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 producing 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 technology]

[0003] 3D printing or additive manufacturing refers to any of a variety of processes for printing three-dimensional objects. For large quantities of polymer products to be produced cheaply, traditional techniques such as injection molding can be used. However, for relatively small quantities of three-dimensional objects, 3D printing or additive manufacturing allows for faster, more flexible, and cheaper production.

[0004] Additive manufacturing is expected to become even more important in the future, as manufacturers face increasing pressure from their competitors to not only combine high quality with manufacturing economy, but also to reduce product development time and costs. In fact, product life cycles are becoming ever shorter. Therefore, time to market, as well as quality and cost, is becoming increasingly important for product success.

[0005] Three-dimensional objects can be manufactured using directed energy beams to selectively solidify powder or liquid materials for the purpose of producing them. Computer-controlled additive manufacturing machines can be used to sequentially solidify multiple layers, particularly to build desired designs layer by layer. This typically involves a build-up process under computer control, where successive layers of material are deposited. These objects are manufactured from 3D models or other sources of electronic data and can achieve almost any shape or form.

[0006] To print a three-dimensional object, a printable model must be created using a computer design package or a 3D scanner. The input is usually a 3D CAD file, such as an STL, STEP, or IGS file. The file must be processed by software before the object can be printed from the CAD file. This software converts the model into a series of thin layers. Machine settings are then configured and vectors are generated to control the creation of each of these successive layers.

[0007] A laser in a computer-controlled additive manufacturing machine then solidifies successive layers of liquid, powder, or sheet material to create a 3D object from successive cross sections. In this process, these layers (which represent virtual cross sections from the CAD model) are simultaneously bonded or fused together to produce the final 3D object. Summary of the Invention [Problem to be solved by the invention]

[0008] Known methods for printing three-dimensional objects include: -In the process chamber, solution (At this time, the material solution the surface level of the object defines the object work area), - solidifying a selected layer portion of the material at a surface level using a solidification device; Equipped with.

[0009] One of the challenges when manufacturing three-dimensional objects, especially metal objects using additive manufacturing, is how to ensure safe manufacturing while maintaining product quality.

[0010] The present disclosure aims to provide a method and apparatus that achieves high quality and high safety. [Means for solving the problem]

[0011] To this end, the invention provides a method for manufacturing an object by additive manufacturing, the method comprising the steps of: -In the process chamber, solution and - 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 material solution The surface level of the defines the object work area.

[0012] It is known that three-dimensional objects can be manufactured in environments containing relatively high levels of inert gas to reduce oxidation of the material during solidification, thereby improving the quality of the manufactured object.

[0013] The present disclosure is based, at least in part, on the discovery that using a low amount of inert gas results in relatively high oxygen levels (due to a combination of low inert gas feed rates and air leakage into the process chamber). High oxygen levels generally can have a substantial adverse effect on product quality. Therefore, increasing the inert gas feed rate may improve product quality. However, increasing the inert gas feed rate has the disadvantage of reducing oxygen levels and therefore making the work environment less safe.

[0014] Alternatively, oxygen levels can be reduced by combining oxidation of the material during solidification with an airtight process chamber, which reduces oxygen levels and improves product quality, but at the expense of a less safe working environment.

[0015] At certain relatively low oxygen levels, waste particles resulting from the solidification process can be oxidized, either directly or after condensation, without oxygen 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. This results in the generation of relatively large amounts of heat energy, which can cause these waste particles to ignite. Ignition of waste particles can create a dangerous environment for operators and / or equipment because sudden ignition of waste particles is explosive.

[0016] The objectives of the present invention are 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 the waste particles can be controlled, thereby controlling the temperature of the waste particles below their ignition temperature.

[0017] The above-described method may advantageously further comprise the step of evacuating the mixture of gas and waste particles from the process chamber using an evacuation device. Evacuation of this mixture is advantageous in that it allows for oxidation of the waste material while reducing the potential impact of controlled oxidation on solidification within the process chamber. This allows for a relatively low oxygen level within the process chamber, reducing the risk of ignition of the waste particles. In other words, the process of controlled oxidation of the waste particles is separated from the process of solidification occurring within the process chamber.

[0018] In some embodiments of the method of the present disclosure, the evacuating step evacuates the mixture of gas, waste particles, and oxidized waste particles from the process chamber. This has the advantage that controlled oxidation of the waste particles can be achieved not only within the process chamber but elsewhere as well, further reducing the risk of the waste particles rising above their ignition temperature, either within the process chamber or elsewhere.

