1. Property of Roger Cortesi, MIT Precision Engineering Research Group. DO NOT COPY or TRANSMIT without written permission. The Standard MiniMill™ Precision Engineering Research Group Massachusetts Institute of Technology, Mechanical Engineering Department A small milling machine using ball screws and linear rails Phone: (617) 253-1953 Fax: (617) 258-6427 http://pergatory.mit.edu/ Room 3-470 77 Massachusetts Ave. Cambridge, MA 02139 By: Roger Cortesi rcortesi@mit.edu http://pergatory.mit.edu/rcortesi/

2. Property of Roger Cortesi, MIT Precision Engineering Research Group. DO NOT COPY or TRANSMIT without written permission. The Standard MiniMill™ An Alternate to the original MiniMill™ By Roger Cortesi MIT Mechanical Engineering Precision Engineering Research Group 27 FEB 00

3. Property of Roger Cortesi, MIT Precision Engineering Research Group. DO NOT COPY or TRANSMIT without written permission. The Modified MiniMill™ Is the original machine design. It uses linear motors for motive power and air bearings for the linear guides. The Standard MiniMill™ This machine is the same as the modified machine, but the motive power is provided by ball screws. Ball Rails are the linear guides. The transition from the traditional technology in The Standard MiniMill™ to the technology in The Modified MiniMill™ can be done incrementally!!! I.E. it is very easy to have a machine that is: Powered by Ball Screws Guided by Air Bearings or Powered by Linear Motor Guided by Ball Rails

4. Property of Roger Cortesi, MIT Precision Engineering Research Group. DO NOT COPY or TRANSMIT without written permission. Using the traditional motive components (ball screws and ball rails) is less of a market risk than the linear motors and air bearing version of the MiniMill™. Why The Standard MiniMill™

5. Property of Roger Cortesi, MIT Precision Engineering Research Group. DO NOT COPY or TRANSMIT without written permission. The Standard MiniMill™ Features The same structural “L” shapes are used by both the Standard and Modified MiniMill™s. The same “L” mold can be used for either machine. Only the threaded insert patterns are different.

6. Property of Roger Cortesi, MIT Precision Engineering Research Group. DO NOT COPY or TRANSMIT without written permission. The Structural “L” for the Standard and Modified MiniMill™s The Standard MiniMill™The Modified MiniMill™

7. Property of Roger Cortesi, MIT Precision Engineering Research Group. DO NOT COPY or TRANSMIT without written permission. More Standard MiniMill™ Features All three axis use identical ball screws, ball nuts and ball rails for cost savings. Depending on the customer’s accuracy and price constraints, position sensing on the standard MiniMill™ can be done by a rotary encoder on the motor or a linear position encoder on the carriages.

8. Property of Roger Cortesi, MIT Precision Engineering Research Group. DO NOT COPY or TRANSMIT without written permission. Design Issues Still In Progress Axis motor selection –Currently Maxon™ Motor is the most likely. Stiffness estimates for the Standard MiniMill™ –The Standard MiniMill™ should be much stiffer than the Modified MiniMill™ Determine required accuracy grades on ball screw and linear rails and trucks Type and mounting locations for limit switches Type and mounting locations and type for bumpers Mounting hardware and locations for cable carriers

9. Property of Roger Cortesi, MIT Precision Engineering Research Group. DO NOT COPY or TRANSMIT without written permission. Parts to Order From Star Linear™

10. Property of Roger Cortesi, MIT Precision Engineering Research Group. DO NOT COPY or TRANSMIT without written permission. A View of the Standard MiniMill™’s X Axis Linear Position Encoder Not Shown Motor Mounted Here Details TBD

11. Property of Roger Cortesi, MIT Precision Engineering Research Group. DO NOT COPY or TRANSMIT without written permission. Optional Linear Position Encoder 12x5 Ball Screw Motor Mounted Here Details TBD 15mm Rails Fixed Pillow Block Floating Pillow Block Ball Nut A View of the Standard MiniMill™’s Y Axis

12. Property of Roger Cortesi, MIT Precision Engineering Research Group. DO NOT COPY or TRANSMIT without written permission. The New X and Y Carriages Obviously the X and Y Carriage from the Modified MiniMill™ wouldn’t work so here are the new ones X CarriageY Carriage Y Ball Nut Z Ball Nut Z Trucks (4) Y Trucks (4) Mounting Point for Optional Linear Encoder X Trucks (4)