An integrative head set sold in four focal lengths, from a short 38.1mm engraving lens to a long 101.6mm cutting lens, all feeding off a 25mm mirror. Built for larger CO2 cutters; a K40 needs real rework.
XYNLHZQ sells this integrative head in four sets that look identical and behave very differently. The difference is the lens: a D18 at 38.1mm, or a D20 at 50.8, 63.5 or 101.6mm. Every set feeds the lens from a 25mm black silicon mirror, and every lens is from II-VI, a long-established maker of infrared optics.
| Set | Lens | Strength | Weakness |
|---|---|---|---|
| D18F38.1 | 18mm, FL38.1 | Smallest spot, crisp fine engraving | Very shallow focus; poor on thick cuts |
| D20F50 | 20mm, FL50.8 | All-round, the K40's own focal length | Middle of the road on thick stock |
| D20F63 | 20mm, FL63.5 | Deeper focus for thicker cuts | Larger spot; needs more bed drop |
| D20F101 | 20mm, FL101.6 | Longest focus zone for deep material | Large spot; needs a lot of clearance |
The lead option is the D20F63 set. A 63.5mm focal length is the usual cutting choice on bigger machines: the beam stays tight through more material, so cut walls come out straighter in thick plywood and acrylic.
II-VI is a long-established infrared optics maker, which is why its name turns up on premium CO2 lenses. Lens quality matters most on a machine that cuts every day, where a lens that absorbs even a little extra heat fogs and fails sooner.
Buy for the work you do most, not the work you might do. A shop that engraves nine jobs in ten will be happier with the short lens and an occasional slow cut than with a long lens that blurs every photo.
| Spec | Value |
|---|---|
| Brand | XYNLHZQ |
| Head type | Integrative mount CO2 laser head set |
| Lead set | D20F63: 20mm lens, 63.5mm focal length |
| Lens maker | II-VI |
| Short-focus set | D18 lens, FL38.1mm |
| Standard set | D20 lens, FL50.8mm |
| Mid-focus set | D20 lens, FL63.5mm |
| Long-focus set | D20 lens, FL101.6mm |
| Mirror | 25mm black Si mirror |
| Mirror mounts | Adjustable installation holes |
| Body material | Aluminium |
| Finish | Black oxide coating |
| Air assist | Air assist nozzle |
| Mounting hardware | Joint plate and belt fastener |
| Lens retention | Locking ring with plastic buffer ring |
XYNLHZQ gives the mirror mounts adjustable installation holes rather than fixed ones. Slotted mounting lets you slide a mount a few millimetres before tightening, which helps when your gantry's holes do not match the mount's pattern exactly.
That adjustability is the feature to lean on during a retrofit. On a machine that was not built for this head, you can often shift a mount into line with the beam instead of drilling fresh holes. It is not a cure for a mount that sits at the wrong height, though; height mismatches still need shims or a spacer plate.
Once aligned, connect the air assist nozzle to a steady pump. The full beam-walk method is in the alignment guide.
Mark each mount's final position with a scribe line once the beam is centred. If a mount gets knocked or you pull it for cleaning, the line takes you straight back instead of starting the alignment from scratch.
XYNLHZQ sells this set for laser cutters and does not name the K40. A stock K40 uses 20mm mirrors, a 12mm lens and a 50.8mm focal length, with a shallow case and a fixed clamp plate. This head changes all of those at once.
The long lens is where owners go wrong. With 101.6mm of focal length, the focal point lands far below where a stock K40 bed sits. Unless you have a deep adjustable bed or have cut out the floor for a pass-through, you cannot reach focus.
Measure before you buy. Take the height from the stock head's lens to the bed, add the new head's height difference, and compare with your bed travel. The K40 dimensions page lists the stock case figures to start from.
If the sums do not work, the D20F50 set is the only one that keeps the K40's standard focus distance. Even then, you are still converting the machine to 25mm mirrors, which is a full rebuild of the beam path rather than a head swap.
The weight is worth a thought too. An integrative head with its joint plate is heavier than the stock K40 head, and the K40's small steppers and thin belts were sized for the lighter part. Lower your engraving speeds at first and watch for skipped steps.
Most K40 owners are better served by a head built for the machine. The FONLAND and Lightobject air-assist heads keep the 20mm mirrors and bolt on in an afternoon. The XYNLHZQ set is for a different job: a machine with 25mm optics, or a rebuild moving to them on purpose.
Within its own class, the set has close relatives. ZQDWMND sells an integrative head with the same lens range and a 25mm Si mirror, described with a CVD lens. The ZNNRKMYO kit bundles a head with a 20mm lens and three 25mm mirrors. XYNLHZQ's case rests on the named II-VI lens and the adjustable mount holes.
Price the whole conversion, not just the head: new mounts, three 25mm mirrors and possibly a bed. Work through these checks with calipers in hand:
Keep the machine attended on its first jobs after any head change, with air assist running and a fire extinguisher in reach. The K40 upgrade order ranks optics against every other fix.
Not as a simple swap. It uses a 25mm mirror and a 20mm lens, and a stock K40 uses 20mm mirrors and a 12mm lens. Fitting it means converting the beam path.
FL38.1 for fine engraving, FL50.8 for mixed work, FL63.5 for thicker cuts, and FL101.6 only if you have deep bed travel.
A long-established maker of infrared optics, including zinc selenide lenses for CO2 lasers.
Yes. The head has an air assist nozzle that needs a pump or compressor behind it.