WO2017194106A1

WO2017194106A1 - Additive manufacturing systems

Info

Publication number: WO2017194106A1
Application number: PCT/EP2016/060632
Authority: WO
Inventors: Esteve COMAS; Emilio Carlos CANO; Vicente GRANADOS ASENSIO; Jordi BLANCH
Original assignee: Hewlett-Packard Development Company L.P.
Priority date: 2016-05-12
Filing date: 2016-05-12
Publication date: 2017-11-16

Abstract

Techniques for determination of presence of a failure condition within an enclosure (106) of an additive manufacturing system are described. In an example, the additive manufacturing system includes an enclosure (106) of a fusing lamp assembly (108) and a circulating unit (112) to circulate a cooling fluid through the enclosure and maintain a predetermined pressure within the enclosure. The additive manufacturing system also includes a sensing unit (116) coupled to the enclosure to determine a drop in pressure of the cooling fluid within the enclosure, from the predetermined pressure, and perform a predefined action to mitigate effect of the failure condition within the enclosure.

Description

ADDITIVE MANUFACTURING SYSTEMS

BACKGROUND

[0001] Additive manufacturing, also referred to as '3D printing' can involve generating three dimensional (3D) objects by selective addition of material in layers. Solidification can occur by subjecting the material to heat energy. The heat energy may be generated by sources such as a fusing lamp included within the additive manufacturing system.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] The following detailed description references the drawings, wherein:

[0003] FIG. 1 depicts a block diagram of an example additive manufacturing system, according to an example of the present subject matter;

[0004] FIG. 2 depicts a block diagram depicting an example enclosure for a fusing lamp assembly of an additive manufacturing system, according to an example of the present subject matter; and

[0005] Fig. 3 illustrates a method of determining presence of failure condition within the enclosure of an additive manufacturing system, according to an example of the present subject matter; and

[0006] Fig. 4 illustrates a network environment implementing a non-transitory computer-readable medium for operating an additive manufacturing system, according to an example of the present subject matter.

DETAILED DESCRI PTION

[0007] Additive manufacturing can allow individuals to generate three dimensional (3D) objects based on digital information. The 3D objects may be generated using an additive manufacturing system, which are also colloquially referred to as 3D printers. Systems implementing additive manufacturing often generate objects by selectively adding build material at one or more predefined points. The points at which build materials may be added may depend on the shape and configuration of the object which is to be generated. In this way, the build material can be added systematically in layers in order to generate (or 'print') a 3D object. As would also be understood, 3D printing have found use in a variety of applications in different fields of engineering.

[0008] In order to generate a 3D object, build material may be deposited in layers and caused to fuse at points which define the 3D object to be built. For additive manufacturing, as the build material is deposited in a printing area, it is subjected to fusing energy. The fusing energy enables fusing of the build material to form a desired shape which is in conformance with the shape and configuration of the 3D object being generated. In some cases, various other fusing agents or additives may also be added. The fusing energy can be provided by way of a fusing lamp assembly, which forms a part of the additive manufacturing system.

[0009] The fusing lamp assembly may have an array of fusing lamps which generate the fusing energy. The fusing lamp assembly may be enclosed in an enclosure having an open end, which may be covered by a transparent shield or lens, such as quartz glass to allow fusing energy to pass through and at the same time, also provide a separation between the fusing lamp assembly and the printing area.

[0010] Fusing lamps may be implemented as longitudinally extending glass tubes with filaments. Generally, while operating the fusing lamp assembly, the section of the fusing lamp assembly having the filament generates the fusion energy and the temperature within the enclosure is raised to about 300° C. In order to ensure that the fusing lamps function in the desired manner, cooling fluid is circulated through the enclosure and an environment having a desired ambient temperature is created. [0011] However, during operation, faults may occur within the enclosure which may cause damage to different parts of the additive manufacturing system. For example, the shield may break. The breaking of the shield would remove the separation between the enclosure and the printing area, thereby allowing the build material to enter the enclosure. Due to the temperature difference between the enclosure area and the printing area, and the circulation of the cooling fluid within the enclosure, a cloud of build material may be developed. The cloud may disperse the build material to different areas of the additive manufacturing system, thereby damaging its different parts and components, like cooling fans, printing heads, unprotected print-carriage, etc. The cloud of the build material may also come in contact with the fusing lamp assembly, potentially causing deflagration and damage to the 3D printer.

