Method and apparatus for manufacturing objects by additive manufacturing - Patents.com

Abstract

A method for manufacturing an object by additive manufacturing, comprising: - receiving a bath of material in a process chamber; - solidifying a selected layer portion of the material at a surface level using a solidification device; - controlling the oxidation of the waste particles resulting from the solidifying step by controlling the oxidation level so as to obtain oxidized waste particles and thereby prevent ignition of the waste particles; The surface level of the bath of material defines the object working area. [Selected Figure] Figure 1

Description

Technical Field

[0001] In a first aspect, the present disclosure relates to a method for manufacturing an object using additive manufacturing.

[0002] In a second aspect, the present disclosure relates to an apparatus for manufacturing an object using additive manufacturing.

Background Art

[0003] 3D printing or additive manufacturing refers to any of a variety of processes for printing three-dimensional objects. When manufacturing a large number of polymer products at low cost, conventional techniques such as injection molding can be used. However, when producing a relatively small number of three-dimensional objects, 3D printing or additive manufacturing enables faster, more flexible, and less expensive production.

[0004] Additive manufacturing is expected to become even more important in the future. This is because manufacturing companies are under increasing pressure from competitors not only to achieve both high quality and cost reduction in manufacturing, but also to reduce product development time and costs. In fact, the lifespan of products is constantly getting shorter. Therefore, for a product to succeed, not only quality and cost, but also the timing of market introduction is becoming increasingly important.

[0005] For the purpose of manufacturing a 3D object, a 3D object can be manufactured using an energy beam directed to selectively solidify a powder or liquid material. In particular, a plurality of layers can be continuously solidified using a computer-controlled additive manufacturing apparatus to form a desired design layer by layer. In this case, the lamination process is mainly used under computer control, and successive layers of material are laminated. Such objects are manufactured from a source of 3D models or other electronic data and can achieve almost any form or shape.

[0006] To print a 3D object, it is necessary to create a printable model using computer design packages or 3D scanners. The input is typically a 3D-CAD file such as an STL, STEP, or IGS file. The file needs to be processed by software before printing the object from the CAD file. This software converts the model into a series of thin layers. Furthermore, the device is configured and vectors are generated to control the creation of each of these continuous layers.

[0007] Subsequently, a laser equipped in a computer-controlled additive manufacturing system solidifies the continuous layers of liquid, powder, or sheet material with the aim of forming a 3D object from the continuous cross-sections. This creates a 3D object from the continuous cross-sections. In this process, these layers (corresponding to virtual cross-sections from a CAD model) are simultaneously joined or fused. This results in the production of the final 3D object. [Overview of the project] [Problems that the invention aims to solve]

[0008] Known methods for printing 3D objects are: - A step of receiving a tank of material in a process chamber (at which point the surface level of the tank of material defines the object work area), - A step of solidifying a selected layer of material at the surface level using a solidification device, It is equipped with.

[0009] One of the challenges in manufacturing 3D objects (especially metal objects using additive manufacturing) is how to ensure safe manufacturing while maintaining product quality.

[0010] This disclosure aims to provide methods and apparatus for achieving high quality and high safety. [Means for solving the problem]

[0011] For this purpose, the present invention provides a method for manufacturing an object by additive manufacturing. This method is - The step of receiving the material in a tank within the process chamber, - A step of solidifying a selected layer of material at the surface level using a solidification device, - A step to control the oxidation of waste particles caused by the coagulation step by controlling the oxidation level so that the waste particles do not ignite by obtaining oxidized waste particles, It includes the following: The surface level of the material tank defines the object's working area.

[0012] It is known that three-dimensional objects can be manufactured in an environment containing relatively high levels of inert gas to reduce oxidation of the material during solidification. This improves the quality of the manufactured objects.

[0013] This disclosure is based, at least in part, on the finding that using a small amount of inert gas results in relatively high oxygen levels (due to a combination of low inert gas supply rates and air leakage into the process chamber). Generally, high oxygen levels can have a substantially adverse effect on product quality. Therefore, increasing the supply of inert gas may improve product quality. However, increasing the supply of inert gas leads to a decrease in oxygen levels, which has the disadvantage of reducing the safety of the working environment.

