Device and method for continously providing a filament

Abstract

The invention relates to a device (10) for continuously providing a filament (15, 16) for an additive manufacturing installation (29), comprising a base part (11) which has a passage region (13) with a through-opening (14) which has a free cross section, wherein at most one filament (15, 16) at a time can pass through the cross section. An off-running filament (15) can be pulled through the through-opening (14) in a conveying direction (18) as far as the end (17) of the off-running filament (15), wherein the device (10) has an arm (12), which is movable in relation to the base part (11) and which has a clamping device (22) for a new filament (16) and which can be deflected under spring load by elastic deformation of at least one spring element (25, 26) counter to the conveying direction (18). The invention also relates to a corresponding method.

Description

[0001] Device and method for the continuous provision of a filament

[0002] The present invention relates to a device for the continuous supply of a filament for an additive manufacturing system, a corresponding method for the continuous supply of a filament, and a component produced by the method.

[0003] In additive manufacturing or 3D printing systems, filaments, for example made of thermoplastic materials, are fed from a spool or reel into the additive production process. The length of the filaments on the spools is inherently finite, so the fed filament must be changed manually or by a material handling station. Such a spool change can interrupt the manufacturing process if, for example, the required filament length for a component exceeds the available filament length on a spool. Manual changes can lead to downtime of the production system until the change is completed. Furthermore, there is the issue that remnants on spools and reels cannot be completely used up or must be weighed and selected specifically for the respective manufacturing process.

[0004] It is therefore the object of the present invention to provide a device and a method for the continuous supply of a filament, as well as a component produced by the method. The object of the invention is achieved by the features of the independent claims. Further preferred developments can be found in the dependent claims, the description, and the figures.

[0005] A device for the continuous supply of filament to an additive manufacturing system is proposed, comprising a base part. The base part has a passage area with a through-hole that has a free cross-section, the cross-section of which can accommodate a maximum of one filament at a time. A filament being fed can be pulled through the passage area in a conveying direction until its end is reached. The device includes an arm movable relative to the base part, which incorporates a clamping device for a new filament. This arm is spring-loaded and deflectable against the conveying direction by elastic deformation of at least one spring element. The new filament can be positioned in an initial section with its beginning at the passage area in contact with the filament being fed and at a clamping position within the clamping device.The initial section of the new filament is subjected to pressure between the passage area and the clamping device by the arm, which is spring-loaded and deflected against the direction of conveying, so that as soon as the unwinding filament passes through the passage opening with its end, at least part of the initial section of the new filament is pushed through the passage opening by the arm.

[0006] With the proposed device, it is possible to preload a new filament from another spool, which is automatically pushed behind the end of the unwinding filament and thus reloaded. The unwinding filament is, for example, pulled through the feed opening by a conveyor system of a production plant. Accordingly, the initial section of the new filament can be pushed in the conveying direction of an additive manufacturing plant to such an extent that the beginning of the new filament can be grasped by the conveyor system and pulled in the conveying direction. The new filament is preferably pushed by the arm with its beginning against the end of the unwinding filament in the conveying direction, at least for a portion of its initial section, so that the unwinding filament and the new filament lie abutting behind the feed opening downstream in the conveying direction.A conveying device of an additive manufacturing plant can therefore preferably, without modifications, convey a new filament without interruption following an outgoing filament using an upstream device of the proposed type and continuously supply it to a production process.

[0007] The clamping device is preferably designed such that the clamping force on the filament in the conveying direction is less than the clamping force against the conveying direction.

[0008] The device can be manufactured cost-effectively and used universally with various additive manufacturing systems. It offers very low susceptibility to malfunctions and, with its purely mechanical operation, avoids the additional power consumption and programming effort required by material stations. Furthermore, the device functions even with flexible filament materials. It also allows for the complete use of the extruded filament, which offers an advantage over conventional material stations. In a preferred embodiment, the arm is rotatably mounted at a pivot point on the base. The clamping device can therefore preferably be guided along a pitched circle by the arm.

