Storage compartment for printing material of an additive manufacturing system, in particular a 3D printer and additive manufacturing system

Abstract

Storage compartment (12) for printing material of an additive manufacturing system (10), in particular a 3D printer, wherein the storage compartment (12) has a pressure chamber (14) which can be sealed from the environment and can be opened and closed, wherein the storage compartment (12) has a fluid source (26) and / or a fluid connection by means of which the storage compartment (12) can be connected to a fluid source (26), so that the storage compartment (12) in the closed state has an increased pressure compared to the environment outside the pressure chamber (14), wherein the overpressure in the pressure chamber (14) prevents that particles can penetrate through gaps, wherein the storage compartment (12) has at least one temperature setting element.

Description

[0001] The present invention relates to a storage compartment for printing material of an additive manufacturing system, in particular a 3D printer, and to an additive manufacturing system, in particular a 3D printer.

[0002] In the context of 3D printing of plastics, especially for medical applications (e.g., implants), the currently achievable component quality is the focus of many scientific studies. Two of the most important challenges that play a decisive role with regard to component quality are moisture and component tolerance, and component sterility or component particle deposition.

[0003] For example, DE 10 2015 111 504 A1 already discloses a 3D printing device, in particular an FFF printing device, with at least one print head unit, wherein the print head unit is provided in at least one operating state to melt a printing material formed at least partially from a high-performance plastic, in particular a high-performance thermoplastic.

[0004] Furthermore, EP 2 261 009 A1 discloses a device and a method for producing a three-dimensional object, wherein the device comprises a vacuum pump coupled to a feed reservoir to generate an air flow through the feed reservoir.

[0005] In addition, EP 3 023 228 A1 shows an additive manufacturing device having a gas flow system for providing a gas flow over the area of the build platform of the additive manufacturing device.

[0006] Furthermore, EP 3 173 233 A1 discloses a three-dimensional manufacturing device which has a processing space which is heated by a processing space heating unit provided for this purpose.

[0007] In addition, US 6,033,301 A discloses a combined fan-filter unit intended for filtering the air of an air circuit in a clean room.

[0008] Furthermore, US 6,722,872 B1 shows a three-dimensional modeling device which is intended to build three-dimensional objects within a heated construction chamber.

[0009] In addition, US 6,817,941 B1 shows a diffuser for generating a uniform air flow within a process chamber, which is used, for example, in the production of semiconductor chips.

[0010] Furthermore, US 2015 / 110911 A1 shows an environmental monitoring or control unit that is used, for example, as an interface in additive manufacturing technologies to their respective environments.

[0011] Furthermore, WO 2016 / 063198 A1 shows a method and a device for producing three-dimensional objects by “fused deposition modelling”, wherein the production device has radiant heating elements which can heat a surface of the object to be produced which is exposed to them.

[0012] In addition, a cleanroom technology for 3D printers and so-called bioprinters is known from WO 2017 / 040675 A1.

[0013] WO 2017 / 108477 A1 also discloses a method for producing a three-dimensional object using a “Fused Deposition Modelling” printer.

[0014] Further systems are known from the publications US 2017 / 0157855 A1, US 2001 / 0038168 A1, US 2015 / 0108687 A1, US 7,063,285 B1, DE 103 42 883 A1 and US 2015 / 0210008 A1.

[0015] Based on the solutions proposed in the prior art, the problem with these additive manufacturing devices still exists, in particular in terms of component sterility and / or freedom from contamination, such as particles, which is not sufficient for medical applications.

[0016] It is therefore the object of the present invention to advantageously further develop a storage compartment for printing material of an additive manufacturing system of the type mentioned at the outset.

[0017] This object is achieved by a storage compartment having the features of claim 1.

[0018] The invention is based on the basic idea that when closed, the storage compartment can be sealed off from the environment and that, by means of the pressure chamber, it can also be ensured at the same time that the printing material can be inserted and processed in a space that is clearly separated from the environment.

[0019] The use of a pressure chamber also prevents the ingress of contaminants into the pressure chamber. In particular, the pressure chamber can be designed to operate at a higher pressure than the ambient pressure, preventing particles from the air from entering the pressure chamber.

