1. PolyMUMPS Flexure Design
Garet Kim
Jessica McAlister
Lydia Tse

2. Overview
Project Goal
Design Background
Pulling Mechanism
Conclusion

3. Project Goal
1) A folding/extending stage is to be designed using flexure joints.
2) Produce predictable movement with the zero-backlash flexure.
3) Create a test bench of flexure designs

4. Flexure Spring Background

5. Flexures: Advantages Simple and inexpensive to manufacture
Virtually no irreversible deformations
Displacements are smooth and continuous
Predictable, repeatable motions
(even at atomic resolution)
Linear relationship between applied force and displacement for small distortions

6. Types of Flexures Leaf Hinge Notch HInge
Distributes deflection over length of hinge
-lower stress
-higher deflection to beam length ratio
More immune to parasitic forces

7. Predicting Motion
Simple application of bending theory:

8. Our Design Basic flexure (single or cascaded)
H flexure (single or cascaded)
Buckling flexure

9. BEAM LENGTH AND BEAM RATIO
Our Design
Test bench: To study the effects of varying different design properties
50 + variations
JOINT
DESIGN
NECK DESIGN
AND LENGTH
NUMBER OF FLEXURES
IN CASCADE
BEAM
WIDTH
BEAM LENGTH AND BEAM RATIO

10. Basic Flexure Anchor (Poly1 encloses Anchor1) Neck (Poly1)
Beam Length: 60 um
Beam Width: 12 um
Beam Ratio: 1 to 1
Neck Length: 5 um
Anchor (Poly1 encloses Anchor1)
Neck (Poly1)
1 um,
5 um,
9 um,
11 um,
13 um
33 um,
41 um,
49 um
Beam (Poly1)
Length: 60 um, 88 um, 90 um, 120 um, 168 um, 180 um, 248 um, 330 um, 660 um
Width: 8 um, 12 um
Ratio: 1 to 1, 1 to 3, 1 to 5, 2 to 1, 3 to 1, 5 to 1, 10 to 1

11. Basic Flexure Samples: Beam Length: 90 um Beam Width: 12 um
Beam Ratio: 2 to 1
Neck Length: 13 um
Beam Length: 180 um
Beam Width: 12 um
Beam Ratio: 5 to 1
Neck Length: 49 um
Beam Length: 168 um
Beam Width: 8 um
Beam Ratio: 3 to 1
Neck Length: 1 um
Beam Length: 330 um
Beam Width: 12 um
Beam Ratio: 10 to 1
Neck Length: 33 um

12. Animation (Basic)

13. Cascaded Basic Flexure
Linear (longitudinal) combinations of multiple basic flexures
Result in increasingly smaller / bigger movements than single basic flexure
Beam Length / Flexure: 248 um
Beam Width / Flexure: 8 um
Beam Ratio / Flexure: 5 to 1
Number of Flexures in Cascade: 3
Type of Joint Used: Spring #3

14. Number of Flexures in Cascade: 2, 3 Joint between 2 Flexures (Poly1)
Beam Length / Flexure: 168 um
Beam Width / Flexure: 8 um
Beam Ratio / Flexure: 3 to 1
Number of Flexures in Cascade: 2
Type of Joint Used: Spring #1
Number of Flexures in Cascade: 2, 3
Joint between 2 Flexures (Poly1)
Beam Length per Flexure: 168 um,
248 um
Beam Width per Flexure: 8 um
Beam Ratio per Flexure: 1 to 3, 3 to 1, 1 to 5, 5 to 1
Spring #1
Spring #2
Spring #3
Flexure

15. Connection Between Flexures
Prevents shear effects at the tip
Experimental. 4 kinds of connections (Flexure, 3 different springs

16. Animation (Cascade)

17. ‘H’ Flexure
Linear (both transverse and longitudinal) combinations of basic flexures
Transversely join two flexures at their anchors
Longitudinally join flexures as in cascaded basic flexures discussed in the previous section
Do not result in longitudinal movements
Beam Length / Flexure: 660 um
Beam Width / Flexure: 12 um
Beam Ratio / Flexure: 10 to 1
Number of Flexures in Cascade: 4
Type of Joint Used: Spring #3

18. ‘H’ Flexure Beam Length / Flexure: 660 um Beam Width / Flexure: 12 um
Beam Ratio / Flexure: 10 to 1
Number of Flexures in Cascade: 8
Type of Joint Used: Flexure
Beam Length / Flexure: 660 um
Beam Width / Flexure: 12 um
Beam Ratio / Flexure: 10 to 1
Number of Flexures in Cascade: 4
Type of Joint Used: Spring #1

19. Buckling Flexure Buckling should be avoided? Why?
Disadvantage: Tricky to get the output, need much more force to operate than basic shapes.
Advantage: Various transfer characteristics, most likely linear, and NEW !

20. Animation (Buckling)

21. Pulling Mechanism Pull-rings
Ad: Simple, guaranteed to work, easy operation
Dis: Inaccurate movements, low precision, relatively large

22. Pulling Mechanism Heatuators
Ad: Relatively simple, high precision and accuracy in movement, practical
Dis: Small range of movement, need a bank of them to work with flexures, occupy a larger area than a pull-ring

23. Pulling Mechanism Linear Stepper Motor
Ad: Large range of operation, practical
Dis: complicated, large units of movement, significant real estate required

24. Test Bench
Our designs are placed to test effects caused by different shapes or parameters of flexures.
Example (Single basic with a regular neck)
Different Lengths
Name
Length
Width
Neck
Ratio
basic_660_a13_10to01
660 11
13 X 4
10:01
basic_330_a13_10to01
330
Width
Name
Length
Buckling_598_thin_good
598 11
Buckling_598_good 16
Different Springs
Name
Length
Width
Neck
Ratio
# Cascades
Spring
h2x2_10x1_sn_s3
330 10
11 X 3
10:01 4 s3
h2x2_10x1_sn_s2 s2

25. Test Bench Different Necks Different Ratios Length Width Neck Ratio
Name
Length
Width
Neck
Ratio
basic_360_a13_05to01
360 11
13 X 4
5:01
basic_360_a11_05to01
11 X 4
basic_180_a13_02to01
180
2:01
basic_180_a11_02to01
Different Ratios
basic_180_a13_05to01

26. Conclusion
Hope all the flexures work as predicted. Let’s cross our fingers!
Hope our flexures would provide insights for future designs that can produce precise movements on the angstrom scale.
Any Questions?