Learnt something today about red diodes

[ElektroFreak]

In my experience it's because you seem to be using acrylic lenses. The plastic expands from the heat as the diodes warm up, thereby altering the beam.. I've even seen the back melt completely out of those acrylics when being used with LOCs. My recommendation is to use the glass collimators, which come in metal threaded housings. They are much less affected by temperature changes.

[andy_con]

these are 7020h lens from roithner not crappy aixiz ones. although they are acrylic

[ElektroFreak]

It's the acrylic that's the issue from my experience.. too much expansion and contraction. LOCs are fairly powerful, and the heat from them greatly affects plastic lens assemblies.

[p1t8ull]

Try removing one mirror mount so the beam doesn't go through the telescope to see if it suffers with the same effect..

[andy_con]

you coming to the meet simon, i wana have a chat with you?

when i get some time ill do some more testing and see if i can narrow down the problem. i say problem its not a problem just an observation

[catalanjo]

It's the acrylic that's the issue from my experience.. too much expansion and contraction. LOCs are fairly powerful, and the heat from them greatly affects plastic lens assemblies.

Fascinating how they fix themselves is this was the case !

Originally Posted by mccarrot
Do you also have this problem without the telescope.

I think this might give us a clue !



Cheers

[p1t8ull]

Yes mate, most probably the Saturday

you coming to the meet simon, i wana have a chat with you?

when i get some time ill do some more testing and see if i can narrow down the problem. i say problem its not a problem just an observation

[ElektroFreak]

Fascinating how they fix themselves is this was the case !

Originally Posted by mccarrot
Do you also have this problem without the telescope.

I think this might give us a clue !



Cheers

They fix themselves?

Sorry, I'm not following what you're saying...

In my experience, having used both acrylic/plastic and glass/metal assemblies, this exact problem was solved by NOT using acrylic lenses with diodes over 100-150mW. I can almost guarantee you that were you to ask Roithner, they'd tell you not to use Acrylics with high-powered diodes. It's not that they're fixing themselves, it's that the assemblies warmed up or were already warm as Andy set the divergence the first time, and now once they cool down the beam characteristics change because of the difference in temperature, which causes a minute change in the dimensions of the lens assembly. It's simply expansion and contraction of the lens assemblies. This is why the beam improves as the module warms up.. I'm only sharing my experience with this exact problem.. unless there's some very important detail that I missed when Andy described the problem, in which case I could be completely wrong. Take it or leave it.. makes no matter to me.

[andy_con]

Take it or leave it.. makes no matter to me.

easy, were only discussing.

i will do a few more tests and see what i can find

[ElektroFreak]

It was not my intention to promote hostility. I apologize if that's how it came off. It's just mildly frustrating to try to help only to have someone who clearly doesn't have any better idea tell you you're flat wrong. But as you said, we're only discussing.. that's what we do here. Apologies for getting involved. Let us know what you find Andy..