[0014] Alternatively, the oxygen level can be reduced by combining the oxidation of the material during solidification with an airtight process chamber. This lowers the oxygen level and improves product quality. However, this comes at the disadvantage of reduced safety in the work environment.

[0015] At certain relatively low oxygen levels, waste particles resulting from the coagulation process can be oxidized directly or after condensation to an oxygen-free state or at least below a certain level. When exposed to relatively high oxygen levels, oxidation of these waste particles occurs at a relatively high rate. As a result, a relatively large amount of thermal energy is generated, and these waste particles may ignite. Ignition of waste particles can create a hazardous environment for operators and / or equipment because the sudden ignition of waste particles is explosive.

[0016] The objective of this invention is achieved by a method for oxidizing waste particles in a controlled manner. By oxidizing waste particles in a controlled manner, the heat generated by the oxidation of waste particles can be controlled. This makes it possible to control the temperature of the waste particles to a level below the ignition temperature.

[0017] The aforementioned method is useful if it further includes a step of discharging a mixture of gas and waste particles from the process chamber using a discharge device. Discharging this mixture is useful because it allows for the oxidation of the waste while reducing the potential impact of controlled oxidation on solidification within the process chamber. This allows for maintaining relatively low oxygen levels within the process chamber and reducing the risk of waste particle ignition. In other words, the controlled oxidation process of waste particles is separated from the solidification process that occurs within the process chamber.

[0018] In one embodiment of the method according to this disclosure, in the discharge step described above, a mixture of gas, waste particles, and oxidized waste particles is discharged from the process chamber. This is advantageous because it allows control of waste particle oxidation to be achieved not only within the process chamber but also elsewhere. This further reduces the risk of the waste particle temperature rising above the ignition temperature, either within the process chamber or elsewhere.

[0019] In this respect, the present method is advantageous if it further includes a step of filtering the mixture of the emitted gas and waste particles using a filter device to collect waste particles. Filtering the mixture is advantageous because it allows the aforementioned gas to be reused in the process chamber, for example, by recycling, while the waste particles are collected in the filter device. On the other hand, recycling the mixture of the aforementioned gas and waste particles is not very attractive because recycling such a mixture increases the amount of waste in the mixed gas, thereby increasing the potential hazard to the working environment.

[0020] In one embodiment of the method according to the present disclosure, the filtering step described above filters a mixture of gas, waste particles, and oxidized waste particles. Filtering the emitted mixture of gas, waste particles, and oxidized waste particles is advantageous because it allows the aforementioned gas to be reused in the process chamber, for example, by recycling the waste particles and oxidized waste particles while collecting them in the filtering device. In contrast, recycling the aforementioned mixture of gas, waste particles, and oxidized waste particles is less attractive because recycling such a mixture increases the amount of waste in the mixed gas, thereby increasing the potential hazard to the working environment.

[0021] It should be noted that waste particles can be formed by the condensation of gases generated by the solidification of materials. Such waste particles can be formed by condensation that occurs simultaneously with or after contact between the gas and the filter device.

[0022] In the actual embodiment of the method described above, the method further comprises the step of transferring the waste particles removed from the filter device to a storage device for storage. This is advantageous in that it can further reduce the risk of a hazardous working environment.

[0023] Preferably, this storage device is configured for controlled oxidation. Thereby, the oxidation levels in the process chamber and in the filter device can be kept relatively low, and the risk of ignition of the waste particles can be reduced. In other words, the process of controlling the oxidation of the waste particles and the process of filtering the waste particles are separated from the process of coagulation occurring in the process chamber and from the process of filtering occurring in the filter device.

[0024] Advantageously, the method further comprises the step of measuring the oxygen level in the process chamber using a measuring device. By measuring the oxygen level, it is advantageous because the oxidation can be controlled taking this oxygen level into account.

[0025] Preferably, in the step of controlling the oxidation, a controlled amount of oxygen is supplied to the waste particles in order to obtain waste particles that are oxidized without ignition.