[0020] Furthermore, it is provided that the storage compartment has a fluid source, in particular a compressed air source and / or a compressed air connection by means of which the storage compartment can be connected to a compressed air source, so that the storage compartment, when closed, has a higher pressure than the environment outside the pressure chamber. It is also conceivable that the process gas used is not air, but another gas such as nitrogen. In principle, it is also conceivable in this context that the storage compartment with its pressure chamber has a higher pressure than the environment not only when closed, but also when open. The compressed air source then ensures that the pressure or compressed air flows out of the open storage compartment or the pressure chamber of the storage compartment, thus preventing particles from entering the pressure chamber.When inserting printing material, especially filaments, into the print chamber, it can be ensured to a very high degree that little or no contamination can occur. The pressure must be only slightly higher than the ambient pressure. The pressure must be selected such that light particles, such as dust particles, cannot enter the print chamber itself when the print chamber is open. For example, a higher pressure than the ambient pressure of less than 50 Pa is conceivable, but also a pressure of approximately 0.25 bar or more, for example even 0.5 bar or more, is conceivable.

[0021] Furthermore, the storage compartment is provided with at least one temperature adjustment element. The temperature adjustment element can be used for both heating and cooling. Furthermore, by adjusting the temperature, the humidity within the pressure chamber or storage compartment can be more accurately controlled. This improves the climate within the storage compartment. Furthermore, by regulating the humidity, the proliferation of microorganisms such as bacteria or fungi can be influenced accordingly.

[0022] Furthermore, at least one temperature sensor can be provided in and / or on the storage compartment. The temperature sensor makes it possible to monitor the temperature within the storage compartment, in particular within the pressure chamber.

[0023] In addition, at least one humidity sensor can be provided in and / or on the storage compartment. By using a humidity sensor, the humidity can be monitored and adjusted accordingly. It is particularly conceivable that, in addition to the humidity sensor, a corresponding control element or a control and / or regulation system for the climate of the pressure chamber is also provided. In this context, it is conceivable that the temperature adjustment element, temperature sensor, and humidity sensor are linked to the corresponding control element or control unit, thus enabling the temperature and humidity, as well as the pressure, to be adjusted in the pressure chamber.

[0024] Furthermore, at least one gas sensor can be provided in and / or on the storage compartment. It is particularly conceivable to determine the humidity directly or indirectly by measuring the gas composition. It is also conceivable to adjust the humidity in the installation space by adjusting the gas content or the gas proportion of certain gases.

[0025] In addition, at least one pressure relief valve can be provided in and / or on the storage compartment. The pressure relief valve makes it possible to set the pressure range in the pressure chamber to the desired level. If it is determined that an excess pressure has developed within the pressure chamber that no longer meets the specifications, the pressure can be compensated accordingly semi-automatically (e.g. by means of a corresponding display and warning) or automatically. In a semi-automatic system, a display would suggest that the pressure needs to be adjusted accordingly or that the pressure relief valve should be activated. In this context, it is also conceivable for the pressure chamber to be equipped with one or more pressure sensors to monitor the pressure.

[0026] Furthermore, it can be provided that at least one continuous temperature control element is provided in and / or on the storage compartment. The temperature of the process gas, in particular the compressed air, can be adjusted by means of the continuous temperature control element. It is conceivable that the continuous temperature control element is arranged, for example, on the supply line for the compressed air. It is particularly conceivable that the continuous temperature control element is arranged on the supply line before or upstream of the compressed air inlet. The continuous temperature control element can be a continuous flow heater and / or a continuous flow cooler. The process gas, in particular the compressed air for the pressure chamber, can be heated accordingly by means of a continuous flow heater. The process gas, in particular the compressed air, can be cooled by means of a continuous flow cooler.

[0027] At least one filament passage can be provided in and / or on the storage compartment. The filament passage can have a lock function, preventing contaminants or the like from entering the storage compartment and vice versa. It is conceivable that the opening of the filament passage is adapted to the diameter of the filament, enclosing it almost completely and simultaneously guiding it.

[0028] In particular, a pressure adjustment element can be provided between the compressed air source and the pressure chamber. For example, the pressure adjustment element can be a pressure reducer or the like.

[0029] Furthermore, a valve element can be provided between the compressed air source and the pressure chamber. Using this valve element, it is possible to completely interrupt the compressed air supply to the pressure chamber, thereby preventing further pressure buildup within the pressure chamber. It is also conceivable that a corresponding control unit could link the compressed air supply, the corresponding valve element for interrupting the compressed air supply, and the control of the pressure relief valve for releasing pressure from the compressed air chamber, thus enabling automatic pressure regulation in the pressure chamber.