[0009] Preferably, the base part has a contact surface for the pressure-loaded initial section of the new filament. This effectively prevents kinking or buckling of the initial section, allowing the new filament to be better pressure-loaded, first pressing it onto the passage area and, once the passage opening has been cleared by the unwinding filament, pushing it through the passage opening.

[0010] In advantageous embodiments, the contact surface is curved. This further increases the stability of the initial section against buckling and is particularly advantageous when the clamping device is guided on a partial circular segment of the arm. According to a further development, the contact surface has a partial cylindrical segment around the pivot point of the arm in order to achieve a consistent support effect from the contact surface over the arm's range of motion.

[0011] Preferably, the base part and / or the arm has at least one integral spring element for spring-loaded movement of the arm relative to the base part against the conveying direction. The base part and / or the arm can, for example, be made of plastic, so that an integral spring element can be easily provided on the base part and / or arm. The base part and / or the arm are preferably additively manufactured. According to a further development, it is proposed that an integral first spring element is arranged on the base part and an integral second spring element on the arm, which support each other and counteract a deflection of the arm against the conveying direction with a spring force. This enables an advantageous force distribution.

[0012] In an advantageous embodiment, the passage area is funnel-shaped. This ensures that the beginning of the new filament can be safely pre-charged under pressure as long as the end of an unwinding filament has not yet passed through the passage opening, and that after the end of the unwinding filament has passed, the beginning of the new filament is pushed through the passage opening.

[0013] In a preferred embodiment, the clamping device on the arm has a slot for clamping the new filament at the clamping position. The slot can be easily designed and manufactured to match the diameter of the filament. Furthermore, the new filament can be very easily fixed at the clamping position by pressing it into the slot in the clamping device.

[0014] Preferably, the gap between an end plate and a clamping plate is formed at an angle of between 30° and 60° to each other. The end plate and the clamping plate are preferably aligned converging towards each other in the conveying direction. This allows for a higher clamping force to be achieved against the conveying direction than in the conveying direction, which is advantageous for the function of the device. The required tensile force of a conveying system in a production plant can thus be reduced. Preferably, the end plate is aligned perpendicular to the axis of rotation around the pivot point of the arm.

[0015] Furthermore, to solve the problem of the invention, an additive manufacturing process with a device of the type described above is proposed, comprising the following steps:

[0016] - Guiding an unwinding filament through the passage opening;

[0017] - Deflection of the arm against the direction of conveying;

[0018] - Placing the beginning of a new filament at the passage area;

[0019] - Clamping the new filament at a clamping position in the clamping device of the arm deflected against the direction of conveying.

[0020] This ensures that the new filament is automatically advanced after the outgoing filament has passed through the opening with its end, and at least part of the initial section is pushed through the opening.

[0021] Filament feeding preferably has no downtime, as the nozzle does not need to be purged. In other words, the filament change is not detected by an additive manufacturing system.

[0022] The advantages and effects are the same as those of the proposed device.

[0023] According to a further development, it is proposed that the new filament be guided behind the initial section through a passage opening of another device of the type described above. In this way, a corresponding number of additional new filaments can be continuously supplied by using several devices.

[0024] Furthermore, to solve the problem, a component is proposed which is manufactured using an additive manufacturing process of the type described above or according to one of claims 11 or 12.

[0025] Interruptions in the manufacturing process often lead to visible seams or gaps in the component being manufactured, creating a corresponding weakness. This can be avoided with the proposed additive manufacturing process using a device for the continuous supply of filament to an additive manufacturing system. Undesirable seams and weaknesses can thus be avoided in components manufactured using the described additive manufacturing process. The component therefore exhibits fewer, and preferably no, irregularities, resulting in higher component quality.

[0026] The invention is explained below with reference to preferred embodiments and the accompanying figures.

