3D printing monitoring and control method

Abstract

The present invention relates to an improved method of 3D printing / metal powder bed melting, allowing analysis of the measured temperature by measuring the temperature of the metal powder layer, analysis of the measured temperature on the basis of the introduced energy, melting temperature and latent heat in order to identify adverse temperature points, and adjustment of the process on the basis of these points, thereby significantly improving the monitoring and control of such process. This allows identification of even potential very small problems in order to react very early and to prevent potential problems occurring in high-requirement applications with correspondingly manufactured parts. Furthermore, the invention relates to a computer program product which causes a computing entity to perform such a method. Furthermore, the invention relates to a 3D printing device capable of implementing the method of the invention.

Description

Technical Field

[0001] The present invention relates to an improved method of 3D printing for manufacturing a 3D printed part. Additionally, the present invention relates to a computer program product adapted to implement the inventive method. Furthermore, the present invention relates to a storage device containing such a computer program product. Additionally, the present invention relates to a 3D printing device adapted to manufacture a 3D printed part according to the inventive method. Background Art

[0002] 3D printing is a relatively new manufacturing method utilized in industrial applications. While it is relatively easy to print parts made from polymeric materials, the utilization of metallic materials is still subject to additional problems and a growing demand and issues to be solved. In particular, it should be noted that parts that are utilized near their limits and are subject to high strains during their subsequent application require significantly improved manufacturing processes.

[0003] In this context, it should be noted that particularly high strain applications, such as continuous flow engine applications, require high reliability of the corresponding manufactured parts. In this context, it can be required to invest a lot of effort in checking the corresponding parts with respect to their properties in order to avoid problems and even voluminous damages from small causes. In particular, in application cases, such as hot gas path parts of continuous flow engines, the combination of thermal and mechanical strains already requires that such parts be used close to their possible strains and, therefore, are very susceptible to even very small deviations or problems during manufacturing.

[0004] Therefore, there is a need to further optimize the manufacturing process of such parts in order to provide safe and reliable manufacturing as well as properties that meet the high demands in this context.

[0005] These problems are solved by methods and products as disclosed hereinafter and in the claims. Further advantageous embodiments are disclosed in the dependent claims and in the further description. These advantages can be used to adjust the corresponding solution to specific needs or to solve further problems. Summary of the invention

[0006] According to one aspect, the present invention relates to a method of controlling a 3D printing process in order to manufacture a 3D printed part,

[0007] wherein the method comprises selectively melting the metal powder layer by directing an energy beam at the metal powder layer so as to introduce energy into the metal powder layer,

[0008] The energy introduced selectively melts the metal powder layers to build the 3D printed part layer by layer.

[0009] The metal powder layer is composed of metal powder.

[0010] Among them, metal powder provides melting temperature and latent heat,

[0011] wherein the method comprises continuously measuring the temperature of the melted powder material,

[0012] Therein, the method comprises analyzing the measured temperature taking into account the introduced energy, the melting temperature and the latent heat in order to identify unfavorable temperature points,

[0013] Among other things, the method includes automatically adjusting the 3D printing process based on the identified unfavorable temperature points.

[0014] Such an "unfavorable temperature point" as used herein refers to a temperature point that provides a higher temperature than a specified temperature. Such a specified temperature can be a predetermined temperature in a simple system that requires minimal processing power. Herein, such a predetermined temperature can be defined as an absolute value such as 50°C above the melting temperature or a percentage value such as 5% above the melting temperature. However, in a typical embodiment, such a specified temperature depends on the specific component of the 3D printed part to be created at that point. For example, it can be a specified percentage value such as 5% above the melting temperature at a position representing the outer surface of the 3D printed part, and a specified percentage value such as 30% above the melting temperature at a position representing the inner surface of the 3D printed part. Herein, such a position representing the outer surface of the part is a position where the melted part of the powder layer extends until the outer surface of the 3D printed part.

