To obtain more design freedom and realize fast fabrication of mechanisms, a concept of non-assembly mechanism is introduced, which is digitally assembled and later directly fabricated using selective laser melting (SLM) technology. The effect of display on the number of support within the clearance is analyzed when the key points of directly fabrication of metal mechanism are obtained; then the effect of titling display on fabrication quality of clearance is studied. Some specimens with different angles are fabricated under different scanning speeds in order to obtain the critical fabrication angle; for experimental verification, a slider-crank mechanism with a minimum clearance of 0.2 mm is designed and two ones are fabricated by SLM using horizontal display and tilting display respectively under the process parameters of laser power of 150 W, scanning speed of 600 mm/s, powder thickness of 0.035 mm and track space of 0.12mm. Result shows that the slider-crank mechanism can be successfully fabricated by SLM. The methodology of directly fabrication of non-assembly mechanism will allow more design freedom and fast fabrication of mechanisms.