[0026] In a preferred embodiment of the method according to the first aspect of the present disclosure, a controlled amount of oxygen is supplied to the waste particles taking into account the measured oxygen level. This is attractive in that a controlled oxidation rate (preferably, a relatively constant controlled oxidation rate) can be achieved, whereby the amount of heat generated by the oxidation of the waste particles can be controlled, and thus the temperature of the waste particles can be kept below the ignition temperature.

[0027] Advantageously, the aforementioned method further comprises the step of determining the oxidation rate taking into account the measured oxygen level and the amount of oxygen supplied. By determining the oxidation rate, it is possible to judge whether the waste particles have been oxidized or whether oxidation is occurring. If it is determined that the oxidation rate is zero or substantially zero in an environment where oxygen is present, a relatively safe working environment with respect to the ignition of the waste particles is realized because a relatively large amount of the waste particles have already been oxidized.

[0028] To prevent oxidation of a subset of the waste particles, in the step of controlling oxidation, it is advantageous for a controlled amount of chalk to be supplied to the waste particles. Preventing oxidation of a subset of the waste particles is advantageous in that it can reduce the amount of oxidation that occurs, thereby reducing the amount of thermal energy generated during the time interval. Reducing the amount of thermal energy generated by oxidation is advantageous in that it can reduce the risk of ignition of the waste particles.

[0029] In a practical embodiment of the method according to the first aspect of the present disclosure, the process chamber is configured to allow outside air to enter the process chamber in the step of coagulating described above. And in order to control the oxygen level of the waste particles to obtain oxidized waste particles, in the step of controlling oxidation, a controlled amount of inert gas is supplied to the process chamber in order to obtain a desired oxygen level in the process chamber.

[0030] At this time, it is advantageous for a controlled amount of inert gas to be supplied in consideration of the measured oxidation rate. By controlling the supply of the inert gas in consideration of the measured oxidation rate, the supply of the inert gas can be controlled more accurately, and thereby the oxidation of the waste particles can be controlled more accurately.

[0031] Preferably, in the step of coagulating, the oxygen level in the process chamber is 50 ppm or more and 1000 ppm or less. The fact that the oxygen level is 50 ppm or more and 1000 ppm or less is preferable in that it can achieve controlled oxidation while maintaining the quality of the product relatively high.

[0032] In an embodiment of the method according to the first aspect of the present disclosure, the step of controlling oxidation is performed in the step of coagulating. This is preferable in that it can realize an effective method without interrupting the step of coagulating to oxidize the waste particles. Thereby, it is possible to safely maintain the working environment, maintain the high quality of the product, and manufacture the product in a relatively short time.

[0033] In this process, the oxidation control step is performed within a process chamber, and it is advantageous for the oxygen level within the process chamber during the solidification step to be between 50 ppm and 1000 ppm. It is preferable that the oxygen level be kept constant during the solidification step, and more preferably between 50 ppm and 1000 ppm. Maintaining an oxygen level between 50 ppm and 1000 ppm is advantageous because it allows for controlled oxidation while maintaining high product quality. Maintaining a constant oxygen level within the process chamber during the solidification step is advantageous because it allows for a relatively constant oxidation rate.

[0034] In one embodiment of the method according to the first aspect of this disclosure, the oxidation control step is performed in the solidification step and in the filtering and / or transfer step. This is advantageous in that the oxidation control of waste particles can be performed in two separate locations, and thus the risk of the temperature of waste particles in the process chamber, the filtering device or the storage device rising above the ignition temperature can be further reduced.

[0035] In a very useful embodiment of the method according to the first aspect of this disclosure, the material is a metal powder.

[0036] It is advantageous if the emitted gas is returned to the process chamber. This is advantageous because it allows for relatively low gas consumption.

[0037] In the coagulation step, it is advantageous if the coagulation device is controlled taking into account the measured oxygen level and the determined oxidation rate. This is advantageous because it allows for control of waste particle oxidation at a relatively low oxidation rate, and therefore reduces the risk of waste particle ignition during oxidation control.

