The 3D printing process consists of creating 3D Model > Slicing > Printed Part > Post Processing. Slicing is the most important part where the model is sliced layer by layer and the process parameters are defined for 3D printing. The aim of this study is to evaluate different user interface of slicing software for Digital Light Processing (DLP) 3d printing. To evaluate the user interface of the software heuristic evaluation (HE) was performed with the help of 10 expert evaluators. To cross check the heuristic evaluation’s outcomes, a quantitative study was conducted with 60 users (30 users with beginner level of knowledge and 30 users with expert level of knowledge) to analyse the existing problems while using these software’s. It was found from HE that the principles: flexibility and efficiency of use, recognition rather than recall and visibility of the system were highly violated. Similarly, users with beginner level of knowledge finds the interface difficult to understand and operate as compared to the expert users which leads to the poor outcome. This study concludes that the user interface needs to be improved to increase its functionality and usability which helps to improve the productivity.