Additive manufacturing techniques may generate a three-dimensional object on a layer-by-layer basis through the solidification of a build material. In examples of such techniques, build material is supplied in a layer-wise manner and a solidification method may include heating the layers of build material to cause melting in selected regions. In other techniques, other solidification methods, such as chemical solidification methods or binding materials, may be used. In some examples, the temperature of the build material is increased prior to the melting process.
Examples will now be described, by way of non-limiting example, with reference to the accompanying drawings, in which:
Printing apparatus may be used to generate two-dimensional printed images. Additive manufacturing techniques may generate a three-dimensional object through the solidification of a build material. In some examples, the build material may be a powder-like granular material, which may for example be a plastic, ceramic or metal powder. The properties of generated objects may depend on the type of build material and the type of solidification mechanism used. Build material may be deposited, for example on a print bed and processed layer by layer, for example within a fabrication chamber.
In some examples, selective solidification is achieved through directional application of energy, for example using a laser or electron beam which results in solidification of build material where the directional energy is applied. In other examples, at least one print agent may be selectively applied to the build material, and may be liquid when applied. For example, a fusing agent (also termed a ‘coalescence agent’ or ‘coalescing agent’) may be selectively distributed onto portions of a layer of build material in a pattern derived from data representing a slice of a three-dimensional object to be generated (which may for example be generated from structural design data). The fusing agent may have a composition which absorbs energy such that, when energy (for example, heat) is applied to the layer, the build material coalesces and solidifies to form a slice of the three-dimensional object in accordance with the pattern. In other examples, coalescence may be achieved in some other manner.
In addition to a fusing agent, in some examples, a print agent may comprise a coalescence modifying agent (referred to as modifying or detailing agents herein after), which acts to modify the effects of fusing for example by reducing or increasing coalescence or to assist in producing a particular finish or appearance to an object, and such agents may therefore be termed detailing agents. Such a detailing agent may be used to prevent fusing of a portion of build material by cooling the build material, for example.
Additive manufacturing systems may generate objects based on structural design data. This may involve a designer generating a three-dimensional model of an object to be generated, for example using a computer aided design (CAD) application. The model may define the solid portions of the object. To generate a three-dimensional object from the model using an additive manufacturing system, the model data can be processed to generate slices of parallel planes of the model. Each slice may define a portion of a respective layer of build material that is to be solidified or caused to coalesce by the additive manufacturing system.
An example additive manufacturing process may involve various processes. A layer of build material may be formed on a print bed, or build platform using, for example, a build material distributor, which may, in one example, deposit and spread build material onto the print bed at an intended thickness. Prior to the build material being fused, the layer of build material and/or the print bed may be preheated using, for example, a radiation source such as an infrared lamp, or by some other means.
A simplified schematic of an example heating module, which may be a preheating lamp, a fusing lamp, or, more generally, a lamp assembly having an array of lamps, for use in a printing apparatus is shown in
The heating module 100, in some examples may be located above a print bed, in or above a fabrication chamber of an additive manufacturing apparatus, and may be used to supply radiation, such as heat, into the fabrication chamber and towards the print bed, for example as part of the preheating process discussed above. In such a preheating process, the print bed and/or build material on the print may be heated, for example using the heating module 100, in a uniform manner, to a temperature just below the fusing or melting temperature of the build material to which fusing agent has been applied. In some other examples, the heating module 100 may comprise a lamp used to deliver heat to fuse the build material to which fusing agent has been applied. In a two-dimensional printing apparatus, the heating module 100 may comprise an array of curing lamps, as described above. The heating module 100 may include a plurality of individual lamps, or heat elements 102. In the example shown in
In some examples, the heat elements 102 may be halogen lamps which may generate a large amount of near-infrared radiation. In other examples, infrared light emitting diodes (LEDs) or infrared bar radiators may be used as heat elements 102.
The heat elements 102 are, in the example shown, arranged in a spaced-apart manner on a surface of the heating module 100, in a configuration that allows heat from the heat elements to be distributed approximately evenly or uniformly through the fabrication chamber and onto the print bed, or print area. In other examples, the heating module 100 may include more or fewer heat elements 102, and may be arranged in a different configuration. For example, in an additive manufacturing apparatus having a larger fabrication chamber, the heating module 100 may include more heat elements 102 in order to provide sufficient heat to increase the temperature of the print bed and/or build material on the print bed.