[0038] In one embodiment of the method according to the first aspect of this disclosure, the oxidation control step is performed in the filtering step and / or transfer step. This keeps the oxygen level within the process chamber relatively low, reducing the risk of waste particle ignition. In other words, the process of controlling the oxidation of waste particles is separated from the solidification process that occurs within the process chamber. This is advantageous because it can avoid or significantly reduce the impact of oxidation control on the environment within the process chamber, thus maintaining a safe working environment while keeping product quality high.

[0039] In this case, the filter device and / or storage device are configured to allow outside air to enter the filter device and / or storage device during the solidification step. In order to control the oxygen level of the waste particles in order to obtain oxidized waste particles, a controlled amount of inert gas is supplied to the filter device and / or storage device in the step of controlling oxidation to obtain a desired oxygen level within the filter device and / or storage device.

[0040] At this time, a controlled amount of inert gas is supplied, taking into account the determined oxidation rate. By controlling the supply of inert gas in consideration of the determined oxidation rate, the supply of inert gas can be controlled more precisely, thereby allowing for more precise control of the oxidation of waste particles.

[0041] A second aspect of this disclosure relates to an apparatus for manufacturing an object by additive manufacturing. This apparatus is - A process chamber that receives the material tank, - A solidification device that solidifies a selected layer of material at the surface level, - An oxidation device configured to control the oxidation of waste particles resulting from the solidification step by controlling the oxidation level so as not to cause ignition of the waste particles by obtaining oxidized waste particles. The surface level of the material tank defines the object working area.

[0042] In this case, it is advantageous for the apparatus to further include an exhaust device that discharges a mixture of gas and waste particles from the process chamber. The exhaust device that discharges the mixture is useful because it can oxidize the waste particles while reducing the potential impact of oxidation control on solidification within the process chamber. This allows for maintaining a relatively low oxygen level within the process chamber and reducing the risk of waste particle ignition. In other words, the process of controlling the oxidation of waste particles is separated from the solidification process that occurs within the process chamber.

[0043] In this case, it is advantageous to further include a filter device configured to collect waste particles from a mixture of discharged waste particles and gas. A filter device that filters the discharged mixture is advantageous because it allows the aforementioned gas to be reused in the process chamber, for example, by recycling the waste particles while collecting them within the filter device. In contrast, recycling the mixture of the aforementioned gas and waste particles is not very attractive because recycling such a mixture increases the amount of waste in the mixed gas, thereby increasing the potential hazard to the working environment.

[0044] Preferably, the apparatus further comprises a storage device configured to store waste particles. This is useful in further reducing the risk of a hazardous work environment.

[0045] In this case, it is even more advantageous if the storage device is configured to control oxidation. This allows for relatively low oxygen levels within the process chamber and filter device, reducing the risk of waste particle ignition. In other words, the process of controlling waste particle oxidation is separated from the coagulation process that occurs within the process chamber and from the filtering process that occurs within the filter device.

[0046] In one embodiment of the apparatus according to a second aspect of this disclosure, the oxidation device is configured to maintain the oxygen level in the process chamber at 50 ppm to 1000 ppm while the material is solidifying. An oxygen level of 50 ppm to 1000 ppm is preferable because it allows for controlled oxidation while maintaining relatively high product quality.

[0047] It is advantageous for the apparatus to further include a measuring device for measuring the oxygen level in the process chamber. Such a measuring device is advantageous because it allows for the control of oxidation while taking the oxygen level into consideration.

[0048] Preferably, the apparatus further comprises a filter device configured to collect waste particles from a mixture of discharged waste particles and gas. A measuring device is configured to measure the oxygen level within the filter device. This is advantageous in that the oxidation of waste particles can be controlled in two separate locations, thus further reducing the risk that the temperature of waste particles in the process chamber, the filter device, or the storage device will rise above the ignition temperature. [Brief explanation of the drawing]

[0049] The method and apparatus relating to this disclosure will be explained using the following attached drawings. [Figure 1] This is a schematic diagram of an apparatus configured to manufacture objects using additive manufacturing according to the present invention. [Figure 2] This is a schematic diagram of an apparatus configured to manufacture objects using additive manufacturing according to the present invention. [Figure 3] This is a schematic diagram of an apparatus configured to manufacture objects using additive manufacturing according to the present invention. [Figure 4] This is a schematic diagram of an apparatus configured to manufacture objects using additive manufacturing according to the present invention.

