Apparatus and method for producing a three-dimensional shaped article

Abstract

Device (100) for producing a three-dimensional shaped object (200) by applying material in layers S n with n=1 to N, having: - at least one material dispensing device (300) for applying physically or chemically consolidatable material to a printing substrate (400) or a consolidated layer S located thereon n of the shaped object (200); - a drive device (410) for positioning the printing base (400) and the at least one material dispensing device (300) relative to one another; - a control device (500) with a data memory (510) for storing image data (210) of the three-dimensional shaped object (200), wherein the control device (500) is in control connection with the drive device (410) and the at least one material dispensing device (300); - a monitoring device (600) for checking the layers S nof the three-dimensional shaped object (200), wherein an evaluation device (610) is arranged downstream of the monitoring device (600); - a material removal device (700), wherein the evaluation device (610) and the material removal device (700) are in control connection with the control device (500) and the material delivery device (300) has a leveling device (310) for leveling the respectively applied layer S n is arranged downstream, characterized in that the evaluation device (610) for determining a layer S n with n=x, in which at least one error was detected by the monitoring device (600), for checking the layer S after the faulty layer x subsequent layers S n with n=x+1, x+2... to a faulty geometric change of the shaped article (200) which exceeds a predetermined amount, to generate an error signal for the layer S xin case of incorrect geometry changes of the subsequent layers S n n=x+1, x+2... and to forward the generated error signal for this first of the faulty layers S x to the control device (500); that the material removal device (700) for removing the material of a partial area (T) of the three-dimensional shaped object (200) from the last printed layer S N up to the first of the faulty layers S x , for which an error signal was generated, wherein the material removal device (700) is designed such that when the material is removed, complete layers S n are removable.

Description

[0001] The invention relates to a device for producing a three-dimensional molded article by applying material in layers, comprising at least one material dispensing device for applying physically or chemically solidifiable material to a printing substrate or a solidified layer of the molded article located thereon, a drive device for positioning the printing substrate and the at least one material dispensing device relative to one another, a control device with a data memory for storing image data of the three-dimensional molded article, wherein the control device is in control connection with the drive device and the at least one material dispensing device. Furthermore, the device has a monitoring device for checking the layers S nof the three-dimensional shaped object, wherein an evaluation device is arranged downstream of the monitoring device. The device further comprises a material removal device, wherein the evaluation device and the material removal device are in control connection with the control device and the material dispensing device has a leveling device for leveling the respectively applied layer S n is subordinate.

[0002] Furthermore, the invention relates to a method for producing a three-dimensional shaped article by applying material in layers S n with n = 1 to N, comprising the following steps: - Application of physically or chemically consolidable material in layers S n on a printing substrate, - Checking the three-dimensional shaped object for at least one existing defect. - Leveling of each applied layer of Sn; - Determining a layer Sx of the three-dimensional shaped object in which the at least one defect was detected and - Check - the following layers S n with n=x+1, x+2... on incorrect geometric changes of the shaped object.

[0003] In the field of additive processes using layer-by-layer material deposition, documents DE 10 2016 013 610 A1, DE 10 2016 013 317 A1, and EP 3 294 529 B1 are known, for example. EP 3 294 529 B1 shows a device and a method for producing three-dimensional molded objects. The device shown in this document applies material to a rotatable printing base and produces the three-dimensional molded object at high speed and with high print quality. Should a defect occur in the three-dimensional molded object during the printing process, the entire molded object must be disposed of as waste and the printing process restarted. If the defect only occurs at the end of a printing process, the loss is greater than at the beginning of the printing process. This can lead to high to very high costs, depending on the size of the object to be printed.Accordingly, production times increase, which in turn leads to higher costs. Not only do financial losses occur, but environmental concerns also play a role when large quantities of material have to be destroyed.