[0015] The metal powder is a powder made of a metal or a metal alloy. Since small amounts of, for example, organic or non-organic substances other than the metal or metal alloy can be included in order to, for example, influence the flow behavior of the metal powder, it is generally preferred that the weight percentage of such additional components is a maximum of 1%, more preferably a maximum of 0.1%, even more preferably a maximum of 0.05%, based on the total weight of the material of the metal powder layer. In this context, non-metallic components such as silicon or carbon included in the alloy are not included when determining this content.

[0016] It should be noted that the method of the invention can be very beneficially utilized to identify problems, such as problems during manufacturing or deviations from a known or simulated manufacturing procedure. Such problems during manufacturing can be, for example, uneven distribution of metal powder or unevenness of the metal powder layer caused by contamination of the metal powder by agglomerates or another material. Such deviations from a known or simulated manufacturing procedure can be, for example, an increased or decreased number of parts manufactured simultaneously or a different arrangement of parts on a build plate. It should be noted that even small changes, such as those mentioned above, still provide sufficient properties of the manufactured parts in many cases. However, in cases where very high reliability is required, such as, for example, for continuous flow engine parts, it is possible that even very small deviations lead to a distinct possibility of different thermal behavior that easily damages the properties of the manufactured part in a way that makes its use impossible or even dangerous. It is surprisingly noted that such problems are significantly higher than originally expected in real industrial applications. Too high temperatures can damage, for example, the overall 3D printing, mechanical stability and / or heat resistance of the produced parts. Such excessively high temperatures can easily be caused by, for example, rearrangement of parts without leaving enough space between them, resulting in heat not being able to dissipate quickly enough from the 3D printed part. Too low temperatures can lead to, for example, incomplete melting of the metal powder, leading to, for example, mechanical weak points resulting from, for example, insufficient fusion of the material or subsequent failure of the heat intended to be dissipated from the surface of the 3D printed part during its use based on different thermal conductivity in this area. Such too low temperatures can easily be caused by, for example, manufacturing a single part instead of a large batch, which leads to different overall temperature distribution profiles within the metal powder layer and the already manufactured part of the part or an interruption of the 3D printing process that allows the material to cool further and removes from the part some of the basic heat originally included in the manufacturing process and originally intended to be compensated by reducing the energy introduced in the metal powder layer at determined locations. For example, based on 3D printing the structure on some already nearly molten material of the metal powder layer that is selectively melted below.

[0017] Although the adjustment of the manufacturing program can usually be achieved by simulating the manufacturing in advance, the processing power required is enormous and makes such a task impossible in reality for future applications that require flexible adjustment and a more robust process that allows easy implementation of this method for a wide range of industrial applications. Allows (for example) to quickly change the number of parts manufactured to serve current needs, or to take advantage of different types of 3D printing devices currently available that require rearrangement of parts on the building plate based on different geometric provisions of the building plate available in different types of 3D printing devices. The invented method allows the detection of resulting deviations at an early stage without the need for much processing power, thereby allowing a significant increase in the utilization of 3D printing for such sensitive applications. This improved flexibility and reliability is extremely important for the future implementation of this method.

[0018] According to another aspect, the invention relates to a computer program product tangibly embodied in a machine-readable storage medium, comprising instructions executable to cause a computing entity to perform the inventive method.

[0019] According to another aspect, the invention relates to a storage device for providing an inventive computer program product, wherein the device stores the computer program product and / or provides the computer program product for further use.

[0020] According to another aspect, the invention relates to a 3D printing device adapted to manufacture a 3D printed part according to the inventive method. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] To simplify the understanding of the present invention, reference is made to the following detailed description and the accompanying drawings and their descriptions.Herein, the drawings should be understood not to limit the scope of the present invention, but to disclose preferred embodiments that further explain the invention.

[0022] Figure 1 A schematic drawing of a 3D printed part located in a powder bed during a layered 3D printing process is illustrated, wherein the automatic adjustment according to the method of the invention is not employed.

[0023] Figure 2 A scheme of the inventive method is illustrated schematically.

