Apparatus and methods for monitoring and controlling multi-layer laser cladding

An automated laser cladding system for use in modifying an amount of material deposited on a substrate, comprising:

• a laser outputting a beam, including means for focussing the beam onto a localized area of the substrate, the laser having an energy of sufficient power to melt the substrate at least within the localized area;
• means for moving the beam and substrate relative to one another;
• means for feeding the material to be melted into the melt pool for accumulation into the localized area as a material deposit;
• and
• feedback control means operative to sense the height of the material deposit and automatically adjust the rate of material deposition in accordance with the height.

A system for automatically fabricating an article, comprising:

• a computer-aided design database including a description of the item to be fabricated;
• a work table for supporting a substrate;
• a controllable laser having a beam directed at a localized region of the substrate to form a melt pool thereon;
• means coupled to the laser for feeding material to be melted into the melt pool so as to create a material deposit having a height;
• translation means for moving the substrate relative to the laser and feeding means;
• optical detection means operative to output an electrical signal indicative of the height of the material deposit as it is being created;
• and
• a feedback controller operatively interfaced to the translation means and laser to automatically adjust the height of the material deposit in accordance with the description of the article to be fabricated in the computer-aided design database.

A method for fabricating an article, comprising the steps of:

• a) providing a description of the article to be fabricated;
• b) providing a substrate upon which to form the article;
• c) providing a controllable laser having a beam to heat a localized region of the substrate to form a melt pool thereon;
• d) feeding material into the melt pool so as to create a material deposit having a height;
• e) optically monitoring the height of the material deposit;
• f) automatically controlling the height in accordance with the description of the article to be fabricated;
• g) advancing to a different localized region of the substrate;
• and
• h) repeating steps c) through g) until the fabrication of the article is complete.