This contribution deals with the identification of roughness as a function of gloss in manufacturing using Particle Swarm Optimization (PSO) methods. The proposed PSO method uses a Least Squares Method as a cost function to be optimized. The identification structure uses a Gaussian and a Trigonometric Regressor characterized by seven parameters to be estimated. In PSO algorithms, there is a delicate balance to maintain between exploration (global search) and exploitation (local search) and this is one of the most important issues of this optimization method. An analysis of an increment of the dimension of the search space of the PSO is proposed. This is realized through an increment of its exploitation dimension to improve the precision of the search phase of the PSO, at the cost of more computations in each iteration. Nevertheless, convergence time results to be shorter in the presented case. Thus, an optimal increment of the dimension exists which states a compromise between velocity of the convergence and precision. Measured results from a manufacturing system with and without enlargement of the search space are shown together with results obtained using a Genetic Algorithm (GA) for comparison. Advantages and drawbacks are pointed out.