Beam combiner for red dot versus no beam combiner in Chinese lasers

Hi all,

New the forum, first post ...

I'm trying to buy a 600mm x 900mm laser, and have quotes from multiple places (G Weike, Perfect Laser, Light Object, Novakon, GCC, etc.). I am leaning towards getting a Chinese laser directly; I've heard horror stories but also good stories and I'm fairly technical. They are so much cheaper...

But I have a question about the red dot laser -- some machines use a beam combiner, but others (I think the G Weike and Perfect Laser?) mount the red laser on the side of the head, which means it's hard to keep it aligned to where the cutting will actually occur.

Does anyone know what the tradeoffs are? E.g. does the beam combiner take some power away, or something? Is it not really a big deal to see where cutting will happen exactly?

Thanks! The discussions here have been really helpful.

Mike

Generally no big deal - unless you do a lot of engravings on expensive details and misplacement can lead to extra costs.

All Chinese machine-assembling brands should be able to add a beam combiner. It is a standard off-the-shelf component as everything else they use. Just ask them to include it.

Thanks for the replies; indeed, I asked G Weike to include it, and they said they will.

Curiously, I also asked Perfect Laser if they could install a beam combiner, and they seem very confused by the request, insisting the red dot laser must be mounted on the head.

Quote:

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Originally Posted by mikemccand

Curiously, I also asked Perfect Laser if they could install a beam combiner, and they seem very confused by the request, insisting the red dot laser must be mounted on the head.

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Unfortunately, most of the Chinese sales reps know very little about the products they sell. Typically they are hired on these positions because speak some basic English, not because they can answer technical questions. Quite often these assembly factories don't have qualified engineers either. They would call their technicians engineers, but of course, technicians are not engineers and don't have the necessary qualification to make upgrades.

Maybe ask the sales rep to submit your request to their "engineer". If they are still confused I would suggest giving up on Perfect Laser and focussing on the other brands.

I think I can add some helpful feedback as we currently supply both Bodor and Aeon lasers here in the States. I had a major part in designing a Quality Control program here in our Melbourne, FL facility and have laid hands on almost every laser that's come through here.

Bodor attaches their red pointer at the laser head while Aeon utilizes a beam combiner. Part of our quality control process before we ship is to align these systems for the end user. Since we deal with both, I think I can do a good job of outlining the pros and cons for you.

Hands down, the red pointer on the Bodor is far easier to align. However, the minute you need to clean your lens, the alignment has to be redone. Furthermore, if you decide to purposely take your machine out of focus, the red pointer will no longer be aligned. Minor draw backs, but a heck of a lot easier than working with a beam combiner.

Now, the beam combiner has always been the ideal solution for me. Mainly because, it serves as a visual aid for aligning your laser, especially when you first get your machine and notice all your mirror brackets needs to be moved. In our line of work, anything is better than repeated burn tests. However, not a single Chinese machine I've ever worked on, including G Weike has succeeded at doing this. They all claim you can use the red beam for alignment, but no matter how hard you try, it's nearly impossible to calibrate the red beam so it overlaps the infrared beam perfectly.

A few years back, we flew YouTube sensation, Russ Sadler in from England to help us develop our QC program and a functional beam combiner. He went as far as designing tube brackets from scratch that also hold mirror 1 and the beam combiner at the right height, angle and pitch so they could finally overlap. After all was said and done, we came to the conclusion that there just wasn't enough adjustment range in the standard red pointer bracket to where both beams would ever perfectly overlap.

Until recently, we had to settle for solely using the beam combiner as a red pointer for your work area, but when Aeon released their new MIRA and NOVA series with beam combiners, we found ourselves back in the lab trying to achieve the impossible. The solution involves, removing mirror 1, and the side panel of the machine and then setting up targets near and far so you can pulse the laser clear across the room and adjust the beam combiner and the laser tube until they overlap. It's actually quite fun, but painstakingly tedious to say the least.

We find it's worth the extra time so that our customers can have a stress free experience when installing and aligning their CO2 lasers for the first time. We also include acrylic targets that mount over each mirror to make steering the red pointer into position even easier. It's a beautiful thing when it's all said and done, but beware, you will likely go absolutely mad in the process.

Aside from being a complete pain to get just right, the nice thing about the beam combiner is that it actually sends the beam through the focal lens. The red dot it produces in the end is much more precise and in focus than the ones that mount on the side of the laser head. Another plus is that removing the focal lens for cleaning or purposely taking the beam out of focus, has no affect on your red pointer.

The only long term downside is that you are giving up a minuscule amount of power by transmitting the laser through an extra lens. Not really anything to lose sleep over. It pales in comparison to what you are inevitably losing since only 95-97% of the infrared beam is reflected each time it encounters a mirror. If it really bothers you, you could always upgrade your mirrors to account for the minor loss.

I hope this helps answer your question. Feel free to reach out to me if you have any questions or if you'd like pricing on any of our CO2 lasers. Aside from our stellar QC program, we offer startup training and unlimited technical support with all of our lasers.

Danny
Engraving Machines Plus, Corp.
(321) 821-7774
Melbourne, FL

If you really want a hassle free beam combiner, take a look at the TR Series laser tubes offered by SPT. The only downside is that they don't offer anything less than 90W, but having the beam combiner mounted right on the laser tube eliminates all of the headache. We purchased one last year to test with and it was surprisingly accurate.

Tr series laser tube

Danny
Engraving Machines Plus, Corp.
(321) 821-7774
Melbourne, FL

Thanks @Dmart321, that is a very thorough explanation! It sounds like the summary is that the beam combiner is much harder to align, yet once you do it is very accurate and stays in alignment even through focus lens cleaning. But the head mounted red dot is quite easy to align, but won't be correct if you raise the platform and take the laser out of focus intentionally (but why would you ever want to do that?).

I hadn't realized the beam combiner also requires work to align, but it makes sense that it does.

OK indeed Perfect Laser consulted the engineer and confirmed that they can use a beam combiner instead of the red dot laser mounted on the head.