The off-line quality engineering is an important aspect that regards the manufacturing engineering process optimization. This target may be achieved by implementing the robust engineering principles. Therefore, the present paper reflects the results of the Taguchi Method approach applied for a fractioned factorial designed experiment in case of deep peck drilling with a twist drill, of a composite material. The scope was to optimize the surface state, characterized by his roughness, optically measured. (C) 2013 The Authors. Published by Elsevier B.V.