Max Depth on 30W Fiber // Deep Cutting Routines

[Matt Schrum]

The lens may have more to do with it than we may think. ....

I think I found the type of lens NCEngraver was referencing in his (now private) video. Based on what I recall seeing, the Alibaba link below to a telecentric F-Theta lens looks quite similar to the lens he was bragging about in his video. For what it is worth, NCEngraver responded to me saying they provide lens info to customers that buy fiber lasers from him (and he didn't want competitors, so he made the video private)-- so I told him I'd like to buy one, at which point he said they don't sell fiber lasers, but are thinking about maybe selling them in the future. Well, phooey, that's not helpful at all.

Regardless, from what I can find, the standard F-Theta lenses that come with our eBay fiber machines make sure the beam is in focus-- but the beam still exits the lens at quite an angle as you get to the edges of your work area. A telecentric F-theta lens also ensures that the beam is close to perpendicular when it exits the lens (and not at a steep angle). I've currently got data sheets and am waiting on pricing through Alibaba on the lenses to see what they run. I've seen basic listings from $100-$1000 for this type of lens, so I'll be curious to see what the total cost is (for reference, the default lens that ships with our eBay machines seems to be in the $50-$100 range on Alibaba).

The current data sheets I have indicate a pretty small working area (2" x 2" or less)-- but some of the other listings indicated working areas closer to the 4" x 4", etc.

https://wavelength-tech.en.alibaba.c...2ce83e5foTyZEI

one more link
https://www.alibaba.com/product-deta...71ac35b7LH25v3

[Kev Williams]

Well, the beam can only exit at a right angle up to the physical diameter of the lens glass -- then what?

So then, a lens with 4" diameter optics can ONLY engrave within a 4" diameter circle. A typical 4"/100mm lens gives you a 4" SQUARE working area, which is a substantial increase over a 4" circular area, diagonally you gain over an inch of work area (depending)...

So it makes sense a 2x2" work area of a TC lens would be practical due to the overall lens size. I have a 75mm 'normal' lens, which renders barely over 2x2" workspace, and it's an animal, VERY aggressive... If the focal distance of a 2x2 TC lens the same as my 2" lens, the power density of a focused perpendicular beam, wow...

Nice as it sounds, for my type of work, I couldn't justify the expense and limitations...