[0004] To counteract this, DE 10 2017 208 497 A1, for example, proposes a correction process that corrects each printed layer of the three-dimensional component at an early stage, i.e. immediately, if an error has occurred during printing of the layer. The correction depends on the type of error that has occurred. If, for example, too little material was applied to one area of the component, the correction process only applies material to the affected area. The correction process also includes the option of not correcting the defective area in the case of minor defects, but rather adapting the subsequent machine code. If, for example, too much material was applied to one area of the component, this excess material can be removed by grinding and / or milling.A disadvantage of this publication, however, is that the process is very time-consuming, as recalculations must be performed for each subsequent layer, resulting in printing pauses. Furthermore, a correction process is defined for each defect type, allowing for differentiation between the different types. A disadvantage is the time required to identify the individual defect types, and the suggested repair measures, such as replenishing material in the event of a shortage, result in a loss of component quality.

[0005] Correction processes by material removal are also known from US 2018 / 0 071 987 A1 and US 2018 / 0 361 668 A1.

[0006] Based on the known prior art, the object of the invention is to further develop a device and a method of the type mentioned at the outset in such a way that the disadvantages of the prior art are eliminated, the productivity of the manufacturing process is increased and, nevertheless, a high quality of the three-dimensional shaped object is made possible.

[0007] The following definitions are used: Printing process

[0008] In this context, the printing process is understood as the application of material in layers to produce a three-dimensional shaped object. Material delivery device

[0009] A material dispensing device is understood to be a device by means of which a solidifiable liquid, pasty, powdery, or gaseous material can be applied layer by layer to the printing substrate or a solidified layer of the molded article located thereon. The material dispensing device can be configured to dispense material portions, in particular as an inkjet print head. Dismantling process

[0010] The deconstruction process involves using the material removal device to remove material from the three-dimensional molded object layer by layer. This removal occurs in complete layers, i.e., the entire printing surface, and can remove one or more layer thicknesses in a single pass. After the deconstruction process, a new print is made. Layer S

[0011] A layer is a layer of material that is applied by the material dispenser onto the printing substrate or onto an already applied layer. Bottom layer

[0012] The lowest layer with the index n=1 is the first layer that is applied to the printing substrate by the at least one material dispensing device. Top layer S N

[0013] The topmost layer with index N is the last layer applied by the at least one material dispenser onto the previous layer with index N-1 before the printing process is stopped. The printing process is stopped when an error is detected or when the molded article has been completed. Faulty layer S x

[0014] The defective layer is a single first layer with index n between n=1 and N, in which a defect has occurred that is corrected by material removal. This defect affects the subsequent layers. Thus, the layers deposited on top of the single first layer are also defective. Sub-area T

[0015] A sub-area T consists of the layers to be removed with the index N to x (from the top layer to the defective layer) Mistake

[0016] The term "defect" is used in this context to refer to imperfections in the three-dimensional molded object. Examples include defects that contain too little material, such as material shortages, material shrinkage, or similar, which can change the dimensions and shape of a layer. Slicer pointer

[0017] The slicer pointer Z s points to the memory location containing the data for each individual layer with the corresponding X, Y, Z coordinates, layer thickness, etc. generated for the 3D model stored in the image data storage. Object pointer

[0018] The object pointer Zo shows the position of the currently built-up or removed layer. As long as the material application proceeds without errors, the object pointer Zo and slicer pointer Z are S synchronous and point to the same slice. In case of an error, in which the rebuild procedure is activated, the object pointer Zo follows the slicer pointer Z S layer by layer until the object pointer Zo reaches the position of the slicer pointer Z S reached.

[0019] The above-mentioned object is achieved with regard to the device of the type mentioned at the outset in that the evaluation device for determining a layer S nwith n=x, in which at least one fault was detected by the monitoring device, for checking the faulty layer S x subsequent layers S n+1 with n=x to a faulty geometric change of the shaped article that exceeds a predetermined amount, to generate an error signal for the layer S x in case of incorrect geometry changes of the subsequent layers S n with n=x+1, x+2, ... and for forwarding the generated error signal for this first of the faulty layers S x to the control device; that the material removal device for removing the material of a partial area (T) of the three-dimensional shaped object from the last printed layer S N up to the first faulty layer S x, for which an error signal was generated, wherein the material removal device is designed such that when the material is removed, complete layers S n are removable.

