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EP-4036781-B1 - SYSTEM AND METHOD FOR IDENTIFYING DISTORTION-COMPENSATION THRESHOLD FOR SINTERING PARTS WITH COMPLEX FEATURES

EP4036781B1EP 4036781 B1EP4036781 B1EP 4036781B1EP-4036781-B1

Inventors

  • WANG, YONGXIANG
  • BARUA, ANANDA

Dates

Publication Date
20260513
Application Date
20211228

Claims (14)

  1. A system comprising: a memory module configured to store a computer model of a green part for manufacturing with an additive manufacturing machine; and a processor communicatively coupled to the memory module and configured to: receive, from the memory module, the computer model of the green part, discretize the computer model of the green part into a mesh including a plurality of nodes, predict a deformation behavior the plurality of nodes of the mesh under a simulated sintering process performed on the additively manufactured green part, determine a buckling factor for the green part based on the predicted deformation behavior of the mesh, wherein the buckling factor refers to a load multiplier of the load applied to the green part indicating the critical load of the green part, determine whether the buckling factor exceeds a threshold, in response to determining that the buckling factor exceeds the threshold, export the computer model to the additive manufacturing machine for pre-build processing, and in response to determining that the buckling factor does not exceeds the threshold, output, to a display of the system, at least one of an alert that the part is unstable or the buckling factor, wherein the pre-build processing includes a process to pre-distort the computer model of the part based on the predicted deformation behavior such that a desired sintered part can be achieved after sintering of the additively manufactured green part, wherein an additive manufacturing machine of the system is configured to additively manufacture the pre-distorted green part.
  2. The system of claim 1, wherein the buckling factor defines a minimum load at which the green part becomes unstable.
  3. The system of claim 2, wherein the load is a force due to gravity on a portion of the green part situated above a lower portion of the green part.
  4. The system of any one of claims 1-3, wherein the processor is further configured to generate for display a buckling mode shape of the green part, wherein the buckling mode shape illustrates a buckling event of one or more portions of the modelled green part.
  5. The system of claim 4, wherein the buckling mode shape includes a heat map illustration of the green part identifying relative deformation of one or more portions of the modelled green part.
  6. The system of claim 4, wherein the buckling mode shape is determined based on the results of the simulated sintering process applied to modelled green part.
  7. The system of claim 4, wherein the buckling mode shape is determined at one or more time intervals during the simulated sintering process.
  8. The system of claim 4, wherein the buckling mode shape identifies one or more suggested portions of the green part to add support material to reduce the predicted deformation behavior of the green part.
  9. The system of any one of claims 1-8, wherein the processor is configured to predict the deformation behavior of the mesh under the simulated sintering process includes implementing a finite element analysis of the mesh.
  10. The system of any one of claims 1-9, wherein the simulated sintering process is defined by a temperature and a duration for exposing the green part to the temperature.
  11. The system of any one of claims 1-10, wherein the computer model is parameterized to digitally represent a composition and structure of the green part.
  12. A method comprising: receiving, from a memory module, a computer model of a green part; discretizing, with a computing device, the computer model of the green part into a mesh including a plurality of nodes; predicting a deformation behavior the plurality of nodes of the mesh under a simulated sintering process performed on the additively manufactured green part; determining a buckling factor for the green part based on the predicted deformation behavior of the mesh, wherein the buckling factor refers to a load multiplier of the load applied to the green part indicating the critical load of the green part; determining whether the buckling factor exceeds a threshold; in response to determining that the buckling factor exceeds the threshold, exporting the computer model to an additive manufacturing machine for pre-build processing; and in response to determining that the buckling factor does not exceeds the threshold, outputting on a display at least one of an alert that the green part is unstable or the buckling factor, wherein the pre-build processing includes a process to pre-distort the computer model of the part based on the predicted deformation behavior such that a desired sintered part can be achieved after sintering of the additively manufactured green part, wherein an additive manufacturing machine is used to additively manufacture the pre-distorted green part.
  13. The method of claim 12, wherein the buckling factor defines a minimum load at which the green part becomes unstable.
  14. The method of any one of claims 12-13, further comprising generating for display a buckling mode shape of the green part wherein the buckling mode shape illustrates a buckling event of one or more portions of the modelled green part.

