Main influences
Research themes in the local documents repeatedly connect roughness with feed rate, wire speed, tension, material hardness, abrasive wear, and coolant conditions.
For marble experiments, feed rate was reported as the strongest factor among tested variables. For sapphire and silicon tests, speed and feed are often examined together.
Interpretation
Lower roughness is not always the only goal. Productivity, kerf loss, edge chipping, wire life, and downstream polishing allowance must be considered together.
A roughness result from one material cannot be copied directly to another material, even if the same machine and wire are used.