[0019] In this regard, the method advantageously further comprises the step of filtering the exhausted gas and waste particle mixture using a filter device to collect the waste particles. Filtering the mixture is advantageous in that the gas can be reused in the process chamber, e.g., by recycling, while the waste particles are collected in the filter device. In contrast, recycling the gas and waste particle mixture is less attractive because recycling such a mixture increases the amount of waste in the gas mixture, which increases the potential hazards in the working environment.

[0020] In some embodiments of the method according to the present disclosure, the filtering step filters a mixture of gas, waste particles, and oxidized waste particles. Filtering the exhausted mixture of gas, waste particles, and oxidized waste particles is advantageous in that the gas can be reused within the process chamber, e.g., by recycling, while the waste particles and oxidized waste particles are collected in a filter device. In contrast, recycling the mixture of gas, waste particles, and oxidized waste particles is less attractive because recycling such a mixture increases the amount of waste in the gas mixture, thereby increasing potential hazards in the working environment.

[0021] It is noted that waste particles may be formed by condensation of gases resulting from solidification of material. Such waste particles may be formed by condensation occurring simultaneously with or after contact of the gas with the filter device.

[0022] In a practical embodiment of the above method, the method further comprises the step of transferring the waste particles removed from the filter device to a storage device for storing the waste particles removed from the filter device, which advantageously further reduces the risk of a hazardous working environment.

[0023] Preferably, the storage device is configured for controlled oxidation, which allows oxidation levels within the process chamber and filter device to be kept relatively low, reducing the risk of ignition of the waste particles. In other words, the controlled oxidation and filtering of the waste particles is separated from the solidification process occurring within the process chamber and from the filtering process occurring within the filter device.

[0024] Advantageously, the method further comprises the step of measuring the oxygen level in the process chamber using a measurement device, whereby the oxidation can be advantageously controlled taking this oxygen level into account.

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

[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, which is attractive because it allows for a controlled oxidation rate (preferably a relatively constant controlled oxidation rate) to be achieved, thereby controlling the amount of heat generated by oxidation of the waste particles and therefore keeping the temperature of the waste particles below their ignition temperature.

[0027] Advantageously, the method further comprises determining an oxidation rate taking into account the measured oxygen level and the amount of oxygen supplied. By determining the oxidation rate, it is possible to determine whether the waste particles have been oxidized or whether oxidation will occur. If the oxidation rate is determined to be zero or substantially zero in an oxygen-present environment, a relatively large amount of the waste particles have already been oxidized, thereby providing a relatively safe working environment with respect to ignition of the waste particles.

[0028] Advantageously, the step of controlling oxidation provides a controlled amount of chalk to the waste particles to prevent oxidation of the subset of waste particles. Preventing oxidation of the subset of waste particles advantageously reduces the amount of oxidation that occurs, thereby reducing the amount of heat energy generated during the time interval. Advantageously, reducing the amount of heat energy generated by oxidation reduces 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 ambient air to enter the process chamber during the solidifying step, and a controlled amount of inert gas is supplied to the process chamber during the oxidation control step to obtain a desired oxygen level in the process chamber in order to control the oxygen level of the waste particles to obtain oxidized waste particles.

[0030] In this case, it is advantageous to supply a controlled amount of inert gas taking into account the measured oxidation rate. By controlling the supply of inert gas taking into account the measured oxidation rate, the supply of inert gas can be controlled more accurately, thereby allowing for more accurate control of the oxidation of waste particles.

[0031] Preferably, during the solidification step, the oxygen level in the process chamber is between 50 ppm and 1000 ppm, which is preferred because it allows for controlled oxidation while maintaining a relatively high product quality.

[0032] In certain embodiments of the method according to the first aspect of the present disclosure, the step of controlling oxidation is carried out during the solidification step, which is advantageous in that it allows for an effective method without interrupting the solidification step to oxidize the waste particles, thereby maintaining a safe working environment, high product quality, and a relatively short production time.

[0033] In this case, the oxidation control step is carried out in a process chamber, and advantageously, the oxygen level in the process chamber during the solidification step is between 50 ppm and 1000 ppm. Preferably, the oxygen level is kept constant during the solidification step, and more preferably between 50 ppm and 1000 ppm. An oxygen level of between 50 ppm and 1000 ppm is preferred because it allows controlled oxidation while maintaining high product quality. Maintaining a constant oxygen level in the process chamber during the solidification step is advantageous because it allows for a relatively constant oxidation rate.

[0034] In certain embodiments of the method according to the first aspect of the present disclosure, the step of controlling oxidation is performed in the solidifying step and in the filtering and / or transferring step, which has the advantage that the control of oxidation of the waste particles can be performed in two separate locations, thus further reducing the risk of the temperature of the waste particles in the process chamber, filter device or storage device rising above their ignition temperature.

