Diamond Turning

Single Point Diamond Turning (SPDT) plays a key role in nearly all of our polymer optics programs. Whether it’s prototyping, tooling inserts, pilot production, or some combination of the three, diamond turning is a fundamental part of our process.

At Diverse Optics, we diamond turn some of the most challenging optical elements with complex forms and shapes in-house.


  • Can it be made? Optical engineers are constantly challenging us with increasingly difficult designs that push the limits of manufacturability.

  • How will it perform in the system? Rapid prototyping by diamond turning a few optical elements allows engineers to test their optical designs in their systems before heavy investments in tooling capital. Often times, this pays off!

  • Feasibility for polymer in the system? Not sure if a polymer optic will perform as well as glass in your system? Give it a try first and know for sure (usually it does just fine).

  • Diamond turning for molding. Although we are precision injection molders, the diamond turning process is more precise. When we know your optics will ultimately be injection molded, we intentionally diamond turn prototypes in the tolerance range of injection molding to provide prototypes that mirror injection molded optics tolerances. This allows optical engineers to accurately assess whether optical systems contain the proper tolerance stack for molded optics.

Injection Mold Inserts

  • New Optical Mold Inserts – We diamond turn our optical mold surfaces in-house to ensure full control of form, surface roughness, and mechanical dimensions.

  • New or Transfer Mold Insert Error Compensation – Optical surfaces are first diamond turned to the nominal prescription and injection molding trials begin. However, polymer doesn’t always follow the rules and shrink uniformly – especially with free form surfaces. In this case, we perform advanced form metrology, feed that data into our diamond turning machine, and then re-cut the mold inserts to compensate for the inherent error in the molding process. After post-mold shrink and stabilization, the result is a molded optic that meets prescription specifications for form – spot on.

  • Optical Insert Maintenance – We have the equipment onsite to perform 100% cleanup cut to breathe new life into old optical inserts and extend the longevity of molds transferred to Diverse Optics.

Pilot Production

  • Bridge the gap between injection mold build time and immediate market demand

  • Test market acceptance prior to investment in tooling

  • When specifications are just too tight for injection molding

Polymer Quality (Nd)±0.01±0.001± 0.001
Radius± 0.5 %± 0.1 %± 0.05 %
Diameter (mm)+ 0.000 / – 0.050+ 0.000 / – 0.025+ 0.000 / – 0.010
Roughness Ra (nm)7-104-73-4
Surface Finish (scratch/dig)80/5060/4040/20
Freedorm optics geometry (um)10-155-102-5
Irregularities for 25 mm diameter max (fringes)10.50.25
Centering (arc min)210.5