[0012] Similarly, the circulation of the cooling fluid within the enclosure may fail during operation of the additive manufacturing system. For example, the amount of the cooling fluid to be circulated through the enclosure may either be reduced, or stopped due to fault in a circulating unit coupled to the enclosure. Such a fault may cause excessive heating of the enclosure, thereby causing failure of the fusing lamp assemblies, or risk of fire within the additive manufacturing system. Therefore, such faults within the enclosure of the additive manufacturing system may cause damage to the additive manufacturing system and may also pose high risk to users of the additive manufacturing system.

[0013] Aspects for determination of presence of a failure condition within the enclosure of the additive manufacturing system are described. As discussed, the enclosure is implemented within an additive manufacturing system to house the fusing lamp assembly. The fusing lamp assembly includes a fusing lamp which may generate fusing energy in the form of infrared radiations. The enclosure may also include an open end having a shield layer, such as a glass layer which may allow the fusing energy to be incident on the build materials.

[0014] Further, the enclosure may include one or more vents to allow ingress and egress of cooling fluid. The vents of the enclosure may be coupled to a circulating unit to circulate the cooling fluid within the enclosure and maintain an ambient temperature.

[0015] In an example implementation of the present subject matter, the enclosure may also be coupled with a sensing unit. The sensing unit may be coupled to a vent of the enclosure to determine pressure of the cooling fluid within the enclosure. The sensing unit may include a differential pressure sensor to determine the pressure of the cooling fluid within the enclosure.

[0016] In an example implementation of the present subject matter, the determination of the presence of the failure condition within the enclosure is based on determination of drop in pressure of the cooling fluid within the enclosure. In an example, the presence of the failure condition may indicate presence of a fault due to which the pressure of the cooling fluid within the enclosure is improper, thereby resulting in inefficient cooling of the enclosure. For instance, the presence of the failure condition may indicate a fault in a circulating unit for circulating cooling fluid through the enclosure, or may indicate breakage of the layer of shield disposed at the open end of the enclosure.

[0017] In operation, the sensing unit may determine drop in pressure of the cooling fluid within the enclosure to determine presence of the failure condition within the enclosure. In an event of a faulty circulating unit, or breakage of the shield, the pressure of the cooling fluid within the enclosure may reduce. This would result in drop in pressure of the cooling fluid within the enclosure from a predetermined pressure to a lower pressure.

[0018] The sensing unit, upon determining the presence of the failure condition within the enclosure, may perform a predefined action. The predefined action may be performed to mitigate effect of the failure condition within the enclosure. In an example, the predefined action may include different configurable predefined actions, such as generating an alert for the user, powering off the additive manufacturing system, suspending use of the fusing lamp assemblies, and halting printing by the additive manufacturing system.

[0019] Therefore, the use of the sensing unit with the enclosure to determine drop in pressure of the cooling fluid may allow detection of presence of the failure condition within the enclosure. The detection of presence of failure condition within the enclosure may allow a timely action, thereby avoiding damage to the parts of the additive manufacturing system.

[0020] These and other aspects are described in conjunction with various examples as illustrated in FIGS. 1 -4. Wherever possible, the same reference numerals are used in the figures and the following description to refer to the same or similar parts. It should be noted that the description and figures merely illustrate principles of the present subject matter. It is thus understood that various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.