[0030] Furthermore, the present invention relates to an additive manufacturing system, in particular a 3D printer, with at least one storage compartment as described above.

[0031] Further details and advantages of the invention will now be illustrated in more detail with reference to an exemplary embodiment illustrated in the drawing. The single figure shows a schematic representation of the structure of an additive manufacturing system according to the invention and the associated storage compartment for printing material according to the invention.

[0032] They show: Fig. 1 a perspective view of an embodiment of an additive manufacturing system according to the invention; and Fig. 2 a schematic detailed representation of the additive manufacturing system according to. Fig. 1 with filament chamber.

[0033] Fig. 1 shows a schematic representation of an additive manufacturing system 10.

[0034] Fig. 2 shows the additive manufacturing system 10 in detail with the filament chamber.

[0035] The Additive Manufacturing System 10 is designed here as a 3D printer.

[0036] The additive manufacturing system 10 has a storage compartment 12.

[0037] The storage compartment 12 further comprises a pressure chamber 14.

[0038] The pressure chamber 14 is also called the filament chamber.

[0039] At least one unwinding spindle 16 is provided in the pressure chamber 14. In the illustrated embodiment, (at least) one filament spool 18 is threaded onto the unwinding spindle 16. In principle, multiple filament spools can also be threaded here.

[0040] The filament spool 18 is printing material for the additive manufacturing system 10. The filament from the filament spool 18 can be guided through the filament feedthrough 36 from the storage compartment 12 and fed to other elements of the additive manufacturing system 10.

[0041] The pressure chamber 14 can be sealed from the environment and is sealed during operation. The seal does not need to be complete, as the (slight) overpressure in the pressure chamber 14 prevents particles from penetrating through gaps.

[0042] The pressure chamber 14 can be opened and closed.

[0043] Furthermore, a temperature sensor 20 is provided in the pressure chamber 14 itself. In principle, it is also conceivable for several temperature sensors 20 to be arranged in the pressure chamber 14 and / or around the pressure chamber 14.

[0044] In addition, a humidity sensor 22 is provided in the pressure chamber 14.

[0045] It is also conceivable that the temperature sensor and the humidity sensor are designed as a combination sensor.

[0046] Here, too, it is conceivable that several humidity sensors 22 may be provided. These can be arranged in and / or around or adjacent to the pressure chamber 14.

[0047] In addition, the pressure chamber 14 has a pressure relief valve 24.

[0048] Furthermore, a compressed air source 26 is provided. In principle, other fluids or process gases, such as nitrogen, can also be used in addition to air.

[0049] The compressed air source 26 can be part of the storage compartment 12. However, it is also conceivable that it is a compressed air source 26 of the additive manufacturing system 10, or a compressed air source 26 that can be connected to the additive manufacturing system 10 or the storage compartment 12 or is connected in the assembled and operational state.

[0050] In addition, a valve element, in the embodiment shown a solenoid valve 28, is provided.

[0051] A pressure reducer 30 is also provided.

[0052] Furthermore, a continuous flow heater 32 is provided in the embodiment shown.

[0053] In addition, a control unit 34 is provided.

[0054] Compressed air source 26 provides compressed air, which may, for example, be slightly higher than ambient pressure. A pressure range of 0.25 to 0.5 bar higher than ambient pressure or the pressure in the installation room is conceivable. The solenoid valve 28 is located downstream of compressed air source 26. Using the solenoid valve 28, the air flow provided by compressed air source 26 can be stopped or continued to be supplied to storage compartment 12.

[0055] The pressure reducer 30 is provided downstream of the solenoid valve 28. Using the pressure reducer 30, the inlet pressure for the storage compartment 12 can be reduced accordingly to the desired process pressure.

[0056] Downstream of the pressure reducer 30, the flow heater 32 is provided, by means of which the air flow can be tempered to process temperature.

[0057] The control unit 34 is coupled to the temperature sensor 20, the humidity sensor 22, the solenoid valve 28, and the flow heater 32. Furthermore, the control unit 34 (not shown in detail) is coupled to the pressure relief valve 24 and pressure sensors (not shown in detail).

[0058] However, it is also conceivable that the pressure relief valve 24 is not coupled to the control unit 34 as shown and is only set to a corresponding pressure from which the pressure valve is moved into the open position so that excess pressure can be released from the pressure chamber 14.

