GE has published two patents for additive manufacturing acoustic monitoring processes. Referring specifically to powder-bed fusion techniques, GE hopes to simplify the qualification of printed parts with an in-situ monitoring method using acoustic waves. In turn, the company intends to improve the workflow of 3D printing functional metal parts.
Adding sensors to the build chamber
该专利均于2015年提交，并于2017年5月出版，涉及将传感器纳入构建室内以监视和验证生产。
GE is familiar with the certification process for 3D printing metal parts as the company incorporated a 3D printed component in its LEAP engine, the nozzle, which has now alsobeen certified for use by the Federal Aviation Administration.
Last year GE made a considerable move into the 3D printing industry as it在ARCAM和Concept Laser中收雷电竞充值购了两家欧洲添加剂制造公司. The two companies both manufacture powder-bed based additive manufacturing machines and thus it is likely the patent could be applied to these machines. Since the acquisition, the North American company has expanded use of additive manufacturing technology andrecently committed $10 million in 3D printing machines for educational institutions.
Acoustic monitoring method
In the published patent, GE describes the proposed process as,
Generally stated, the acoustic monitoring process includes using an acoustic sensor (68) to measure acoustic signals during the build process and monitoring those signals for irregularities indicative of a defect in the workpiece W. The sensor 68 may be mounted in any location within the apparatus 10 where it can receive acoustic signals generated by the additive build process.
In the figure provided by GE, (fig.1) the acoustic sensors (68) are located just below the build plate (20).
比较声学曲线
According to the patent, the acoustic monitoring process may take place upon completion of the build or it, “may take place in real time.” It uses a “known good” (fig. 4)workpiece as comparison, which means the acoustic profile generated by the sensors is compared to the profile of the already qualified part.
The patent states that “if the workpiece W is properly formed, then the fusing process is smooth and very little variation occurs in the amount of acoustic energy being induced by the fusing process.” While, “ifthe workpiece W experiences a defect such as a crack or void, it will cause a change in the nature of the acoustic signal propagating through the apparatus 10.”This change is shown, 72, in fig.5 and, in other words dips in the line mark the then the part as defective.
Certification of additive manufactured metal
使用增材制造创建最终功能零件的阻碍因素之一是所得对象的资格。雷电竞充值当前，该方法通常涉及使用CT扫描仪，该扫描仪为生产增加了一个额外的过程，并且可能是非常耗时的。对于3D打印金属零件行业的公司而言，这是一个已知的问题，GE的概念激光也同样developed a ‘QM meltpool monitoring’ systemwhich uses a photodiode and a camera to monitor the printing of parts.
然而,随着其最新发明,一般电工实习ic believes it may have“the potential to eliminate post-build quality control processes such as CT scanning currently used in the prior art.”
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Featured image shows Direct Metal Laser Melting solution from GE Additive. Photo via GE Reports/Chris New
