This allows for easier positioning and placement at the workstations. In a preferred embodiment, the applied vacuum can be adjusted to adapt the adhesion strength to the object being transported. The interaction surface of the suction plate, to which the film is suctioned, can be flat or designed as a suction cup.

[0012] The number of mechanical components of the transport system required for picking up and placing the workpiece carrier can be reduced if the first transport means comprises a magnet for moving the magnetizable workpiece carrier and at least one workstation has a workpiece carrier holder with a stop for the magnetizable workpiece carrier. Due to the magnetic interaction, the workpiece carrier adheres to the transport means without the need for a mechanical picking or placing mechanism. Although the magnet can be an electromagnet, so that the adhesion between the workpiece carrier and the transport means can be adjusted via the current, the workpiece carrier holder with a stop also allows the use of a cost-effective permanent magnet, eliminating the need to control the magnetic field.The transport means can position the workpiece carrier in the area of ​​the stop of the workpiece carrier holder and then continue to move in the stop direction, so that the adhesion between the transport system and the workpiece carrier is released by the stop as the transport system is increasingly displaced. Preferably, the workpiece carrier holder forms a vertical stop, so that the transport system deposits the workpiece carrier by displacing it downwards in the workpiece carrier holder, preventing unwanted movement of the workpiece carrier as the transport means approaches.

[0013] The manufacturing process for aligners can be accelerated with a slight increase in the size of the device by using two 3D printers as workstations. Since 3D printing is the most time-consuming step in aligner production, two denture models, preferably the upper and lower jaws, can be printed simultaneously, eliminating downtime at the other workstations. This reduces the manufacturing time for a first complementary pair of aligners, allowing a patient to receive a first pair of aligners ideally at the end of the first appointment, eliminating any further waiting time.

[0014] Although in principle overpressure or underpressure can be applied during thermoforming of the film, additional work steps or modifications to the components can be avoided if the thermoforming station includes a chamber which, in one forming position, together with the workpiece carrier, forms a pressure chamber that can be pressurized with compressed air. As a result of this measure, the chamber is lowered into the forming position onto the workpiece carrier loaded with the denture model and pressed against it upon contact. A heated film is placed between the chamber and the denture model, parallel to the tool carrier. The film can be heated beforehand to the temperature required for thermoforming on a heating platform assigned to the thermoforming station. In the forming position, the tool carrier forms a stop for the chamber so that the tool carrier and chamber form a chamber that can be pressurized with compressed air.The edge of the chamber facing towards the tool carrier can include a sealing ring. Even if the diameter of the film is larger than the diameter of the tool carrier and is therefore located between the tool carrier and the chamber in the forming position, a pressure chamber is still formed between the tool carrier and the chamber due to the contact pressure exerted on the chamber, so that the thermoforming process can be carried out using the overpressure generated by the compressed air. In a preferred embodiment, the overpressure is at least 5 bar. If a second transport means is used to transport the film, the thermoforming station can preferably be loaded and unloaded both via the first transport means with the workpiece carrier containing the denture model and via the second transport means with the film.In this case, in an even more preferred embodiment, the two transport means can be loaded and unloaded at opposite ends of the thermoforming station to make the device even more compact and avoid collisions between the two transport means. Another possibility to increase and simplify production speed is for the 3D printer to be a fused deposition modeling (FDM) printer. Fused deposition modeling (FDM) printers produce the dental models layer by layer from meltable plastic, which, unlike stereolithography-based (SLA) 3D printers, cures itself. This eliminates the additional exposure step required for SLA processes. In a preferred embodiment, the device can include a filament storage unit for the 3D printer.

[0015] In order to implement loading and unloading not only in terms of control technology but also mechanically, it is proposed that the first and / or second transport means be arranged so that they can be moved along the guide via a scissor-type articulated arm. The movement of the transport means can usually be divided into two movement phases: the transport of the workpiece carrier or film between the work stations and the loading and unloading of the work stations, with the transport along the guide and the loading and unloading taking place perpendicular to the guide. If a scissor-type articulated arm is used according to the invention, no separate mechanism for the movement perpendicular to the guide needs to be provided, since the movement along as well as perpendicular to the guide can be controlled via the absolute position of the articulation points of the scissor-type articulated arm on the guide and their relative position to one another along just one axis, namely that of the guide.

[0016] To increase operational safety and maintain high product quality, it is recommended that the workstations and preferably also the guides and transport means are arranged in a box-shaped housing. This not only protects the workstations, denture models, films and dental splints from contamination and the resulting potentially lower product quality, but also prevents unwanted contact with the workstations and the associated risk of injury. In addition, the arrangement in a box makes them easier to transport and stack. The housing can have maintenance openings and / or doors and / or lids for removing the dental splints and denture models, as well as for loading them with the starting materials. Furthermore, the housing can include a fan and / or an extractor and / or waste container to remove or collect the waste, aerosols, particles and vapors generated during production.A further advantage of the housing according to the invention is that environmental conditions can be better controlled during production. For example, an air conditioning unit can preferably be provided to regulate the temperature and / or humidity in the box, since the films commonly used must be stored at a maximum humidity of 30%.

