Six Spindle Optical Polishing Machine FP-6U
A six spindle optical polishing machine that fine-grinds and polishes six small concave lenses at once, each spindle swinging on a spherical centre. R1–R20 mm up to Ø30 mm, pneumatic down-force, six axes running independently.
What this machine does, and what happens before and after it
After a blank has its curve generated, the surface is the right shape but still ground grey and micron-rough. A six spindle optical polishing machine owns the middle finishing steps: it fine-grinds the generated surface true, then polishes it clear, working the radius closer to the drawing while it improves the finish. This is the upper-swing member of the range, which suits concave lenses.
The part comes in from the generating stage and leaves ready for centring and edging. In the J configuration the machine fine-grinds; in the P configuration it polishes — the same six-spindle upper-swing platform in both.
How does a six spindle optical polishing machine hold the radius?
The trick is the swing. Each tool oscillates on an arc whose centre sits at the centre of the sphere it is finishing.
Each of the six heads works one lens. The tool is set at a quasi-spherical centre — the swing height is 70 mm — so as it oscillates in a centripetal arc it stays tangent to the spherical face it is working. That is what keeps the radius true while grey grind turns to clear polish.
The motions that matter:
- Spindle 450–3000 rpm — variable-frequency drive, set for the material and the step
- Swing 0–40 CPM — an eccentric disc drives the swing and can rest at any angle from −10° to +60°
- Pneumatic down-force — the pressure head presses the tool onto the lens with an adjustable air pressure
- Six independent axes — each head runs on its own, so one can be reloaded or paused without stopping the rest
Because a six spindle optical polishing machine gives every head its own coolant feed and its own control, a stalled or reloaded station does not disturb the five still cutting.
You are buying a range, R1–R20 mm up to Ø30 mm, and the tools and pads for your lenses — not a fixed set of radii. Send us the radius, the diameter and the material, and we specify the tooling with the quotation.
Four things that decide the finish
Loading and unloading are by hand, station by station; the grinding and polishing run automatically once a part is under the head. These are what a six spindle optical polishing machine gets right.
Six heads, run as one or singly
Six spindles finish six lenses in parallel, and because each axis is independent, a head can be reloaded, paused or run at its own speed without disturbing the others.
Pneumatic pressure, set to the part
An air-pressure head presses each tool onto its lens, and the pressure is adjustable — the touch a thin or brittle part needs is dialled in rather than fixed.
Eccentric-disc swing, any angle
The swing is driven by an eccentric disc and rests at any angle between −10° and +60°, so the arc is set to the part rather than to a fixed stroke.
Each head has its own coolant
An automatic circulating pump feeds every axis separately, so the slurry or polishing compound each station needs reaches it without robbing the others.
Which lenses and geometries can it handle?
| Item | Capability |
|---|---|
| Process | Fine grinding (J) or polishing (P), single part per head |
| Surface | Spherical, concave — upper-swing layout |
| Radius range | R1 – R20 mm |
| Maximum diameter | Ø30 mm |
| Spindles | 6, each independently controlled |
| Materials | Optical lenses — send your material for a free trial run; suitability confirmed on your own parts |
| Pressure | Pneumatic, adjustable per head |
| Spherical-centre height | 70 mm |
If your drawings are dimensioned to the ISO 10110 framework, send one with the enquiry. On a six spindle optical polishing machine the radius, the diameter and the surface-quality grade are what decide the tooling — see the optical materials data if you are choosing glass.
Technical specifications
The FP-6U is the six spindle optical polishing machine in the upper-swing range; the four-spindle FP-4U does the same job on fewer heads.
| Process | Fine grinding (J) / polishing (P) |
| Surface | Spherical concave, upper-swing |
| Curvature range | R1 – R20 mm |
| Maximum diameter | Ø30 mm |
| Number of spindles | 6 |
| Spindle speed | 450 – 3,000 rpm, variable |
| Swing rate | 0 – 40 CPM, stepless |
| Swing range | −10° to +60°, eccentric disc |
| Spindle accuracy | Axial float 0.01 mm · radial runout 0.02 mm |
| Pressure | Pneumatic, adjustable |
| Spindle thread | M16 × 1 · locating bore Ø18 |
| Total installed power | approx. 1.6 kW |
| Overall dimensions (L × W × H) | 2000 × 800 × 1700 mm |
| Total weight | approx. 750 kg |
| Base construction | Welded steel base, stainless work deck |
The grinding tools, polishing pads and compounds are process consumables chosen for the material and the radius. They are quoted separately — tell us your lenses and we will specify them.
Main assemblies and what each one is for
This is the vocabulary your operator and our service engineer will share on the shop floor.
| Assembly | Function |
|---|---|
| Six spindles & motors | One variable-speed spindle per head, 450–3000 rpm, holding the lens on the tool |
| Upper tool heads | The upper-swing tool that finishes the concave face of each lens |
| Pressure heads | Pneumatic heads pressing each tool onto its lens with adjustable force |
| Eccentric disc | Drives the centripetal swing and holds it at any set angle |
| Swing-frame shaft | Carries the swinging assembly on its spherical-centre arc |
| Coolant system | Automatic circulating pump, a separate feed to each of the six axes |
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.
The FP-6U is an upper-swing machine for concave lenses up to Ø30 mm, loaded by hand at each head — it suits small-batch concave work run in parallel rather than a fully automatic line. A new lens needs its pressure, speed and swing settled on trial parts, the reason we ask for your parts before quoting.
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 FP-6U with all six heads swinging, and a close look at one spherical-centre swing finishing a concave lens.
01 — Six heads finishing in parallel
02 — Spherical-centre swing, one head
Send one drawing and a few lenses
A six spindle optical polishing machine is easy to specify badly from a datasheet. Send us one element drawing — the radius, the diameter, the material and the surface-quality grade you have to hold — with a few of your own lenses. We run them, return them, and send the process sheet with the quotation.
If your lenses are convex, or larger than Ø30 mm, we will point you to the right member of the family instead of quoting this one.
12-month warranty · free trial run on customer-supplied material
Optics customers include Edmund Optics and Coherent
Related equipment and reading:
- Concave lens polishing machine FP-4U — the four-spindle upper-swing version
- Convex lens polishing machine FP-4L — the lower-swing machine for convex lenses
- CNC optical curve generator Auto-SG-50 — the generating stage upstream
- Optical lens fabrication line — how the stations connect