Patent ID: 7705264

Claim:
A method of applying a laser metal formed hard layer with a controlled laser metal forming process on the surface of an article, the method comprising the steps of (a) moving a laser light source and a signal capturing apparatus and the article relative to each other, thereby (b) melting locally the surface of the article using the laser light source with a specific power for forming a melt pool, (c) injecting by means of a nozzle a powder with a carrier gas into the melt pool, the powder comprises a blend of carbides and metal powder or hard particles embedded in a matrix phase, (d) capturing an optical signal from the melt pool using the signal capturing apparatus, (e) using the monitored optical signal for the determination of at least one temperature value and fluctuations in temperature values as properties of the melt pool, (f) using the information of the at least one temperature value and the fluctuations in temperature values of the melt pool from the optical signal within a control system in a feedback circuit to adjust as process parameters one or a combination of the power of the laser light source, the relative speed between the laser light source and the article, the mass feed rate of the added coating material and/or of the carrier gas, the distance between the nozzle and the article and the angle of the nozzle to the article such that desired melt pool properties are obtained and subsequently (g) solidifying the melt pool.