[0017] To avoid having to open the housing to remove the dental splints and / or the denture model, it is proposed that the box-shaped housing be perforated by a removal opening, which is connected via a shaft to a loading opening for the dental splint assigned to the laser cutting system. This also reduces contamination with dirt particles and reduces the risk of injury, as access occurs at a defined location that is physically separated from the workstations by the shaft. The dental model and / or the dental splint can either be transported into the loading opening by the transport system or a separate tool, such as a push arm, can be provided for this purpose.

[0018] Although the device according to the invention requires only a simple transport means, the tool carrier can be easily and reproducibly placed at the same location within a workstation if at least one workstation includes a centering means for the workpiece carrier. For example, a stop adapted to the geometry of the tool carrier can be provided in the workstation, which specifies an optimal position for machining at the respective workstation. The transport system can be programmed to release the tool carrier within the workstation above a certain force threshold, which is triggered by the physical resistance of the stop on the tool carrier. If the workstation includes a workpiece carrier holder with a stop, this workpiece carrier holder can also include the centering means. Brief description of the invention

[0019] The subject matter of the invention is illustrated by way of example in the drawing. It shows: Fig. 1 a schematic side view of a device according to the invention, Fig. 2 a schematic side view of the first transport system during loading of a work station with a workpiece carrier on a larger scale, and

[0020] Fig. 3 shows a side view corresponding to Fig. 2 after loading the work station.

[0021] Ways to implement the invention

[0022] A device according to the invention for producing a dental splint comprises a processing unit 1, a thermoforming station 2 for a film on a denture model 3, a laser cutting system 4, at least one 3D printer 5, and a separating device 6 as workstations. Since dental splints are usually produced for the upper and lower jaw, and printing a denture model 3 is one of the more time-consuming work steps, two 3D printers 5 are present in the illustrated embodiment so that the denture models 3 for the upper and lower jaw can be printed simultaneously. The workstations are arranged along a transport system 7, wherein this transport system has a guide 8 along which a transport means 9 can be displaced in order to transport a workpiece carrier 10.In the illustrated embodiment, the transport means 9 is a scissor-type articulated arm, as this allows for easy control and transport of the workpiece carrier 10 along and across the guide 8. To ensure the most compact design possible for the device, allowing its use in dental practices, the guide 8 is a vertically extending straight guide. The workpiece carrier is moved vertically along the guide 8 for transport between the workstations and horizontally across the guide 8 for loading and unloading the workstations.

[0023] The transport means 9 loads the 3D printer 5 with the workpiece carrier 10, onto which the 3D printer 5 subsequently prints a three-dimensional denture model 3 of a patient's dentures on the workpiece carrier 10 based on the data stored in the computing unit 1. The transport means 9 then unloads the workpiece carrier 10 with the denture model 3 and transports it to the thermoforming station 2, where the three-dimensional contours of the denture model 3 are transferred to the film by thermoforming. For example, after heating, the film can be positioned over the denture model 3 and pressed onto the denture model 3 using an applied pressure difference, so that the film takes on the contours of the denture model 3. The thermoformed film and the denture model 3 are then separated from each other, for example by mechanically securing the film and pulling it away from the locked denture model 3.In the embodiment shown, the separating device 6 is located in the immediate vicinity of the thermoforming station 2, so that the transport system 7 does not have to move the denture model 3 including the film between the two stations.

[0024] The thermoformed film is now transported to the laser cutting system 4. For this purpose, the transport means 9 can, for example, be designed such that it can accommodate and transport not only the workpiece carrier 10, but also the thermoformed film. In the exemplary embodiment shown, however, the transport system 7 comprises a second transport means 11 for transporting the thermoformed film, whereby this second transport means 11 only needs to be designed to transport the film, but not the workpiece carrier 10. Conversely, in the exemplary embodiment shown, the transport means 10 is only designed to transport the workpiece carrier 10. For this purpose, the work stations can comprise centering means for the workpiece carrier 10, which make it easier for the transport means 9 to place the workpiece carrier 10 in a predefined position, so that the automated processing steps of the respective work station can be carried out more easily.For example, the transport means 10 can magnetically fix the workpiece carrier. The second transport means 11 is equipped with a vacuum system (not shown) that includes a suction plate with a nozzle, so that the thermoformed film can be picked up and deposited using applied vacuum. In a preferred embodiment, the transport means 9 also has such a vacuum system.

[0025] In the illustrated embodiment, the thermoformed film separated from the denture model 3 is transferred from the separating device 6 to the second transport means 11, where it is picked up and transported to the laser cutting system 4. There, the second transport means 11 places the thermoformed film on the carrier 12 assigned to the laser cutting system 4. The laser cutting system 4 then cuts the dental splint from the thermoformed film.

[0026] All work steps performed by the various workstations as well as the transport between the workstations can be controlled by the computing unit 1.

