Optical quality assurance in laser beam melting (LBM) using a camera and photodiode

Short Description

Starting point / motivation

The initial starting point for the R&D-project LBMcheck is an additive manufacturing technology with the label LBM (Laser Beam Melting), a 3D-printing method of metallic materials which can't realise its full potential because of insufficient possibilities of quality assurance and documentation.

The advantages of the production process are uncontroversial and are based on the very flexible manufacturing opportunity from single parts (batch size 1) to serial production. This is the reason, why this process is extremely interesting for aerospace industries (Seen in the ESA AM Roadmap v1.3 as well as the nationally coordinated AM Initiative from FFG ALR).

Moreover an efficient usage of resources and raw materials based on the additive manufacturing process (only structures that are needed for the part functionality are built) and the almost complete recyclability of unused powder material is typical for the manufacturing process. Furthermore the unique freedom in construction, which allows the generation of high complex and high quality parts, has to be mentioned. This property is especially interesting for aerospace applications.

Contents and goals

Currently available LBM systems don't allow complete quality assurance of the part quality but only the detection of process abnormalities.

However it is absolutely necessary to reliably detect actual errors three-dimensional located to offer a complete process documentation as well as a gapless documentation of the part quality (transparency and traceability).

Aim of the project is to realise a quality assurance system of the part quality for the laser beam melting process of metals by using a combined photodiode and camera based melt pool monitoring system.


Systems that are available today only detect process abnormalities but no actual part errors in terms of an error catalogue. By means of the suggested combined photodiode and camera based melt pool monitoring system the three-dimensional located detection of actual errors and the following categorisation should be reached.

Expected results

The most important result of the project is the availability of a quality assurance of part quality of the LBM process based on a novel combined photodiode and camera based melt pool monitoring system.

Other results are algorithms for calculating characteristics that allow modelling part quality via sensor data (photodiode and camera). These algorithms should preferably operate without the usage of reference data.

Furthermore a classification strategy which allows modelling individual quality requirements should be developed.

All these results allow a complete process documentation of the building job and a gapless documentation of the part quality (transparency and traceability), like it is required in safety-critical branches (in case of danger for human and/or machine through 3D-printed parts). This fact leads to a tremendous improvement of the Technology Readiness Level of the LBM process.

Project Partners


FOTEC Forschungs- und Technologietransfer GmbH

Project partner

  • Plasmo Industrietechnik GmbH
  • Vienna University of Technology

Contact Address

Forschungs- und Technologietransfer GmbH
Viktor Kaplan-Strasse 2
A-2700 Wiener Neustadt