| TABLE OF CONTENTS |
|---|
| 1. | Critical Factors | 3 |
| 2. | Creating a Reliable Design | 5 |
| 2.1. | Neutral Bend Axis | 5 |
| 2.2. | Bend Angle | 5 |
| 2.3. | Thickness | 6 |
| 2.4. | Bend Radius | 6 |
| 2.5. | Bend Ratio | 7 |
| 2.6. | Static vs. Dynamic Applications | 7 |
| 2.7. | Materials and Construction | 8 |
| 3. | Tips and Tricks | 10 |
| 4. | Summary | 11 |
| 5. | Figures | |
| 5.1. | Figure 1: A Circuit's Neutral Bend Axis, Ideally Located on the Central Plane of the Material Stack, Experiences None of the Tension or Compression That Affect Other Layers When the Circuit Is Bent | 3 |
| 5.2. | Figure 2: If a Circuit Is Not Properly Designed and Handled, Outer Layers Can Tear or Crack and Inner Layers Can Wrinkle or Delaminate | 3 |
| 5.3. | Figure 3: The Forces Created When a Circuit Is Flexed-Tension on the outside and Compression on the inside of a Bend-Increase with the Angle of the Bend | 5 |
| 5.4. | Figure 4: Because Circuits That Are Formed by Hand Can Be Bent Unevenly, It Is Preferable to Use a Forming Tool That Controls the Bend When It Is Formed | 5 |
| 5.5. | Figure 5: The Thicker a Circuit Is, The Less It Can Be Flexed without Damage | 6 |
| 5.6. | Figure 6: Sharper, i.e., Small Radius, Bends Increase the Risk of Damage When a Circuit Is Bent | 6 |
| 5.7. | Figure 7: Bend Ratio Is the Ratio of Bend Radius to Circuit Thickness | 7 |
| 5.8. | Figure 8: Plated through Holes Located near the Center of a Bend Can Be Stretched on One Side and Compressed on the Other Leading to Circuit Failure | 8 |
| 5.9. | Figure 9: Conductors Running through a Bend Area Should Always Run Perpendicular to the Bend as Shown on the Left, Not at an Angle as Seen on the Right | 8 |
| 5.10. | Figure 10: Because Conductors Stacked on Top of one Another Increase the Effective Thickness of the Circuit, It Is Preferable to Stagger the Conductors | 8 |
| 5.11. | Figure 11: Stitched Vias, Like through Holes, Should Be Kept out of Bend Area | 9 |
| 5.12. | Figure 12: Potentially Damaging Forces Can Sometimes Be Reduced by Unbonding Layers in the Bend Area | 10 |
| 5.13. | Figure 13: If the Unbonded Area Is Too Short (less than .75") the Resulting Buckling Can Lead to Unacceptably Tight Bend Radii | 10 |
