Raytools Original Protective Lens D37 x 7mm for 12KW

Key Features

• Original Raytools protective window, not an unbranded near-size substitute
• High-purity fused silica (quartz), plane-parallel and polished on both faces
• AR coating on both faces, centred on the 1064-1080 nm fiber laser band
• Over 99% transmittance, so beam power reaches the sheet instead of heating the glass
• Exact 37 mm diameter and 7 mm thickness for the Raytools drawer-type lens holder
• The largest focusing-side size in the Raytools range, listed for 12-15 kW heads
• Both faces coated identically, so there is no orientation to get wrong on a shift change
• Bulk supply across India with GST invoice on every order

Specifications at a Glance

Diameter and thickness decide fitment, and both have to match the seat. Everything else describes how the optic behaves once it is in and the drawer is closed on it.

The Two Protective Windows in a Raytools Head

This is the distinction worth getting right before you order anything, because both windows are described as "the protective lens" in everyday conversation and they are entirely different parts. One is a routine consumable; the other should barely move for months:

Confirming This Is the Right Raytools Window for Your Head

Fitment is decided by diameter and thickness, not by the model name on the head, so the window you are removing is the most reliable specification available. Take it out, read the size off it if it is marked, and confirm it with a vernier if it is not - across the flat face for diameter, across the edge for thickness, taking each reading at two or three points. Two windows that differ by a few millimetres look very similar lying on a bench, and 37 mm against 30 mm is exactly that kind of difference: obvious with a caliper, easy to wave through by eye.

Use the range chart below for orientation, then verify. It maps sizes to stages and power classes rather than to individual head models, so treat it as a guide and not as a compatibility guarantee:

The Raytools protective lens range fits BM109, BM111, BM114S, BT210S, BT240S and BT240S-RC heads with drawer-type lens holders. If your head is not on that list, if the machine came rebadged from an integrator, or if the old window is already broken, send a photo of the head label on WhatsApp at +91 92740 95891 and we will confirm the size before you order.

What "Original" Means on This Listing

Original means the genuine Raytools part, supplied in the brand's own packaging and channel. Where that specifically earns its place is in the paperwork rather than in the optics: machines running under a service agreement that names genuine parts, and workshops that need brand-marked packaging for internal traceability or audit. If either applies to your machine, this is the listing that satisfies it without a conversation.

What decides whether any protective window actually works in your head is narrower than the branding, and worth knowing whichever grade you buy. The diameter and thickness have to match the seat so the window sits square and the holder closes properly. The substrate has to be fused silica so it passes 1064-1080 nm without absorbing. The anti-reflective coating has to be intact and present on both faces. All three are checkable at a bench in a couple of minutes with a vernier and a bright light, and it is worth doing on receipt rather than with the head already open.

What to Have on the Bench Before You Open the Head

Opening a cutting head is itself a contamination event, so it is worth doing everything the head needs in one go rather than going back in a week later. On a 12 kW machine that usually means four things within reach before the drawer comes out:

• The replacement 37 × 7 mm focusing-side window, inspected at an angle under a bright light before it goes anywhere near the head
• The seal for the window seat, since a flattened or perished seal lets dust past continuously and is the usual reason contamination climbs into the head
• A 24.9 × 1.5 mm collimation-side window on the shelf, so that if the upper one turns out to be filmed or marked you are not stopped mid-service
• A known-good nozzle, because nozzle condition is the single biggest driver of how fast this window is consumed
• Lint-free optical tissue with isopropyl alcohol or acetone, plus clean gloves or finger cots
• A vernier, to confirm both dimensions on the new window rather than assuming the packet is right

When to Replace It, and Why It Sometimes Goes Faster Than It Should

There is no fixed hour count. Life on a focusing-side window depends on the material, the assist gas, how often the machine pierces and the condition of the nozzle above it, so inspect at every shift change and replace on evidence. Hold the window at an angle under a bright light rather than looking straight through it - damage that is invisible face-on shows up clearly as scatter when the light rakes across the surface. Replace on pitting, burn craters or bonded spatter, on haze that survives a wet clean, on patchy or rainbow coating discolouration, on any chip or crack at the edge, or when cut quality drifts through the shift and recovers after a change.

The one pattern worth treating differently is a sudden collapse in window life. When protective lenses start dirtying every few hours instead of every few shifts, the window is not the problem - it is the symptom. A nicked, oval or off-centre nozzle tip stops clearing molten material down through the kerf and starts flicking it upward at the optics instead, and every extra shift run on a damaged nozzle eats window life. Inspect the nozzle before ordering more glass; replacing it usually returns consumption to normal on its own.

Fitting and Handling

• Hold it by the rim in lint-free finger cots or clean gloves, because skin oil on the clear aperture burns in permanently
• Inspect at an angle under a bright light before fitting, not after the head is back together
• Clean a fume film with a lint-free tissue wetted with isopropyl alcohol or acetone, drawn across the face once and then discarded
• Never dry-wipe a gritty window, as bonded spatter dragged across the glass cuts the scratches that become the next absorption sites
• Anything still visible after a wet pass is in the coating rather than on it, and no further cleaning will recover it
• Check the seal and the seating face every time the window is out, since a compromised seal lets dust reach the optics above continuously
• Seat it squarely and close the retainer firmly without forcing it against the glass
• Both faces carry the same AR coating, so there is no orientation to worry about during a fast change
• Keep a pack on the shelf rather than a single spare, because this is the optic most likely to stop the machine

Features and Benefits

How to Order the Right Window First Time

1. Take out the window you are replacing and measure it, or read the size off it if it is marked. The old part is the most reliable specification you have.
2. Confirm both numbers. A 37 mm window in the wrong thickness will seat and still be wrong, and so will a 7 mm window in the wrong diameter.
3. Confirm the stage. The focusing side (lower) takes this window; the collimation side (upper) takes the much thinner 24.9 × 1.5 mm one, and they are not interchangeable in either direction.
4. Choose the grade deliberately. Original suits a machine under a service agreement naming genuine parts, or where brand-marked packaging is needed for traceability.
5. Add the seal, and put a collimation-side window on the order too if the head has not been opened in a while.
6. Order in a pack sized to your consumption rate, ask for bulk rates if you run several machines, and request a GST invoice so the input credit is documented properly.

Applications & Industries

• High-power fiber laser cutting machines running 12-15 kW Raytools heads
• Heavy plate fabrication, structural steelwork and pressure-vessel manufacturing
• Shipbuilding, railway and heavy engineering fabrication shops
• High-throughput job-work lines cutting thick section on continuous shifts
• Steel processing units and coil-to-plate cutting lines
• Laser machine service engineers stocking head service kits for site visits
• OEM machine builders and spare-parts dealers supplying high-power users

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