Home/Technical Glossary/Laser Annealing Laser Annealing Laser Annealing is a surface heat-tempering mark. The heat effect of the laser beam causes an oxidation process underneath the material surface, resulting in a color change on the metal surface. This dark, permanent mark is ideal for medical device applications where material removal is prohibited to ensure part integrity and performance. Learn more about Laser Marking by reading our Blog ‘Marking Methods: When Lasers Make Sense