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

[0036] Advantageously, the exhausted gas is returned to the process chamber, which has the advantage that gas consumption is relatively low.

[0037] Advantageously, in the solidifying step, the solidifying device is controlled taking into account the measured oxygen level and the determined oxidation rate, which is advantageous in that controlled oxidation of the waste particles can be achieved at a relatively low oxidation rate, thus reducing the risk of ignition of the waste particles during controlled oxidation.

[0038] In certain embodiments of the method according to the first aspect of the present disclosure, the step of controlling oxidation is performed during the filtering and / or transferring steps. This allows for a relatively low oxygen level in the process chamber, reducing the risk of waste particles igniting. In other words, the process of controlling oxidation of waste particles is separated from the process of solidification occurring in the process chamber. This is advantageous in that the impact of controlling oxidation on the environment in the process chamber can be avoided or significantly reduced, maintaining a safe working environment while maintaining high product quality.

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

[0040] At this time, a controlled amount of inert gas is supplied in consideration of 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 accurately, and thus the oxidation of waste particles can be controlled more accurately.

[0041] A second aspect of the present disclosure relates to an apparatus for manufacturing an object by additive manufacturing, the apparatus comprising: -Materials solution a process chamber for receiving the a solidification device for solidifying selected layers of material at a surface level; an oxidation device configured to control 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. solution The surface level of the defines the object work area.

[0042] Advantageously, the apparatus further comprises an exhaust device for exhausting the mixture of gas and waste particles from the process chamber. The exhaust device for exhausting the mixture is useful in that it can oxidize the waste particles while reducing the potential impact of controlled oxidation on solidification within the process chamber. This allows a relatively low oxygen level to be maintained within the process chamber, reducing the risk of waste particles igniting. In other words, the process of controlled oxidation of the waste particles is separated from the process of solidification occurring within the process chamber.

[0043] Advantageously, the apparatus further comprises a filter device configured to collect waste particles from the discharged mixture of waste particles and gas. A filter device for filtering the discharged mixture is advantageous in that the gas can be reused in the process chamber, e.g., by recycling, while the waste particles are collected in the filter device. Recycling a mixture of gas and waste particles, on the other hand, is less attractive, since recycling such a mixture increases the amount of waste in the gas mixture, which increases potential hazards in the working environment.

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

[0045] It is further advantageous if the storage device is configured to control oxidation, thereby maintaining a relatively low oxygen level in the process chamber and in the filter device, reducing the risk of ignition of the waste particles. In other words, the process of controlling oxidation of the waste particles is separated from the process of solidification occurring in the process chamber and from the process of filtering occurring in the filter device.

[0046] In certain embodiments of the apparatus according to the second aspect of the present disclosure, the oxidation device is configured to maintain an oxygen level in the process chamber of between 50 ppm and 1000 ppm during solidification of the material, which is preferred for achieving controlled oxidation while maintaining a relatively high product quality.

[0047] Advantageously, the apparatus further comprises a measuring device for measuring the oxygen level in the process chamber, such a measuring device advantageously allowing the oxidation to be controlled taking the oxygen level into account.

[0048] Preferably, the apparatus further comprises a filter device configured to collect waste particles from the discharged waste particle and gas mixture. The measurement device is configured to measure the oxygen level in the filter device. This is advantageous in that control of the oxidation of the waste particles can be performed in two separate locations, thus further reducing the risk of the temperature of the waste particles in the process chamber, the filter device or the storage device rising above their ignition temperature. [Brief explanation of the drawings]

[0049] The following accompanying drawings are used to illustrate the method and apparatus according to the present disclosure. [Figure 1] FIG. 1 is a schematic diagram of an apparatus configured to manufacture objects using additive manufacturing, in accordance with the present invention. [Figure 2] FIG. 1 is a schematic diagram of an apparatus configured to manufacture objects using additive manufacturing, in accordance with the present invention. [Figure 3] FIG. 1 is a schematic diagram of an apparatus configured to manufacture objects using additive manufacturing, in accordance with the present invention. [Figure 4] FIG. 1 is a schematic diagram of an apparatus configured to manufacture objects using additive manufacturing, in accordance with the present invention.