[0020] The fact that a leveling device is arranged downstream of the material dispensing device has the advantage that errors due to excess material, i.e. too much material being applied, cannot occur. The leveling device automatically limits the layer thickness. This means that excessive material elevation is leveled out and the “excess material” error therefore does not have to be corrected. Advantageously, the leveling takes place directly after the still liquid material has been applied, so that the material removal device, which removes the already solidified material, is not used. Advantageously, the printing process is not restricted in terms of speed and productivity by correcting this type of error. The fact that the monitoring device checks the three-dimensional molded article for at least one existing error has the advantage that the various types of error, such as a lack of material or changes in the geometry orVolume changes due to shrinkage of the material of the applied layers S. n , can be recognized. Advantageously, an evaluation device is arranged downstream. The downstream evaluation device represents a layer S n with n=x, in which the at least one error was detected by the monitoring device. This is advantageously a layer S n , on which at least one further layer S n+1 was applied. Therefore, the printing process can advantageously be continued in the usual way, without having to x to stop the printing process and the defective layer S x In these, after the defective layer S x following layers S n with n=x+1, x+2..., the effect of the error of the faulty layer S x. The printing process is thus advantageously given time to compensate for certain errors, which subsequently have no effect on the geometry of the molded article. Only when the layer S x If an error occurs that causes a change in the geometry of the subsequent layers that exceeds a specified value, the evaluation device generates an error signal for this faulty layer S x For example, a volume change of the material may have occurred, leading to shrinkage. Advantageously, a faulty geometry change is detected by the monitoring device, and the evaluation device generates an error signal for this first of the faulty layers S x , which in the subsequent layers S nThis creates a geometric change, generates it, and forwards it to the control unit, which then stops the printing process. Advantageously, this eliminates the need to correct each individual layer, which would dramatically increase the production time for the molded part, as the inspection and evaluation, determination of the location of the error, decision on an appropriate corrective measure, and ultimately elimination of the error, all take a significant amount of time. A correction is only made once a predetermined limit is exceeded.

[0021] Advantageously, the material removal device carries the material of a partial area (T) of the three-dimensional shaped article from the last printed layer S N up to the faulty layer S xfor which an error signal was generated. The material removal device and the evaluation device are connected to the control device. This means that all layers up to the defective layer S x removed. On the defective layer S x Further layers have already been applied. It is considered that not only the top layer S N removed, but rather a subsection T of layers. This has the advantage that the defective molded article can always be corrected and does not have to be disposed of.

[0022] Advantageously, the partial area T of the three-dimensional shaped article of the last printed layer S N up to the faulty layer S x at least one layer S n , especially between two and four layers S n , preferably more than four layers S nThis makes it possible to carry out the dismantling process efficiently and without any loss of time, since removing, i.e. dismantling, each individual layer is time-consuming and relatively expensive due to the cost-intensive evaluation intelligence, which would increase the cost of the manufacturing process of the three-dimensional shaped object as a whole.

[0023] Advantageously, the material removal device is designed in such a way that complete layers n can be removed during the removal of the material. This means that no repair, such as material refilling in a single layer in the case of, for example, a "material shortage" error, is necessary, since the entire layer S nis removed by the material removal device. Thus, no distinction is made between individual defect types; instead, a removal process is used for all defect types that removes the individual layer completely, not partially. This simplifies the evaluation and accelerates the process.

[0024] Advantageously, the material removal device is designed for machining, in particular by means of milling, grinding and / or scraping.

[0025] Advantageously, the material removal device is designed such that when removing the material, the thickness of a layer S n or the thickness of at least two layers S n This allows any number of layers S n be removed and the dismantling process can be accelerated.

[0026] Advantageously, the monitoring device is designed as an optical monitoring device, in particular a CCD camera, a CCD camera in combination with a laser beam, an optical or mechanical scanning device, a layer thickness measuring device, or a measuring laser. This allows defective layers S x can be determined with a high degree of accuracy.

