Optical components which transmit light can be made through various processes and materials, such as glass, thermosets, or thermoplastics. These components are then assembled with fiber optic cables and light sources to complete the full optical assembly. This potential mixture of different types of materials can impact dimensional position of various alignment features needed for low signal loss. In this paper, we show the beneficial or detrimental effects of mixed materials and component design on dimensional alignment in optical assemblies. For assembly, solder reflow capable thermoplastic resins are evaluated and compared to other commercially available material classes in ease of assembly, design, and performance parameters.