I posted a while ago about the G2 and G8 lens’s and how the stock lens is probably a G2.
I recently saw a pic of a small engraving with a stock lens and a G8 lens.
And the G8 lens is only $20 as pointed out by this reseller:
I’ll let you know what I find out.
You ordered a G8 lens?
If so then I’m looking forward to your insights!
some people have said it’s a bigger deal for 20W lasers than 7W or even 15W. I suspect that is because of the size of the LED array. ie The array is larger for 20W than 7W and slightly larger than 15W.
Will let you all know what I find.
UPDATE: The G8 lens I got didn’t quite work as well as I thought. The stock lens is inside a threaded barrel which is then threaded a tiny bit into the large adjustment wheel. The actual lens is about 2.5mm from the top of that barrel and the G8 lens I got was about 7.5mm from the top of the barrel. So what I got was a focused beam but with lots of laser light also forming a hazy circle around the focused dot. ie LED light not getting focused.
I could put the threaded barrel in upside down and get a clean focused dot but the large focus knob wasn’t tight in the heatsink so it would not be possible to use this way as it would just wiggle loose.
I mentioned all this to the ebay store owner I purchased from so maybe he has a better option or it just ends this way.
PS: The Ortur lens holder(barrel) is really soft aluminum… I tried to remove just the lens but the aluminum just tore apart. The G8 I purchased was steel and looked of good quality.
I finally ordered a 3 element lens and will get back to testing on my 15W when it arrives.
I saw lots of questions on the lens by 20W owners on the Ortur facebook page so I turned them onto the ebay vendor I got my lens from as other 20W owners said they work fine with the 20W. Then I found this quick video showing how much better a G8 single element lens works on the 20W. The G8 provided a better focus than the stock 3 element(?) G2 and with the single element comes less loss in the optics and surprisingly a tighter dot - https://www.youtube.com/watch?v=pY_7MC39qCY
I made the Ortur lens holder which extends the part with the o-ring higher on the threads of the lens because the G8 and G7 lens only catches ~3 threads for a focus point around 35mm. I then did a rough horizontal laser(disconnected and laid sideways on a table) test of the lens:
Lens focal length $0.02
G7-3element 35mm tight round dot, bit less power
stockG2 40mm oval dot, good power
G8 50mm tight roundish dot, good power.
Both G7-3 and G8 want to be only 3 turns into the threaded laser housing so their focal length has limited adjustment and would be best with some form of z-axis adjustment either on the laser or on the surface bed area.
Stock G2 was powerful but large dot and poor shape so it does a finer line along X axis but fatter line along the Y axis.
To test I placed the laser head on the table and ran at 80% power then manually moved a 2.7mm thick wooden disc into view at the focal point at a very slow rate. Observing cut, smoke and penetration.
Test 2 will be mounted and controlled Y axis movement.
Line cut at 80% power 2mm/S speed of 2.70mm plywood round pogs.
See the 3 cuts and see the burn on the pog directly below the one being cut. You would want to look at the straight lines which are also labeled with the lens and focal distance.
NOTE: the cut movement was in the Y direction which is the widest because the laser diode elment runs along the X axis. The G8 and G7 were pretty tight dots(G7 best) and the stock G2 has a much more oval/elongated ‘dot’ as seen by the widths of the burns. At this speed and power all 3 cut completely through the 2.7mm thick plywood and into the wood behind it.
