Chamfers and Flanges in QUADOA® Optical CAD
In QUADOA® Optical CAD you can define the complete lens edge geometry, including chamfers and flanges, directly in the optical design. This tutorial shows how to enable chamfers, add symmetric or asymmetric chamfers, choose one of four chamfer geometry options and add flanges for mounting. Because the non-optical surfaces are already part of the design, optimization takes the real lens dimensions into account, the usual post-processing step in mechanical CAD software can be skipped, and ISO 10110 lens drawings including the chamfer specification can be generated directly.
Key points
- Chamfers and flanges are set in the Lens Settings Editor, under Non-Optical Surfaces.
- A symmetric chamfer is entered once and applied to all lens edges. An asymmetric chamfer has a different geometry on each surface.
- Four geometry options: 45° by Height, 45° by Diagonal, Height & Length and Angle & Height.
- On cemented lenses, chamfers are added only to the outer surfaces.
- Flanges are mainly used on injection-molded polymer lenses to integrate mounting features.
- Chamfers and flanges always start at the clear aperture: the lens diameter grows, the clear aperture and the optical surfaces stay the same.
- Edge thicknesses and edge air spaces include chamfers and flanges, so optimization is based on the real physical dimensions.
Terms used in this article
- Chamfer
- An angled surface cut at the outer edge of a lens, between the optical surface and the lens rim.
- Flange
- A flat ring outside the optical surface, typically used as a mounting or reference feature.
- Non-optical surfaces
- All lens surfaces outside the clear aperture that do not take part in imaging, such as chamfers, flanges and the lens rim.
- Clear aperture
- The region of a surface that all traced rays pass through.
- Physical diameter
- The full outer diameter of the lens, including chamfers and flanges.
Why define lens edges in the optical design software?
Defining the complete lens geometry, including the non-optical surfaces, in QUADOA® has several advantages:
- More realistic optimization. Edge thicknesses and edge air spaces are calculated with the chamfers and flanges included, so the optimizer works with the real physical dimensions of the lenses, including the geometry outside the clear aperture.
- The design looks like the manufactured part. The optical system shows the real geometric dimensions of each element, in the 3D view and in the lens drawing.
- No post-processing in mechanical CAD. Chamfers and flanges are usually added later in mechanical design software. With the geometry already defined in the optical design, this step can be skipped.
- Complete ISO 10110 drawings. Lens drawings according to ISO 10110, including the chamfer specification, are generated directly from the design (File tab → ISO 10110 Lens Drawing). The table with lens properties and tolerances can be edited, is saved with the model, and the drawing can be exported as PDF or SVG. Tolerance settings can be saved as default or stored in a file and reused.
- CAD export with real dimensions. With Export to CAD (STEP, IGES or STL), the lenses are exported with their physical size, so mechanical designers receive the actual part geometry.
What is a chamfer and why add one?
A chamfer is added to the outer perimeter of a lens for three main reasons:
- Protection: it reduces the risk of chipping during handling or mounting.
- Weight: larger chamfers reduce the weight of the lens.
- Space: larger chamfers make room for other components, such as iris diaphragms.
Chamfers are always added outside the clear aperture. Adding a chamfer therefore increases the physical diameter of the lens.
How to enable chamfers
- In the Optical Design Editor, select the lens element you want to add a chamfer to.
- Click the plus (+) icon next to the lens type description. The Lens Settings Editor opens.
- Under Non-Optical Surfaces, activate the Enable checkbox.
How to add a symmetric chamfer
In many cases the same chamfer geometry is used on all lens edges. A symmetric chamfer is specified only once and applied to all edges of the lens.
- Select the lens in the Optical Design Editor.
- Click the plus (+) icon to open the Lens Settings Editor.
- Under Non-Optical Surfaces, check Enable and Symmetric.
- Choose how the chamfer is defined (see chamfer geometry options) and enter the value.
- Click Update.
Example: For a singlet lens, choose 45° by Height and enter a height of 1.5 mm. After Update, the chamfer appears on both surfaces in the 3D view and in the lens drawing.
How to add an asymmetric chamfer
An asymmetric chamfer has a different geometry on each surface of the lens. Use it when mechanical, manufacturing or assembly requirements differ between the two sides.
- Select the lens in the Optical Design Editor.
