CNC Optical Curve Generator Auto-SG-50
A CNC optical curve generator that grinds a spherical or flat surface on one blank at a time, loaded from a tray, with the sagitta measured and corrected inside the cycle. Sapphire, optical glass and technical ceramics, Ø10–55 mm.
What this machine makes, and what happens before and after it
An optical element starts as a sawn or pressed blank and ends as a coated, centred lens. A CNC optical curve generator owns one step in the middle: it cuts the radius of curvature into the face of the blank and brings the centre thickness close to the drawing. Everything upstream supplies it; everything downstream inherits whatever it leaves behind.
The part that leaves this machine is not finished. Its radius and centre thickness are close enough to specification that the lapping and polishing stage removes microns rather than re-cutting the curve. That is the whole job — and it is why the depth of subsurface damage left in the optical lens at this stage matters more than the surface finish you can see.
Think of a CNC optical curve generator as the machine that decides what shape the lens is. The machines after it decide how smooth it is.
How does a CNC optical curve generator produce a radius?
No template, no copy former, no profile cam. On this class of machine the radius comes out of an angle.
Two spindles do the work. The tool spindle carries a diamond cup wheel — a ring whose rim is charged with diamond grit — and turns it at up to 8,000 rpm. The workpiece spindle holds the blank on a vacuum chuck, rotates it slowly at 0–35 cycles per minute, and feeds it axially into the wheel under servo control.
Because the cup wheel is tilted, its circular cutting edge sweeps out a sphere as the blank turns underneath it. The radius of that sphere is fixed by geometry alone:
- sin θ = d / (2R) — where θ is the spindle tilt, d the effective cutting-edge diameter of the cup wheel, and R the radius produced
- θ = 0° — the two axes are parallel and the machine generates a plane
- θ up to 45° — the steeper the tilt, the shorter the radius, down to R5 mm
- Convex or concave — decided by which side of the workpiece axis the wheel is tilted to
Set the angle once at setup and every part in the tray comes out with the same radius. This is why a CNC optical curve generator has no tooling to change between one radius and the next — only the angle and the wheel.
You are not buying a fixed set of radii. You are buying a range, R5 mm to plane, and the wheels that suit your materials. Ask for the wheel specification with the quotation, not after it.
Four things the machine does while nobody is watching
This is where a CNC optical curve generator separates itself from a manually operated one. Each of these replaces a decision an operator would otherwise make part by part.
Measures the sagitta and corrects itself
A data-transmitting micrometer touches the machined face inside the cycle and reports the sagitta — the depth of the curve. If the wheel has worn and the reading has drifted, the machine compensates the feed on the next part. Nobody has to notice the drift first.
Tells the two faces of a blank apart and flips it
Many blanks arrive with one face already worked. The machine identifies which face is presented and turns the part over when it needs to, so a tray does not have to be hand-sorted before it goes on.
Dresses its own wheel on a set interval
An oilstone dressing device trues the cup wheel automatically. You set the interval and the number of dressing passes on the touchscreen; a blunt wheel stops being something the operator has to catch.
Refuses to run on an empty chuck
Vacuum on the workpiece hold-down is monitored continuously. If the part is not there or has released, the cycle does not start. Empty cycles are what crash a cup wheel into a chuck.
Five stages, set independently
On a CNC optical curve generator the axial feed is not one continuous plunge. It runs as a five-stage servo program, and the stroke and speed of each stage are set separately on the touchscreen. In practice that means a fast approach, an aggressive rough stage while there is stock to remove, then progressively lighter stages as the surface comes up — so the last microns are taken off a brittle material at a feed it can survive.
| Element | Motion | What it controls |
|---|---|---|
| Tool spindle | Rotation, 8,000 rpm | Cutting speed at the diamond rim |
| Tool spindle mount | Tilt 0°–45°, set at setup | The radius that will be generated |
| Workpiece spindle | Rotation, 0–35 cpm | Sweeps the wheel edge over a full sphere |
| Workpiece spindle | Servo axial feed, 5 stages | Stock removal rate and final thickness |
| X / Y modules | Travel 600 / 400 mm | Positions blank tray and finished-part tray |
| Pneumatic transfer | Linear strokes and swing arm | Pick, centre, clamp, flip, return each part |
On any CNC optical curve generator a five-stage program is only as good as the stage boundaries. Getting them right for a new material takes trial parts, not a manual. This is the main thing we work out with you during commissioning — and the reason we ask for your blanks before quoting.
Which materials and geometries can it handle?
| Item | Capability |
|---|---|
| Surfaces generated | Convex and concave spherical surfaces; plane (flat) surfaces |
| Radius range | R5 mm to plane, set by tool-spindle tilt 0°–45° |
| Workpiece diameter | Ø10 – Ø55 mm |
| Workpieces per cycle | 1 — single-part handling from tray |
| Materials | Sapphire, optical glass (crown / flint), technical and optical ceramics, and other hard brittle optical substrates |
| Thickness control | In-process sagitta measurement with automatic feed compensation |
| Face recognition | Automatic identification of both faces, with automatic flip when required |
| Wheel dressing | Automatic; interval and dressing count settable on the touchscreen |
| Part-presence check | Vacuum monitoring of the hold-down; empty cycles prevented |
If your drawings are dimensioned to the ISO 10110 framework, send one with the enquiry. The radius tolerance and centre-thickness tolerance on that drawing are what decide whether this class of CNC optical curve generator is right for the job — not the material.