In the example of
Each of the heat elements 102 is connected to control circuitry (not shown) via which each heat element may be controlled and receive power. In the example of
In order to create a uniform distribution of heat throughout the fabrication chamber and across the print bed, or over the print area of a two-dimensional printing apparatus, the heat elements 102 may be independently operated, such that each heat element can be controlled to deliver specific amounts of radiation towards a particular area or particular areas of the print bed. The power supplied to each heat element may also be controlled independently. Therefore, each heat element 102 may be connected to a connection terminal of control circuitry (whether or not via a PCA 106) via a corresponding connector (not shown), such as a connection cable or harness. If any of the heat elements 102 are connected incorrectly to the control circuitry, for example if the connections between the control circuity and two of the heat elements 102 are switched, then the heat elements may be caused to operate in an unintended manner. For example, the print area, or print bed, may be caused to heat up in one area when the intention is to heat the print bed up in another area. In another example, some areas of the print bed could be caused to receive heat from more than one heat element, resulting in excessive heating, and/or some areas of the print bed could be caused to receive heat from none of the heat elements, which could result in the print bed or build material not being heated sufficiently uniformly.
A method will now be described which can be performed by a suitable apparatus or system, and which can be used to determine connection information of the heat elements 102 such as, for example, whether a heat element is connected to an incorrect terminal of the control circuitry.
At block 204, the method comprises detecting, using a detector, a change resulting from radiation from the first radiation source. The detector may be the detector 104 discussed above with reference to
Reference is now made to
According to some examples, the switching on (block 202), the detecting (block 204) and the determining (block 206) processes may be further performed sequentially for each of the other radiation sources of the plurality of radiation sources, as indicated by the arrow extending from block 206 to block 202. In other words, the processes described above with reference to blocks 202, 204 and 206 may be performed for a first radiation source, or heat element 102, then for a second radiation source, and so on, until the processes have been performed for all of the radiation sources in the plurality of radiation sources. In some examples, the method may at this stage store, in a memory, the connection information for each of the plurality of radiation sources.
Prior to switching on the first radiation source, the method may further comprise, in block 302, measuring an ambient temperature within the fabrication chamber, or of the print area. The ambient temperature measurement may be made using the detector 104 of the heating module 100, or by a different thermal sensor located within the fabrication chamber, or near to the print area, and which may form part of the heating module. The measured ambient temperature may be stored in a memory within or remote from the additive manufacturing apparatus, and/or may be measured periodically by one or more sensors located within the fabrication chamber.
After performing the processes described above with reference to
Once the system has determined which area or zone of the print area, or print bed, is affected (changed, for example by being heated up) by each radiation source 102, it may be possible to determine whether any connection errors exist in the system, or whether there exist any other errors concerning the radiation sources. In some examples, the method may further comprise, in block 306, determining, using a processor, whether any portions of the surface undergo a change caused by radiation from more than one of the plurality of the radiation sources. Thus, it is possible to determine whether any portions of the print bed are receiving radiation from two or more radiation sources 102, rather than from a single radiation source. This may result from a radiation source 102 being tilted or aimed incorrectly, such that radiation from the source is unintentionally directed to a portion of the print bed served by another radiation source.
The method may, in some examples, comprise, in block 308, determining, using a processor, whether any portions of the surface do not undergo a change caused by radiation from any of the plurality of the radiation sources. Thus, it is possible to determine whether any portions of the print bed are receiving no radiation (or an amount of radiation falling below a defined threshold) from any of the radiation sources 102. Again, this might be indicative of a radiation source 102 being tilted or aimed incorrectly, or of a faulty connection between the radiation source and the control circuitry.
In some examples, the method may include making the determinations of both blocks 306 and 308, while in other examples, one of these determinations, or neither of the determinations, may be made. If either of the determinations of blocks 306 or 308 are made, and a potential error (for example, an area is receiving heat from two sources or an area is not receiving heat from any sources) is identified, then the method according to some examples may further comprise, at block 310, providing an indication of a potential error to a user. Such an indication may comprise an audio warning, such as an alarm signal, or visual warning, such as a warning message displayed on a display of the additive manufacturing apparatus, for example. An indication may be made to the user when it is determined that either (i) a portion of the print bed undergoes a change caused by radiation from more than one of the plurality of the radiation sources; or (ii) a portion of the surface does not undergo a change caused by radiation from any of the plurality of the radiation sources.
In some examples, the method may determine that a heat element in the heating module is not generating radiation when it is switched on. For example, the method may detect that no current consumption is measured by the PCA via which a particular heat element is connected. In other examples, the method may determine that a heat element in the heating module has malfunctioned. For example, the method may detect that the current consumption by a particular heat element is lower or higher than expected.
The method, may further comprise, at block 312, storing, in a memory, the connection information for each of the plurality of radiation sources. In some examples, the storing (block 312) may be done after the determinations made in blocks 306 and/or 308, if no potential errors are identified, as shown in
The processes discussed herein with reference to blocks in
The determining process discussed above with reference to block 206 will now be discussed in greater detail with reference to
For each heat element, the method may compare, using a processor, the detected temperature change on the print bed with a plurality of templates, examples of which are shown schematically in
Referring to
In other examples, templates may include values other than 1 and 0. For example, a template may include fields (i.e. squares) having values of 0.5, which may represent areas adjacent to the area directly under the heat element, and which, as a consequence, receive a relatively smaller amount of heat or radiation from the heat element.
