Defining and tolerancing freeform surfaces for manufacturing

The adoption of freeform optics by designers and manufacturers has increased in recent years. With the increase of flexibility, a freeform surface can bring a system, it also brings more sensitivities. To effectively control these sensitivities during integration, the tolerancing needs to incorporate the limits of the metrology device for the tolerance operand under test. Understanding a vendor’s manufacturing and metrology capabilities is critical to designing and tolerancing a freeform surface that uses its physical features to aid in integration. Interfacing with a vendor early in the design process may improve manufacturing timelines due to the alignment of the freeform definition with the available metrology. Favorable freeform definitions will be reviewed along with tolerancing and specification recommendations.