The Challenge: Using tools found in the standard Fab Lab inventory, build a universal XYZ gantry capable of serving as the foundation for a variety of low cost personal fabrication machines.
The Story: In August 2009, MIT graduate student Maxim Lobovsky and I were sent to India by the MIT Center for Bits and Atoms to build a personal fabrication machine in the just erected Pune Fab Lab. We spent the first four days of our trip machining the aluminum structural tubes of the XY stage and Z axis using a ShopBot CNC wood router. Another day was consumed producing the plywood base, and yet another designing and laser-cutting the table. We also had the opportunity to work with students from the College of Engineering, Pune, (COEP) during the assembly process. After a week and a half the machine was producing networked stepper motor drivers capable of controlling the machine itself. This work was then presented at FAB5, the Fifth International Fab Lab Forum and Symposium on Digital Fabrication, which took place concurrently on the COEP campus. Since our trip, the machine design has been iterated upon four times. One of the descendants (shown above) was used by students in MIT's "MAS.863: How To Make (almost) Anything" to produce circuit boards for their weekly assignments.
Selected Design Features: Two perpendicular shafts, each pulled by a set of belts and a high-resolution stepper motor, control the position of a toolhead located at their intersection. These shafts are supported by ball bearings which roll on inside surfaces of an aluminum tubular frame. A high-speed (20k RPM) spindle is implemented with $60 of entirely off-the-shelf components. Future plans involve adding an extrusion head and experimenting with combined extrusion and milling to increase accuracy and potentially reduce build times.
|FabMate Rev. 2 was constructed at FAB5 in Pune, India.||The aluminum structural tubes were milled on a CNC wood router.|
|Students from the College of Engineering, Pune, were eager to help us during assembly.||The machine's working volume is roughly 8" x 8" by 6".|
|The machine's spindle is constructed entirely from off-the-shelf components.||Circuit boards can be milled at three times the speed of the Roland Modella, the standard Fab Lab PCB-making tool.|
|The first object fabricated on the machine was an Internet Zero networked stepper motor driver board, intended to control the machine which made it. Mwahahaha.||FabMate Rev. 3 was built at MIT upon returning from India.|
|Students in "MAS.863: How To Make (almost) Anything" fabricated their assignment on the machine.||FabMate Rev. 1 was milled on a manual Bridgeport knee mill.|
|A planar design was aimed at halving the height of the XY stage.||A single length of bent tubing was explored as a possible alternative to stacked tubes.|
|A folded T-profile aluminum version was built in an attempt to reduce cost, weight, and assembly steps.||FabMate Rev. 4 is currently in the works.|