Single Point Diamond Turning (SPDT)
Single Point Diamond Turning (SPDT) is a highly precise and advanced machining technique used to manufacture complex optical and mechanical components. The process employs a single-point diamond tool to remove material from a workpiece with exceptional accuracy, producing ultraprecision surfaces and geometries.
The primary advantage of SPDT lies in its ability to create intricate shapes and features with sub-micron level precision. This makes it ideal for fabricating components such as lenses, mirrors, prisms, and other optical elements used in industries including aerospace, defense, telecommunications, and medical devices. It is particularly effective for materials that are difficult to machine using conventional methods.
Beyond its remarkable precision, SPDT offers several additional benefits: reduced lead times, cost-effectiveness for small production runs, and the ability to achieve superior surface finishes without requiring post-polishing. As technology continues to advance, SPDT’s capabilities are expected to expand further, enabling the development of cutting-edge optical and mechanical systems across various industries.
Single crystal diamond turning tool is a kind of ultra-precision machining tool, which is mainly used in the processing of non-ferrous metals and non-metallic hard brittle materials such as nickel, copper, optical glass, ceramics and silicon wafers. Litian Century Diamond Tools has the state-of-the-art equipment for both producing and measuring our diamond turning tools. Our technicians have been working with diamond for more than 20 years now. We are constantly innovating and driving the company years ahead of the competition.
Contact Litian Century's engineering team to discuss your diamond turning tool requirements, request sample tooling, or arrange a technical consultation for custom tip geometries and tolerances.
Single-Point Diamond Turning (SPDT) — LTCT Single-Crystal Diamond Turning Tools
Single-point diamond turning (SPDT) tools are the industry standard for ultra-precision machining of non-ferrous metals, optical polymers and infrared materials. LTCT’s single-crystal diamond turning tools are engineered for demanding optical and micro-optical applications, enabling the production of high-quality surfaces and complex freeform geometries used in imaging, sensing and infrared systems.
Capabilities
· Geometry: Aspheres, diffractive/Fresnel structures, toroidal surfaces, conics, spheres and plano optics.
· Workpiece diameters: Suited for sub-millimeter features up to several-hundred millimeters (typical SPDT applications cover ~1–300 mm class parts).
· Materials: Optical polymers (PMMA/Acrylic, COP/COC, PS, Zeonex/Zeonor, Ultem), metals (nickel, aluminum, copper, brass) and infrared materials (silicon, chalcogenide glasses).
· Surface finish & tolerances: Tooling and process support ultra-low roughness finishes and tight form control. In industry practice, diamond-turned surfaces commonly reach tens of Å (angstroms) RMS and sub-micron to nanometer-level figure control for high-end applications; final polishing can further reduce residual tool marks when required.
Equipment & Tooling
· Engineered single-crystal diamond tips with very small radii for high-resolution feature generation (industry tool radii can be as small as a few micrometers).
· Compatible with high-precision SPDT lathes (NanoForm-class or equivalent) used for both rotationally symmetric and freeform optics.
· Suitable for both direct prototyping (polymer turning) and for producing master molds/inserts for high-volume replication such as injection molding.
Metrology & Quality Control
· Surfaces are validated with interferometry, white-light interferometry and profilometry to measure figure, micro-structure relief (diffractive/Fresnel) and roughness.
· Post-processing options to remove or reduce residual tool marks include bonnet polishing, magnetorheological finishing (MRF) and ion beam figuring (IBF), enabling optics to meet the tightest performance requirements.
Typical Applications
Imaging lenses and microscope optics, infrared and night-vision components, micro-optics, TIR and LED illumination optics, spectrometers, head-up displays, security domes, and precision sensors across automotive, medical, defense and consumer product markets.
Single Point Diamond Turning (SPDT) for Infrared Optical Components
Single Point Diamond Turning (SPDT) is a precision machining process that uses a diamond-tipped cutting tool to manufacture high-quality aspheric optical elements. It is particularly suited for producing ultra-precise infrared optical components, including infrared aspheric lenses, diffractive optics, spherical optics, and gratings.
By employing lathes equipped with diamond-tipped tools, SPDT allows for mechanical machining of infrared optical components with exceptional accuracy. This technique enables the production of crystal-based optical products with a level of precision that surpasses what is achievable with conventional machining methods.
FAQ
Q: What materials can be diamond-turned?
A: SPDT is commonly used with optical polymers (PMMA, COP/COC, PS, Zeonex, Zeonor, Ultem), non-ferrous metals (Ni, Al, Cu, Brass) and certain IR materials like silicon and chalcogenides. For many glass optics, the industry approach is to diamond-turn molding inserts and then produce glass parts via pressing or molding.
Q: What surface finish can be achieved?
A: Typical diamond-turned surfaces range from a few dozen to a few hundred Å RMS depending on material and process; specialized cases achieve single-digit–to–dozens of Å RMS on metals and sub-100 Å on polymers. Additional polishing steps can improve finish and remove tool marks as needed.
Q: Can SPDT be used for high-volume production?
A: Yes. SPDT is widely used for prototyping, for producing master molds/inserts, and for applications where the diamond-turned surface itself is acceptable for production volumes. When very high optical precision or glass optics are required, diamond-turned masters are commonly used to create molds for subsequent replication.