[0021] FIG. 1 illustrates a block diagram of an additive manufacturing system 100 for generating one or more 3D objects. The block diagram merely illustrate logical blocks representing functional entities of the additive manufacturing system 100. The block diagram does not indicate any specific arrangement of such blocks. Any arrangement of blocks may be implemented without deviating from the scope of the present subject matter. In the present example, the additive manufacturing system 100 includes a print assembly 102 and a printing area 104. The print assembly 102 in turn may include enclosures 106-1 , 2, housing fusing lamp assemblies 108-1 , 2, respectively.

[0022] In an example implementation of the present subject matter, the enclosures 106- 1 , 2 of the print assembly 102 may each include a shields 1 1 0-1 and 1 1 0-2 at their open ends.

[0023] For the ease of reference, the enclosures 106-1 , 2 have been commonly referred to as enclosures 106. Similarly, the fusing lamp assemblies 108-1 , 2 have been collectively referred to as fusing lamp assemblies 108. Also, shields 1 10-1 , 2 have been collectively referred to as shields 1 10.

[0024] The print assembly 102 of the additive manufacturing system 100 may be utilized for different purposes, such as to provide fusion energy to the print area 104 along with additive materials, or to provide build material at selective points within the printing area 104. The printing area 104 may include an enclosure to receive build materials, additive materials, and fusion energy to generate the 3D object. In an example implementation of the present subject matter, one or more print assemblies 1 02 may provide build materials to the printing area to generate the 3D object.

[0025] As described earlier, the enclosures 1 06 may house the fusing lamp assemblies 108. Since the fusing lamps provide fusing energy to the printing area 104, the temperature of the enclosures 106 may often vary from about 300° C to normal room temperature. Accordingly, the enclosures 106 may be formed of heat resistant materials to withstand large changes in temperature during the operation of the fusing lamps. Further the enclosures 106 may also include vents to allow ingress and egress of cooling fluid so that the fusing lamp assemblies 108 can be cooled and an ambient temperature can be maintained during the operation of the additive manufacturing system 100.

[0026] Each of the fusing lamp assemblies 108 may include one or more fusing lamps which may be longitudinally extending tubes positioned along the length of the enclosures 106. The fusing lamps may be composed of an elongated tube carrying filament which generate fusing energy on application of electrical power. The shields 1 10 at the open end of the enclosures 106 may allow the fusing energy generated by the fusing lamp assemblies 108 to pass through the enclosures 1 06 and be directed upon any build material that may be placed within the printing area 1 04. The shields 1 10 may be made of any material, such as glass and transparent quartz to allow fusing energy to be transferred from the fusing lamp assemblies 108 to the printing area 1 04.

[0027] In an example implementation of the present subject matter, the enclosures 1 06 may be coupled to circulating units 1 12-1 and 1 12-2. The circulating units 1 12-1 , 2 have been commonly referred to as circulating units 1 12 for the purpose of description, hereinafter. The circulating units 1 12 may circulate cooling fluid through the enclosures 106 to maintain an ambient temperature during operation of the fusing lamp assemblies 108. The circulating units 1 12 may be coupled to vents of the enclosures 106. For example, the circulating unit 1 1 2-1 may pump the cooling fluid from one vent allowing the cooling fluid to spread within the enclosure 106-1 , and leave from other vents of the enclosure 106-1 .

[0028] The print assembly 102 may also include a carriage 1 14. The carriage 1 14 may include an inkjet array, also referred to as print heads, which dispenses fusing agents, such as fusing agent and detailing agent, for generating a 3D object. The carriage may also include a material coating unit which may coat the fusing agent over the build material.

[0029] In an example implementation of the present subject matter, the enclosures 106 may also be coupled with sensing units 1 1 6-1 , 2. The sensing unit 1 1 6-1 , 2 have been commonly referred to as sensing unit 1 1 6 for the purpose of description, hereinafter. The sensing units 1 1 6 may be coupled to a vent of the enclosures 1 06 to determine pressure of the cooling fluid within the enclosures 1 06. The sensing unit 1 1 6 may determine drop in pressure of the cooling fluid within the enclosure 1 06 to determine presence of a failure condition within the enclosure 1 06.

