Post Exposure Unit

Abstract

A post-exposure unit (1) for post-exposing an object (2) manufactured by an additive manufacturing method from a radiation-curable material, the post-exposure unit (1) comprising at least one radiation source (7) configured for post-exposure, the post-exposure unit (1) comprising at least one radiation sensor (8) configured to capture radiation emitted by the radiation source (7), wherein the post-exposure unit has a receiving space for receiving the object to be post-exposed, and the radiation sensor is configured to capture radiation emitted by the radiation source and traversing at least a portion of the receiving space at least once.

Description

[Technical field]

[0001] The present invention relates to an apparatus for post-curing an object produced by a 3D printing process from a radiation-curable substance, the post-curing unit being equipped with at least one radiation source capable of further final curing the part, and at least one radiation sensor (e.g. a light sensor) being included in the post-exposure unit, which is capable of capturing radiation and can be connected to a control unit / processing unit, which is capable of controlling or regulating the at least one radiation source and reading the radiation sensor.

[0002] The invention also relates to a method for intelligent and sensor-assisted post-exposure of a layered built-up object made of a radiation-curable substance received in a vat, the object being at least partially cured or dimensionally stable, wherein process variables related to the post-curing are captured via at least one suitable radiation sensor (e.g., photodiode, photoresistor), and optionally process-related states of the exposure chamber (chamber) and / or the object are captured via at least one sensor to ensure a stable and traceable post-exposure process that may, for example, constitute part of a post-processing chain. [Background technology]

[0003] Devices and methods for building three-dimensional objects in layers from a substance that can be cured by radiation are also known under the terms 3D printing, additive manufacturing or rapid prototyping. Thereby, cross-sectional information of a substance, for example a photosensitive resin, to be cured in layers by electromagnetic radiation is generally created by mask projection or a laser light source (for example by a stereolithography process). In generative manufacturing machines that allow a continuous printing process, pixel-controlled DLP (digital light processing), MEMS (microelectromechanical systems), LC (liquid crystal) displays, LED displays or controllable lasers are mainly used for the exposure of the cross-sections or layers. The exposure thereby produces a solid layer from the liquid photosensitive substance. This layer is attached to a support and is removed or dislodged from the reference surface by lifting the support. In the subsequent manufacturing steps, the cured layer removed from the reference surface serves as a support. Three-dimensional objects are thus obtained or formed continuously from the photosensitive substance.

[0004] A known problem here is that in post-processing, especially during post-exposure, it cannot be guaranteed whether the process variables correspond to the specifications and whether the state of the process chamber or post-exposure unit corresponds to the target state.

[0005] US Patent Application Publication No. 2019 / 0240924 relates to an apparatus for the post-treatment of 3D printed parts made of photoreactive materials. A post-exposure unit is also described therein, having a vertical motor drive shaft, in which the part to be cured is irradiated by a radiation source via a deflection mirror. The part can be irradiated by multiple lamps, which can also have different wavelengths.

[0006] DE 102016102811 A1 relates to a post-exposure apparatus comprising a receiving device for receiving products produced by stereolithography, an emitting device for irradiating the products received in the receiving device and a radiation sensor for detecting the radiation intensity and the radiation wavelength of the radiation source. The radiation sensor is arranged to perform a self-test to verify the desired performance and function. DE 102016102811 A1 does not disclose the arrangement of the radiation sensor relative to the receiving device.

[0007] While known apparatus for the final curing of 3D printed semi-finished products is known, there is a need for improved, optionally automated, apparatus, in particular apparatus that allows for a wider capture of conditions and precise control of process parameters. Summary of the Invention

[0008] The object of the present invention is to create an apparatus and a method as specified at the beginning, which allows the capture and control of process variables and the capture of the state of the post-exposure unit (chamber) in the simplest and most reliable way possible, thus allowing a reliable and especially stable post-curing of objects with as little waste as possible. Furthermore, error states in the post-exposure step should be reliably detected or avoided.

[0009] To this end, the invention provides an apparatus according to claim 1 and a method according to claim 10. Advantageous embodiments and developments are specified in the dependent claims.

[0010] According to the present disclosure, a post-exposure unit is provided having a receiving space into which an object to be post-cured can be introduced, for example by hanging it on a build platform, the object is irradiated with radiation from at least one side, and a radiation sensor is configured to capture radiation emitted by a radiation source and traversing at least a portion of the receiving space at least once. That is, the radiation sensor is arranged to capture radiation that has traversed at least a portion of the receiving space. For example, at least one radiation sensor can be located within or outside the receiving space, capable of capturing radiation emitted by the light source or a spectrum emitted.

[0011] Here, the post-exposure unit may constitute at least part of an equipment for post-processing of 3D printed objects and may constitute a so-called post-processing sub-step, the entire process can be made more stable by means of sensor systems, the entire 3D printing process consists of "printing" and the entire post-processing can be better automated by means of determined data.

[0012] For this purpose, the post-exposure unit can be equipped with different radiation sources, such as LEDs emitting visible or UV radiation of a certain wavelength or, for example, of a predefined spectrum when several LEDs are combined.

[0013] The object to be post-cured here can be introduced into the receiving space or chamber from above by an automatic gripper with the aid of a build platform, and the object can finally be cured, for example by electromagnetic radiation, in particular by light, such as visible light or UV (ultraviolet) light. In particular, the chamber can be brought to a certain temperature, for example 50-120° C., by a heating device and can optionally also be filled with a process gas / protective gas, such as nitrogen.

[0014] The build platform, which may be suitably designed as a flat plate, may serve as a platform on which the object is mounted and may optionally serve as an additional reflector and end cover for the exposure chamber.

[0015] The sensor system integrated into the chamber can be used to draw conclusions about, among other things, the power density of the radiation source, the state of the radiation source or its change over time, as well as the state or degree of contamination of the chamber and the presence of objects on the build platform. Furthermore, when multiple radiation sources are used in combination with multiple sensors, the post-exposure unit can control the radiation intensity depending on the position and type of object.

[0016] With the aid of a radiation sensor, which may for example be arranged opposite the radiation source, conclusions can also be drawn about the radiation distribution in the post-exposure unit.

[0017] The chamber may be connected to a controller / processing unit capable of driving the radiation source, reading a sensor system comprising at least one radiation sensor, and forwarding all signals for further processing.

[0018] The interior of the chamber may be designed to be at least partially reflective.

[0019] The sensor system can, for example, compensate for aging of the radiation source, compensate for temperature-dependent behavior, adapt the radiation intensity and optionally the wavelength or spectrum, detect failure of the radiation source, determine chamber contamination, confirm the presence of an object, calibrate the chamber, and determine and set the exposure time and dose.

[0020] The sensor may be suitably housed within the chamber or, when LEDs are used as the radiation source, may be provided together with the LEDs on a corresponding circuit board.

[0021] When the description refers to the terms height, horizontal, vertical, top, bottom, upward, or downward, these terms or other location or direction designations should be understood in the position of use of the device.

[0022] According to an exemplary embodiment of the apparatus, the radiation sensor may be connected to a control unit / processing unit configured to process the radiation values ​​captured by the radiation sensor.

[0023] The processing unit may comprise a microprocessor or microcontroller for this purpose. Furthermore, the processing unit may be connected to a data memory containing data and / or program commands for processing the radiation values ​​captured using the radiation sensor. The processing unit may be connected to an input / output device, for example a touch screen, for operation of the processing unit by an operator. The operations desired for the post-exposure of the 3D object can be performed automatically by providing the processing unit. In contrast, an operator without a processing unit would perform these operations manually, for which purpose the radiation sensor may be connected to a display unit for displaying the captured measurements.

[0024] In order to enable appropriate control of the apparatus, the radiation sensor may be connected via a processing unit to a control unit for a radiation source provided for irradiating the object to be post-cured, the processing unit being configured to control the radiation source depending on the values ​​captured by the radiation sensor.

[0025] For example, the intensity values ​​captured by the radiation sensor can be transmitted from the radiation sensor to a processing unit and processed therein. When the processing unit has corresponding information about the object to be cured and is designed to control the radiation source, the object can be irradiated by the processing unit depending on the radiation intensity captured in the chamber.

[0026] The drive unit may enable the building platform, and thus the object, to be moved out of the receiving space in at least one direction. The drive unit may be designed to move the building platform and / or the object into the chamber. The drive unit may comprise an electric motor, e.g. a stepper motor, connected to the building platform. In particular, the electric motor may engage a height-adjustable rod, the rod being connected to the building platform.

[0027] When the processing unit with the control unit for the radiation source can additionally be connected to a temperature sensor capable of measuring the temperature at least at one point in the receiving space or chamber, the object can be irradiated by the radiation source depending on the temperature. An IR camera can also be used to monitor the temperature of the object during final curing.

[0028] The control unit for the radiation source, and therefore also the processing unit, is optionally designed to control the radiation intensity and / or duration of irradiation. The radiation source can be a light source, for example a light source for visible or UV light. The radiation intensity and / or duration of irradiation generally affect the final properties of the cured object.

[0029] It may further be envisaged that the chamber will be connected to an adjustable heating device for setting the temperature within the chamber, and / or an adjustable protective gas source for adjustable supply of a suitable gas (e.g., nitrogen) within the chamber.

[0030] To be able to appropriately control the apparatus, the radiation sensor may be connected via a processing unit to an adjustable radiation source and / or an adjustable heating device and / or an adjustable protective gas source, which may be configured to control the radiation source and / or the heating device and / or the protective gas source depending on the intensity value captured by the radiation sensor. The radiation sensor may capture a current intensity value of at least one radiation source in the chamber.

[0031] When the radiation sensor is connected to an adjustable radiation source via a control unit / processing unit, the radiation source can be driven by the control unit / processing unit in order to modify the current radiation intensity in the chamber.

[0032] When the radiation sensor is connected to an adjustable heating device via the control unit / processing unit, the heating device can be driven by the control unit / processing unit in order to control the radiation source and / or the heating device depending on the current temperature in the chamber.

[0033] When the radiation sensor is connected to an adjustable protective gas source via the control unit / processing unit, the radiation source can be driven by the control unit / processing unit to control the light intensity depending on the atmosphere in the chamber.

[0034] The at least one radiation source and the at least one radiation sensor may be protected by a receiving and holding container to prevent direct contamination of the radiation source and / or radiation sensor surfaces (protective function). The receiving and holding container may be open at the top to receive the build platform with the object attached thereto. The at least one radiation source and / or the at least one radiation sensor may be located behind the respective surfaces of the receiving and holding container. The receiving and holding container may be made of a material that is particularly poorly absorbent for the wavelength and / or spectrum used.

[0035] According to a further embodiment of the apparatus, each radiation source has a radiation sensor, resulting in an array of multiple radiation sources and radiation sensors which can then be driven and read individually and / or sequentially.

[0036] Optionally, the radiation sensors of the plurality of radiation sensors may be arranged in a row, for example in a single row (i.e., a one-dimensional or 1D arrangement of sensors). The radiation sensors of the plurality of radiation sensors may also be arranged in at least two rows. The at least two rows of radiation sensors may form a grid (or lattice) of radiation sensors, the grid comprising at least three rows in each dimension of the grid (i.e., a two-dimensional or 2D arrangement of sensors).

[0037] The radiation sensor or sensors may be fixed relative to the receiving space and / or the radiation source, i.e. the radiation sensor may be arranged in a fixed or stationary position.

[0038] The radiation sensor or sensors or at least one of the radiation sensors may be movable relative to the receiving space and / or the radiation source. For example, the radiation sensor or sensors may be moved around the receiving space to capture the spatial distribution of the radiation in more detail, which may allow for more accurate monitoring and, optionally, control of the uniformity.

[0039] In particular, the radiation source and the radiation sensor may be combined on a circuit board, at least one circuit board being provided for each post-exposure unit.

[0040] With respect to this method, the present disclosure also provides that the radiation sensor may be an optical sensor, and the intensity of the radiation source is captured using the optical sensor, and the intensity of the radiation source is variable and the optical sensor must have a corresponding measurement range.

[0041] In order to avoid repetition of parts of the apparatus description, reference is also made to the previous apparatus description for the method description, insofar as it is applicable to the method.

[0042] According to an optional embodiment of the invention, it can be provided that the intensity captured using the radiation sensor is compared in a processing unit connected to the radiation sensor with an expected value of the intensity of at least one radiation source, and at least one method parameter is set depending on the difference between the captured intensity and the expected value. The value of the method parameter can be captured by the radiation sensor. In particular, by repeatedly comparing the intensity captured using the radiation sensor with the expected value of the intensity, the method parameter can be set or adjusted to a target value. The method parameter can be set by or controlled by the processing unit itself.

[0043] According to the present disclosure, any light source that emits radiation capable of curing an object can be used as a radiation source. Suitably, but not necessarily, these are radiation sources that emit primarily in the UV range, in the wavelength range of about 350-420 nm. For example, flash lamps or LEDs can be used as radiation sources. When LEDs are used as radiation sources, multiple LEDs with different central wavelengths can be combined to achieve a certain radiation spectrum.

[0044] For example, at least one circuit board equipped with LEDs and radiation sensors and / or several individual circuit boards may be mounted in the equipment such that they illuminate the exposure space as uniformly as possible.

[0045] In particular, the radiation power is about 10 mW / cm 2 ~100mW / cm 2 , preferably 40 mW / cm 2 It can be said that:

[0046] A radiation source emitting at 405 nm may be used.

[0047] Each radiation source may suitably comprise a radiation sensor capable of capturing optical radiation from the opposing radiation source and / or from the reflector and transmitting it to the control unit.

[0048] The receiving space or exposure chamber is preferably accessible at the top or at least at one point and can be closed by a build platform which can be a support for the object to be cured.

[0049] The receiving space may suitably have a receiving and holding container that protects the radiation source and radiation sensor from direct contamination, and the receiving and holding container may be made of a material that is as transparent as possible or as little absorbing as possible to the radiation emitted by the radiation source.

[0050] In particular, it can be provided that on the basis of intensity values ​​of the radiation source captured using the at least one radiation sensor it is possible to draw conclusions about the falloff of the radiation power.

[0051] Furthermore, it may be provided that the radiation power of the radiation source is increased according to the intensity captured using the sensor.

[0052] As an alternative to a certain capture value of the intensity, the relative or absolute change in intensity over the operation time of the at least one radiation source can also be used by the processing unit to control the at least one radiation source.

[0053] According to a further embodiment of the method, a radiation sensor can be used in combination with a radiation source to provide for determining the location or position of at least one object to be cured. The shadow cast by the at least one object can be used to detect its position. If the cast shadow changes during the post-exposure process, a fault condition can be inferred, such as the separation of the object from the build platform. In this way, the presence of an object in the receiving space can also be detected.

[0054] Preferably, it can be provided that the post-exposure unit can be calibrated with the aid of a control unit using radiation captured by the at least one radiation sensor and emitted by the at least one radiation source.

[0055] In particular, with the aid of a number of radiation sensors, the uniformity of the radiation within the chamber or receiving space or holding vessel can be captured locally and temporally by the control unit, as well as its temporal and spatial variations.

[0056] The invention will now be explained in more detail using preferred, non-limiting exemplary embodiments with reference to the drawings. [Brief description of the drawings]

[0057] [Figure 1] 1 shows a schematic representation of a post-exposure unit according to the invention for post-exposure of a 3D printed object. [Diagram 2] 1 shows a detailed schematic diagram of a circuit board that can be used in a device according to the invention. [Figure 3a] 2 illustrates a schematic diagram of the exemplary intensity diagram of FIG. 1. [Figure 3b] 1 shows schematic diagrams of exemplary emission angles of possible radiation sources. [Figure 4] An example calibrated intensity profile is shown diagrammatically in FIG. [Diagram 5] 2 shows a schematic diagram of the apparatus of FIG. 1 with different soils on the surface of the receiving holding vessel; [Figure 6] 4 shows a schematic representation of an exemplary measurement signal and an actual target value in the case of contamination; [Figure 7] 2 shows a schematic diagram of the apparatus of FIG. 1 with time-resolved and spatially resolved intensity measurements and a diagram of the intensity measurements. [Figure 8] 2 shows a schematic diagram of the apparatus of FIG. 1 with the dislodged part in a receiving and holding container; [Figure 9] 2 shows a schematic diagram of an exemplary aging curve of a radiation source as a function of operating time; [Figure 10] 2 shows a schematic of the apparatus of FIG. 1 with the spatially resolved intensity set to a target value; [Figure 11] 1 shows diagrammatically an apparatus according to the invention in which the radiation source is regulated as a function of temperature; [Figure 12a-12b]Figure 12a shows a schematic diagram of the intensity of a radiation source as a function of temperature, and Figure 12b shows a schematic diagram of the temperature compensated behavior of the radiation source. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0058] In the illustrated figures, parts of the device that do not play a role in explaining the respective figure have been omitted for the sake of clarity.

[0059] FIG. 1 shows a post-exposure unit 1 for post-exposure of an object 2 (see FIG. 7) hanging on a build platform 3, which comprises a receiving and holding container 4, a number of circuit boards 5, 6, and a radiation source 7 and a radiation sensor 8 mounted on the circuit boards 5, 6 and connected via a control unit / processing unit 9. The intensity of the at least one radiation source 7 is captured by at least one radiation sensor 8 located on and at the opposing circuit boards 5, 6, respectively. As a result, the radiation intensity in the chamber 10 or at least one radiation source 7 can be captured, set or calibrated. This calibration can be performed after a certain period of time and / or before each post-exposure process. The control unit / processing unit 9 can for this purpose readjust the at least one radiation source 7 according to the measured radiation intensity. When LEDs are used as radiation sources, this can be done via the LED current. The intensity of the light source 7 is measured here by the respective opposing radiation sensor 8.

[0060] 2 shows a circuit board 5 that can be used, for example, in a post-exposure unit 1 and is equipped with multiple radiation sources 7 and radiation sensors 8. Each radiation source 7 has at least one radiation sensor 8, or optionally multiple radiation sensors 8, to increase the local measurement resolution.

[0061] 3a and 3b show schematic calibration results adapted to the exemplary structure of fig. 1. fig. 3a shows individual measurement curves captured at radiation sensor 8 after a certain time period. From the angle-dependent radiation behavior of the radiation source shown in fig. 3b, the expected radiation intensity can be inferred based on the position of the radiation source. In fig. 3b, an LED radiation behavior was assumed. The measured intensity at sensor 8 allows conclusions to be made about the radiation angle, the status of the radiation source, etc.

[0062] The calibration result based on the example shown in FIG. 1 is shown diagrammatically in FIG.

[0063] FIG. 5 shows the post-exposure unit 1 according to FIG. 1 after at least one post-exposure process in which there has been a contamination 11 of the receiving container 4, which prevents and / or interferes with the uniform illumination of the chamber 10 and therefore makes it no longer possible to guarantee in a new post-exposure process that the object to be exposed is completely cured within the time period specified by the control unit / processing unit 9 according to the specifications of the corresponding material. As a result of the contamination 11 on at least a part of the receiving container 4, as shown by way of example in FIG. 5, a value lower than the target value is measured at at least one radiation sensor 8 on the opposite side. The target value can correspond to a calibration value. In such a case, an output can be made via the control unit / processing unit 9, which informs the user of the unit 1 about the error that has occurred and, optionally, requests that the receiving container 4 be cleaned. This provides further process reliability and ensures that the contamination and intensity of the post-exposure unit 1 over a given post-exposure duration does not adversely affect the curing process or even prevents it completely in the case of severe contamination.

[0064] Figure 6 shows the radiant intensity I achieved when there is no contamination. cal The figure shows the plot of I cal represents the reference value that must be reached before each exposure process. dirt represents a possible measurement in the presence of some soiling of the receiving and holding vessel 4 (for example as shown in FIG. 5). calIf this is not reached, an error message can be output via the control unit / processing unit 9 and / or cal Attempts can be made to increase the radiation intensity of the radiation source 7 at least in certain regions so as to reach

[0065] FIG. 7 shows the post-exposure unit 1 according to FIG. 1, where an object 2 has been introduced into the post-exposure unit 1 and is hanging on the build platform 3. Here, as shown, a radiation source 7 can be used in combination with a radiation sensor 8 in order to detect the presence of an object 2 in the post-exposure unit 1. Shadowing at the radiation sensor 8 is now captured differently depending on the geometry of the object 2. In the example shown in FIG. 7, one radiation sensor 8 is completely blocked and is not able to capture any measurements to enable a comparison with previously captured target values. The target values ​​here can be obtained from a chamber calibration as shown in FIG. 1.

[0066] The printing result can optionally also be checked based on the cast shadow, e.g. whether the captured contour of the object corresponds to the expected contour. For this purpose, one or more movable radiation sources and / or movable radiation sensors can optionally be provided (e.g. linearly movable or pivotable or rotatable around the receiving volume).

[0067] The detachment of the object 2 from the build platform 3 is shown as an example in Fig. 8. Thereby, local changes of the object 2 during and / or after the post-exposure process can be detected, for example by a difference in the shadow cast by the object 2 as compared to the case shown in Fig. 7. Based on detecting the detachment of the object 2 during the post-exposure process, an output can be given to a user to manually remove the object 2 from the receiving container 4. This ensures further process reliability and prevents collisions (breakage) when new objects are introduced into the receiving container 4.

[0068] 9 shows an exemplary progression of the decrease in intensity over the operating time of the radiation source 7. Here, as an example, we consider an LED as the radiation source 7. Initially, the radiation source has an intensity I new and this intensity I new is a specific operation time t old followed by the value I aged By using at least one radiation sensor 8, the current intensity value of the radiation source 7 can be captured together with the operating time, which makes it possible to draw conclusions about the expected service life of the radiation source 7 and / or to detect failures of the radiation source 7, thus contributing to an increased process reliability.

[0069] 10 shows in cross section a post-exposure unit 1 as described above, the entire post-exposure unit 1 being calibrated when no build platform 3 is installed. In this case, all present radiation sources 7 are switched on simultaneously and / or individually and / or sequentially, while measurements are captured by the opposing radiation sensors 8.

[0070] In the example shown in FIG. 11, the post-exposure unit 1 can also be heated. An increase in temperature in the receiving and holding vessel 4 serves to, for example, accelerate the curing process or provide assistance by activating further unused initiators in the object 2. An increase in temperature in the post-exposure unit 1 causes a change in the operating point of the radiation source 7 and thus results in an emission behavior of the at least one radiation source 7 that is a function of temperature. To compensate for this, intensity values ​​can be captured in the at least one radiation sensor 8, which can be kept constant by adjusting the intensity of the radiation source 7 when the temperature increases. This can be done by tracking the LED current when using LEDs as radiation sources 7.

[0071] This is also advantageous because the radiation source 7 itself, i.e. without a heater, can cause an increase in temperature in the post-exposure unit 1. Thus, also in this case, a decrease in the intensity of the radiation source 7 over the exposure period can be compensated for.

[0072] FIG. 12a shows the progression of the temperature in the post-exposure unit 1, where the light intensity emitted by the radiation source 7 falls as the temperature increases. This therefore leads to the fact that less radiation intensity than specified reaches the object 2, and therefore the post-exposure time is not sufficient to cure the object 2 all the way through. This can distort the properties of the part and cause production errors. To prevent this, the radiation values ​​captured by the radiation sensor 8 can be used to readjust the radiation source 7 integrated in the post-exposure unit 1. The readjustment here is carried out in such a way that the light intensity remains constant as the temperature increases. This can be achieved, for example, in an LED that can be used as the radiation source 7, by adjusting the LED current.

[0073] The present disclosure can optionally achieve the following variations and advantages. LED sensor controlled post-exposure unit At least one sensor per panel (measures light intensity, LED aging / dirt) -Measurement of the irradiance power of each panel by the opposing panel -Measure and readjust the uniformity of each panel Combination of multiple wavelengths to achieve a wider wavelength range Optical output power calibration Compensation for LED degradation Efficient cooling / temperature control to improve LED performance stability Calibration every power on -Measurement of shadows cast by generated objects - Measuring whether the generated object is inside the box (shadow) LED Clustering Measuring glass contamination during calibration Measurement of fresh contamination during exposure Individual illumination according to the occupancy of the build platform

[0074] Further schematic embodiments: 1. An apparatus for post-exposure of an object 2 produced by an additive manufacturing method from a radiation-curable material, said apparatus comprising a receiving and holding container 4 for protecting at least one radiation source and at least one radiation sensor 8, said apparatus further comprising a build platform 3 as a support for said object 2, 1. An apparatus comprising: an at least partially enclosed chamber (10) formed, said chamber (10) comprising a receiving and holding vessel (4) capable of being irradiated by at least one radiation source (7), and further comprising at least one radiation sensor (8) mounted such that it can capture radiation emitted by said radiation source (7) and transfer it to a control / processing unit (9). 2. The device described in embodiment 1, characterized in that the radiation sensor 8 is connected to a control unit / processing unit 9 configured to process the measurement values ​​captured by the radiation sensor 8. 3. The device according to embodiment 2, characterized in that at least one radiation sensor 8 is connected to at least one radiation source 7 via said control unit / processing unit 9, and the intensity of the at least one radiation source 7 can be controlled. 4. An apparatus according to any one of embodiments 1 to 3, characterized in that any change in the state of the chamber 10, e.g. from a predefined calibration value, can be captured with the help of at least one radiation sensor 8 and appropriate measures can be taken via the control unit / processing unit 9. 5. The device according to embodiments 2 and 4, characterized in that at least one radiation sensor 8 for capturing radiation from at least one radiation source 7 is arranged opposite the radiation source 7. 6. An apparatus according to any one of the preceding embodiments, characterized in that the chamber 10 can be closed by a build platform 3 supporting at least one object 2. The following is a summary of the claims as originally filed: [1] A post-exposure unit for post-exposure of an object produced by an additive manufacturing method from a radiation-curable material, the post-exposure unit comprising at least one radiation source configured for post-exposure, the post-exposure unit having at least one radiation sensor configured to capture radiation emitted by the radiation source, A post-exposure unit, characterized in that the post-exposure unit has a receiving space for receiving an object to be post-exposed, and the radiation sensor is configured to capture radiation emitted by the radiation source and traversing at least a portion of the receiving space at least once. [2] The post-exposure unit according to [1], characterized in that the radiation sensor is configured to capture the radiation intensity and / or radiation wavelength of the radiation emitted by the radiation source. [3] The post-exposure unit according to [1] or [2], wherein the radiation sensor and the radiation source are disposed on opposite sides of the receiving space. [4] The post-exposure unit described in [3], characterized in that the post-exposure unit comprises at least two radiation sensors and at least two radiation sources, both of which are arranged on at least one side of the receiving space. [5] A post-exposure unit as described in [3] or [4], characterized in that the receiving space is formed within a receiving and holding container, and the at least one radiation source and / or the at least one radiation sensor are arranged outside the receiving and holding container. [6] A post-exposure unit described in any one of [1] to [5], characterized in that the at least one radiation sensor is connected to a control unit / processing unit, and the control unit / processing unit is configured to monitor the captured radiation signal. [7] A post-exposure unit as described in [6], characterized in that the control unit / processing unit is configured to signal deviations of the radiation signal from a predefined expected value. [8] A post-exposure unit described in any one of [1] to [7], characterized in that the at least one radiation sensor and the at least one radiation source are connected to a control unit / processing unit, and the control unit / processing unit is configured to control the radiation source based on a radiation signal captured by the radiation sensor. [9] The post-exposure unit described in [8], characterized in that the control unit / processing unit is configured to control the radiation source based on the radiation intensity and / or radiation wavelength captured by the radiation sensor.

[10] A post-exposure unit according to [8] or [9], characterized in that the control unit / processing unit is configured to adjust the radiation intensity and / or the radiation wavelength, respectively, to a target value.

[11] A post-exposure unit described in any one of [1] to

[10] , characterized in that a plurality of radiation sensors are configured to capture the radiation emitted in different directions by the radiation source.

[12] The post-exposure unit according to

[11] , wherein some of the plurality of radiation sensors are arranged in a row.

[13] The post-exposure unit according to

[12] , characterized in that some of the plurality of radiation sensors are arranged in at least two rows.

[14] The post-exposure unit of

[13] , wherein the at least two rows of radiation sensors form a grid of radiation sensors, the grid comprising at least three rows in each dimension of the grid.

