Designing a low cost XY stage for abrasive water jet cutting

Abstract

This thesis guides the reader through the design of an inexpensive XY stage for abrasive water jet cutting machine starting with a set of functional requirements and ending with a product. Abrasive water jet cutting allows for mass customization of 2D parts, such as inlaid tiles. Most water jet cutters are based on a prismatic-prismatic design (gantry type). In an effort to reduce the number of precision parts in the machine, a rotary-rotary parallel drive design is proposed. The proposed mechanism will be actuated by electric DC windshield wiper motors directly coupled to the links, this eliminates the need for gearing mechanisms that add up to the total cost and complexity of the design. Kinematics of the design is simulated for a working area of 310mm x 310mm. Dynamic analysis is performed and the concepts of decoupled and configuration invariant inertia are derived, simplified to a set of conditions on the kinematic structure/mass properties of the arm linkages and applied to significantly simplify the mechanism's control system. The XY stage was designed to be inexpensive and small enough to be placed in hardware stores, garages and small machine shops. A vision of water jet cutters sold in boxes stacked on shelves in Wal-Mart, available for all machinists, artists, schools, and industries might one day thus become a reality if the pumps could also be made cheaply.