Derive a basic analytical model for the volume build rate of a direct, single-laser SL process in terms of the following parameters: Effective laser spot size, the cured line width on the surface (Lw) and scan speed (V); liquid resin layer thickness (Zr) and cure (volume) shrinkage (S); and the time per layer to configure the liquid, wiper time (tw). Assume neighboring tracks are just touching (not overlapping). Apply this model to the following problems: a. For Zr = Lw = 0.1 mm, Vs = 2000 mm/s, and S = 15 vol %, what is the volume build rate per hour, neglecting the wiper time.
b. From (a), calculate the time to build a single 10 x 10 cm layer and a 10-cm cube (= 1 L).
c. For what wiper cycle time, does the wiper time add 10% to the total time in this case.
d. For what (smaller) layer area does the wiper time double the total time.