[0050] Figure 1 shows an overview of apparatus 1 for manufacturing object 2 using additive manufacturing. Apparatus 1 is formed from several frame components 11, 12, and 13. The apparatus includes a process chamber 3 for receiving a tank of solidifiable material 4. A shaft is formed within frame component 11, where a support 5 is provided for positioning object 2 in relation to the surface level L of the tank of material 4. The support 5 is movably provided within the shaft. This allows the support 5 to be lowered after a layer has solidified, so that further layers of material can be solidified on top of the already formed object 2. A solidification device 7 for solidifying a selected portion of the material is provided at the top 13 of apparatus 1. In the illustrated embodiment, the solidification device 7 is a laser device. This laser device is configured to generate electromagnetic radiation in the form of laser light 71 for the purpose of dissolving the powder material given to the support. However, the present invention is not limited to the type of solidification apparatus. As shown, the electromagnetic radiation 71 emitted from the laser device 7 is deflected by a deflection unit 74. The deflection unit 74 uses a rotatable optical component 75 to guide the irradiated radiation 71 toward the surface L of the layer of material 4. Depending on the position of the deflection unit 74, the radiation may be emitted along, for example, rays 72, 73.

[0051] Apparatus 1 comprises an oxidation device 81 connected to an oxygen source (not shown). The oxygen source may contain dry, clean air with approximately 20% oxygen and approximately 80% nitrogen. The oxidation device 81 further comprises a feeder 83 for supplying oxygen from the oxygen source to the process chamber 3. The process chamber 3 is substantially sealed and can be filled with an inert gas such as argon or nitrogen through a gas feeder 6.

[0052] A measuring device 85 equipped with a sensor 86 is provided to measure the oxygen level in the process chamber 3. The measuring device 85 and the oxidizing device 81 are communicatively connected to a controller 87. The controller 87 is configured to control the amount of oxygen supplied to the process chamber 3 through the feeder 83. In doing so, the controller 87 takes into account the oxygen level in the process chamber 3 measured by the measuring device 85 in order to maintain the oxygen level in the process chamber 3 at a predetermined concentration of 50 ppm to 1000 ppm.

[0053] Alternatively, instead of connecting an oxygen source to the controller 87 (or in addition to it), the oxygen level in the process chamber of apparatus 1 may be maintained at a predetermined concentration of 50 ppm to 1000 ppm by connecting the gas supply unit 6 to the controller 87 in a communicative manner. In this alternative configuration of apparatus 1, air may leak into the process chamber. In this case, the oxygen level may be controlled by controlling the amount of inert gas supplied to the process chamber through the gas supply unit 6, while taking into account the oxygen level in the process chamber 3 measured by the measuring device 85.

[0054] Figure 2 shows a further embodiment of the apparatus 101 according to the present disclosure. Parts of apparatus 101 that are similar to parts of apparatus 1 are denoted by the same reference numeral as the parts of apparatus 1 plus 100. Apparatus 101 includes an exhaust device consisting of a fan 189 for exhausting a mixture of gas, waste particles, and oxidized waste particles from the process chamber 103 through an exhaust connection 190. Before the gas is returned to the process chamber 103 through a return line 195, the exhausted mixture of gas, waste particles, and oxidized waste particles is led to a filter device 191 for separating waste particles from the gas. By supplying oxygen to the filter device 191 using a second feeder 110 on the opposite side of the return line 195, the waste particles collected by the filter device 191 can be oxidized.