[0027] Advantageously, the material dispensing device is designed such that it can be moved into a parking position, where a service station is located for checking for malfunctions in the material dispensing device and for eliminating any malfunctions. This allows the material dispensing device to be serviced to correct any malfunctions that impair its function while the material removal device removes the partial area with the defective layers. If necessary, the material dispensing device can also be easily replaced with a corresponding spare part when the error signal occurs.

[0028] Advantageously, the printing support is mounted so that it can rotate about a rotation axis relative to the at least one material dispensing device, so that the printing support can be continuously moved throughout the entire printing process. This enables rapid printing progress.

[0029] Advantageously, the drive device is designed to position the material dispensing device relative to the printing support, which is fixed in the vertical direction, or to position the printing support relative to the material dispensing device, which is fixed in the vertical direction. Due to the fact that several layers S n printed before deciding whether to initiate the dismantling process, the printing speed can be maintained without interruption.

[0030] The above-mentioned object is achieved with regard to the method of the type mentioned at the outset in that - an error signal for this first of the faulty layers S x generated and forwarded to a control device if an incorrect geometry change of the subsequent layers S n with n=x+1, x+2... which exceeds a predetermined level; - Stop material application in layer SN according to the error signal; - in the image data of the shaped object a slicer pointer (Z S ) to the first faulty layer S x is set; - a partial area (T) of the three-dimensional shaped object from the last printed layer S N up to the faulty layer S x , for which an error signal was generated, is removed, whereby the layers S N up to layer S x be completely removed and - the previously removed layers and any further layers are then applied and checked layer by layer until the molded article is completed.

[0031] The advantages of the method according to independent claim 9 correspond to the advantages mentioned above with reference to the device. Further advantageous embodiments of the method of the invention are specified in the subclaims.

[0032] Further details, features and advantages of the present invention will become apparent from the following description of the embodiments of an apparatus for producing a three-dimensional shaped article with reference to the drawings.

[0033] It shows: Fig. 1 a schematic representation of the device in an arrangement according to a first embodiment, Fig. 2 a side view of a molded article and an associated image data model in the printing process, Fig. 3 a side view of the molded article and the associated image data model after defect detection, Fig. 4 a side view of the molded article and the associated image data model at the start of the dismantling process of a first embodiment, Fig. 5 to Fig. 8 a side view of the molded article and the associated image data model of the first embodiment during the dismantling process, Fig. 9 a side view of the molded article and the associated image data model of the first embodiment after the dismantling process, Fig. 10 a side view of the molded article and the associated image data model of the first embodiment at the start of the new printing process, Fig. 11 a side view of the molded article and the associated image data model of the first embodiment after completion of the new printing process Fig. 12 a schematic representation of the device in an arrangement according to a second embodiment, Fig. 13 a side view of the molded article and the associated image data model at the start of the dismantling process of the second embodiment, Fig. 14 a side view of the molded article and the associated image data model of the second embodiment after the dismantling process, Fig. 15 a side view of the molded article and the associated image data model of the second embodiment at the start of the new printing process and Fig. 16 a side view of the molded article and the associated image data model of the second embodiment after completion of the new printing process.

[0034] The invention is described in detail below in the form of exemplary embodiments with reference to the figures. In all figures, the same technical elements are designated by the same reference numerals.

[0035] Fig. Figure 1 shows an apparatus 100 according to the invention in an arrangement according to a first exemplary embodiment. The apparatus 100 serves to produce a three-dimensional shaped article 200 and to provide a partial region T of the shaped article 200 with a defective layer S x The three-dimensional shaped object 200 is formed into layers S n For this purpose, the device 100 has a material dispensing device 300 for applying the material in layers S n The first layer S n with n=1 is applied to a printing substrate 400. The material dispensing device 300 is followed by a leveling device 310, which prevents excess material from accumulating on the applied layer S n Furthermore, the device 100 has a material removal device 700 for removing a partial area T of the applied material from the uppermost layer S Nup to a faulty layer S x , with x: {1, ..., N}. In the following, the first layer S applied to the printing substrate 400 n with n=1 as the bottom layer. The last layer applied S N is called the top layer. The top layer S Ncan be the last layer with which the three-dimensional molded article 200 was completed or any layer before completion of the molded article 200, at which the printing process is interrupted due to error detection. Both the material dispensing device 300 and the material removal device 700 are controlled by a control device 500. The control device 500 has a data memory 510 in which image data 210, as shown in the following figures, of the three-dimensional molded article 200 to be produced are stored. Furthermore, the control device 500 controls a drive device 410, which positions the printing base 400 and the material dispensing device 300 relative to one another. In this first exemplary embodiment, the drive device 410 positions the printing base 400 relative to the material dispensing device 300, which is stationary in the vertical direction.This is done in such a way that when the material is applied layer by layer in layers S. n the printing base 400 is moved vertically downwards and during the layer-by-layer material removal of the layers S N to x, the printing support 400 is moved vertically upward toward the material removal device 700, which in this embodiment is also vertically fixed. The direction of movement of the printing support 400, which is effected by the drive device 410, is symbolized by vertical double arrows.