[0030] Although the description for the additive manufacturing system 100 as depicted in FIG. 1 is provided considering a set of fusing lamp assemblies 108 housed in two enclosures 106, it would be noted that the same would also be applicable for single fusing lamp assembly 108-1 or 108-2 housed in the enclosure 106-1 , 2 respectively. Accordingly, the sensing unit 1 1 6-1 may determine presence of the failure condition based on drop in pressure of the cooling fluid within the enclosure 106-1 . The operation of the sensing units 1 1 6-1 , 2 has been further described in reference to Fig. 2.

[0031] Fig. 2 depicts a block diagram representing an enclosure 106, housing a fusing lamp assembly 108, according to an example implementation of the present subject matter. In an example, the enclosure 106 may include the layer of shield 1 10 at the open end. The enclosure 106 may also be coupled to a circulating unit 1 12. The circulating unit 1 12 may be coupled to a vent of the enclosure 106 to circulate the cooling fluid within the enclosure 106 and maintain a predetermined pressure of the cooling fluid within the enclosure 1 06. The vents of the enclosure 106 may allow ingress and egress of the cooling fluid. The cooling fluid may flow within the enclosure 106 in any direction, such as depicted by flow 202. As depicted in flow 202, the cooling fluid may enter the enclosure 106 from one vent, and may leave the enclosure 106 from another vent.

[0032] In an example implementation of the present subject matter, the enclosure 106 may be coupled to the sensing unit 1 1 6. The sensing unit 1 1 6 may be coupled to a vent of enclosure 106 to determine pressure of the cooling fluid within the enclosure 106. In an example, the sensing unit 1 1 6 may include a differential pressure sensor to determine the pressure of the cooling fluid within the enclosure 1 06.

[0033] The sensing unit 1 1 6 may also determine any drop in pressure of the cooling fluid within the enclosure 106 during the operation of the additive manufacturing system 100. It would be noted that faults may occur during the operation of the additive manufacturing system 1 00. In such situations, the pressure of the cooling fluid may drop within the enclosure 106. The sensing unit 1 1 6 may determine such drop in pressure of the cooling fluid within the enclosure 106 to identify presence of a failure condition within the enclosure 106.

[0034] In an example, the presence of the failure condition may indicate occurrence of a fault within the enclosure 106, due to which the pressure of the cooling fluid within the enclosure 106 drops, and may result in inefficient cooling of the enclosure 106. For instance, the presence of the failure condition may indicate a fault in a circulating units 1 12, or may indicate breakage of the shield 1 10 disposed at the open end of the enclosure 106. The presence of the failure condition may also indicate leakage of cooling fluid through the open end of the enclosure 106 due to faulty fixing of the shield, or breakage of walls of the enclosure 1 06, resulting in leakage of the cooling fluid.

[0035] In an example implementation of the present subject matter, the sensing unit 1 1 6 may determine the drop in pressure, and may compare the drop in pressure to a predetermined threshold. If the drop in pressure is beyond the predetermined threshold, the sensing unit 1 1 6 may perform a predefined action, such as generating an alert for the user, powering off the additive manufacturing system, suspending use of the fusing lamp assemblies, and halting printing work of the additive manufacturing system. The predefined action may be performed to mitigate effect of the failure condition within the enclosures 106.

[0036] In an example implementation of the present subject matter, the alert generated by the sensing unit 1 1 6 may notify to a user, of the additive manufacturing system 100, about occurrence of a fault within the enclosure 106. In another example, the powering off of the additive manufacturing system 100 may disconnect electric supply to the fusing lamp assemblies 108, thereby avoiding any deflagration and damage to the users.

