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Laser Head Question

Posted: Mon Aug 14, 2017 7:20 pm
by BanksCNC
So I just ordered one of these. and I have a question. I have a 50.8 Lens and was wondering how far from the bottom of the air cone to the material the space should be?
Pro Laser Head Mount for 25mm Mirror & 20mm Focus Lens. LR Type
http://www.lightobject.com/Pro-Laser-He ... -P586.aspx

Thanks
Brandon

Re: Laser Head Question

Posted: Tue Aug 15, 2017 4:23 pm
by litterbox99
Once you have it installed, stick a toothpick up in the air cone (carefully)
until it touches the lens. Mark the toothpick where it comes out the cone.
Pull out the toothpick and measure, subtract that from 50.8 mm and you
have your 'cone to material' measurement.

This will give you a good starting point to dial the focus in.

Re: Laser Head Question

Posted: Wed Aug 16, 2017 8:24 am
by BanksCNC
Thanks for the input :-) Great idea!

Re: Laser Head Question

Posted: Wed Aug 16, 2017 11:57 am
by Tech_Marco
Sorry but I have to disagree of using a toothpick trying to touch the lens. The coating of the lens is easy got damage. Even smoke on the surface of the lens will affect the output cutting power!

Simple way for us is to fire laser at lower power and find the tiniest spot. Or, you can burn a line in a slopping wood stick and you can see he burning path from wide to narrow then getting wider again. The narrow point is where the focus point located

Hope this help

Marco

Re: Laser Head Question

Posted: Wed Aug 16, 2017 4:59 pm
by litterbox99
I didn't know the lens was that sensitive to damage, please disregard my advise.

This weekend I'll pull my focus lens and check it, right now I'm working on engraving.
Trying to find the best speed/power for engraving from and image to simple wood.

Re: Laser Head Question

Posted: Wed Aug 16, 2017 5:39 pm
by Tech_Marco
Yes it did. If you rug a little harder on the lens or mirror with a cotton ball and alcohol, you will see scratches.
If that happen, beam spot may be diffused and cutting power will be affected.

Marco

Re: Laser Head Question

Posted: Wed Aug 16, 2017 6:32 pm
by BanksCNC
Good information...Curious what is a/the proper way to clean lenses and mirrors?

Brandon

Re: Laser Head Question

Posted: Thu Aug 17, 2017 9:12 am
by Tech_Marco
I'd to use 50% alcohol(91%) + 50% acetone
Then use a cotton ball (better to have de-grease ) or quality lens clean paper.
Do not rug the lens but apply pressure gently with your finger and move in half circular motion. Do not over-lap with the same cleaning paper or cotton but use a new one. So, one time per cleaning

Hope this help

Marco