Study on dimension change law from CAD model to prototype of rapid investment casting based on selective laser sintering

Rapid Investment Casting can overcome the cost involved in designing and fabrication of metal tooling for wax injection process. The present investigation is aimed to determine the effects of CAD model placement degree and size on the dimension error of prototype base on Selective Laser Sintering. The experimental results show that the dimension change law of length, width and height is different from each other, it mainly due to the intersection angle between important edge and forming plane. When the angle is 0 degrees and 90 degrees, staircase effect is smaller and dimension accuracy is higher, when the angle is 45 degrees, the staircase effect is biggest and dimension accuracy is lowest. The CAD model size has significantly influence on dimension accuracy because of secondary sintering, when the model size is 86mm, the secondary sintering reduces to minimum, the dimension error is 0, the secondary sintering is more obvious with the decrease of CAD model dimension.