Technical specifications
The larger Auto-SG-80C is the same CNC optical curve generator architecture with a Ø5–80 mm capacity and 2.0 kW installed power.
| Curvature machining range | R5 mm – flat (plane) |
| Diameter machining range | Ø10 – Ø55 mm |
| Spindle adjustment angle | 0° – 45° |
| X / Y travel | 600 mm / 400 mm |
| Tool spindle speed | 8,000 rpm |
| Spindle accuracy | ≤ 0.01 mm |
| Workpiece speed | 0 – 35 cpm |
| Spindle mounting | Ø24 / M20 × 1.5 |
| Total installed power | 1.8 kW |
| Overall dimensions (L × W × H) | 1400 × 900 × 1600 mm |
| Total weight | approx. 800 kg |
| Air supply | 5 kgf/cm² (≈ 0.5 MPa) |
| Base construction | Cast iron, hand-scraped mating surfaces |
| Control | PLC with 7″ touchscreen, English interface |
Principal components
Brands are indicated for reference. Equivalent components of the same or higher grade may be fitted; the stated performance is maintained in all cases.
| Component | Brand / standard |
|---|---|
| Spindle motor | Premium servo brand |
| HMI / PLC | Delta or equivalent |
| Spindle bearing | NSK or equivalent |
| Servo motor / drive | Delta or equivalent |
| Control system | Proprietary, developed in house |
| Pneumatics | AirTAC or equivalent |
| X / Y linear module | Minebea or equivalent |
| Linear guide / ball screw | HIWIN / TBI |
| Electrical components | Omron or equivalent |
| Measuring gauge | Sylvac or equivalent |
Main assemblies and what each one is for
Ten sub-assemblies make up the CNC optical curve generator. If something needs attention on the shop floor, this is the vocabulary your operator and our service engineer will share.
| Assembly | Function |
|---|---|
| X / Y module | Servo-driven linear gantry carrying the workpiece between the blank tray and the finished-part tray |
| Workpiece trays | Parallel blank tray and finished-part tray for automatic loading and unloading |
| Tool spindle head | Carries the diamond cup wheel; tilt adjustable 0°–45° to set the generated radius |
| Workpiece spindle | Vacuum chuck with servo axial feed; runs the five-stage machining program |
| Oilstone dressing device | Automatic wheel dressing; interval and count settable |
| Sagitta measuring device | Data-transmitting micrometer checking sagitta and feeding back for compensation |
| Pneumatic transfer group | Cylinder combinations performing pick-up, transport, centring, clamping and flipping |
| Coolant system | Circulating supply with the tank in the machine base |
| Operation panel | External hard buttons plus 7″ touchscreen for parameters, inspection and troubleshooting |
| Electrical cabinet | Control system and electrical components; residual-current protection fitted |
Utilities, environment and safety
Electrical supply, compressed air, coolant, floor loading and the ambient conditions the machine is to run in are confirmed with us for each order, together with the safety and protective arrangement supplied with it. These figures depend on the voltage and frequency of your site, the material you are running and the destination market, so we do not publish a single set of them here.
Send us the site conditions with your enquiry and we will return the utility and environmental requirements in writing, before the order is placed.
On a CNC optical curve generator the diamond cup wheels and dressing stones are process consumables chosen for the material and the radius being generated. They are quoted separately from the machine — tell us your materials and radii and we will specify them.
What happens after the machine is installed?
The same terms apply to every machine we ship, wherever in the world it goes.
| Warranty period | 12 months from final acceptance |
| Response during warranty | Response within 8 hours · solution proposed within 24 hours · issue resolved within 48 hours, including procurement, installation and commissioning of parts |
| After the warranty period | Service and spare parts available for the life of the machine |
| Certification | CE |
Specifications are subject to change as a result of design upgrades. Minor differences may occur at certain parts. For a binding specification, refer to the order confirmation.
See the machine running
The CNC optical curve generator running spherical generating on optical glass, and the tray-to-tray loading cycle with nobody at the machine.
01 — Spherical generating cycle, optical glass blank
02 — Tray-to-tray loading, flipping and unloading
Send one drawing and a few blanks
A CNC optical curve generator is easy to specify badly from a datasheet. Send us one element drawing — diameter, radius, centre thickness, material and the tolerance grade you have to hold — together with a few of your own blanks. We run them, return them, and send the process sheet with the quotation.
If your tolerances need a machine class we do not build, we will tell you that instead of quoting.
12-month warranty · free trial run on customer-supplied material
Optics customers include Edmund Optics and Coherent
Related equipment and reading:
- Optical lens grinding machine range — all eight generating machines compared
- Automatic lens profiling edger Auto-EG-80 — the edging stage downstream
- Optical lens fabrication line — how the six stations connect
- Full equipment range