[0024] Figure 3 Another embodiment of the method of the invention is shown in the figure. DETAILED DESCRIPTION

[0025] Preferably, unless otherwise specified, the embodiments described below include at least one processor and / or data storage unit to implement the inventive method.

[0026] Unless otherwise indicated, terms such as "compute", "process", "determine", "generate", "configure", "reconstruct" and similar terms refer to actions and / or processes and / or steps of modifying data and / or creating data and / or transforming data, wherein the data is present as physical variables or can be obtained as such.

[0027] The term "data storage" or similar terms as used herein refers, for example, to temporary data storage such as RAM (Random Access Memory) or long-term data storage such as a hard drive or data storage units such as CDs, DVDs, USB sticks and the like. Such data storage can additionally comprise or be connected to a processing unit in order to allow processing of the data stored on the data storage.

[0028] The term "continuous flow engine" as used herein refers to a device that utilizes a continuous flow of a fluid (such as a gas or liquid). Herein, such a continuous flow engine generally provides a rotor that is located in a fluid and interacts with the fluid. Herein, such a fluid can also be utilized to provide a rotational motion of a rotor that can be converted into, for example, electrical energy. An example of such a continuous flow engine is a gas turbine or a steam turbine. Alternatively, the rotor can be actively rotated, thereby allowing, for example, compression of the fluid. An example of such an application is a compressor such as, for example, utilized in an oil refinery.

[0029] According to one aspect, the invention relates to a method as specified above.

[0030] According to another embodiment, it is preferred that the 3D printed part is a continuous flow engine part, more preferably a hot gas path continuous flow engine part. It should be noted that such applications generally benefit significantly from the inventive method based on the high requirements of such applications.

[0031] According to another embodiment, preferably, the step of analyzing the measured temperature takes into account the temperature measured in the lower layer of the 3D printed part. Herein, such analysis can be utilized, for example, to identify deviations from the expected behavior of the powder material layer. Such deviations can be too high or too low a temperature of the currently printed powder material layer. Such deviations indicate an increase or decrease in heat transfer compared to the expected behavior.

[0032] According to another embodiment, it is preferred that during the selective melting of the metal powder layer, the introduction of energy is achieved by directing a laser beam or an electron beam onto the metal powder layer. The corresponding manufacturing method provides a very uniform and controlled introduction of energy into the metal powder layer, thereby allowing reliable control of this aspect of the process and significantly reducing the need for additional measuring devices such as energy, which are introduced in order to track this feature that allows the implementation of the inventive method. Therefore, the overall effort required to put the inventive method into practice is reduced.

[0033] According to another embodiment, preferably, the method comprises adjusting the 3D printing process based on a deviation of the measured temperature of the metal powder layer from a theoretical temperature,

[0034] Wherein, the theoretical temperature represents the temperature based on the heat energy available in the 3D printed parts and metal powder and the energy introduced by the energy beam. Herein, this deviation can simply be caused by defects in the metal powder layer or problems during 3D printing. Such as interruptions or deviations in the temperature of some protective gases. It is allowed, for example, to speed up the 3D printing speed by increasing the energy introduced by the faster movement of the energy beam and the beam when the temperature is lower than expected or drops, or even suspend manufacturing when the temperature is too high. Those skilled in the art are well aware of how to calculate this theoretical temperature based on the heat energy available in the 3D printed parts and metal powder and the energy introduced by the energy beam. Using existing models that take into account the distribution of heat loss to the surrounding environment (such as the atmosphere above the components of the 3D printing device and the powder material layer) and the powder material and 3D printing, it is possible to determine the theoretical temperature at a given position. And how the temperature should change when energy is introduced.

