1. What is Blank Size Calculation?

Blank size calculation determines the required size of lens blanks needed for optical manufacturing. It ensures proper material allocation and minimizes waste in the lens production process.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• Lens Diameter — The final diameter of the finished lens (mm)
• Margin — Additional material needed for processing and edging (mm)

Explanation: The margin accounts for material lost during cutting, polishing, and fitting the lens into frames.

3. Importance of Blank Size Calculation

Details: Accurate blank size calculation is crucial for cost-effective lens production, minimizing material waste, and ensuring proper lens fit in frames without compromising optical quality.

4. Using the Calculator

Tips: Enter the final lens diameter and required processing margin in millimeters. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical margin value?
A: Margin typically ranges from 2-5mm depending on the lens type and manufacturing process.

Q2: Does blank size affect lens thickness?
A: While blank size primarily affects diameter, it can indirectly influence edge thickness in minus lenses and center thickness in plus lenses.

Q3: Are there standard blank sizes?
A: Yes, manufacturers typically produce blanks in standard sizes (e.g., 65mm, 70mm, 75mm), so calculated sizes are rounded up to the nearest available standard.

Q4: How does lens material affect blank size calculation?
A: Different materials may require different margin values due to varying processing characteristics and brittleness.

Q5: Can this calculator be used for both single vision and multifocal lenses?
A: Yes, though multifocal lenses may require additional margin for proper segment placement and optical alignment.