In the example of
While the above method lends itself to use in additive manufacturing apparatus which use a fusing lamp to fuse portions of build material and a preheating lamp to increase the temperature of the print bed and/or the build material prior to fusing, the method is also suitable for use in a laser sintering system, such as a selective laser sintering (SLS) system, in which a heating module may be used to provide heat during a preheating process, but a laser is used to selectively fuse portions of build material.
The above method may also be used in systems where radiation from the radiation sources is used in a fusing process rather than, or in addition to, a preheating process. For example, the method described herein may be used in systems in which ultraviolet (UV)-curable inks or latex inks are used.
The method described herein may be considered to be a calibration of the heat elements of radiation sources of the heating module, which may be performed while, or after, the heating module or printing apparatus is manufactured, during or after a servicing procedure, or as a user calibration between uses, or periodically.
In some examples, the heat sources 502 may correspond to the heat elements 102 of
The sensor 504 may, in some examples, measure a change in temperature of a portion of a surface onto which heat from the first heat source is directed. In some examples, the surface comprises a print area of a printing apparatus, or a print bed of the additive manufacturing apparatus.
In other examples, the sensor 504 may measure a change other than a change in temperature. For example, the sensor 504 may detect or measure light intensity, colour, or an amount of light reflected from a surface.
In some examples, the identified thermal change comprises an indication of a position of a change in temperature of a portion of a surface onto which heat from the heat lamp is directed. The machine-readable medium 602 may further comprise instructions which, when executed by the processor 604, cause the processor to provide an indication to a user when it is determined that either: (i) a portion of the surface undergoes a temperature change caused by heat from more than one of the plurality of the heat lamps; or (ii) a portion of the surface does not undergo a temperature change caused by heat from any of the plurality of the heat lamps.
As discussed above, the indication to a user may be made, for example, as an audible or visual indication, such as a warning signal or warning message.
In other examples, the detection apparatus may be used by the processor to identify a change other than a thermal change. For example, the detection apparatus may detect or measure light intensity, colour, or an amount of light reflected from a surface.
Examples in the present disclosure can be provided as methods, systems or machine readable instructions, such as any combination of software, hardware, firmware or the like. Such machine readable instructions may be included on a computer readable storage medium (including but is not limited to disc storage, CD-ROM, optical storage, etc.) having computer readable program codes therein or thereon.
The present disclosure is described with reference to flow charts and/or block diagrams of the method, devices and systems according to examples of the present disclosure. Although the flow diagrams described above show a specific order of execution, the order of execution may differ from that which is depicted. Blocks described in relation to one flow chart may be combined with those of another flow chart. It shall be understood that each flow and/or block in the flow charts and/or block diagrams, as well as combinations of the flows and/or diagrams in the flow charts and/or block diagrams can be realized by machine readable instructions.
The machine readable instructions may, for example, be executed by a general purpose computer, a special purpose computer, an embedded processor or processors of other programmable data processing devices to realize the functions described in the description and diagrams. In particular, a processor or processing apparatus may execute the machine readable instructions. Thus functional modules of the apparatus and devices may be implemented by a processor executing machine readable instructions stored in a memory, or a processor operating in accordance with instructions embedded in logic circuitry. The term ‘processor’ is to be interpreted broadly to include a CPU, processing unit, ASIC, logic unit, or programmable gate array etc. The methods and functional modules may all be performed by a single processor or divided amongst several processors.
Such machine readable instructions may also be stored in a computer readable storage that can guide the computer or other programmable data processing devices to operate in a specific mode.
Such machine readable instructions may also be loaded onto a computer or other programmable data processing devices, so that the computer or other programmable data processing devices perform a series of operations to produce computer-implemented processing, thus the instructions executed on the computer or other programmable devices realize functions specified by flow(s) in the flow charts and/or block(s) in the block diagrams.
Further, the teachings herein may be implemented in the form of a computer software product, the computer software product being stored in a storage medium and comprising a plurality of instructions for making a computer device implement the methods recited in the examples of the present disclosure.
While the method, apparatus and related aspects have been described with reference to certain examples, various modifications, changes, omissions, and substitutions can be made without departing from the spirit of the present disclosure. It is intended, therefore, that the method, apparatus and related aspects be limited only by the scope of the following claims and their equivalents. It should be noted that the above-mentioned examples illustrate rather than limit what is described herein, and that those skilled in the art will be able to design many alternative implementations without departing from the scope of the appended claims. Features described in relation to one example may be combined with features of another example.
The word “comprising” does not exclude the presence of elements other than those listed in a claim, “a” or “an” does not exclude a plurality, and a single processor or other unit may fulfil the functions of several units recited in the claims.
The features of any dependent claim may be combined with the features of any of the independent claims or other dependent claims.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2016/064760 | 6/24/2016 | WO | 00 |