[0035] According to another embodiment, it is preferred that the method comprises storing temperature data of the printed metal powder layer,

[0036] wherein the method comprises utilizing a theoretical temperature of the metal powder layer,

[0037] wherein the theoretical temperature of the metal powder layer is obtained based on historical data, simulation of 3D printing, thereby calculating the temperature based on stored temperature data of the printed metal powder layer and the energy introduced during melting of the metal powder bed, or a combination thereof,

[0038] The method comprises identifying defects in the metal powder layer based on a deviation of a measured temperature of the metal powder layer from a theoretical temperature of the metal powder layer,

[0039] Therein, the energy introduced into the metal powder layer is adjusted based on defects of the metal powder layer. It should be noted that the invented method allows reliable identification of defects such as non-homogeneities or contamination of the metal powder based on the difference between the measured temperature and the theoretical temperature. Considering the invented method based on thermal energy monitoring, taking into account the melting temperature and the latent heat allows very easily monitoring the output caused by the introduced energy and indirectly identifying problems. Allowing to immediately adjust the manufacturing program in order to solve the specific needs of the manufacturing.

[0040] According to another embodiment, it is preferred that the step of analyzing the measured temperature in order to identify an unfavorable temperature point comprises determining a problem for a subsequently to be printed layer of powder material,

[0041] Therein, the subsequent 3D printing process of the powder material layer is adjusted in order to compensate for the unfavorable temperature points. It should be noted that the method of the invention allows the identification of potential unfavorable temperature points, such as overheating areas at an early stage, which can be compensated quite easily at such a stage. For example, by including an interruption in the printing process to allow the material to cool or adjusting the printing speed or the position where the metal powder layer starts printing in order to allow some localization to at least partially dissipate.

[0042] According to another embodiment, it is preferred that the measured temperatures and / or identified adverse temperature points of at least 80% of the 3D printed layers of the product are stored in a database. Storing such data allows for possible applications that were not even known when the 3D printed part was printed, for example, to be subsequently evaluated regarding potential problems or the like. Additionally, it allows for example to run degradation models with surprisingly improved accuracy, in order to even improve existing very sophisticated and reliable wear and maintenance requirements calculations that are already available.

[0043] According to another embodiment, preferably, the method comprises the step of assigning a unique identifier to the 3D printed part,

[0044] wherein the method comprises assigning a unique identifier to manufacturing data collected according to the method of the invention,

[0045] Therein, the manufacturing data and the unique identifier are stored in a database. It should be noted that providing for this possibility in order to identify very specific 3D printed parts at any later time is surprisingly beneficial for the invented method. For example, the data obtained during this method allow to ensure the clarification of subsequent problems. Such as in the case where a part does not meet the required requirements and requires early repair. This leads to a significant impact on the utilization of (for example) continuous flow engines (such as gas turbines), which are adjusted to operate without interruption for more than months or even years. Since the invented method allows the manufacture of parts with reliability, enabling utilization even closer to its limits than before, the possibility of determining the cause of a later problem provides a surprisingly large benefit for this method.

[0046] According to another aspect, the invention relates to a computer program product tangibly embodied in a machine-readable storage medium, comprising instructions executable to cause a computing entity to perform the inventive method.

[0047] According to another aspect, the invention relates to a storage device for providing an inventive computer program product, wherein the device stores the computer program product and / or provides the computer program product for further use.

[0048] According to another aspect, the invention relates to a 3D printing device adapted to manufacture a 3D printed part according to the inventive method.

[0049] According to another embodiment, preferably, the 3D printing device comprises an infrared camera adapted to continuously monitor infrared radiation from the powder material layer. It should be noted that such continuous monitoring of the temperature of the powder material surface allows additional detection of deviations in the cooling of the powder material layer, indicating that the thermal distribution and / or cooling of the lower powder material layer is different from the expected behavior and indicating a problem.

[0050] The following detailed description of the drawings uses the drawings in order to discuss illustrative embodiments, which together with features and further advantages thereof, are not to be construed as limiting.

[0051] Figure 1 A schematic diagram of a 3D printed part 1 located in a powder bed during a layered 3D printing process is shown, wherein the automatic adjustment according to the method of the invention is not used. The inventive 3D printing device is still utilized and is thus adjusted so as to continuously monitor the temperature of the metal powder layer. Here, the part 1 is built up layer by layer from metal powder material on a build plate 7. The metal powder material is not in the Figure 1 The illustration in FIG. 4 makes it possible to illustrate the side of the already 3D printed component of part 1 .