[0050] Figure 1 shows an overview of an apparatus 1 for manufacturing an object 2 using additive manufacturing. The apparatus 1 is formed from several frame parts 11, 12, 13. The apparatus is provided with a solidifiable material 4. solution The frame part 11 includes a process chamber 3 for receiving the material 4. The shaft is formed in the frame part 11. solution A support 5 is provided for positioning the object 1 relative to the surface level L of the layer of material 4. The support 5 is operably provided within the shaft. This allows the support 5 to be lowered after a layer has solidified and a further layer of material to be solidified on top of the already formed object 2. A solidification device 7 is provided at the top 13 of the apparatus 1 for solidifying selected portions of the material. In the illustrated embodiment, the solidification device 7 is a laser device. The laser device is configured to generate electromagnetic radiation in the form of a laser beam 71 for the purpose of melting the powder material provided in the support. However, the 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 element 75 to direct the emitted radiation 71 towards the surface L of the layer of material 4. Depending on the position of the deflection unit 74, the radiation may be emitted, for example, along beams 72 and 73.

[0051] The apparatus 1 includes an oxidation device 81 connected to an oxygen supply (not shown). The oxygen supply may include dry, clean air with approximately 20% oxygen and approximately 80% nitrogen. The oxidation device 81 further includes a supplier 83 for supplying oxygen from the oxygen supply 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 supplier 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 oxidation 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 supply 83. The controller 87 then 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 not less than 50 ppm and not more than 1000 ppm.

[0053] Alternatively, instead of (or in addition to) connecting an oxygen source to controller 87, gas supplier 6 could be communicatively connected to controller 87 to maintain the oxygen level in the process chamber of apparatus 1 at a predetermined concentration of at least 50 ppm and no more than 1000 ppm. 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 gas supplier 6, taking into account the oxygen level in process chamber 3 measured by measurement device 85.

[0054] 2 illustrates a further embodiment of an apparatus 101 according to the present disclosure. Parts of the apparatus 101 similar to those of the apparatus 1 are designated by the same reference numerals as the apparatus 1, but with the addition of 100. The apparatus 101 includes an exhaust device formed by 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. The exhausted mixture of gas, waste particles, and oxidized waste particles is directed to a filter device 191 for separating the waste particles from the gas before the gas is returned to the process chamber 103 through a return line 195. A second supply 110 is used on the other side of the return line 195 to supply oxygen to the filter device 191, thereby oxidizing the waste particles collected by the filter device 191.

[0055] The measuring device 185 includes a first sensor 186 and a second sensor 188. The first sensor 186 is provided for measuring the oxygen level in the process chamber 103. The second sensor 188 is provided for measuring the oxygen level in the filter device 191. The measuring device 185 and the oxidation device 181 are communicatively connected to a controller 187. The controller 187 is configured to control the amount of oxygen supplied to the process chamber 103 through the supply 183. The controller 187 takes into account the oxygen level in the process chamber 103 measured by the measuring device 185 to maintain the oxygen level in the process chamber 103 at a predetermined concentration of not less than 50 ppm and not more than 1000 ppm. The controller 187 is further configured to control the amount of oxygen supplied to the filter device 191 through the second supply 110. At this time, the controller 187 takes into account the oxygen level within the filter device 191 in order to maintain the second oxygen level within the filter device 191 at a predetermined concentration of not less than 50 ppm and not more than 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 gas flow in the opposite direction (i.e. from the return line 95 side). For this purpose, the apparatus 101 comprises a cleaning nozzle 190 directed towards the clean side of the filter device 191 for applying said gas flow in the opposite direction. Alternatively, it is also conceivable to remove the waste particles and oxidized waste particles from the filter device by vibrating the filter device.

[0057] The apparatus 101 further includes a choke supply 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 supply source 108 is configured to supply a layer of choke to the filter device 191, thereby causing the waste particles to solidify into the choke supplied to the filter device 191. The choke supplied to the filter device 191 may be removed from the filter device 191 and stored in the storage device 197 by applying the aforementioned reverse gas flow or vibration. The choke supply source 108 is communicatively connected to a controller 187 for controlling the amount of choke supplied from the choke supply source 108, taking into account the aforementioned measured oxygen level and / or the aforementioned second oxygen level and / or the amount of oxygen supplied to the mixture of gas, waste particles and oxidized waste particles.

[0058] 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 the apparatus 201 that are similar to parts of the apparatus 1 are designated by the same reference numerals as the parts of the apparatus 1, but with the addition of 200. As in the previous embodiment, a first solidification device 207 is provided for solidifying selected portions of material using electromagnetic radiation. The top part 213 of the apparatus 201 further comprises a second solidification device 207′ for solidifying selected portions of 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 towards the surface L of the layer of material 204.