[0055] The measuring device 185 comprises a first sensor 186 and a second sensor 188. The first sensor 186 is provided to measure the oxygen level in the process chamber 103. The second sensor 188 is provided to measure the oxygen level in the filter device 191. The measuring device 185 and the oxidizing device 181 are communicably connected to a controller 187. The controller 187 is configured to control the amount of oxygen supplied to the process chamber 103 through a feeder 183. In doing so, the controller 187 takes into account the oxygen level in the process chamber 103 measured by the measuring device 185 in order to maintain the oxygen level in the process chamber 103 at a predetermined concentration of 50 ppm to 1000 ppm. Furthermore, the controller 187 is configured to control the amount of oxygen supplied to the filter device 191 through a second feeder 110. At this time, the controller 187 takes into account the oxygen level in the filter device 191 in order to maintain the second oxygen level in the filter device 191 at a predetermined concentration of 50 ppm to 1000 ppm.

[0056] The waste particles and oxidized waste particles collected by the filter device 191 can be transferred to a storage device 197 for storing the waste particles and oxidized waste particles. The waste particles can be removed from the filter device 191 by applying a reverse gas flow (i.e., from the return line 95 side). For this purpose, the apparatus 101 is equipped with a cleaning nozzle 190 directed towards the clean side of the filter device 191 to apply the aforementioned reverse gas flow. Alternatively, one could consider removing the waste particles and oxidized waste particles from the filter device by vibrating it.

[0057] The apparatus 101 further includes a choke source 108 on the opposite side of the return line 195 of the filter device 191 for supplying choke to the filter device 191. The choke source 108 is configured to supply a layer of choke to the filter device 191. This causes waste particles to be solidified in the choke supplied to the filter device 191. The choke supplied to the filter device 191 may be removed from the filter device 191 by applying the aforementioned reverse gas flow or vibration and stored in the storage device 197. The choke source 108 is communicably connected to a controller 187 for controlling the amount of choke supplied from the choke source 108. The controller 187 takes into account the aforementioned measured oxygen level and / or the aforementioned second oxygen level and / or the amount of oxygen supplied to the aforementioned mixture of gas, waste particles and oxidized waste particles.

[0058] Figure 3 shows an overview of an apparatus 201 for manufacturing an object 202 using additive manufacturing, according to a further embodiment of the present invention. Parts of apparatus 201 that are similar to those of apparatus 1 are denoted by the same reference numeral as those of apparatus 1 plus 200. As in the previously described embodiment, a first solidification device 207 is provided for solidifying a selected portion of the material using electromagnetic radiation. The top 213 of apparatus 201 further comprises a second solidification device 207' for solidifying a selected portion of the material using electromagnetic radiation. As shown, electromagnetic radiation 271' emitted from the second solidification device 207' is deflected using a second rotatable deflection unit 275' and directed to the surface L of a layer of material 204.

[0059] In the embodiment shown in Figure 3, the first solidification device 207 and the second solidification device 207' are laser devices. They are configured to generate electromagnetic radiation in the form of laser light to dissolve powdered material given on a support (which, by cooling, forms the solidified portion of the object to be produced). However, the present invention is not limited to this type of solidification device and generally includes solidification devices that use electromagnetic radiation. Furthermore, the type of electromagnetic radiation emitted from multiple solidification devices may be the same with respect to each solidification device. However, the type of electromagnetic radiation emitted from multiple solidification devices may differ in at least two of the solidification devices.

[0060] Figure 3 shows that multiple deflection devices 275, 275' are positioned near a line C perpendicular to the plane defined by the object work area L. Furthermore, this line C passes through the geometric centroid of the object work area L. In other words, the deflection devices 275, 275' are positioned almost directly above the object work area L. This allows each of the multiple solidification devices to easily reach almost the entire object work area. Therefore, for example, different parts of a single object can be solidified simultaneously. By solidifying different parts of a single object simultaneously, the object can be manufactured more quickly, thus reducing the overall manufacturing time.

[0061] Figure 4 shows an overview of an apparatus 301 for manufacturing an object 302 using additive manufacturing, according to a further embodiment of the present invention. Parts of apparatus 301 that are similar to parts of apparatus 101 or 201 are denoted by the reference numerals of the parts of apparatus 101 or 201 plus 200 and 100, respectively.

