With spin casting, a faster speed creates a steeper curve.

With spin casting, a faster speed creates a steeper curve.

• A. Slower
• B. No effect
• C. Faster
• D. Both

Answer: (C)

Spin casting relies on centrifugal forces to shape the liquid lens as it sits between the mold surfaces. When you spin faster, the liquid experiences stronger outward forces, redistributing more material toward the edge and thinning the center. That thinner center and tighter fit to the mold boundary produce a surface with a smaller radius of curvature, i.e., a steeper curve. If you spin more slowly, the center remains thicker and the curve is flatter. Since speed directly changes how the film thickness and surface profile respond, a faster spin indeed creates a steeper curve.

Spin casting relies on centrifugal forces to shape the liquid lens as it sits between the mold surfaces. When you spin faster, the liquid experiences stronger outward forces, redistributing more material toward the edge and thinning the center. That thinner center and tighter fit to the mold boundary produce a surface with a smaller radius of curvature, i.e., a steeper curve. If you spin more slowly, the center remains thicker and the curve is flatter. Since speed directly changes how the film thickness and surface profile respond, a faster spin indeed creates a steeper curve.