- Click the plus (+) icon to open the Lens Settings Editor.
- Under Non-Optical Surfaces, check Enable and leave Symmetric unchecked.
- Choose how the chamfer is defined and enter the values for each surface.
- Click Update.
Example: For a doublet, choose Height & Length, enter 0.5 mm height and 0.5 mm length for the first outer surface, and different values for the second outer surface.
Cemented lenses: Chamfers can also be applied to cemented lens elements. QUADOA® adds the chamfer only to the outer surfaces and leaves the cemented surface unchanged.
Chamfer geometry options
The chamfer can be defined in four ways. Choose the one that matches how the chamfer is given in your drawing or specification, so you don’t need to convert values.
| Option | Values you enter | Chamfer angle |
|---|---|---|
| 45° by Height | Height of the chamfer, measured perpendicular to the optical axis | 45° |
| 45° by Diagonal | Length of the chamfer surface itself | 45° |
| Height & Length | Height (perpendicular to the optical axis) and length (parallel to the optical axis) | Follows from height and length |
| Angle & Height | Height and the angle between the chamfer surface and the outer surface of the lens (parallel to the optical axis) | As entered |
For a 45° chamfer, height and length are equal, and the diagonal is √2 times the height. For example, a 0.5 mm × 45° chamfer by height has a diagonal of about 0.71 mm.
What is a flange and how do I add one?
For injection-molded polymer lenses, the non-optical surfaces are subject to far fewer manufacturing constraints than for ground and polished glass lenses. This freedom can be used to build mounting features directly into the lens. One of the most common is a flange.
Steps
- Select the lens in the Optical Design Editor and click the plus (+) icon to open the Lens Settings Editor.
- Under Non-Optical Surfaces, enter the Flange Size at the bottom, for example 1.5 mm.
- Click Update.
Flanges on doublet lenses
Flanges can also be asymmetric. For doublet lenses, QUADOA® offers additional options for defining the flanges.
Surfaces with different clear apertures
If the two surfaces of the lens have different clear apertures, the flange size you enter refers to the smaller clear aperture. QUADOA® automatically enlarges the second flange to close the gap between the specified flange and the larger clear aperture.
How chamfers and flanges relate to the clear aperture
Important: Chamfers and flanges always begin at the clear aperture. The overall lens diameter increases by the size of the chamfer or flange, while the clear aperture, which contains all traced rays, remains unchanged. Adding chamfers or flanges does not affect the optical surfaces.
The size of the clear aperture itself is controlled by the aperture settings of each surface. To learn how floating apertures and aperture margins work, see Floating apertures and lens edge settings in QUADOA®.
Video tutorial: chamfers and flanges
This 5-minute video shows how to define chamfers and flanges on lens edges in QUADOA® Optical CAD.
Video length: 5:27 min · Also on YouTube: Chamfers and Flanges in QUADOA® Optical CAD
Frequently asked questions
A chamfer is a small angled surface at the outer edge of a lens. It reduces the risk of chipping during handling and mounting. Larger chamfers can also save weight or make space for other components such as iris diaphragms.
No. In QUADOA® Optical CAD, chamfers and flanges always start at the clear aperture. The overall lens diameter increases to accommodate them, while the clear aperture, which contains all traced rays, and the optical surfaces stay the same.
Yes. Edge thicknesses and edge air spaces are calculated with chamfers and flanges included, so the optimization is based on the real physical dimensions of the lenses, including the geometry outside the clear aperture. This gives a more realistic optimization result.
A symmetric chamfer uses one geometry that is applied to all edges of the lens, so you enter it only once. An asymmetric chamfer lets you define a different chamfer on each surface of the lens.
Yes. For cemented lens elements, QUADOA® adds the chamfer only to the outer surfaces. The cemented surface is left unchanged.
There are four options: 45° by Height, 45° by Diagonal, Height & Length, and Angle & Height. You can enter the chamfer in the format given on your drawing or specification, without converting values.
The flange size you enter refers to the smaller clear aperture. QUADOA® automatically enlarges the second flange to close the gap between the specified flange and the larger clear aperture.
Yes. Once the lens edge geometry is defined, QUADOA® Optical CAD generates lens drawings according to ISO 10110 directly, including the chamfer specification.
As PDF or SVG. The table with lens properties and tolerances can be edited and is saved together with the model.