[0027] Fig. 1 shows a device with an extruding and a supplied new filament;

[0028] Fig. 2 shows a device with a new filament pressed through the passage opening; and

[0029] Fig. 3 shows a schematic representation of an additive manufacturing system with a device and a component. Figures 1 and 2 show an advantageous embodiment of a device 10 for the continuous supply of a filament 15, 16 for an additive manufacturing system 29. The device 10 serves for the automatic changeover from an exhausted filament 15 to a new filament 16. The filaments 15, 16 are supplied in a conveying direction 18 and can, for example, be drawn from the device 10 into the conveying direction 18 by a conveying unit of an additive manufacturing system 29 (see Figure 3).

[0030] The device 10 has a base part 11 which has a passage opening 14 for exactly one filament 15, 16. The passage opening 14 has a free cross-section which is selected according to the diameter of the filament 15, 16 such that only one filament 15, 16 can pass through the passage opening 14 at a time. The passage opening 14 is surrounded by the passage area 13, which in this advantageous embodiment tapers in a funnel shape towards the conveying direction 18. A contact surface 24 for an initial section 20 of the new filament 16 adjoins the passage area 13.

[0031] A movable arm 12 is arranged on the base part 11 at a pivot point 23. A clamping device 22 is arranged at the end of the arm 12, which can be pivoted with the arm 12 along a partial circular path about the pivot point 23. The arm 12 can be pivoted against the conveying direction 18 under elastic deformation of at least one spring element, in this advantageous embodiment two spring elements 25, 26. The clamping device 22 has an end plate 27 and a clamping plate 28, which are arranged at an angle to each other, forming a gap. In advantageous embodiments, the gap width is adapted to the diameter of the filament 15, 16 so that sufficient clamping effect is achieved, whereby the clamping effect can be overcome by a tensile force in the conveying direction 18.

[0032] Figure 1 shows the device 10 in a pre-loaded state, in which an unwinding filament 15 is guided through the passage opening 13 and can be pulled in the conveying direction 18, for example, according to the requirements of a production process. A new filament 16 with its start 19 is placed in the passage area 13 of the base part 11, with the passage opening 14 being blocked by the unwinding filament 15. A starting section 20 of the new filament 16, formed between the start 19 and a clamping position 21, is subjected to pressure in the state shown in Figure 1. For this purpose, the new filament 16 is clamped at the clamping position 21 in the clamping device 22, so that the start 19 is pressed against the passage area 13 by the force of the spring elements 25, 26.

[0033] As soon as the unwinding filament 15 has been pulled far enough in the conveying direction 18 that its end 17 has passed through the opening 14, the arm 12 pushes the new filament 16 with its beginning 19 behind the unwinding filament 15. The starting section 20 of the new filament 16 is thus pushed through the opening 14 by the deflected arm 12.

[0034] Figure 2 shows a state in which the new filament 16 with its initial section 20 has been pushed through the opening 14. The initial section 20 of the new filament 16 can thus be gripped, for example, by a conveyor immediately following the unwinding filament 15 and pulled further through the opening 14 as required by a production process. The clamping effect in the conveying direction 18 can easily be overcome by the tensile force of a conveyor.

[0035] The device 10 thus automatically provides the new filament 16 after the expiring filament 15 has been completely used up.

[0036] In other possible embodiments, several of the devices 10 can be used to enable more than one automatically fed new filament 16. In this case, the new filament 16 is the unwound filament 15 in another device 10. In this way, for example, three spools of filaments 15, 16 can be supplied to an additive manufacturing process without interruption.

