New Lens Causing BIG Flare ups Speedy 300

[Chris Edens]

I just put a new lens in my Speedy 300 80w and it is flaring up a lot. I have my air assist turned on and I use an Atmos Exhaust system. The replacement lens is made by Design Research optics. I know some other use them for lenses and I was wondering if you experience this too. I am engraving rubber for stamps. I ended up putting the old lens back in because I could not get it to stop by changing the settings.

[Mark Sipes]

Did you do a ramp test to verify the focal length of the new lense??

[Chris Edens]

Mark

I have had these things for over a year and my knowledge is limited and its sad. I always focus these with the focus tool. When you mean ramp test are you talking about having job control focus the the laser?

[Mike Lysov]

Do not trust your focus tool. It is not that there is something wrong with it it may happen that they have sent you a wrong lens. So using the focus tool that does not match the lens won't help.

I bought 3" lens from some Chinese seller on ebay more than a year ago. After I receive it I set focal distance to 3" and tried to cut through MDF with it.
It made very wide 2mm kerf and did not cut through. I tried adjusting focal distance +-5mm and I did not see any improvement.
Then I gave up thinking it was just a bad lens.

However I had some spare time yesterday and want it to give this lens another try but this time instead of setting focal distance to 3" I put a piece of wood at some angle with minimum focal distance close to 2.8" and maximum about 4.5". After I did a test line cut I figured out that they sent me 4" lens instead of 3".

[Mike Null]

Chris

I think everybody is leaning toward the same solution. The new lens does not appear to be the same focal length as the old and that may be causing all your problems.
Run tests on wood or plastic at .25" height increments until you determine which focal length you have.

The new lens may be shorter so run your test as if the lens were both shorter and longer.

You didn't mention anything but the flare up. Can you tell us about the engraving quality or is the flare up destroying the piece?

[Bryan Jater]

Hi Chris, You need to get a piece of anodised aluminium and engrave a black square on it. Whilst it is engraving use the up and down arrows on the control pad to move the bed up and down. Where the flash from the aluminium is brightest is where your optimum focal point is.

[Dan Hintz]

Make sure the lens isn't upside down, either... they may have mounted it incorrectly.