Design of a Tensile Load Frame for a Scanning Electron Microscope Senior Design Project 04004

1. Design of a Tensile Load Frame for a Scanning Electron Microscope Senior Design Project 04004 Project Manager - Robert Rinefierd Faculty Mentor - Dr. Elizabeth Debartolo Kate Gleason College of Engineering

2. Team Members • Project Manager – Robert Rinefierd • Lead Engineer – Evan Kastner • Mechanical Engineers • Nicholas Currier, Evan Kastner, Robert Rinefierd, Blaine Stuart • Industrial Engineer • Kennedy Mogwai • Computer Engineer • Evan Brunner Kate Gleason College of Engineering

3. Agenda • Project Overview • Objectives and Specifications • Final Design • Manufacturing and Assembly • Production Report • Recommendations Kate Gleason College of Engineering

4. Project Overview • Design and construct a load frame to apply tensile loads to specimens inside the Scanning Electron Microscope (SEM) in the CIMS Materials Science Lab • The load frame should be lightweight, modular, and easy to carry between buildings • Developed for Mechanical Engineering Department faculty and students performing metallographic research • Funded by the Mechanical Engineering department Kate Gleason College of Engineering

5. Objectives and Specifications • Performance • 200 lbs Compression, 2000 lbs Tension • Position and Load Control • Live Displays • Implementation • Cylindrical Threaded Specimen • Remove Part of Position Frame • Evaluation • Pass Fatigue and Stress Calculations • Safety • Vacuum • Electrical Grounding Kate Gleason College of Engineering

6. Design Constraints • Spatial constraints • Vacuum compatibility • CIMS Materials Lab owns the SEM; Mechanical Engineering department will own the load frame • Load frame to mount to existing position fixture • Limited to existing ports for vacuum feedthrough • Budget - $7,500 Kate Gleason College of Engineering

7. Existing SEM Load Frames • Lehigh University concept • Tension, bending, compression • Spur gears and worm gears • US Patent • Temperature controlled • Southwest Research Institute (Dr. Davidson) • Fatigue testing capability • Custom designs for individual applications • Provided general ideas Kate Gleason College of Engineering

8. Final Design Motor and gearbox Specimen Gears Load cell Six basic Modules • Motor and Gear Box • Drivetrain • Gripping • Base and frame • Control system • Vacuum interface Grip and collar Lead screw Fixed end and base Free end Kate Gleason College of Engineering

9. Motor and Gearbox Selection • Motor Specifications: • Vacuum Rating – 10-7 torr • Maximum torque of 2 in·lb, driven at ~1 in·lb • Gearbox Specifications: • Vacuum Rating – 10-7 torr • Reduction Ratio – 700:1 • Maximum torque output of 1040 in·lb • Cost is high, but parts are necessary Kate Gleason College of Engineering

10. Drivetrain - Gears • Consists of two 2.5” diameter spur gears and a 1” diameter pinion gear. • Gearing reduction of 2.5 • Case hardened 8620 steel • Spur gears transmit torque to the power screws though keys. Kate Gleason College of Engineering

11. Drivetrain - Power Screws • ACME 1-10 2G threaded rods with end machining - self locking capability • Gray iron ACME nuts inserted in free end ACME thread Bearing shaft Gear shaft Keyway Kate Gleason College of Engineering

12. Drivetrain – Bearings and Nuts • Fixed end – bearing bores for shafts • Bearings and washers to reduce friction and add stability • Free end – ACME nuts instead of taps Kate Gleason College of Engineering

13. Grip Design • 3/8 – 24 threaded grip • Load cell acts as opposite grip • Easy to change samples • Standard ASTM threaded samples • Test Area • Gage length of 1 inch • Diameter of ¼ inch Collar Grip Load Cell Kate Gleason College of Engineering

14. Base and Frame • Purpose • Interface between load frame and SEM • Mounting surface for stage • Hold SEM position resolution device • Function • Matched bolt holes • Designed to withstand 100 lb external force (leaning) while it sits on a table. Kate Gleason College of Engineering

15. Control System- Physical Layout Kate Gleason College of Engineering

16. Controls • Control through LabView • End user definable • USB Minilab 1008 • Stock or freeware libraries • Hard emergency stop Kate Gleason College of Engineering

17. Vacuum Interface Vacuum chamber Available port 2 ¾ “ Flange Pro/E Model Kate Gleason College of Engineering

18. Stress Analysis Selected hand calculations for major components Kate Gleason College of Engineering

19. Stress Analysis • Verified preliminary calculations done for major parts • Shear stress, Von Mises stress, and displacement in gears, free end, and ACME shafts • Load conditions were maximum possible Kate Gleason College of Engineering

20. Design for Manufacture and Assembly • Assembly sequence • DFA Index – 6.23% • Minimum Number of Parts - 15 • Theoretical number of parts -61 • Estimated cost - $7223.50 Kate Gleason College of Engineering

21. Manufacturing and Assembly • Manufacturing Plan • Machine sequence • Tolerances • Quality checks • Total hours • Pro/E drawings • Cutting speed and feed rates • Machine tools Kate Gleason College of Engineering

22. Cost Analysis Kate Gleason College of Engineering

23. Production Report • Early March: • Completed of all aspects of mechanical design • Submitted purchase order for components • Mid-March: • Completion of detailed design including FEA analysis • Design for assembly analysis • April: • Fabrication of steel components • Development of control system with LabView • Submit order for all additional standard components • May: • Assembly and troubleshooting • Early June: • Motor and gearbox expected to arrive for assembly • Electromechanical integration and system troubleshooting Kate Gleason College of Engineering

24. Recommendations • Weight of load frame may be an issue • Alignment – threads are general fit rather than precision fit • Position resolution - encoder • Optimize control system after motor arrives Kate Gleason College of Engineering

25. Acknowledgements • Dr. DeBartolo – Faculty Mentor • Dave Hathaway and Steve Kosciol • Dave Fister, Mike Haselkorn, Newton Green – NCR³ • Charlie Clark and Frank Rheaume – Gleason Works • Ron Foster – Empire Magnetics Kate Gleason College of Engineering

26. Questions and Discussion Kate Gleason College of Engineering