Hardware restrictions for bigger tube? What's stopping me?

Community Laser Talk
1

I have a 45 watt FSL PS 12x20 that I threw a ruida controller in.

My question is regarding a new tube, I know FSL sells a 75 watt upgrade and powersupply, but what is stopping me from throwing in a 90? or 100? or 150? You get the idea.

I’m thinking maybe 90 watt might be nice for this machine but just want to make inquire about what issues or problems I might run into?

Would something like this be a good " plug and play" ?? anything else I need to consider upgrading/changing going from 45 to 90 watts? I realize that I would need to fashion up an " extension box for the back of the tube "

Thanks!

2

One consideration you’ll have is the physical capacity of the laser enclosure. My 60W laser tube died and it really wasn’t a true 60W. When I replaced it with a genuine 60W tube, it extended about 30 cm outside of the enclosure. The enclosure has a hatch cover which I replaced with a laser-cut (of course) protective box to keep hands away from the hot end of the tube.

Moving from 45W to a much higher power tube will likely present the same considerations of space.

Plug-and-play I’m not sure, as I have no experience with an upgrade of that magnitude. My intuition is that you’ll be identifying the wiring components on the old system and matching them to the new power supply, which should be straight-forward.

3

Absolutely nothing generally speaking…

However, physically, it may induce a reality limit…

If you go with a bigger tube, not only is it longer, it’s probably a bit larger in diameter…

This will require you to either raise all the mirrors/head or lower how the tube sits in it’s mount.

I didn’t have the room, up or down, to move either of them 15mm as the next worthwhile step was up to an 80W tube, but it has an 80mm diameter, mine was 50mm, probably like yours. There was the 60W at 55, but another 20% wasn’t worth the efforts.

This is a general chart I’ve used for the past few years and seem to be a good reference…

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As @fred_dot_u pointed out, it will probably need to have the extension for the tube… I looked all over, they are virtually unavailable. I 3d printed mine…

Good luck

:smile_cat:

4

Mirrors and lenses seem to have an upper power limit which is at least as poorly specified as anything else in this game, but AFAICT the cheap ones top out somewhere around 100 W.

The beam diameter also increases as the power goes up, so it may be too large by the time it hits the third mirror and lens.

I’d expect power supplies to get larger, but that’s the sort of thing you’d want to measure in any event: you don’t want to screw it onto the outside of the box.

5

That’s a great point, I knew I would have to fashion up some sort of extension box - But failed to consider the center point of the new tube with fatter diamter.

My tube is a 40 watt that they advertise as a 45 watt peak power. I would think If im going to do this i’d want to atleast double my power ( 80 or 90 watt )

I’ll have to see if there is enough adjustability in the mirrors and head to come up 15 mm to be able to align out.

6

What I found with my OMTech and probably all the similar machines, is the is no way to do a Z adjustment on the head.

I replaced my original tube holders with one of Sadlers tube mounts. It will allow me to go to 55mm by removing the spacers… The mirror mount is part of the tube mount, making it easily adjustable and the exactly perfect angle. You can see the acrylic spacers that hold the 50mm instead of the 55mm tube.

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I do mostly engraving, at low power and when I cut, I rarely have to cut acrylic above about 6mm (1/4"). I do all of what I need to do with 10 to 30% power, which relates to about a 4W - 13W range, except when cutting… I can cut at 100% power if I need to, it isn’t going to break it, as it is within the specification and can’t exceed that. Usually I cut around the high 80 or low 90% range… This is a grade A tube with documentation of it’s operation from the manufacturer…

Having a lot of power is only good for cutting thicker stuff… not so great for engraving… you lose the bottom end of the power of the tube.

One of the good tube manufacturers stated on their specifications that their 60W tube has a power range of 12W to 60W… This indicates to me that they do not expect the tube to be operated at anything below 20% power…

If you needed 4W, that wouldn’t be in the manufacturers range of operation… the best you could do is three times that…

I believe as many do, that it can damage a tube to run it at or near it’s lase point… The gasses are not responding like expected and can shorten tube life.

I spent lots of time looking at burn spots on my tubes output at low power…

I have a lower limit based on the target results, not if it lases or not.

I bought a China Blue 50W machine from OMTech… I measured the output with a Mahoney power meter and it was 44W, which is about right for the 880mm length…

Clearly OMTech is ripping us off by knowingly inflating the specifications. I think they all do it to some extent.

If the need is to drive a tack, would you pick the tiny tack hammer or a 20lb sledge? Both are hammers, do the same type of job, which gives you the best control, precision and results?

So, in the end I replaced it with a Cloud Ray 40W and have been very content… and it is 40W…

Big is not always best, it all depends on what you want to do…

Of course, all of this is just my opinion and position…

Good luck

:smile_cat:

1 Like
7

Excellent points,

I do " MOSTLY " engravings, but on the same token it would be nice to easily cut through 1/4 or 3/8" wood / acrylic in a clean pass. While techincally I can do it, it really is a stretch for the 40 watt tube.

Looks like at the very least I would need to get a nice laser head, doesn’t look like there is much adjustability.

The mirrors look like they are already maxed out on height, but nothing a spacer on the mounting end couldn’t fix.

Tube brackets look like they would adjust just fine for a 80mm tube if needed.

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8

EDIT - You know what , Im thinking about this all wrong. Instead of raising my mirrors, Why couldnt I just lower the tube? The current brackets in there have a bunch of spacers already, Take out 15mm of spacers and I should be lined up in the ball park. Or am I over seeing something?

9

I was going to mention they have a stack of spacers under the tube.

A couple things to keep in mind… if you have to extend the case, there is a large difference in tube length. I was lucky in that the size I needed I was able to 3d print on my printer.

This is for tube protect, not anode voltage protection… most of these materials will offer little to no protection from a tube failure and the probable hv result that will find a return path.

Good luck

:smile_cat:

10

Think about mirror 1 and how it aims the beam. Its only purpose i to aim the beam parallel to the Y rail. So if the tube or even one end if the tube is raised or lowered sending the beam at a slight angle, Mirror one is still capable of sending the beam parallel to the rail. Once that is done, do the standard alignment and you are in business.

11

When I put a new tube in one of my machines, it was more powerful and the tube was wider, I just changed the tube holders with ones I could adjust up and down, didn’t touch the mirrors. It was a fairly simple job, new tube, power supply and tube holders. I already had the extension box.

12

When everything lines up ok, it’s great … Haven’t had a lot of good experiences with these things lining up… :face_with_spiral_eyes:

:smile_cat: