Patent Publication Number: US-2022219393-A1

Title: Thermal Insulation Fastening System

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation application of U.S. application Ser. No. 16/543,133, entitled “Thermal Insulation Fastening System,” which was filed on Aug. 16, 2019, which claims priority to German Patent Application No. 102018120083.8, filed on Aug. 17, 2018, and German Patent Application No. 102018124975.6, filed on Oct. 10, 2018, each is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a device for additive manufacturing of components or  3 D printing, in particular for an SLM process, in which SLM is the abbreviation for selective laser melting. 
     BACKGROUND 
     Selective laser melting (SLM) is a generative manufacturing process, which belongs to the group of beam melting processes. With selective laser melting, the material to be processed is distributed in powder form onto a base plate in a thin layer. By means of laser irradiation the material is melted in the respective locations necessary for producing the desired shape. After the material has solidified, a layer of solid material results. In a next step the base plate/machine table is lowered and newly coated with powder and again exposed to laser irradiation. This cycle is repeated until the finished component is produced. In the end the finished component is cleansed from excess powder and taken off the machine table. 
     For production of a component a given work space may be used. The work space can be oversized for the desired component, so that a large quantity of powder is necessary in order to carry out the process, however, the biggest part of the powder is not necessary to produce the component itself. Nevertheless, said powder is heated by the heating of the component and/or the machine table on which the component is produced and is thus reduced in quality for subsequent production cycles. 
     SUMMARY 
     Embodiments provide a device for producing a component by an additive process, in which only the smallest possible amount of powder is spent and/or becomes unusable. 
     The additive process may for example be the SLM or SLS process. The SLS process, the abbreviation SLS stands for selective laser sintering, is a generative production process, in which a component is produced layer by layer. In doing so, spatial structures are created from a material in powder form using a laser. 
     Furthermore, such a device is provided, that the component to be produced is not built up on the machine table but on an assembly, so that the component does not have to be separated from the machine table by a mechanical process, e.g. by disc grinding or sawing. 
     As first embodiment of the invention a device for producing a component using an additive process is provided, comprising: an element for producing a component and an assembly for at least partially receiving the element, wherein the component is additively built up on the element and/or wherein in the assembly an embedding mass for thermal insulation and/or fastening the element is provided. 
     By means of the embodiment of the invention by additively printing the component on an element or semi-finished component, a support structure otherwise necessary in additive processes can be omitted. 
     The device is formed in such a way, that powder which is not needed is isolated from the heated machine table and wherein an element for producing a component is disposed in a receptacle, so that a component may be additively built up on the element, wherein within the device a means may be present, in which the element is at least partially embedded, whereby the element is mechanically supported. 
     Exemplary embodiments are described in the dependent claims. 
     According to an also exemplary embodiment of the invention, a device is provided, wherein the element is embedded by the embedding mass and thereby mechanically fastened. 
     From the element and the component may result a hybrid component. The element may for example have been formed in a non-additive production process, for example by milling or turning. Prior to the start of the additive process the element may be treated with a mixture of various heat-conducting and anti-corrosive additives, in order to ensure that the additive process does not negatively affect the quality of the component. 
     Furthermore, prior to the start of the process the thermal insulation and/or the fastening embedding mass may be coated with a surface sealing material. This results in the thermal insulation and/or the fastening embedding mass not causing any impurities in the powder (still to be processed) and/or the work space. Because of this impurities can also be avoided in reused powder and consistent component quality can be ensured. 
     The assembly for installation of the elements may take place on multiple levels. Usually on a machine table a base plate is fastened, which is in direct contact with the elements. Thereby for example a heat transfer from the heatable machine table up to the element is ensured. Thereby temperature may be introduced into the elements in a targeted way. 
     In a further embodiment an insulating layer, which is implemented by the embedding mass, is disposed between multiple elements and/or the machine table. This is to avoid the potential heating of the non-processed filling powder in the powder bed and at the same time ensure a fastening of the elements. 
     The embedding mass may be curable, whereby securely fastening and positioning the elements in the work space is ensured. 
     In a further embodiment a heat conducting foil may additionally be placed between the machine table and the element. 
     Furthermore, a location fit between the element and the heat conducting foil/material/tub may enable an additional positioning/fastening of the element. This serves for the digital model being precisely built up on the element as well as for stress transfer from the element to the heat conducting foil/material/tub. 
     According to an exemplary embodiment of the invention a device it provided, wherein the embedding mass has a coefficient of thermal expansion which is equal to or higher than that of the element. 
     In a further exemplary embodiment, a device is provided, wherein the coefficient of thermal expansion of the putty is lower than that of the element and/or wherein the coefficient of thermal expansion of the component is different from that of the element. 
     By means of a higher coefficient of thermal expansion of the embedding mass it is ensured, that the fastening function of the embedding mass with respect to the element is fulfilled. 
     According to a further exemplary embodiment of the present invention a device is provided, wherein the material properties of the component are inhomogeneous and/or wherein the embedding mass is a compound of a ceramic part and a non-ceramic part. 
     According to an exemplary embodiment of the invention a device is provided, wherein the process is suited for selective laser melting (SLM) or selective laser sintering (SLS). 
     In a further embodiment of the invention a device is provided, wherein the device is disposed within the work space of an additive process, wherein the component is produced within the work space. 
     According to a further exemplary embodiment of the present invention a device is provided, wherein the embedding mass is a thermal insulation, in order to save unprocessed powder from heat during the additive production process. 
     In a further embodiment according to the invention a device is provided, wherein the element is treated with a mixture of various heat conducting and anticorrosive additives prior to the start of the process and/or wherein the embedding mass is covered with a surface sealing material prior to the start of the process. 
     Thus, it is avoided hat the powder is contaminated by the embedding mass. 
     According to a further exemplary embodiment of the present invention a device is provided, wherein a location fit between the element and the heat conducting foil/material/tub enables positioning the element and/or wherein a foil is disposed between the element and the component, whereby separating component and element is made easier or unnecessary, because the component and the element are present separately. 
     In order to reuse any non-melted powder of the additive process, an unintended heating of the powder has to be prevented. By using an additional insulating layer, the powder, which is for example not disposed in close proximity of the elements or the component, can be protected from unintended heat exposure. 
     It may be considered an embodiment of the invention to provide a device, which reduces the amount of powder spent in an additive process and furthermore facilitates separating the finished component from the machine table. 
     In a further embodiment of the invention the embedding mass may be formed inhomogeneous with respect to its thermal conductivity, so that a heat exposure of the component occurs in different ways and non-uniform. Thus, an inhomogeneous formed component may be produced, which is for example characterized by areas of different toughness and/or hardness. 
     A further embodiment of the invention is the printing of the component on a thin foil, which is stretched over the element prior to the start of the process. This assembly (element equipped with foil) is, as in the previously described embodiment, fastened in its entirety, by means of the embedding mass, which may be present as a curable embedding mass, to the base plate. 
     The individual features may of course be combined with each other, whereby in part advantageous effects may result, which surpass the sum of individual effects. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details and advantaged of the invention will be apparent from the exemplary embodiments illustrated in the drawings, which show 
         FIG. 1  shows a device for selective laser melting (SLM); 
         FIG. 2  shows a device having a measuring system  16  (camera/laser/gauge) for positioning; 
         FIG. 3  shows a method for making a component; and 
         FIG. 4  shows a further method for making a component. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
       FIG. 1  shows a device for selective laser melting, wherein a powder depot  14  having a lift table  6  is provided. In order to supply a powder  5 , the lift table is driven upwards, whereby a metered amount of powder  5  can be transferred by a wiper  4  from the powder depot  14  to the area  15 , in which the component is fused by a precisely introduced laser beam. The next layer is created by the machine table  7  being lowered and by the wiper  4  filling a new layer of powder  5  into the resulting depression. By means of a laser  1 , a laser irradiation  3  results in certain locations of the powder bed  12 . In said locations of the powder bed  12  a molten bath/microstructural change of the powder  5  results, which leads to a solidification after cooling. Thus, a component of the desired shape may be produced. After a laser irradiation process the machine table  7  is again lowered and the resulting depression is again filled up with powder from the powder depot  14  by means of the wiper  4 . The process is repeated for so long until the component  13  is completed. Next the component  13  is removed from the area  15  and cleansed from powder. 
     The device comprises a heat conducting mold  8 , which can be formed as a tub or a heat conducting foil/material. In the tub  8  an element  11  can be disposed, which can constitute a part of the completed component or which can only be provided for heat conduction to the component  13 . In any case the element  11  serves for heat of the machine table  7  being directed to the component  13 , so that the additive/SLM/SLS process maybe used. The tub  8  is filled with a thermal insulation and/or a bedding embedding mass  9 , which is insulating from heat. Furthermore, in addition a thermal insulation and/or a bedding embedding mass  9  may be provided, which is additionally/also heat-insulating. By means of the embedding mass  9 , which can be present as a curable composite, it is ensured, that the powder  12 , which is not necessary for production of the component  13 , is not heated and thus can be reused for subsequent production cycles without reduction in quality. 
       FIG. 2  shows a device, wherein a camera  16  localizes the position of the element  11 , so that the mirror  2  can adjust the laser beam  3  in such a way that the component is in fact produced on the element  11 , and not next to it, by the additive process. 
     The advantages of the device result from the powder  12  not being damaged and thus being available for subsequent production processes. Moreover, the component  13  is directly applied onto the element  11 , which, with the component  13 , constitutes the complete component to be created or which can be removed from the component  13  in a simple manner. A complex removal for example by disc grinding the component  13  from the machine table can be omitted. 
       FIG. 3  shows a method  30  for making a component. The method  30  is performed at a device. The device comprises a powder depot, a work space and a laser, wherein the work space comprises a powder bed and an assembly, and wherein the assembly comprises a thermally insulating embedding mass and a heat conducting mold. The method  30  includes, at  32 , fastening, by the assembly, an element at the work space and forming the component at  34  at the element. Forming the component includes repeatedly moving, at  34   a , by a wiper, powder from the powder depot to the powder bed at the work space and heating, at  34   b , by a laser beam of the laser in an additive process, portions of the powder in the powder bed so that the component is built on the element, wherein the additive process comprises selective laser melting (SLM) or selective laser sintering (SLS), and wherein the embedding mass is independent and distinct from the powder and the component. 
       FIG. 4  illustrates a method  40  for making a component. The method  40  includes fastening, at  42 , by an assembly, an element at a work space, wherein the assembly comprises a thermally insulating embedding mass and a heat conducting mold and forming the component at  44  at the element. Forming the component further includes providing, at  44   a , powder at the element, melting, at  44   b , portions of the powder so that a portion of the component is built at the element, wherein melting comprises selective laser melting (SLM) or selective laser sintering (SLS), lowering, at  44   c , a table on which the assembly is placed and repeating, at  44   d ,  44   a - 44   c  until the component is finished, wherein the embedding mass is independent and distinct from the powder and the component. 
     It shall be mentioned, that the term “comprise” does not preclude additional elements or process steps, just as the term “a” and “an” does not preclude multiple elements and steps.