Arcus 3D C1 Cable 3D Printer by Daren Schwenke

cults3d

just to find it easier, just render some pieces to do it. The project is not mine, it's from Daren Schwenke, look for the info on hackaday https://hackaday.io/project/26938-arcus-3d-c1-cable-3d-printerhttps://github.com/Arcus-3d/C1-Hardware Proyect by Daren Schwenke This project aims to be a very low cost portable 3D printer with a scalable build diameter and reasonable accuracy. The design as rendered (OpenSCAD source) can scale from about 200mm to 600mm build diameter with the same parts just by using different length connecting rods. The build height is approximately equal to the build diameter. The printer can also be 'flat packed' for transport by removing the vertical rods as just the system tension holds them firmly in place. Hardware and software are working as designed now. The current focus is on dialing in the tripod kinematics and homing settings, and then generating a methodology for others to use to do the same. Origin I wanted to make a simple, low cost 3D printer using the available parts I had leftover from other projects, so the C1 was born. Designed it in my head, and then modeled the parts in OpenSCAD. All I didn't have on-hand was the rods (driveway markers and a garden stake) which cost me a total of $12. I started independently on this path, but then a forum post pointed me to the Flying Skydelta. Awww... It's a lot like that, with cheaper hardware. System overview An octahedral equal length frame made from low cost fiberglass driveway markers support 3D printed corners. The vertical components of the frame are held firmly in place by the line tension of the system, allowing them to be removed. This facilitates flat packing of the printer for transport. Each of the top corners house three pulleys sharing a shaft, through which cables are routed from the base mounted spool rod and steppers. The relatively large distance from the pulleys to the spooling shaft results in a single layer of tightly wound cable. This minimizes the error from the cable spooling up to less than 0.012mm allowing it to be ignored. The outer two cables are wrapped in the same direction and serve to position the print head using tripod kinematics, while the center cable is wound in the opposite direction and is routed to apply tension to a central push-rod. So as the outer cables wind up, the central cable unwinds to maintain tension. The top of the push-rod is free to move, so as the end effector is moved right, the top of the push-rod will pivot and move left maintaining constant down-force throughout the build area. The opposing forces on the spooling shaft also cancel each other out, resulting in the stepper motors only needing to support the weight of the end effector and not provide any actual tension on the lines. The required cable length is not a constant however. As the end effector is moved up, the required cable length of this system becomes shorter. A compression spring mounted on the push-rod serves to make up this difference and maintain tension in all the lines. Virtual pulleys Tripod kinematics without any compensation assumes the end connections are points in space. They are not. Pulleys can introduce significant error into the calculations: An 11mm diameter pulley can introduce up to 5mm of error into the resulting positioning. This happens because as the angle to the pulley increases, the cable will wrap onto the pulley which will change the effective cable length and generate a horizontal and vertical offset. https://www.youtube.com/watch?v=v1TQYhRJY1Yhttps://www.youtube.com/watch?v=sj8qMLb-2Zohttps://www.youtube.com/watch?v=9uQ6Beqq47Ahttps://www.youtube.com/watch?v=S1xXMig5daohttps://www.youtube.com/watch?v=KQ19fT4BQQU