[0052] The metal powder material is spread as a metal powder material layer and is selectively melted by irradiating the metal powder material with a laser beam originating from a laser source 3. By irradiating a plurality of subsequent metal powder layers, the part 3 is continuously built up over time. During the layered production of the part 1, the energy introduced by the laser leads to unfavorable temperature points within the local overheating area 5, which results from repeated melting at the same location with the same laser power of the laser source 3.

[0053] While the selective laser melting is taking place and during the application of the subsequent metal powder material layer before the next selective laser melting takes place, unfavorable temperature points are noted by the temperature measuring device 2, which is an infrared camera that continuously monitors the heat distribution. Based on the measured temperatures, and taking into account the melting temperature and the latent heat, the thermal energy content is monitored.

[0054] like Figure 1 The example illustrated in the figure intentionally does not include adjustments to the 3D printing process according to the method of the invention to avoid the creation of local overheated areas. Based on this overheated area 5 that is continuously built up during the repeated selective laser melting steps, the structure provides a local weak point due to the lack of cooling sufficient to harden the material. The melting of the upper metal powder layer raises the temperature of the lower layer above the melting temperature, because the heat transferred from the upper layer and the inherent heat still contained in the lower layer exceeds the current heat and latent heat contained in the material, causing the material to exceed the melting temperature.

[0055] This partially remelted lower layer easily leads to many possible defects in the manufacture of 3D printed parts. A very simple problem is that, for example, unmelted metal powder material of the lower metal powder layer can be introduced into the remelted material, thereby significantly reducing the mechanical strength and other properties of the manufactured part.

[0056] The corresponding manufacturing method provides a very uniform and controlled introduction of energy into the metal powder layer, thereby allowing reliable control of this aspect of the process and significantly reducing the need for additional measuring devices such as energy, which are introduced in order to track this feature allowing the inventive method to be implemented. Thus, the overall effort required to put the inventive method into practice is reduced.

[0057] Figure 2 The scheme of the invented method is illustrated. Here, the 3D printed part 1, which is a turbine blade to be used in a gas turbine, is also manufactured layer by layer by selectively melting the metal powder material with the laser from the laser source 3. Figure 1 As in the comparative example of FIG. 1 , the temperature of the layer of powder material is continuously measured with a temperature measuring device 2, which is an infrared camera. The measurement data are transmitted to a processing unit 12, which analyzes the measurement data taking into account the melting temperature and the latent heat of the metal powder material. Based on the measured temperatures, which include the critical temperature during the phase change based on the latent heat and the energy introduced by the laser source 3, the temperature within the topmost metal powder layer and the lower layers that have been printed is monitored. In the case of an unfavorable temperature point being detected, the information is forwarded to the control unit 13, which modifies the manufacturing program so as to take into account the unfavorable temperature point. For example, surprisingly low temperatures based on increased temperature dissipation can be compensated by increasing the energy introduced by the laser source 3, which is based on a different arrangement of the 3D-printed parts to be manufactured or based on a simple suspension of manufacturing due to some faults. For example, some identified unfavorable temperature points based on some surprisingly increased temperatures of the metal powder layers formed by the more rapid manufacturing of each layer can be compensated by taking into account the already available heat, which is based on the decreasing total number of simultaneously 3D-printed parts, where the energy introduced by the laser source 3 is decreased by the control unit 13. Alternatively, the melting path can be rearranged by the control unit 13, causing the laser to start melting the next metal powder layer at the opposite end of the part 1, in order to allow the powder material to cool more.

[0058] The data collected and the data about the unfavorable temperature points are forwarded to a cloud database 15 located in the cloud 14, which allows an easy exchange of data with external service providers. It should be noted that this allows to easily exploit the expert opinions of specialized experts. For example, a deviation between the measured temperature and the theoretical temperature, which should be caused by the introduced energy, usually indicates some problems, such as contamination of the powder material. Enabling the exchange of some cloud-based data proves to be a very efficient way to exploit such external expert opinions in order to evaluate such deviations with regard to their potential impact on the overall printing process. Based on the value of the expert opinions and experience collected, it should be noted that the insight into such experience will become increasingly rare, and providing the possibility of such exchange has solved the problem in order to enable the exploitation of third-party databases, the use of which will not be shared for a long time in order to make adjustments or even stop the manufacturing process, thus ending with a faulty part at an early stage.