[0059] Ideally, when the Additive Manufacturing System 10 is set up and ready for operation, the compressed air supply is at the top and the outlet / pressure relief valve is at the bottom so that particles can be removed in a targeted manner.

[0060] Through the coupling with the temperature sensor 20 and the humidity sensor 22, the control unit 34 is able to record corresponding measured values from the pressure chamber 14 itself with regard to temperature and humidity. These parameters then make it possible to control the solenoid valve 28 and the flow heater 32 accordingly, so that compressed air can be supplied at the appropriate temperature. It is also conceivable that dehumidifying agents are also provided along the path of the compressed air provided by the compressed air source 26. This can also be used to adjust the humidity accordingly. However, this can also be done via the flow heater 32 alone.

[0061] Studies have shown that the moisture in the filament, i.e. the printing material, can have a significant influence on the printing results.

[0062] Thermoplastic filament can absorb moisture from the air during storage, which is why it is often stored in drying cabinets or similar facilities according to current technology. Furthermore, it is usually specifically dried before printing.

[0063] According to the present invention, this is no longer necessarily the case, since drying can already take place in the inserted state in the 3D printer in the storage compartment 12 for the printing material.

[0064] This solves the problem of moisture absorption by the filament while it is in the printer. The fact that the filament chamber 12 is tightly sealed from the outside world prevents moisture penetration and environmental contamination. Furthermore, the filament is constantly supplied with dry air, in the illustrated embodiment, using compressed air. The compressed air from the compressed air source 26 floods the filament chamber 12 and thus ensures that the humidity within the filament chamber 12 can be kept at a very low level. The humidity sensor 22 within the filament chamber 12 is set to a defined value that must not be exceeded.If the limit is reached, the solenoid valve 28 is controlled via the control unit 34 and dry air is provided via the compressed air source 26, which is further heated by the flow heater 32, and then flows into the filament chamber 12.

[0065] This mechanism can also be used for the initial drying of filament.

[0066] The pressure relief valve 24 also ensures that the overpressure in the chamber 12 cannot exceed a predetermined level. The overpressure also ensures that no external particles enter the filament chamber 12 and that the filament cannot be contaminated during the manufacturing process. Reference symbol 10 Additive Manufacturing System 12 storage compartments 14 pressure chamber 16 Unwinding spindle 18 filament spools 20 Temperature sensor 22 Humidity sensor 24 Pressure relief valve 26 Compressed air source 28 Solenoid valve 30 pressure reducers 32 instantaneous water heaters 34 Control unit 36 Filament feedthrough

Claims

[1] Storage compartment (12) for printing material of an additive manufacturing system (10), in particular a 3D printer, wherein the storage compartment (12) has a pressure chamber (14) which can be sealed from the environment and can be opened and closed, wherein the storage compartment (12) has a fluid source (26) and / or a fluid connection by means of which the storage compartment (12) can be connected to a fluid source (26), so that the storage compartment (12) in the closed state has an increased pressure compared to the environment outside the pressure chamber (14), wherein the overpressure in the pressure chamber (14) prevents that particles can penetrate through gaps, wherein the storage compartment (12) has at least one temperature setting element. [2] Storage compartment (12) according to one of the preceding claims, characterized bythat at least one temperature sensor (20) is provided in and / or on the storage compartment (12). [3] Storage compartment (12) according to one of the preceding claims, characterized by that at least one humidity sensor (22) is provided in and / or on the storage compartment (12). [4] Storage compartment (12) according to one of the preceding claims, characterized by that at least one gas sensor (22) is provided in and / or on the storage compartment (12). [5] Storage compartment (12) according to one of the preceding claims, characterized by that at least one pressure relief valve (24) is provided in and / or on the storage compartment (12). [6] Storage compartment (12) according to one of the preceding claims, characterized by that at least one continuous temperature control element (32) is provided in and / or on the storage compartment (12). [7] Storage compartment (12) according to one of the preceding claims, characterized bythat at least one filament passage (36) is provided in and / or on the storage compartment (12). [8] Storage compartment (12) according to one of claims 1 to 5, characterized by that a pressure adjustment element is provided between the compressed air source (26) and the pressure chamber (14). [9] Storage compartment (12) according to one of claims 1 to 5, characterized by that a valve element is provided between the compressed air source (26) and the pressure chamber (14). [10] Additive manufacturing system (10), in particular 3D printer, with at least one storage compartment (12) according to one of the preceding claims.

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