Purpose - This paper aims to propose methods for on-line monitoring and process quality assurance of Selective Laser Melting (SLM) technology as a competitive advantage to enhance its implementation into modern manufacturing industry.

Design/methodology/approach - Monitoring of thermal emission from the laser impact zone was carried out by an originally developed pyrometer and a charge-coupled device (CCD) camera which were integrated with the optical system of the PHENIX PM-100 machine. Experiments are performed with variation of the basic process parameters such as powder layer thickness (0-120 mu m), hatch distance (60-1,000 mu m) and fabrication strategy (the so-called "one-zone" and "two-zone").

Findings - The pyrometer signal from the laser impact zone and the 2D temperature mapping from HAZ are rather sensible to variation of high-temperature phenomena during powder consolidation imposed by variation of the operational parameters.

Research limitations/implications - Pyrometer measurements are in arbitrary units. This limitation is due to the difficulty to integrate diagnostic tools into the optical system of a commercial SLM machine.

Practical implications - Enhancement of SLM process stability and efficiency through comprehensive optical diagnostics and on-line control.

Originality/value - High-temperature phenomena in SLM were monitored coaxially with the laser beam for variation of several operational parameters.