[0037] It would be noted that the sensing unit 1 1 6 may include different values of the predetermined threshold to determine presence of the failure condition within enclosure 106. For example, a drastic drop in pressure of the cooling fluid within the enclosure 106 may allow the sensing unit 1 1 6 to identify breakage of the shield 1 10. However, a slight drop in pressure of the cooling fluid may allow the sensing unit 1 1 6 to determine fault in the circulating units 1 12. [0038] Fig. 3 illustrates a method 300 of determining presence of a failure condition within the enclosure of an additive manufacturing system, according to an example of the present subject matter. The method 300 can be implemented by processor(s) or computing system(s) through any suitable hardware, a non-transitory machine readable medium, or a combination thereof. Further, although the method 300 is described in context of the aforementioned additive manufacturing system 1 00, other suitable computing or printing systems may be used for execution of the method 300. It may be understood that processes involved in the method 300 can be executed based on instructions stored in a non-transitory computer-readable medium, as will be readily understood. The non-transitory computer-readable medium may include, for example, digital memories, magnetic storage media, such as a magnetic disks and magnetic tapes, hard drives, or optically readable digital data storage media.

[0039] Referring to Fig. 3, at block 302, a cooling fluid is circulated within an enclosure of a fusing lamp assembly in an additive manufacturing system. The cooling fluid may be circulated by a circulating unit to maintain a predetermined pressure within the enclosure.

[0040] At block 304, a drop in pressure of the cooling fluid within the enclosure is determined. The drop in pressure of the cooling fluid may be determined by a differential pressure sensor of a sensing unit of the additive manufacturing system 1 00. In an example implementation of the present subject matter, the drop in pressure is greater than a predetermined threshold. For example, the predetermined pressure of the cooling fluid within the enclosure may be about 2 Atmosphere (atm) and the predetermined threshold may be set at 0.5 atm. In an event, due to occurrence of a fault in the circulating units 1 12, the pressure of the cooling fluid within the enclosure may drop to 1 atm. In such situations, since the drop in pressure is greater than the predetermined threshold, the sensing unit may identify presence of the failure condition within the enclosure.

[0041] In an example implementation of the present subject matter, at block 306, a predefined action is performed to mitigate the effects of the failure condition within the enclosure. In an example implementation of the present subject matter, the predefined action may include different configurable predefined actions, such as generating an alert for the user, powering off the additive manufacturing system, suspending use of the fusing lamp assemblies, and halting printing by the additive manufacturing system.

[0042] Fig. 4 illustrates a system environment 400 implementing a non-transitory computer readable medium for operating an additive manufacturing system, according to an example of the present subject matter. In an example implementation, the system environment 400 may be a additive manufacturing system, for example the additive manufacturing system 100. The system environment 400 includes a processor 402 communicatively coupled to the non-transitory computer-readable medium 404 through a communication link 406. In an example, the processor 402 may be a processing resource of the additive manufacturing system that fetches and executes computer-readable instructions from the non-transitory computer-readable medium 404.

[0043] The non-transitory computer- readable medium 404 can be, for example, an internal memory device or an external memory device. In an example implementation, the communication link 406 may be a direct communication link, such as any memory read/write interface. In another example implementation, the communication link 406 may be an indirect communication link, such as a network interface. In such a case, the processor 402 can access the non-transitory computer-readable medium 404 through a network. The network may be a single network or a combination of multiple networks and may use a variety of different communication protocols.

[0044] The processor 402 and the non-transitory computer-readable medium 404 may also be communicatively coupled to additive manufacturing system resource(s) 408. The additive manufacturing system resource(s) 408 may include sensing unit of the additive manufacturing system coupled to the enclosures housing the fusing lamp assemblies. In an example implementation, the non-transitory computer-readable medium 404 includes a set of computer-readable instructions for operating sensing unit coupled to the enclosure 106 of the additive manufacturing system 100. The set of computer-readable instructions can be accessed by the processor 402 through the communication link 406 and subsequently executed to detect present of failure condition within the enclosure 106.

[0045] Referring to Fig. 4, in an example, the non-transitory computer-readable medium 404 may include instructions 410 to circulate a cooling fluid within an enclosure of a fusing lamp assembly of the additive manufacturing system, to maintain a predetermined pressure within the enclosure. The instructions 41 0 may enable a circulating unit of the additive manufacturing system to circulate the cooling fluid.