[0062] Using apparatus 1, waste particles resulting from the solidification of material 4 by irradiation with laser device 7 can be oxidized directly or after condensation in a manner that controls the oxygen level in the process chamber 3. During the solidification of material 4, the oxygen level in the process chamber 3 is measured using sensor 86. The measured oxygen level is compared by controller 87 to a target oxygen level. If it is determined that the oxygen level in the process chamber 3 is lower than a predetermined level, oxygen is supplied to the process chamber 3 through feeder 83 until it reaches the predetermined level. The oxygen level in the process chamber 3 is maintained at a predetermined value by the continuous supply of oxygen through feeder 3. Based on the oxygen supply rate through feeder 83 and the measured oxygen level in the process chamber 3, the controller 87 determines the oxidation rate. A relatively low oxidation rate indicates a relatively low rate of waste particle generation or that a large amount of waste particles are oxidized. If oxidation occurs at a relatively high rate below the target oxygen level, the solidification rate of the material may be reduced to maintain a relatively safe working environment.

[0063] Using apparatus 201, waste particles resulting from the solidification of material 204 by irradiation with the first laser device 207 and the second laser device 207' can be oxidized directly or after condensation in a manner that controls the oxygen level in the process chamber 203 (similar to the case using apparatus 1).

[0064] Using apparatus 101, waste particles resulting from the solidification of material 104 by irradiation with laser device 107 can be oxidized directly or after condensation in a controlled manner, with the oxygen level in process chamber 103 and a second oxygen level in filter device 191. During the solidification of material 104, the oxygen level in process chamber 103 is measured using sensor 186. The measured oxygen level is compared by controller 187 to a target oxygen level. If the oxygen level in process chamber 103 is determined to be lower than a predetermined level, oxygen is supplied to process chamber 103 through feeder 183 until it reaches that predetermined level. The oxygen level in process chamber 103 is maintained at a predetermined value by the continuous supply of oxygen through feeder 183. Based on the oxygen supply rate through feeder 183 and the measured oxygen level in process chamber 103, the controller 187 determines the oxidation rate.

[0065] During the solidification of material 104, a sensor 188 measures the second oxygen level in the filter device 191. The measured second oxygen level is compared by the controller 187 to a target oxygen level. If the second oxygen level in the filter device 191 is determined to be lower than a predetermined level, oxygen is supplied to the filter device 191 through the second supply unit 110 until it reaches the predetermined level. The oxygen level in the filter device 191 is maintained at a predetermined value by the continuous supply of oxygen through the second supply unit 110. Based on the oxygen supply rate through the supply unit 110 and the measured oxygen level in the filter device 191, the controller 187 determines the oxidation rate.

[0066] After removing waste particles and oxidized waste particles from the filter device 191, the removed gas is returned to the process chamber 103 through the return line 195. If the second oxidation rate is determined to be zero (or relatively low), the waste particles and oxidized waste particles are removed from the filter device 191 and transferred to the storage device 197 by applying a reverse gas flow using the washing nozzle 190.

[0067] Using apparatus 301, waste particles resulting from the solidification of material 304 by irradiation with the first laser device 307 and the second laser device 307' can be oxidized directly or after condensation in a manner similar to that using apparatus 101.

Claims

1. 1. A method for producing an object by additive manufacturing, comprising the steps of: - receiving a solution of material in a process chamber; - solidifying a selected layer portion of said material at surface level using a solidification device; - controlling the oxidation of waste particles due to gases generated by the solidification of said material, controlling the oxidation level so as to obtain oxidized waste particles and thereby avoiding ignition of said waste particles; Equipped with a surface level of said solution of material defines an object working area; The method further comprising measuring an oxygen level in the process chamber with a measurement device.

2. 10. The method of claim 1, further comprising the step of exhausting the mixture of gas and waste particles from the process chamber with an exhaust device.

3. 3. The method of claim 2, further comprising filtering the exhausted gas and waste particles mixture with a filter device to collect the waste particles.

