Method for detecting errors and compensating for heat dissipation during additive manufacturing processes

Abstract

A system and method are provided for monitoring a powder bed additive manufacturing process in which layers of additive powder are fused using an energy source and electromagnetic radiation signals are measured by a melt pool monitoring system to monitor the printing process. The method includes determining the thermal conductivity of the part and the powder bed, for example by estimating the thermal lag between printing of adjacent portions of the part, or by using a thermal model of the part and powder bed to determine thermal resistance. The method may include obtaining a predicted radiation signal based at least in part on the thermal conductivity properties, and comparing to the measured radiation signal. An alert may be provided or a process adjustment may be made when the difference between the measured and predicted radiation signals exceeds a predetermined error threshold.

Description

[0001] priority information [0002] The applicant claims a U.S. Provisional Patent Application entitled "Method for Detecting Errors and Compensating for Thermal Dissipation in an Additive Manufacturing Process," filed November 9, 2018 Priority of Serial No. 62 / 757,859, the disclosure of which is incorporated herein by reference. technical field [0003] The present disclosure relates generally to additive manufacturing machines, or, more particularly, to error detection systems and methods for additive manufacturing machines. Background technique [0004] In contrast to subtractive manufacturing methods, additive manufacturing (AM) processes typically involve the build-up of one or more materials to make net-shape or near-net-shape (NNS) objects. Although "Additive Manufacturing" is an industry standard term (ISO / ASTM52900), AM encompasses a variety of manufacturing and prototyping techniques known by various names, including freeform manufacturing, 3D printing, rapid pro...

AI Technical Summary

Problems solved by technology

[0010] However, most melt pool monitoring systems and associated control methods do not take into account the initial temperature of the zone prior to fusing powder in the zone when detecting processing errors.

Therefore, if the tool path of the energy source heats the part or a single zone within the powder bed multiple times in a short period of time, for example, before the thermal energy has had time to dissipate, a process failure may be triggered even if there is no problem

Also, most melt pool monitoring systems do data analysis after construction is complete, or are otherwise complex and delay in identifying processing issues

Additionally, such melt pool monitoring systems are often ineffective at identifying process failures that lead to finished part quality issues, part scrap, increased material costs, and excessive machine downtime

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