D3-TIG

Our project goal is to design and build a functioning prototype of the VandalForge V2 3D printer to include: a more user friendly interface, ease of manufacturability, and increase printing capability while maintaining a relatively low manufacturing cost to allow for future retail sale.

Problem Definition
Design and build a functioning prototype of the VandalForge V2 3D printer to include: a more user friendly interface, ease of manufacturability, and increase printing capability while maintaining a relatively low manufacturing cost to allow for future retail sale.

Background
A. Previous Work: 1)Pre-built MIG welder for print head 2)Smoothieboard x5 to control 3d printer motion B. Ways to improve on previous design: 1)More control over weld characteristics: A.Wire-feed and welder power should be independent B.AC and DC welds C. Variable power in frequencies 2)Easier to put together/assemble 3) Modular design, with welder and printer space separate C) Our solution: 1) TIG Welder completely controlled by microcontroller A)TIG vs MIG welders B)TIG welders: separate electrode and wire feed C) MIG welders: the wire (welded material) is the electrode

Solution Path
We are using a TIG welder instead of a MIG welder. Now state why, here.

Project Learning
Welding: TIG welding is a welding technology that uses an electric arc to heat/melt an area of the material in question. The arc can then be used to move around the base metal to some extent, or typically a metal rod or wire is added into the melted zone (otherwise known as the puddle) to act as filling material. We learned that TIG uses constant current with variable voltage to keep the electric arc stable.

Motion system: With 3D printing there are multiple well known motion control arrangements. We chose to go with what’s known as a CORE-XY motion system for several reasons. The first reason relates to client requirements, as the project mandates that we use a box style frame. With a box style frame the most efficient use of space for anything but a very small printer is to have the print head, or in our case a TIG nozzle and wire feed system, mobile in both the X and Y directions. To do this there are two common belt setups, one is called Hbot and the other is the aforementioned CORE-XY. While the Hbot is simpler, requiring significantly less belting and fewer pulleys, it applies a torquing force to the XY gantry that we concluded was less desirable than the extra cost and complication of implementing the CORE-XY system. In our design we also have to allow for a very stiff metal print bed that has active cooling to remove the heat from the welding process. In this we decided to have the print bed fixed and thus move the XY motion system in the Z direction as well. In doing this, we realized why every commercial printer, off the shelf kit and home build plans move the bed in the Z direction rather than the the XY system. It’s because moving the the XY system in the vertical is a lot more work. When moving only the bed the only forces that really need consideration are the vertical force of supporting the weight. When moving the XY system the vertical force of the system must be considered as well as dynamic forces on the system of the moving print head.

Control system: The control system of the 3D printer must govern multiple systems. First, it must control the XYZ movement of the printer. Second, it must control the characteristics of the weld by changing the power applied. Third, it must use feedback loops to ensure that the whole system runs smoothly, with as little human intervention as possible. To fill these requirements, we decided to use the Smoothieboard x5, given that the board has enough stepper motor outputs, as well as GPIO pins, to facilitate our system control.

Team Meetings

 * Team meetings occur twice weekly
 * Generally, only team members attend one of the meetings to discuss different aspects of the project
 * The other meeting includes all team members, our lead instructor/Client, and all technical advisors. This meeting is used to discuss all design decisions and planning for project completion



Research

 * EE
 * ME