MCWlaser CVD II-VI ZnSe 12mm Focus Lens Focal Length 50.8mm/ 2 inch CO2 Laser Lens for CO2 Laser Engraving Cutting Engraver/Cutter 40W-200W

Good Item with Fast Delivery

Lens worked well in my k40 and there where no fitment issues. Slightly better cut but can't say huge improvement over the stock, perhaps just got a better stock lens.

Unit came well packed and in a timely manner. Works really well and so far with reliable performance.

Product was dispatched on time lens was OK but have since upgraded to a better quality lens

Good replacement for original stock lens seems to be better than original.

This lens gives great focal power at its focal length

I'm a professional artist and engineer – and use lasers practically every day. I’m vastly experienced and technical. I ordered a MCWlaser USA CVD II-VI ZnSe 18mm Laser Focus Lens Focal Length 63.5mm/ 2.5 inch to replace my original standard laser lens - because I read it was better than mine – and a 101.6mm lens (for deeper work). Halfway through a large batch of acrylic artworks I replaced the original 63.5mm lens with the new MCWlaser one - clearly marked 63.5mm (see the photo). I didn't change anything on the cutting and engraving job as the lens was the same(…?). To my horror the 5mm clear cast acrylic sheet (the same I have been cutting and engraving all week) caught fire! Extremely luckily, I happened to be very close by and noticed the fire early on (I don't normally monitor repeat jobs more than about every five minutes), and put it out. But the LED lights, auto-focus, and air assist tube and fixings were badly burnt – and needed to be replaced. Obviously, I lost a lot of time (a whole day’s work, it turned out). I couldn’t understand why this happened. I thought long and hard about it. What’s changed…? Same 5mm clear acrylic sheet (I buy in bulk), same laser job settings (same memory loaded job), same focus distance (using the focal distance measurer for the standard 63.5mm lens supplied with the machine). I’ve done this many times perfectly… I double-checked the lens fitting, that it was the correct way up, not dirty – everything looked fine. After sleeping on it, I woke up and the question popped into my mind: the only thing I changed was the lens. I assumed it was 63.5mm, but is the lens actually 63.5mm…? I managed to replace the air pipe (with parts I had) and got the laser back working without autofocus (I always manually focus anyway) or LEDs. I did a ramp test (a series of laser pulses on a inclined plank of wood to find what focal distance produces the smallest burn dot). I started where I normally would start a ramp test with a 63.5mm lens – at about 50mm - but the pulse spot was alarmingly large. I moved downwards. At 63.5mm the pulse spot was smaller, but still far too large. I continued down the ramp, and in the mid 70’s it was at its smallest (76mm) before it started getting bigger again (see photos). Clearly this lens marked 63.5mm was NOT 63.5mm – it was 76mm! And, low and behold, MCWlaser supply a 76mm lens… To prove this point, I put back my original 63.5mm lens and did the same ramp test. Sure enough, it peaked at 63.5mm – exactly as it should. I also tested the new 101.6mm lens, and sure enough it was a 101.6mm lens. As I final check, I put the original 63.5mm lens back and repeated the job I’ve been doing all week – and it worked flawlessly. So the only rational conclusion is that the lens I received marked 63.5mm was in fact a 76mm lens! And because the lens wasn’t powerful enough to cut through the acrylic sheet where it normally would, it ignited the acrylic sheet instead. I raised this with MCWlaser, and they naturally asked for further evidence – which I gave then in the form of more photos. They came back to me and said :- “Our engineer checked your pictures and judge that you might bought the wrong focal length.” I don’t know if that statement was their lack of English – that I BOUGHT the wrong lens…! The fact is they SENT me the WRONG lens – but worse still, it was LABELLED as a 63.5mm lens! They went on to say :- “In order not to waste your time, we would like to know what you thought is about this issue and you need.” (Clearly English is not their mother tongue). I replied with a short list of the parts and materials that needed to be replaced (and time to replace them), and compensation for loss of a day’s work. They never got back to me! I lodged a complaint with Amazon after ten day’s silence. “Coincidentally”, MCWlaser got back to me the day after I complainted to Amazon, apologising they had been on a “business trip” (yeah – right). And then they had the temerity to say :- “Also, we're not sure how much you know about laser engraving. However, based on our ten years of experience, the lens will only have an effect on the engraving or cutting results, and will not damage the machine. When this happens, we think it should be caused by the machine malfunctioning in some way. Therefore, we recommend that you contact the manufacturer of the machine to communicate the problem. For the lenses you requested to return, we have already implemented a refund, which we believe you have already received. This is the only way we can help you.” Gob-smacked, I replied :- “I laser practically every day. This is my business. The out-of-focus lens (because it was 76mm and was focused for my standard 63.5mm) caused the acrylic to combust. The flames of the burning acrylic burned the laser head - including the autofocus, air inlet pipe, and the LED strip in the gantry. I was there, I saw it - and very luckily for you I very quickly put the fire out. The exact same sheets I was cutting with my previous 63.5mm lens with no problems umpteen times before I changed to your lens, and the first time I used your 63.5-labelled lens the material caught fire. There was, and is, absolutely nothing wrong with the laser (since I replaced the fire-damaged parts). I’m still using it now with the original 63.5mm lens every day. Go figure. You are exceedingly lucky I was present and stopped the fire so quickly - otherwise the whole place would have burned down, and I’d be suing you for criminal negligence and hundreds of thousands of £ for damages.” Since then they have completely ignored me. I am gob-smacked about their attitude and their cavalier approach to supplying really critical, but dangerous, laser parts. All these lenses look the same – but they have very different effects! They range from doing a perfect laser cut and/or engraving job – to burning your house/building down! All the more reason why sending the correctly ordered lenses – and labelling them CORRECTLY – is absolutely vital. Clearly you cannot trust any lens you buy from MCWlaser, and they should not be allowed to be in business. They are a serious danger to customers and their lasers and property, and their negligence could cause serious fires, and ultimately they are a danger to life (people being present in a house/building they indirectly, but undeniably, cause to burn down). DO NOT BUY ANYTHING FROM THESE COWBOYS…!!

Great improvement on original ones