4. 4. The method of claim 3, further comprising the step of transferring waste particles removed from the filter device to a storage device for storing waste particles removed from the filter device.

5. 5. The method according to claim 1, wherein in the step of controlling the oxidation, a controlled amount of oxygen is supplied to the waste particles to obtain oxidized waste particles without the waste particles igniting.

6. 6. A method according to claim 4 or 5, characterized in that a controlled amount of oxygen is supplied to the waste particles taking into account the measured oxygen level.

7. 6. The method of claim 4 or 5, further comprising the step of determining the oxidation rate taking into account the measured oxygen level and the amount of oxygen delivered.

8. 8. The method of claim 1, wherein in the step of controlling oxidation, a controlled amount of choke is provided to the waste particles to prevent oxidation of a subset of the waste particles.

9. The process chamber is configured to allow outside air to enter the process chamber during the solidifying step; 5. The method according to claim 1, wherein in the step of controlling the oxidation, a controlled amount of inert gas is supplied to the process chamber to obtain a desired oxygen level in the process chamber, for the purpose of controlling the oxygen level of the waste particles to obtain oxidized waste particles.

10. The method of claim 9, wherein the controlled amount of inert gas is supplied taking into account the determined oxidation rate.

11. 11. The method according to claim 1, wherein in the solidifying step, the oxygen level in the process chamber is between 50 ppm and 1000 ppm.

12. 12. The method according to claim 1, wherein the step of controlling the oxidation is carried out during the step of solidifying.

13. The step of controlling the oxidation is performed within the process chamber; an oxygen level in the process chamber during the solidifying step is between 50 ppm and 1000 ppm; 13. The method of claim 12, wherein the oxygen level is kept constant during the coagulating step.

14. 4. The method of claim 3, wherein the step of controlling the oxidation is performed during the step of filtering.

15. 15. The method according to any one of claims 1 to 14, wherein the material is a metal powder.

16. 3. The method of claim 2, wherein exhausted gases are returned to the process chamber.

17. 8. The method of claim 7, wherein in the coagulating step, the coagulation device is controlled taking into account the measured oxygen level and the determined oxidation rate.

18. 5. The method of claim 4, wherein the step of controlling the oxidation is performed during the step of transferring the removed waste particles to a storage device.

19. the filter device and / or the storage device are configured to allow ambient air to enter the filter device and / or the storage device during the solidifying step; 20. The method of claim 18, wherein in the step of controlling the oxidation, a controlled amount of inert gas is supplied to the filter device and / or the storage device to obtain a desired oxygen level within the filter device and / or the storage device for the purpose of controlling the oxygen level of the waste particles to obtain oxidized waste particles.

20. 20. The method of claim 19, wherein the controlled amount of inert gas is provided taking into account the determined oxidation rate.

21. 1. An apparatus for manufacturing an object by additive manufacturing, comprising: - a process chamber for receiving a solution of material; - a solidification device for solidifying selected layers of said material at surface level; - a solidification device for solidifying selected layers of said material at surface level; an oxidation device configured to control the oxidation of waste particles due to gases generated by the solidification of said material, to obtain oxidized waste particles, thereby controlling the oxidation level so that ignition of said waste particles does not occur; a measurement device for measuring an oxygen level within the process chamber; Equipped with The apparatus, wherein a surface level of the solution of material defines an object working area.

22. 22. The apparatus of claim 21 further comprising an exhaust device for exhausting a mixture of gas and waste particles from the process chamber.

23. 23. The apparatus of claim 22, further comprising a filter device configured to collect waste particles from the exhausted waste particle and gas mixture.

24. 24. The apparatus of any of claims 21 to 23, further comprising a storage device configured to store the waste particles.

25. 25. The apparatus of claim 21, wherein the oxidation device is configured to maintain an oxygen level in the process chamber between 50 ppm and 1000 ppm during solidification of the material.

26. 26. The apparatus of claim 25, further comprising a filter device configured to collect waste particles from the exhausted waste particle and gas mixture, the measurement device configured to measure an oxygen level within the filter device.

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