[0036] Furthermore, the Fig. The device 100 of the first embodiment shown in Figure 1 has a monitoring device 600, which is followed by an evaluation device 610. The monitoring device 600 checks the three-dimensional molded article 200 for any errors that may have occurred.

[0037] To detect a defective layer Sx In order to detect and correct any defects that may arise in or on the three-dimensional shaped article 200 during the printing process, the three-dimensional shaped article 200 is checked by the monitoring device 600. For example, by comparing the shaped article 200, which consists of several layers S n to N, with the specified image data of the three-dimensional shaped object 200 stored in the data memory 510, the error is detected. The evaluation device 610, arranged between the monitoring device 600 and the control device 500, evaluates the detected error and assigns a layer S to the error detected by the monitoring device 600. x with x: {1, ..., N}. The evaluation device 610 checks the following layers S nwith n = x+1, n = x+2, etc., to a faulty geometric change of the shaped article 200 that exceeds a predetermined value and then generates an error signal. The generated error signal for this first of the faulty layers S x is forwarded to the control device 500. The printing process is stopped by the control device 500 because in a layer S n an error has occurred which affects the subsequent layers and a demolition process for removing the material of a partial area T of the previously printed three-dimensional shaped article 200 is initiated. This demolition process is described in the Fig. 3 to 8 described.

[0038] In alternative embodiments, the monitoring device 600 and the evaluation device 610 can be replaced by testing personnel. The device 100 according to the invention otherwise functions as in the first and second embodiments. The testing personnel or monitoring personnel detects the error based on their specialist knowledge and outputs the data for this first of the faulty layers S x via an input terminal, so that the control device 500 further processes the entered data as described above. The inspection personnel can also enter the depth of the material to be removed using the thickness specification (travel path for the milling cutter in the Z-axis) in millimeters, and the control device (500) calculates how many layers fit into the specified millimeter specification and sets the slicer pointer Zs to the calculated position of layer S x .

[0039] Fig. 2 shows on the left side the three-dimensional shaped object 200 and on the right side the corresponding image data 210 of the shaped object 200. Schematically, an object pointer Z o and a slicer pointer Z s indicated. The slicer pointer Z s records the shift data of a shift S n , which is to be printed according to the image data 210. The object pointer Z o , which on the printer side represents the respective layer S n follows the slicer pointer Z s in order to control or position the material delivery device 300 accordingly. This way, the layers S n of the molded article 200 is printed according to the image data 210. If a layer S n-1 completely printed, the slicer pointer Z jumps s to the next layer to be printed S n and the object pointer Z o follows so that the layer S n on layer S n-1is applied. This process continues until the three-dimensional molded article is completed or a defect is detected by the monitoring device 600 or the inspection personnel.

[0040] Fig. 2 represents a defect-free printing process in which the three-dimensional shaped article 200 was printed without defects and all layers S n with n=1 to n=N were correctly constructed. To apply the material, the printing substrate 400 was moved vertically according to the first embodiment. This illustration and the illustrations of the molded article 200 and the image data 210 in the following figures apply accordingly to the second embodiment and to the alternative embodiments of the device 100 according to the invention described above.

