Anyone replaced an RF laser tube with a glass one?

[ruvane bernstein]

Hi all,


I have an Epilog Legend 24 30W and unfortunately it's time to tend to the tube.


I'm considering a recharge of my tube or replacement with a glass one. Has anyone actually done this and can provide any and all info regarding the pros and cons, as well as anything pertinent to the actual process itself?


I understand that up to around 50W the quality of engraving is comparable. Is this true?


Apart from the tube, power supply, and water cooling, does anything else change?

Can I keep the same controls?

What about the driver on my PC?


Can I continue using CorelDraw to prepare jobs as before?

Any and all info is appreciated.


TIA,
Ruvane.

[Keith Winter]

Why would you want to switch to glass? Rf tubes are superior tubes and you'll spend a lot converting the tube.

[Bill George]

Evergreen laser which a Search on here with get you the details can recharge it for under $800. A changeover to a glass tube could be done, but unless you have lots of time on your hands and the technical expertise I would not attempt.

[ruvane bernstein]

Why would you want to switch to glass? Rf tubes are superior tubes and you'll spend a lot converting the tube.

Massive cost difference.

[Glen Monaghan]

It would indeed be a massive cost to convert, considering materials and any non-zero value of your time. The actual operation of a DC excited glass tube quite different from the operation of your Epilog's RF excited metal tube, and their operating characteristics (such as rise and fall times) are quite different as well. You'd basically have to gut your machine and replace tube, power supply, and motherboard. You'd then have to use whatever software stack the new controller allows, probably similar to current Chinese machines' offerings since you'd probably be using one of the same controllers they are using for glass tubes.

[Dave Sheldrake]

On paper it's pretty simple given that a DC PSU is already set up to take PWM signals and a number of machines do actually use genuine PWM to control the tubes.

Glen is correct about rise and fall times so there will be limitations on how much performance you will get compared to an RF excited unit.

If the motherboard outputs the correct PWM signal then it shouldn't be too difficult. Is it worth it? Can't really say, it would depend on the reasons for doing it I guess.

[Dave Sheldrake]

I understand that up to around 50W the quality of engraving is comparable.

Sadly no it's not, RF tubes produce high quality close to single mode beams, DC produce a more brutal often multimode beam. In general a DC powered beam will end up being a larger spot size everything else being the same (unless of course you use Coherant or GSI tubes)

Up through the scales it's usually around a 2:1

a 30 watt RF will keep up with a 60 watt DC until you get to the 150+ range then the DC tubes tend to be as good for both speed and wavefronts.

In short? cheap DC tubes are cheap for a reason

[ruvane bernstein]

Thanks for the replies.

I'm leaning towards getting my tube refurbished.

[Joe Walmer]

I am in the middle of doing this right now. I just got a k40 laser delivered today I am taking the 40w tube out and putting it in my GCC laser machine. Should be as simple as hooking up the pwm to the laser psu and jumping the TTL to on all the time. I have a smoothieboard motion controller with a laser module built into it and they basically have it hot wired on and just turn the laser on and off with pwm so it should work exactly the same. Just waiting on some tube mounts and shooting a test video showing the tube and motherboard of my GCC machine work in case I decide to sell them.

I know its only 800$ to 1200$ for a recharge and the synrad tube has been good to me, worked for 12 years, my epilog has had 3 bad tubes and 2 in the last 3 years. so its a touchy subject here. I figure I need to jump in with the china tubes so here I go.

[Rodne Gold]

for around $3k , you can buy a decent working chinese machine.. we just bought 4 600x400's 60w machines for $11k.
Its cheaper and a better solution than trying to nurse our old 10 yr old GCC's or having the tubes repaired.
We have retired ALL our GCC machines and are running 6 chinese lasers .. 2 of them 5 years old.. they give us NO hassles at all and engrave and cut beautifully.

[Chris Corwin]

I have an epilog Legend 32 that I run a 40w glass tube on. It works but you can tell this machine is made for RF tubes. I bought the laser for $1000 off Craig's list and knew beforehand that the synrad was bad. I had a 40w ps and tube kicking around so it was a no-brainer.

It works but I'm not getting full power from the setup. It does very well on grey scale Picts though! Something that the Chinese DSP's can't do.

[Dave Sheldrake]

Something that the Chinese DSP's can't do.

The AWC series of controllers after the 608C do, they also have a pre-heat control for the bigger tubes to reduce rise times

[Chris Corwin]

I have a 708c (light object x7) in school and I can't do greyscale engraving. If I'm doing something wrong or missing something, please let me know!

[Dave Sheldrake]

Is it the C plus Chris? and is it wired PWM or analog ? (some companies still wire them analog even though they have PWM function)

(And I messed up in the earlier post...should of course have said 708 not 608)

[Andrew Stow]

I have an epilog Legend 32 that I run a 40w glass tube on. It works but you can tell this machine is made for RF tubes. I bought the laser for $1000 off Craig's list and knew beforehand that the synrad was bad. I had a 40w ps and tube kicking around so it was a no-brainer.

It works but I'm not getting full power from the setup. It does very well on grey scale Picts though! Something that the Chinese DSP's can't do.

How involved was that conversion? New power supply? Added water cooling?

I have a Legend 32 made in 2000. It still runs great, but I bought it a couple of years ago as government surplus. It was extremely dirty, and had a bad LCD (seems to be a common problem with old epilogs), but it has given good service the past couple years.

But the tube in it is 15 years old. So I'm thinking ahead to the day when it finally dies.

What tube specifically are you using in it?