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HIGH TEMPERATURE SENSOR FOR POWDER BED 3D PRINTING SYSTEM

IP.com Disclosure Number: IPCOM000242509D
Publication Date: 2015-Jul-21
Document File: 4 page(s) / 105K

Publishing Venue

The IP.com Prior Art Database

Abstract

A technique for acquiring a temperature map during powder bed based 3D metal printing process is disclosed. The technique includes a sensor, which maps temperature distribution of a whole powder bed during three dimensional (3D) metal printing process. The sensor measures temperature ranges from 1000-2000oC, with significant accuracy. The sensor includes charge-coupled devices (CCD) and filters. According to the technique disclosed herein, the CCD is employed to measure NIR radiation from the powder bed at different wavelengths. A transfer function is built between the near IR radiation strengths at different wavelengths and temperature at the surface of the powder bed. The temperature of the surface is then calculated from the NIR radiation captured during the printing process.

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HIGH TEMPERATURE SENSOR FOR POWDER BED 3D PRINTING SYSTEM

BACKGROUND

The present invention relates generally to a three dimensional (3D) metal printing system and more particularly to a technique for acquiring a temperature map during powder bed based 3D metal printing.

Generally, in a metal 3D printing process, real time temperature distribution measurement is of high importance to achieve quality assurance for metal parts.  An infrared (IR) camera is usually used for measuring temperature distribution in the metal 3D printing process. However, the IR camera works efficiently at temperatures lower than 600 degree C, while melting pool for a metal 3D printing material is usually higher than 1000 degree C.

A conventional metal 3D printing process faces several challenges. For example, there exists inconsistency in microstructures of the metal parts undergoing metal 3D printing. Also, there is poor surface finishing for metal printed parts. Further, crack and distortion are produced, which results in a low yield of the metal 3D printing process. Uneven thermal distribution contributes to each of the above mentioned issues. Conventional metal printing processes lack use of sensor that can be used for a close loop process control.

There are some conventional techniques that monitor temperature of the melting pool. However, the techniques do not include temperature monitoring for complete powder bed. Also, these conventional techniques do not allow control over temperature of neighboring areas of the metal undergoing printing, thereby having limited contribution in controlling heat affected zone (HAZ) and in controlling solidification curve.

It would be desirable to have a technique for acquiring temperature mapping during powder bed based 3D metal printing.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 depicts design of a sensor according to an embodiment of the technique described herein.

Figure 2 illustrates interlayer temperature control strategy according to an embodiment of the technique described herein.

DETAILED DESCRIPTION

A technique for acquiring a temperature map during powder bed based 3D metal printing process is disclosed. The technique includes a sensor, which maps temperature distribution of a whole powder bed during three dimensional (3D) metal printing process. The sensor measures temperature ranges from 1000-2000oC, with significant accuracy. The sensor includes charge-coupled devices (CCD) and filters. Figure 1 depicts design of the sensor.

Figure 1

Near infrared (NIR) CCD is used to capture NIR energy from a target, thereby, building a correlation between NIR and temperature. The temperature is determined by NIR energy in one or more wavelengths along a spectrum.

According to the technique disclosed herein, the CCD is employed to measure NIR radiation from the powder bed at different wavelengths. A transfer function is built between the NIR radiation strengths at different wavelengths and temperature at the surface of the powder be...