Dynamic Analysis of a 3D Printer Based on the Delta Mechanism

This work presents the computational modeling and dynamic analysis of a three dimensional printer based on a delta mechanism using the multidisciplinary open source software MBDyn. Three dimensional printers can make complex parts with a minimum waste of material. These printers are usually slower than conventional methods of fabrication like milling. To overcome this problem, different types of mechanism such as Delta and SCARA have been tested in open source 3D printers. They are faster and have less components than cartesian mechanisms, but they demand a inverse kinematic analysis to translate G-code to printer motion. The printing process requires several steps from the computer modeling of the part to the 3d printing. A set of Python scripts and MBDyn analyses were used to mimic this process and to provide the dynamic behavior of the complete model of the printer. To understand the impact of the flexibility of the parallel arms in the printing process, three materials were tested: ABS plastic, aluminum and steel. Besides the arm's material, another element that influences the printer performance is the stepper motor, thus different microstepping strategies were simulated. The dynamic analysis showed that the flexibility of the parallel arms plays an important role in the positioning error of the deposition head. Plastic arms are cheap and easy to build, however, their deformation is excessive in high speed displacements. The microstepping analysis revealed that the ratio between carriage displacement and motor step is more important than the microstepping strategy.