[0027] In the illustrated embodiment, all workstations are arranged in a box-shaped housing 13 to reduce negative external influences on the dental splint production and the risk of injury to the user. This housing 13 can have one, preferably several, removal openings 14, from which the dental splint can be removed after processing in the last workstation. The removal opening 14 can be connected via a shaft to a feed opening (both not shown), into which the first or second transport system 9, 11 or the carrier 12 of the laser cutting system feeds the dental splint.

[0028] Figs. 2 and 3 illustrate the loading and unloading of a workstation with a workpiece carrier 10. In the illustrated embodiment, the thermoforming station 2 is shown as an example workstation; however, for the preferred loading and unloading process shown, it is fundamentally irrelevant which workstation is loaded or unloaded. The workpiece carrier 10 is magnetizable, and the transport means 9 comprises a magnet. As a result of these measures, the workpiece carrier 10 can adhere to the transport means 9 due to the magnetic interaction and can thus be displaced by it without the workpiece carrier 10 falling off the transport means 9.Although an electromagnet can be provided for the transport means 9 so that the adhesion of the workpiece carrier 10 to the transport means can be adjusted via the power supply of the electromagnet, in the illustrated embodiment, which is particularly easy to control, the magnet is a permanent magnet (not shown). In order to reliably load and unload the work station with the workpiece carrier 10 in this case, the work station, in this case the thermoforming station 2, has a workpiece carrier holder 15 which includes a stop 16 for the workpiece carrier 10. For loading, the workpiece carrier 10, which is magnetically adhered to the transport means 9, is brought closer to the workpiece carrier holder 15, wherein the workpiece carrier holder 15 of the illustrated embodiment includes a recess 16 as a guide for the transport means 9, with which the workpiece carrier 10 can be reproducibly placed at the same location in the work station.In the exemplary embodiment shown, a further stop for the transport means 9, which acts in the horizontal direction, serves as a centering means 17 for the workpiece carrier 10. If the transport means 9 is now brought closer to the workpiece carrier holder 15 in such a way that the transport means 9 strikes the centering means 17 and the workpiece carrier 10 is thus pre-positioned as desired, the transport means 9 can now be moved further against the stop 16 in the stop direction 18 until the force against the stop 16 exceeds the magnetic force of attraction between the workpiece carrier 10 and the transport means 9, the workpiece carrier 10 is released from the transport means 9 and now rests in the desired position on the workpiece holder 15. After release, the transport means 9 can simply be removed from the work station in the unloading direction 19. In the exemplary embodiment shown, the stop 16 acts in the vertical direction.Furthermore, the transport means 9 in the embodiment shown has a stop pin 20 which, on the one hand, facilitates the guidance of the transport means 9 in the recess 16 and, on the other hand, forms a stop with the workpiece carrier receptacle 15 when the transport means 9 is to be released from the workpiece carrier 9 by movement in the stop direction 18.

Claims

Patent claims 1. A device for producing a dental splint, comprising a computing unit (1), a thermoforming station (2) for a film on a denture model (3), and a laser cutting system (4) for cutting the dental splint out of the film, wherein a plurality of work stations are provided, which comprise at least one 3D printer (5) for producing the denture model (3) on a workpiece carrier (10), the thermoforming station (2), a separating device (6) for separating the thermoformed film from the denture model (3), and the laser cutting system (4), characterized in that the work stations are arranged along a transport system (7) which comprises a vertical straight guide (8) and a transport means (9) displaceably arranged along the vertical straight guide (8) for loading and unloading the work stations with the workpiece carrier (10).

2. Device according to claim 1, characterized in that the transport system (9) comprises a second transport means (11) for transporting the film from the separating device (6) to the laser cutting system (4).

3. Device according to claim 1 or 2, characterized in that a vacuum system is provided which comprises at least one nozzle arranged on a suction plate on the first and / or second transport means (9, 11).

4. Device according to one of claims 1 to 3, characterized in that the first transport means (9) comprises a magnet for displacing the magnetizable workpiece carrier (10) and at least one work station has a workpiece carrier holder (15) with a stop (16) for the magnetizable workpiece carrier (10).

5. Device according to one of claims 1 to 4, characterized in that two 3D printers (5) are provided as workstations.

6. Device according to one of claims 1 to 5, characterized in that the thermoforming station (2) comprises a chamber which, in a forming position, together with the workpiece carrier (10), forms a pressure chamber that can be pressurized with compressed air.

7. Device according to one of claims 1 to 6, characterized in that the first and / or second transport means (9, 11) are arranged displaceably along the guide (8) via a scissor-type articulated arm.

8. Device according to one of claims 1 to 7, characterized in that the workstations are arranged in a box-shaped housing (13).

9. Device according to claim 8, characterized in that the box-shaped housing (13) is pierced by a removal opening (14) which is connected via a shaft to a loading opening for the toothed rail assigned to the laser cutting system (4).

10. Device according to one of claims 1 to 9, characterized in that at least one work station has a centering means (17) for the Workpiece carrier (10).

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