[0059] Furthermore, the data collected during the inventive method are also stored in the local database 16. Although the value of external expert opinion cannot be underestimated, the collected data cannot be utilized only in order to easily adapt future manufacturing processes in advance. It has become clear that after a short time, some automatic optimization processes can be implemented based on (for example) reinforcement learning in order to (for example) further reduce the processing power required to provide improved manufacturing procedures. It should be noted that, based on the initial simulations, the measured temperatures and / or the identified unfavorable temperature points of at least 80% of the 3D printed layers of the stored product are estimated in order to provide a significantly improved benefit compared to a smaller amount of stored data, and considering the effort and resources required to store such data and subsequently process it.

[0060] In addition, storing such data can also benefit subsequent utilization requirements in order to enable post-manufacturing evaluations of whether future utilization requirements can be met. It should be noted that some enable / disable evaluations at the time of manufacture provide limited benefits in the long term. It should be noted that for applications such as continuous flow engine parts, and especially hot gas path parts of continuous flow engines, long-term utilization changes create questions that are difficult to answer without such collected data. Despite the additional effort, the benefits gained by enabling such later evaluations easily compensate for such efforts for the corresponding applications.

[0061] Figure 3 Another embodiment of the method of the invention is illustrated, explaining the process in the 3D printing device in more detail. Herein, two elements of the 3D printing process are described in more detail. The embodiment of selectively melting 21 of the powder material and the metal powder distribution 24 to provide another metal powder layer is illustrated in more detail.

[0062] During the selective melting, the laser source 3' emits an energy beam 23, which is a laser beam directed onto the surface of the selectively melted metal powder layer 22. As a result, a new layer of the 3D printed part 1' is manufactured. The 3D printed part illustrated only in a very schematic manner is a turbine blade of a gas turbine. During this 3D printing process, the temperature measuring device 2' monitors the temperature of the metal powder layer 22 caused by the selective melting and the continuously manufactured components of the 3D printed part 1'. The data obtained by the temperature measuring device 2' are forwarded to the processing unit 26 for processing the data. In this context, the processing unit 26 analyzes the measured temperature taking into account the introduced energy, the melting temperature and the latent heat in order to identify an unfavorable temperature point. Depending on this unfavorable temperature point, the processing unit 26 automatically triggers an adjustment of the 3D printing process based on the identified unfavorable temperature point in order to prevent undesirable deformation of the 3D printed part based on the unfavorable temperature point.

[0063] The processing unit 26 in this context retrieves data about the underlying layer from the local database 16, which stores data from the underlying layer. The corresponding data are utilized by the processing unit 26 in order to evaluate whether, in addition to the temperature introduced and measured in the top layer, the temperatures already stored in the underlying layer can lead to unfavorable temperature points directly during the printing of the current top layer or indirectly during the printing of a subsequent layer.

[0064] Basically, the same process of monitoring and evaluation occurs during the metal powder distribution 24 step. Herein, the metal powder distributor 25 moves the metal powder layer as indicated above and deposits a new metal powder layer on top. The temperature measuring device 2' also monitors the temperature during this step and sends the data to the processing unit 26. The data can be beneficially utilized by the processing unit to identify deviations from the theoretical temperature and its development based on the cooling and temperature distribution process, which can be predicted using available models. Using this identified deviation, a large amount of additional data can be obtained. Such as non-uniform metal powder distribution, voids, incorrect melting layers, and the like that provide a different thermal energy flow from the metal powder material. This information is allowed to be included in the evaluation of possible unfavorable temperature points and the like in order to further optimize insight and possibilities. Herein, the processing unit can retrieve data from the local database 16 to support the identification of deviations and store the corresponding additional information obtained in the local database 16.

