Development of a laser triangulation sensor for the measurement of powder height in 3D printing

Abstract

Development of a laser triangulation sensor for the measurement of powder height in 3D printing

Metallic additive manufacturing is an industrial process in which 3-D objects are created by depositing small layers of metallic powders and fusing the powder grains together. This process is a fairly recent technology and most developments are limited to the manufacturing of mono-material pieces.

Aerosint developed a printing head that allows for the deposition of up to three different materials at the same time. This has many advantages concerning the characteristics of the resulting pieces, but result in a powder deposition that is not well controlled as well as wasted powder

Precise imaging of the deposited powder layers could allow for in-process corrections and general improvements, reducing the amount of wasted powder and driving down impression costs. As such, the scope of this thesis is to assess imaging possibilities and eventually implement a sensor capable of imaging the deposited powder layers.

A literature search on imaging methods was carried out, and laser triangulation emerged as the most appropriate candidate. The possibility of a laser triangulation sensor had already been tried by Aerosint, but the resolution in height of the sensor proved to be insufficient.

A first prototype was assembled in order to assess the numerous parameters involved in laser triangulation height measurements. The conclusions drawn from the process were useful to conceive a second prototype that allowed imaging of an entire powder layer.

This second prototype successfully imaged a powder layer deposited by Aerosint printing head, approaching the specifications of the project in term of resolution. The results obtained from this prototype as well as theoretical considerations pave the way for a future development by Aerosint.