[0041] Away Fig. 3, it is assumed that the monitoring device 600 or the monitoring / testing personnel has detected an error that affects the subsequent shifts. This error is assigned to the corresponding shift S by means of the evaluation device 610. n As an example, it is assumed that the error is in layer S n-1 of the printed molded article 200. The printing process is stopped. The slicer pointer Z s the image data 210 is applied to the first of the defective layers S x , here on the exemplary layer S n-1 , set.

[0042] As soon as the printing process is stopped because in a layer S nIf an error has occurred, the material delivery device 300 is moved to a parking position and releases the working position for the material removal device 700. This initiates a dismantling process for removing the material from a partial area T of the previously printed three-dimensional molded article 200.

[0043] While the material dispensing device 300 is in the parked position, it is checked by the service facility for any malfunctions. The maintenance performed by the service facility eliminates the malfunction so that after the defective layers have been removed, i.e., after the dismantling process described below, the material dispensing device 300 can apply the material layer by layer without any problems.

[0044] This dismantling process is based on the Fig. 4 to 8 described.

[0045] In Fig. 4, the material removal device 700 is already in the working position to remove the material from the corresponding sub-area T. In this example, the sub-area T comprises the layers n to n-1. The object pointer Z o contains the data of the respective layer that is removed and follows the slicer pointer Z s . Depending on the properties of the material removal device 700, one or more layers S n be removed in a layer-by-layer processing pass of the demolition process. This and the following figures show the removal of one layer S n shown.

[0046] According to Fig. 5 follows the object pointer Z o still the slicer pointer Z s , which remains on the faulty layer n-1 until it is removed. Fig. 5 shows the dismantling process for layer N-1, since layer N has already been removed. For this purpose, the printing substrate 400 was moved by the drive device 410 to the height of the material removal device 700, i.e., in this example, one layer thickness of the printed molded article 200 vertically upwards, since here, for example, one layer thickness is removed at a time. Analogous to Fig. 5 is in Fig. 6 the printing base 400 is moved further vertically upwards by the drive device 410 so that the next layer S n+1 of the molded article 200 can be removed by the material removal device 700. The dashed layers S N and S N-1 of the image data 210 on the right side of the figure indicate that these layers S have already been removed.

[0047] The demolition process continues according to the process described above to remove the layers, one at a time or several at a time. This is described in the Fig. 7 for layer n and in the Fig. 8 for the layer x=n-1 is shown schematically. Only when the object pointer Z o and the slicer pointer Z s are again on the same layer, here n-1, the material removal device 700 is stopped. This ensures that all layers up to the detected defective layer S x with x=n-1 have been completely removed and the dismantling process is finished.

[0048] The material removal device 700 is moved into a parking position and the material discharge device 300 into the working position, as in Fig. 9 for the first embodiment. Since the molded article 200 was defective, the printing process must now be restarted to produce a defect-free molded article 200.

[0049] Fig. Figure 10 illustrates the printing process using the first embodiment. As can be seen in the left-hand illustration of the three-dimensional molded article 200, the previously first of the defective layers S x with x=n-1, is reapplied by the material dispensing device 300 and leveled, i.e., smoothed, by the leveling device 310. The material removal device 700 is raised or moved aside. The material application process continues until the molded article 200 is completely printed without defects. The material application continues until the object pointer Zo reaches the position of the slicer pointer Z. S has reached.

[0050] Fig. Figure 11 shows the molded article 200 after the renewed application of layers n=x to N, i.e., at the end of the new printing process. The printing base 400 has been moved back to its starting position by the drive device 410, and the topmost layer N has been completely applied. The material removal device 700 is in the park position. If a defect has been detected before the molded article has been completely finished, the printing process can be continued (after the removal of damaged layers) until the molded article is completely finished. The removed layers are then reapplied.