[0037] Figure 3 schematically shows an additive manufacturing system 29 with a device 10 for the continuous supply of a filament 15, 16. The component 30 was produced using the additive manufacturing system 29 and the device 10 via the additive manufacturing process, and the continuous supply of the filament 15, 16 eliminates unwanted marks caused by filament changes. Reference numeral list

[0038] 10 Device

[0039] 11 Basic part

[0040] 12 arms

[0041] 13 Passage area

[0042] 14 Passage opening

[0043] 15 expiring filament

[0044] 16 new filament

[0045] 17 End

[0046] 18 Direction of conveyance

[0047] 19 Beginning

[0048] 20 Initial section

[0049] 21 clamping position

[0050] 22 Clamping device

[0051] 23 Pivot point

[0052] 24 Plant area

[0053] 25 spring element

[0054] 26 spring element

[0055] 27 End plate

[0056] 28 clamping plate

[0057] 29 additive manufacturing system 30 component

Claims

Claims:

1. Device (10) for the continuous supply of a filament (15, 16) for an additive manufacturing system (29) with a base part (11) having a passage area (13) with a passage opening (14) having a free cross-section, wherein the cross-section is passable for a maximum of one filament (15, 16) at a time, wherein - an unwinding filament (15) in a conveying direction (18) can be pulled through the passage opening (14) to the end (17) of the unwinding filament (15) , wherein - the device (10) has an arm (12) movable relative to the base part (11), which has a clamping device (22) for a new filament (16) and is spring-loaded and deflectable against the conveying direction (18) under elastic deformation of at least one spring element (25, 26), wherein - the new filament (16) can be placed in an initial section (20) with its beginning (19) at the passage area (13) in contact with the unwinding filament (15) and at a clamping position (21) of the new filament (15) in the clamping device (22), wherein - the initial section (20) of the new filament (16) between the passage area (13) and the clamping device (22) is subject to pressure by the arm (12) which is deflected by spring force against the conveying direction (18), so that as soon as the unwound filament (15) passes the passage opening (14) with its end (17), at least a part of the initial section (20) of the new filament (16) is pressed through the passage opening (14) by the arm (12).

2. Device (10) according to claim 1, characterized in that the arm (12) is rotatably mounted on a pivot point (23) of the base part (11).

3. Device (10) according to claim 1 or 2, characterized in that the base part (11) has a contact surface (24) for the pressure-loaded initial section (20) of the new filament (16).

4. Device (10) according to claim 3 , characterized in that the contact surface (24) is curved .

5. Device (10) according to claim 4 with reference to claim 2, characterized in that the contact surface (24) has a partial cylindrical section around the pivot point (23) of the arm (12).

6. Device (10) according to one of the preceding claims, characterized in that the base part (11) and / or the arm (12) has at least one integral spring element (25, 26) for the spring-loaded mobility of the arm (12) relative to the base part (11) against the conveying direction (18).

7. Device (10) according to claim 6, characterized in that an integral first spring element (25) is arranged on the base part (11) and an integral second spring element (26) is arranged on the arm (12), which support each other and counteract a deflection of the arm (12) against the conveying direction (18) with a spring force. Device (10) according to one of the preceding claims, characterized in that the passage area (13) is funnel-shaped.

9. Device (10) according to one of the preceding claims, characterized in that the clamping device (22) on the arm (12) has a gap for clamping the new filament (16) at the clamping position (21).

10. Device (10) according to claim 9, characterized in that the gap is formed between an end plate (27) and a clamping plate (28), which are positioned at an angle between 30° and 60° to each other.

11. Additive manufacturing process with a device (10) according to one of the preceding claims characterized by the steps: - Guiding an unwinding filament (15) through the passage opening (14) ; - Deflection of the arm (12) against the conveying direction (18) ; - Placing the beginning (19) of a new filament (16) at the passage area (13) ; - Clamping of the new filament (16) at a clamping position (21) in the clamping device (22) of the arm (12) deflected against the conveying direction (18) .

12. Additive manufacturing process according to claim 11, characterized by the step that the new filament (16) is guided behind the initial section (20) through a passage opening (14) of a further device (10) according to one of the preceding claims.

13. Component (30), characterized in that the component (30) is manufactured using an additive manufacturing process according to one of claims 11 or 12.

Images