sajjad pakzad; ebrahim imani
Volume 13, Issue 2 , June 2020, , Pages 129-137
Abstract
The use of parallel mechanisms in the structure of 3D printers are developing. Parallel mechanisms have excellent capabilities in terms of accuracy, stiffness and high load-bearing capacity. This article studies a 3D printer with four degrees of freedom that has three degrees of linear freedom and one ...
Read More
The use of parallel mechanisms in the structure of 3D printers are developing. Parallel mechanisms have excellent capabilities in terms of accuracy, stiffness and high load-bearing capacity. This article studies a 3D printer with four degrees of freedom that has three degrees of linear freedom and one degree of rotational freedom. The advantages of this printer are greater than conventional Cartesian printers, including higher print speed and stiffness, and there are also higher degrees of freedom for manoeuvrability. In this paper, the Newton-Euler analytical method is used to analyse the inverse dynamics and identify the driving forces required by the 3D nozzle motion. By coding the inverse dynamic equations in the MATLAB software environment, the driving forces diagrams are extracted based on the printer's nozzle motion. To validate the inverse dynamics relationships, simulations with the Simmechanic model of MATLAB software have been performed. Through changing the speed of movement of the printer nozzle and also change of the velocity and acceleration of drives, the forces required for the drive also change. The effect of changes in print speed of a specific geometry on the driving forces is also studied. As well as, choosing the optimum print speed with regard to the motor driver power and the dynamics of the forces applied to the drivers and the less print time are the most important factors that are discussed in this article.
advanced manufacturing technology
Saeid Esmaeili; Mohsen Loh-Mousavi; Sayyed Ali Eftekhari
Volume 12, Issue 3 , September 2019, , Pages 85-91
Abstract
Single point incremental forming (SPIF) and fused deposition modeling 3D printing (FDM) are two methods of rapid prototyping. Each method has its own pros and cons. using SPIF method can provide an accurate forming process to shape sheets fabricated by 3D printing with their special characteristics. ...
Read More
Single point incremental forming (SPIF) and fused deposition modeling 3D printing (FDM) are two methods of rapid prototyping. Each method has its own pros and cons. using SPIF method can provide an accurate forming process to shape sheets fabricated by 3D printing with their special characteristics. In this study, single-point incremental forming of Poly Lactic Acid (PLA) sheets fabricated by FDM 3D printer was investigated by experiments. The formability process was evaluated by two different experiments. In the first experiment, a lubricant was used at ambient temperature and SPIF was investigated and for the second experiment hot air and lubrication were employed to achieve better formability. In addition, the effects of sheet thickness and strategy of layering of printed sheets by FDM were also studied on SPIF formability. The results showed that the incremental forming of printed PLA sheets in hot air is a more successful state to produce dome shapes parts and ruptures are less and this forming method can be used for some applications such as making partial curve of skull as a medicine solution in surgeries. Also, it was shown that the best layering strategy to print the PLA sheets used for better forming of SPIF is triangular pattern strategy against with rectangular strategy. It was found that thickness of 2mm printed sheet has better formability and less rupture versus 3mm of thickness.