[0051] Fig. 12 shows a second embodiment for positioning the printing substrate 400 and the material dispensing device 300 relative to each other. Unlike in the embodiment according to Fig. 1, the drive device 410 is in Fig. 12 is arranged on the material dispensing device 300 in order to move it vertically, and the printing base 400 is stationary in the vertical direction. The direction of movement of the material dispensing device 300, which is effected by the drive device 410, is symbolized by vertical double arrows. In this embodiment, the material dispensing device 300 is applied in layers S n onto the printing base 400 by the drive device 410 vertically upwards to produce the three-dimensional shaped article 200. During material removal, the drive device 410 moves the material removal device 700 vertically downwards towards the printing base 400, as shown in Fig. 13 will be described in more detail. Notwithstanding the alternative arrangement of the drive device 410 shown in this figure, the device 100 functions exactly as described with reference to Fig. 1 described.

[0052] In Fig. 13 shows the start of the dismantling process for the second embodiment. In the second embodiment, it is also assumed that an error has been detected in layer n-1, which has an impact on the subsequent layers and therefore the dismantling process is initiated. As already mentioned, the material removal device 700 is moved vertically downwards relative to the printing substrate 400, which is stationary in the vertical direction. The arrow indicates the direction in which the drive device 410 moves the material removal device 700 layer by layer. Regardless of the alternative arrangement of the drive device 410 shown in this figure, the dismantling process functions exactly as with reference to the Fig. 5 to 9 of the first embodiment described above.

[0053] Fig. 14 shows how the material removal device 700 is in a parked position, since the material removal by means of the dismantling process has been completed. The material delivery device 300 is moved to the working position. Since the molded article 200 was defective, the printing process must now be restarted to produce a defect-free molded article 200. This material application begins in layer n-1, on which the slicer pointer Zs and the object pointer Zo are located. As described above, the material application takes place via the material delivery device 300. The leveling device 310 following the material delivery device 300 prevents excess material, and the molded article 200 is rebuilt.

[0054] Fig. Figure 15 illustrates the printing process, starting from layer n-1, which has already been completely rebuilt in this view. The material dispenser 300 is already positioned on the next layer n, to which the slicer pointer Z S in the image data and the object pointer Zo is set accordingly.

[0055] As can be seen in the left-hand representation of the three-dimensional shaped object 200, the previously defective layer S x with x=n-1 by the material dispenser 300. The material application process is continued until the molded article 200 is completely printed without defects, this is Fig. 16. Analogous to Fig.11 of the first embodiment, in this second embodiment, the material dispensing device 300 is moved back to the starting position by the drive device 410, and the uppermost layer N is completely applied. The material removal device 700 is in the parked position. The molded article is finished after flawless material application. If a defect is detected before the molded article is completely finished, the printing process can be continued (after the removal of damaged layers) until the molded article is completely finished. The removed layers are then reapplied.

