function of 'but'

Continuous dyeing or thermosol process do not cause spot dyeing of molten beads as dyeing is not affected through exhaustion but through surface deposition and diffusion and so singeing may be included in pre-treatment sequence.

What is the function of 'but' in this sentence? I think by "dyeing is not affected through exhaustion but through surface deposition and diffusion" means- dyeing is not affected by exhaustion, rather dyeing is affected by surface deposition and diffusion. Am I right?