[0065] The present invention is further described in detail for illustrative purposes only. However, the present invention is not to be understood as being limited to these embodiments, as they represent embodiments that provide benefits in order to solve specific problems or meet specific needs. The scope of protection should be understood to be limited only by the appended claims.

Claims

1. A method for controlling a 3D printing process in order to manufacture a 3D printed part (1, 1'), in, The method comprises selectively melting the metal powder layer (22) by directing an energy beam (23) at the metal powder layer (22) so as to introduce energy into the metal powder layer (22), wherein the introduced energy selectively melts the metal powder layer (22) so as to build the 3D printed part (1, 1') layer by layer, Wherein, the metal powder layer (22) is composed of metal powder. wherein the metal powder provides melting temperature and latent heat, The method comprises continuously measuring the temperature of the metal powder layer (22), wherein the method comprises analyzing the measured temperature taking into account the introduced energy, the melting temperature and the latent heat in order to identify an unfavorable temperature point, The method includes automatically adjusting the 3D printing process based on the identified unfavorable temperature points.

2. The method according to claim 1, in, The 3D printed part is a continuous flow engine part, more preferably a hot gas path continuous flow engine part.

3. The method according to any one of claims 1 to 2, in, The step of analyzing the measured temperature takes into account the temperature measured in the lower layer of the 3D printed part (1, 1').

4. The method according to any one of claims 1 to 3, wherein: During the selective melting of the metal powder layer (22), energy is introduced by directing a laser beam or an electron beam onto the metal powder layer (22).

5. The method according to any one of claims 1 to 4, in, The method comprises storing temperature data of a printed metal powder layer (22), The method comprises utilizing a theoretical temperature of the metal powder layer (22), wherein the theoretical temperature of the metal powder layer (22) is obtained based on historical data, a simulation of the 3D printing, and the temperature is calculated based on stored temperature data of the printed metal powder layer (22) and energy introduced during melting of the metal powder bed, or a combination thereof, The method comprises identifying defects of the metal powder layer (22) based on a deviation between a measured temperature of the metal powder layer (22) and a theoretical temperature of the metal powder layer (22), Therein, the energy introduced into the metal powder layer (22) is adjusted based on the defects in the metal powder layer (22).

6. The method according to claim 5, in, The method comprises adjusting the 3D printing process based on a deviation of the measured temperature of the metal powder layer (22) and the theoretical temperature, Wherein, the theoretical temperature represents a temperature based on the thermal energy available in the 3D printed part and the metal powder and the energy introduced by the energy beam (23).

7. The method according to any one of claims 1 to 6, in, The step of analyzing the measured temperature in order to identify an unfavorable temperature point comprises determining a problem for a subsequently to be printed layer of powder material, Therein, the 3D printing process of the powder material layer is subsequently adjusted to compensate for the unfavorable temperature point.

8. The method according to any one of claims 1 to 7, in, The measured temperatures and / or identified adverse temperature points of at least 80% of the 3D printed layers of the product are stored in a database.

9. The method according to any one of claims 1 to 8, in, The method comprises the steps of assigning a unique identifier to the 3D printed part (1, 1'), wherein the method comprises the step of assigning the unique identifier to the manufacturing data collected by the method according to any one of claims 1 to 8, Wherein, the manufacturing data and the unique identifier are stored in a database.

10. A computer program product tangibly embodied in a machine-readable storage medium, comprising instructions executable to cause a computing entity to perform the method according to any one of claims 1 to 9.

11. Storage means for providing a computer program product according to claim 10, wherein: The apparatus stores the computer program product and / or provides the computer program product for further use.

12. A 3D printing device (11) adapted to manufacture a 3D printed part (1, 1') according to the method according to any one of claims 1 to 9.

13. The 3D printing device (11) according to claim 12, wherein: The 3D printing apparatus includes an infrared camera adapted to continuously monitor infrared radiation from the layer of powder material.

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