This article explains the need for precise lens centering when using diffraction surfaces in IR lenses. The basic data on the characteristics, parameters, materials, ranges of operation of such lenses are given. After that, an example of calculated lens tolerances is considered and it is explained which ones should be observed with accuracy, and which ones have a very small impact on the quality of the contrast obtained. The technology of trimming frames, which will be discussed in this article, combines technologies and has great potential in the processing of high-precision optical products. With this method, the centering error can reach 0.5 microns, which is an extremely effective option for preserving the quality of the calculated lens by contrast and the presence of aberrations.