[0059] In the embodiment shown in FIG. 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 melt a powdered material provided on a support, which is then cooled to form the solidified portion of the object to be created. However, the present invention is not limited to this type of solidification device and includes solidification devices that use electromagnetic radiation in general. Furthermore, the type of electromagnetic radiation emitted by the multiple solidification devices may be the same for each solidification device. However, the type of electromagnetic radiation emitted by at least two of the multiple solidification devices may be different.

[0060] 3, it can be seen that the deflection means 275, 275' are installed near a line C that is perpendicular to a plane defined by the object working area L. Furthermore, this line C passes through the geometric center of gravity of the object working area L. In other words, the deflection means 275, 275' are installed almost directly above the object working area L. This allows each of the multiple solidification devices to easily reach almost the entire object working area. Therefore, for example, different parts of an object can be solidified simultaneously. By solidifying different parts of an object simultaneously, the object can be manufactured more quickly, thereby reducing the overall manufacturing time.

[0061] 4 shows an overview of an apparatus 301 for manufacturing an object 302 using additive manufacturing according to a further embodiment of the invention. Parts of apparatus 301 that are similar to parts of apparatus 101 or 201 are numbered with the same reference numerals as the parts of apparatus 101 or 201 but increased by 200 or 100, respectively.

[0062] Using the apparatus 1, waste particles resulting from the solidification of the material 4 by irradiation with the laser device 7 can be oxidized directly or after condensation in a manner that controls the oxygen level in the process chamber 3. During solidification of the material 4, the oxygen level in the process chamber 3 is measured using a sensor 86. The measured oxygen level is compared with a target oxygen level by a controller 87. 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 a supply 83 until the predetermined level is reached. By continuously supplying oxygen through the supply 3, the oxygen level in the process chamber 3 is maintained at a predetermined value. The controller 87 determines an oxidation rate based on the rate of oxygen supply through the supply 83 and the measured oxygen level in the process chamber 3. A relatively low oxidation rate indicates a relatively low rate of waste particle generation or a large amount of waste particles being 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 relatively safe working conditions.

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

[0064] The apparatus 101 can be used to oxidize waste particles resulting from solidification of the material 104 by irradiation with the laser device 107, either directly or after condensation, in a manner that controls the oxygen level in the process chamber 103 and the second oxygen level in the filter device 191. During solidification of the material 104, the oxygen level in the process chamber 103 is measured using a sensor 186. The measured oxygen level is compared to a target oxygen level by a controller 187. If it is determined that the oxygen level in the process chamber 103 is lower than a predetermined level, oxygen is supplied into the process chamber 103 through a supply 183 until the predetermined level is reached. By continuously supplying oxygen through the supply 183, the oxygen level in the process chamber 103 is maintained at a predetermined value. The oxidation rate is determined by the controller 187 based on the rate of supply of oxygen through the supply 183 and the measured oxygen level in the process chamber 103.

[0065] During solidification of material 104, a second oxygen level within filter device 191 is measured using sensor 188. The measured second oxygen level is compared to a target oxygen level by controller 187. If it is determined that the second oxygen level within filter device 191 is lower than a predetermined level, oxygen is supplied through second supplier 110 into filter device 191 until the second oxygen level reaches the predetermined level. By continuously supplying oxygen through second supplier 110, the oxygen level within filter device 191 is maintained at a predetermined value. An oxidation rate is determined by controller 187 based on the rate of oxygen supply through supplier 110 and the measured oxygen level within filter device 191.

[0066] After removing the waste particles and oxidized waste particles in the filter device 191, the removed gas is returned to the process chamber 103 through the return line 195. When 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 cleaning nozzle 190.

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

Claims

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

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

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

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

5. 5. The method according to claim 1, wherein in the step of controlling 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 determining the oxidation rate taking into account the measured oxygen level and the amount of oxygen supplied.

8. 8. The method of claim 1, wherein the step of controlling oxidation comprises providing a controlled amount of chalk 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. 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 the oxygen level in the process chamber is between 50 ppm and 1000 ppm during the solidifying step.

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

13. 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 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 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 outside air to enter the filter device and / or the storage device during the solidifying step; 19. 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 in 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 supplied taking into account the determined oxidation rate.

21. 1. An apparatus for manufacturing an object by additive manufacturing, comprising: a process chamber for receiving the material; 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 the oxygen level within the process chamber; Equipped with The apparatus, wherein the surface level of the 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 any one of claims 21 to 24, wherein the oxidation device is configured to maintain an oxygen level in the process chamber of at least 50 ppm and at most 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 discharged waste particle and gas mixture, and wherein the measurement device is configured to measure oxygen levels within the filter device.

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