Description
Half-round quartz rod combines a flat mounting face and a curved face in the same fused quartz profile. Unlike standard round rod, the purchasing geometry is defined by the three dimensions that describe the semi-round section — width, height and radius — together with the finished length.
A true half-circle uses a height equal to the radius. Shallower-arc profiles can also be produced when the mounting face and curved working surface must follow a different section.
Dimensions
| Parameter | Range |
|---|---|
| Width | 1–100 mm, based on the parent round-rod diameter range |
| Height | Up to the full radius of the parent diameter |
| Radius | Defined by the required true half-circle or shallower-arc geometry |
| Length | 10–1200 mm standard stock; longer lengths by special order |
| Parent Rod Diameter Tolerance, As-Ground | ±0.05 mm precision grade |
| Length Tolerance | ±0.1–0.2 mm |
Material
| Property | Specification |
|---|---|
| Standard Material | Clear fused quartz; Type I or JGS2-equivalent material can be selected where required. |
| Softening Point | ~1730°C |
| Continuous Working Temperature | 1100–1250°C |
| Short-Term Temperature | Up to 1450°C, subject to part geometry and operating condition |
Production Method
Ground From Round Rod — A flat plane is generated along round fused quartz rod stock, leaving the required curved section and finished width / height relationship.
Direct Profile Forming — Half-round or shallower-arc geometry can also be formed directly when the required section is better controlled as a profile rather than as a secondary ground flat.
Surface Condition — The flat face and curved face can be supplied as-cut, ground or polished according to whether each surface is used for mounting, mechanical alignment or optical transmission.
Application Geometry
Half-round rod is used where the component needs a stable flat reference against a housing or mount while retaining a curved optical or mechanical working face. The flat prevents the part from rolling and can simplify fixture location compared with a full round rod.
| Geometry Requirement | Typical Use |
|---|---|
| Flat mounting datum + curved working face | Optical coupler geometry and alignment fixtures |
| Flat base + light-carrying curved section | Mounted light-guide elements where a full round rod would require a separate anti-rotation clamp |
| Controlled shallow arc | Custom mechanical or optical contact geometry where a true semicircle is not required |
Surface & End Finish
The cross-section and the optical path are specified separately. A half-round rod can therefore use a ground mounting face with a polished curved face, or polished end faces when the rod carries light along its length.
For light-guide use, the optical end condition can follow the Quartz Light Guide Rods specification, including Ra 0.05–0.2 µm polished optical faces and ±0.05 mm precision-grade parent rod diameter tolerance. This page remains focused on the half-round cross-section itself.
What to Specify
| Parameter | Quotation Input |
|---|---|
| Profile | True half-round or shallow-arc section |
| Width / Height / Radius | All three profile dimensions |
| Length | Finished rod length and tolerance |
| Flat Face | As-cut / ground / polished |
| Curved Face | As-formed / ground / polished |
| Ends | Cut / ground / polished / chamfered |
| Optical Requirement | State whether light is transmitted through the rod or through a polished face |
| Quantity | Prototype or production quantity |