[0046] The non-transitory computer-readable medium 404 may include instructions 412 to identify presence of a failure condition in the enclosure based on determination of drop in pressure of the cooling fluid within the enclosure. The failure condition may indicate faults within the enclosure, such as presence of any fault due to which the pressure of the cooling fluid within the enclosure is not proper and may result in inefficient cooling of the enclosure. For instance, the presence of the failure condition may indicate a fault in a circulating unit for circulating cooling fluid through the enclosure, or may indicate breakage of the shield disposed at the open end of the enclosure

[0047] The non-transitory computer-readable medium 404 may also include instructions 414 to generate an alert to notify the presence of the failure condition. The alert may be generated to intimate a user of the occurrence of the failure condition so that the effect of the failure condition can be mitigated by taking corrective measures.

[0048] Although examples for the present disclosure have been described in language specific to structural features and/or methods, it should stood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed and explained as examples of the present disclosure.

Claims

We claim:

1 . An additive manufacturing system comprising: an enclosure of a fusing lamp assembly; a circulating unit to circulate a cooling fluid through the enclosure and maintain a predetermined pressure within the enclosure; and a sensing unit coupled to the enclosure to: determine a drop in pressure of the cooling fluid within the enclosure, from the predetermined pressure; and generate an alert to indicate presence of a failure condition within the enclosure based on the determination of the drop in pressure.

2. The additive manufacturing system as claimed in claim 1 , wherein the enclosure further comprises vents to allow ingress and egress of the cooling fluid.

3. The additive manufacturing system as claimed in claim 1 , wherein the sensing unit is coupled to a vent of the enclosure to determine pressure within the enclosure.

4. The additive manufacturing system as claimed in claim 1 , wherein the failure condition is indicative of breakage of a shield positioned at an open end of the enclosure.

5. The additive manufacturing system as claimed in claim 4, wherein the shield is glass.

6. The additive manufacturing system as claimed in claim 1 , wherein the failure condition is indicative of a fault in the circulating unit.

7. The additive manufacturing system as claimed in claim 1 , wherein the sensing unit comprises a differential pressure sensor.

8. The additive manufacturing system as claimed in claim 1 , wherein the sensing unit generates the alert on identifying the drop in pressure of the cooling fluid within the enclosure to be greater than a predetermined threshold.

9. A method of determining presence of a failure condition in an enclosure of a fusing lamp assembly of an additive manufacturing system, the method comprising: circulating a cooling fluid within the enclosure, by a circulating unit, to maintain a predetermined pressure within the enclosure; determining, by a sensing unit, a drop in pressure of the cooling fluid from the predetermined pressure to identify presence of the failure condition within the enclosure, wherein the drop in pressure is greater than a predetermined threshold; and performing a predefined action to mitigate effect of the failure condition within the enclosure.

10. The method as claimed in claim 9, wherein the failure condition is indicative of breakage of a shield positioned at an open end of the enclosure.

1 1 . The method as claimed in claim 9, wherein the predefined action includes one of generating an alert for the user, powering off the additive manufacturing system, suspending use of the fusing lamp assembly, and halting printing by the additive manufacturing system.

12. The method as claimed in claim 9, wherein the circulating of the cooling fluid is through vents of the enclosure.

13. The method as claimed in claim 9, wherein the determining comprises ascertaining pressure within the enclosure by a differential pressure sensor.

14. A non-transitory computer-readable medium comprising computer-readable instructions, which, when executed by a processor in an additive manufacturing system, cause the processor to: circulate a cooling fluid within an enclosure of a fusing lamp assembly of the additive manufacturing system, to maintain a predetermined pressure within the enclosure; identify presence of a failure condition in the enclosure based on determination of drop in pressure of the cooling fluid within the enclosure; and generate an alert to notify the presence of the failure condition.

15. The non-transitory computer-readable medium as claimed in claim 14, wherein failure condition is indicative of breakage of a shield positioned at an open end of the enclosure.