Claims

[1] Device (100) for producing a three-dimensional shaped object (200) by means of material application in layers S n with n=1 to N, having: - at least one material dispensing device (300) for applying physically or chemically consolidatable material to a printing substrate (400) or a consolidated layer S located thereon n of the shaped object (200); - a drive device (410) for positioning the printing base (400) and the at least one material dispensing device (300) relative to one another; - a control device (500) with a data memory (510) for storing image data (210) of the three-dimensional shaped object (200), wherein the control device (500) is in control connection with the drive device (410) and the at least one material dispensing device (300); - a monitoring device (600) for checking the layers S nof the three-dimensional shaped object (200), wherein an evaluation device (610) is arranged downstream of the monitoring device (600); - a material removal device (700), wherein the evaluation device (610) and the material removal device (700) are in control connection with the control device (500) and the material delivery device (300) has a leveling device (310) for leveling the respectively applied layer S n is subordinate, characterized by that the evaluation device (610) for determining a layer S n with n=x, in which at least one error was detected by the monitoring device (600), for checking the layer S after the faulty layer x subsequent layers S n with n=x+1, x+2... to a faulty geometric change of the shaped article (200) which exceeds a predetermined amount, to generate an error signal for the layer S xin case of incorrect geometry changes of the subsequent layers S n n=x+1, x+2... and to forward the generated error signal for this first of the faulty layers S x to the control device (500); that the material removal device (700) for removing the material of a partial area (T) of the three-dimensional shaped object (200) from the last printed layer S N up to the first of the faulty layers S x , for which an error signal was generated, wherein the material removal device (700) is designed such that when the material is removed, complete layers S n are removable. [2] Device (100) according to claim 1, characterized by that the partial area (T) of the three-dimensional shaped object (200) of the last printed layer S N up to the faulty layer S x at least one layer S n, especially between two and four layers S n , preferably more than four layers S n , includes. [3] Device (100) according to one of the preceding claims, characterized by that the material removal device (700) is designed for machining, in particular by means of milling, grinding and / or scraping. [4] Device (100) according to one of the preceding claims, characterized by that the material removal device (700) is designed such that when removing the material the thickness of a layer S n or the thickness of at least two layers S n is removable. [5] Device (100) according to claim 1, characterized bythat the monitoring device (600) is designed as an optical monitoring device, in particular a CCD camera, a CCD camera in combination with a laser beam, an optical or mechanical scanning device, a layer thickness measuring device or a measuring laser. [6] Device (100) according to one of the preceding claims, characterized by that the material dispensing device (300) is designed such that it can be brought into a parking position at which a service station (800) is arranged for checking a malfunction of the material dispensing device (300) and for eliminating any malfunction. [7] Device (100) according to one of the preceding claims, characterized by that the printing support (400) is mounted so as to be rotatable about a rotation axis relative to the at least one material dispensing device (300). [8] Device (100) according to one of the preceding claims, characterized bythat the drive device (410) is designed to position the material dispensing device (300) relative to the printing base (400) which is fixed in the vertical direction or to position the printing base (400) relative to the material dispensing device (300) which is fixed in the vertical direction. [9] Method for producing a three-dimensional shaped article (200) by applying material in layers S n with n = 1 to N, comprising the following steps: - Application of physically or chemically consolidable material in layers S n onto a printing substrate (400); - checking the three-dimensional shaped object (200) with regard to at least one existing defect, - Leveling each applied layer S n ; - Determining a layer S x the three-dimensional shaped object (200) in which the at least one defect was detected; - Check the following layers S n_ with n=x+1, x+2... on faulty geometry changes of the shaped object (200); characterized by , that - an error signal for this first of the faulty layers S x is generated and forwarded to a control device (500) if an incorrect geometry change of the subsequent layers S n with n=x+1, x+2... which exceeds a predetermined level; - Stop material application in layer S N according to the error signal; - in the image data (210) of the shaped object (200) a slicer pointer (Z S ) to the first faulty layer S x is set; - a partial area (T) of the three-dimensional shaped object (200) from the last printed layer S N up to the faulty layer S x, for which an error signal was generated, is removed, whereby the layers S N up to layer S x be completely removed and - the previously removed layers and any further layers are then applied and checked layer by layer until the molded article is completed. [10] Method according to claim 9, characterized by that the partial area (T) of the three-dimensional shaped object (200) of the last printed layer S N up to the faulty layer S x at least one layer S n , especially between two and four layers S n , preferably more than four layers S n , includes. [11] Method according to one of claims 9 or 10, characterized by that the layers S n be removed by machining, in particular by milling, grinding and / or scraping. [12] Method according to one of claims 9 to 11, characterized bythat when removing the material the thickness of a layer S n or the thickness of at least two layers S n is removed [13] Method according to one of claims 9 to 12 characterized by that the printing base (400) is rotated about a rotation axis. [14] Method according to one of claims 9 to 13, characterized by that a material dispensing device (300) is positioned relative to the printing support (400), which is fixed in the vertical direction, or the printing support (400) is positioned relative to the material dispensing device (300), which is fixed in the vertical direction, by a drive device (410). [15] Method according to one of claims 9 to 14, characterized by that an object pointer (Zo) corresponds to the slicer pointer (Z S ) until the first faulty layer S x is reached. [16] Method according to one of claims 9 to 15, characterized bythat the layers are applied to the printing base (400) or the solidified layer of the shaped article (200) located thereon by means of a material dispensing device (300), and that between the generation of the error signal and the subsequent application of a new layer S n the material dispensing device (300) is checked for a malfunction and - if a malfunction is detected - this is remedied.

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