[15] The post-exposure unit described in any one of [1] to

[14] , wherein the radiation sensor or multiple radiation sensors are fixed relative to the receiving space and / or the radiation source.

[16] A post-exposure unit described in any one of [1] to

[14] , characterized in that a radiation sensor or a plurality of radiation sensors or at least one radiation sensor among the plurality of radiation sensors is movable relative to the receiving space and / or the radiation source.

[17] An apparatus for post-processing an object manufactured by an additive manufacturing method from a radiation-curable material using a post-exposure unit described in any one of [1] to

[16] , comprising a transport device having a drive for moving a build platform relative to the post-exposure unit.

[18] A method for post-exposing an object produced by an additive manufacturing method from a radiation-curable material using a post-exposure unit described in any one of [1] to

[16] or using an apparatus described in

[17] .

Claims

1. 1. A post-exposure unit for post-exposure of an object produced by an additive manufacturing method from a radiation-curable material, the post-exposure unit comprising at least one radiation source configured for post-exposure, the post-exposure unit having at least one radiation sensor configured to capture radiation emitted by the radiation source, the post-exposure unit has a receiving space for receiving an object to be post-exposed, and the radiation sensor is configured to capture radiation emitted by the radiation source and traversing at least a portion of the receiving space at least once; the radiation sensor and the radiation source are disposed on opposite sides of the receiving space; A post-exposure unit, characterized in that the receiving space is formed in a receiving and holding container, and the at least one radiation source and / or the at least one radiation sensor are arranged outside the receiving and holding container.

2. 2. The post-exposure unit of claim 1, wherein the radiation sensor is configured to capture a radiation intensity and / or a radiation wavelength of the radiation emitted by the radiation source.

3. 2. The post-exposure unit of claim 1, characterized in that the post-exposure unit comprises at least two radiation sensors and at least two radiation sources, both of which are disposed on at least one side of the receiving space.

4. 4. A post-exposure unit according to claim 1, characterized in that the at least one radiation sensor is connected to a control unit / processing unit, the control unit / processing unit being configured to monitor the captured radiation signals.

5. 5. A post-exposure unit according to claim 4, characterized in that the control unit / processing unit is adapted to signal deviations of the radiation signal from a predefined expected value.

6. 6. A post-exposure unit according to any one of claims 1 to 5, characterized in that the at least one radiation sensor and the at least one radiation source are connected to a control unit / processing unit, the control unit / processing unit being configured to control the radiation source based on radiation signals captured by the radiation sensor.

7. 7. A post-exposure unit according to claim 6, characterized in that the control unit / processing unit is configured to control the radiation source based on the radiation intensity and / or the radiation wavelength captured by the radiation sensor.

8. A post-exposure unit according to claim 6 or 7, characterized in that the control unit / processing unit is adapted to adjust the radiation intensity and / or the radiation wavelength, respectively, to a target value.

9. A post-exposure unit according to any one of the preceding claims, characterized in that a plurality of radiation sensors are configured to capture the radiation emitted by the radiation source in different directions.

10. 10. The post-exposure unit of claim 9, wherein some of the radiation sensors of the plurality of radiation sensors are arranged in a row.

11. 11. The post-exposure unit of claim 10, wherein some of the radiation sensors of the plurality of radiation sensors are arranged in at least two rows.

12. 12. The post-exposure unit of claim 11, wherein the at least two rows of radiation sensors form a grid of radiation sensors, the grid comprising at least three rows in each dimension of the grid.

13. A post-exposure unit according to any one of the preceding claims, characterized in that the radiation sensor or sensors are fixed relative to the receiving space and / or the radiation source.

14. A post-exposure unit according to any one of the preceding claims, characterized in that a radiation sensor or a plurality of radiation sensors or at least one radiation sensor of said plurality of radiation sensors is movable relative to the receiving space and / or the radiation source.

15. 15. An apparatus for post-processing an object produced by an additive manufacturing method from a radiation curable material using a post-exposure unit according to any one of claims 1 to 14, comprising a transport device with a drive for moving a build platform relative to the post-exposure unit.

16. A method for post-exposing an object produced by an additive manufacturing method from a radiation-curable material using a post-exposure unit according to any one of claims 1 to 14 or using an apparatus according to claim 15.

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