Description

BACKGROUND Technical Field The present specification generally relates to identifying the stability of a green part during high temperature sintering using finite element buckling analysis of the green part under sintering conditions. Technical Background Additive manufacturing (AM) processes are used to fabricate precision three-dimensional components from a digital model. Such components are fabricated using an additive process, where successive layers of material are consolidated, one on top of the other, on a build plate in an additive manufacturing machine (AMM). Certain additive processes may include sintering a part. As a result of the sintering process, the shape of the sintered part may become distorted. Conventional processes may potentially predict a distortion of the sintered part, but to do so, such processes must solve a complex, transient problem that takes a long time (e.g., hours or even days) to solve, making such processes unusable for quick iterative design approaches. Further, the conventional prediction processes use several assumptions about parameters that are hard to validate, making the output of conventional prediction processes less accurate. SANTOS LUIS S. ET AL: "Simulation of buckling of internal features during selective laser sintering of metals" and MARSCHALL DAVID ET AL: "Boundary conformal design of laser sintered sandwich cores and simulation of graded lattice cells using a forward homogenization approach" exemplify the use of simulation for improving the geometric accuracy in additive manufacturing. SUMMARY The invention is defined by the independent claims 1 and 12. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A depicts an illustrative green part prior to a sintering process;FIG. 1B depicts an illustrative part after sintering the green part illustrated in FIG. 1A, illustrating a distortion event of the green part as a result of a sintering process;FIG. 1C depicts an illustrative part after sintering the green part illustrated in FIG. 1A, illustrating a buckling event of the green part as a result of a sintering process;FIG. 2A depicts an illustrative green part in the form of a rod prior to sintering;FIG. 2B depicts a deformation of the rod of FIG. 2A after sintering when no compensation for the deformation of the rod during sintering was implemented;FIG. 2C depicts an illustrative compensated green part configured to anticipate the deformation as a result of sintering according to one or more embodiment shown and described herein;FIG. 3A schematically depicts an illustrative system for predicting whether a green part will lose geometrical stability (e.g., buckle) when sintered, according to one or more embodiments shown and described herein;FIG. 3B schematically depicts an illustrative computing device for predicting whether a green part will buckle when sintered, according to one or more embodiments shown and described herein;FIG. 4 depicts a flow diagram of an illustrative method for predicting whether a green part will buckle when sintered, according to one or more embodiments shown and described herein;FIG. 5 depicts illustrative examples of coupons for calibrating a buckling threshold of a green part, according to one or more embodiments shown and described herein;FIG. 6A depicts an illustrative computer model of a part, according to one or more embodiments shown and described herein;FIG. 6B depicts an illustrative mesh of the computer model of the part depicted in FIG. 6A, according to one or more embodiments shown and described herein;FIG. 6C depicts a magnified portion of the illustrative mesh depicted in FIG. 6B, according to one or more embodiments shown and described herein;FIG. 7A depicts an illustrative buckling analysis result having a heat map illustrating the buckling mode shape of portions of the part based on the sintering conditions, according to one or more embodiments shown and described herein;FIG. 7B depicts an illustrative mode shape of a modelled part at different time intervals during the simulated sintering process, according to one or more embodiments shown and described herein; andFIG. 8 depicts an illustrative example of a redesigned green part for sintering that is designed to be stable under sintering conditions, according to one or more embodiments shown and described herein. DETAILED DESCRIPTION Embodiments of the present disclosure provide systems and methods for predicting whether a component will be stable or not under extreme conditions such as sintering. More specifically the systems and methods identify buckling factors and buckling mode shapes (i.e., the first buckling mode shape) for a part under complex environments such as high temperature. For example, the systems and methods described herein may be used to predict whether a green part will experience a deformation such as a distortion or a buckling event as a result of a sintering process. As used herein "deformation" refers generally to a change in the shape of a part, which