Multi3D system: Advanced manufacturing through the implementation of material handling robotics
Since the rise of additive manufacturing (AM), innovation has been at the forefront. Additive Manufacturing systems that incorporate complex processes are steadily being developed. One example is the Multi3D System, which was designed to integrate the ability to print multi-material parts with that of embedding electronics. To achieve this automated process, the Multi3D incorporates a six-axis robotic arm to transfer a build platform containing a printed part, to various manufacturing stations (two fused deposition modeling (Stratasys, FDM400mc) systems and a computer numerical control router (Techno CNC Router). The robot is a Yaskawa Motoman MH50 chosen for its payload capacity of 50 kg. This research focused on the analysis of motion to determine the placement of the components (manufacturing stations) of the Multi3D System. One fused deposition modeling station was completely modified and tests were made to determine the validity of the modified system, compared to an unmodified 3D printer. There were several factors considered for the positioning of the components, including the reach of the robot, the addition of future components, and the design space. These were validated after developing simulations through CAD (Computer Aided Design) modeling, along with theoretical calculations using Denavit-Hartenberg matrices. Testing of the system proved placement of each manufacturing station to be at a specified distance of 1.47 m. LabVIEW programming was possible through ImagingLab’s Yaskawa robot library. The programming architecture was made to allow certain functions, such as the menu and the pause function. The Menu allows the user to determine the order in which the platform will be transferred, while the Pause function allows the user to interrupt the process for inspection or corrections to be made. The programming also allowed the incorporation of various sensors and acutators, making possible the limited human interaction that was key to the Multi3D System. With limited user input, it is possible for the process to be repeatable, accurate and operational for long periods of time. Through programming, the robot was able to be successfully utilized for a variety of experiments. The robot was used to test multiple traveling objects – the portable build platform and the traveling envelope. From these tests some modifications were recommended to facilitate the placement of the platform and envelope, improving the placement accuracy. Alignment bars and brackets showed improved repeatability in component placement. After modifications, a test was conducted to print a stair step with and without a pause. The pause function for the modified FDM consisted of pausing the build, placing the envelope on the platform, and removing the entire assembly. The reverse was done to allow for printing to resume. After completed, the stair step was compared to one created by the unmodified 3D printer. Results showed the tolerance for both systems in analyzing the layer offset is well within +51µm (0.0020”) and -25µm (0.0010”) from a centerline. This test served to validate that the modified machine printed with results comparable to the original Fortus 400mc machines, but more importantly, it confirmed that the removable platform can be placed and removed accurately by the robot. This is paramount to ensure that the addition of the second modified 3D printer will not have a significant effect on accuracy, and therefore, multi-material parts will possibly be built in the future.
Coronel, Jose Luis, "Multi3D system: Advanced manufacturing through the implementation of material handling robotics" (2015). ETD Collection for University of Texas, El Paso. AAI10000794.