Is there a rule of thumb for increased ability versus added laser wattage?

[Doug Fisher]

Is there a rule of thumb for what improvement in vector cutting a buyer can expect (speed at which you can cut or how deep you can cut) for a given increase in laser tube wattage assuming you hold all other things equal and are using comparable quality tubes and power supplies? Maybe cutting speed is the more accurate measure since cutting depth will be limited by the lens' depth of field characteristics? In other words, how much faster can you expect to cut the same type of acrylic using the same power level if you move from a 40w laser tube to an 80w laser tube? 25%? 50%? Or?

Thanks.

[Kev Williams]

Well, not sure if it's a rule of thumb, but I had a 25 watt, and still have a 40 watt and an 80 watt laser.
The 25 would get thru 1/4" plex, slowly.
My 40 will get thru 3/8" plex running around 4-5mm/second, and will get thru 1/2" at about half that speed. Barely...
My 80 watt I've actually gotten thru a full inch of cherry in one pass, but really slow, like 1/2mm second. That was with a 2" lens. And it wasn't at all a 'clean' cut, it was burnt pretty bad. I tried a 3" lens thinking it should get thru better, but it only made it about 4/5 the way thru. The more focal range couldn't make up for the lesser power density. Haven't tried that thick of plex since I don't have any ;) -- and cherry is the only wood I've gotten thru that thick..

To get much deeper than 3/4" you WILL need longer lenses, and that will require an increase in power. Based on my experiment, the 3" lens only made it 80% as far thru as the 2" lens with the same power. How much more power loss a 4" lens would cause, no clue. But a 4" lens should make for a nice cut, providing you HAD the power. Just a guess, I would think it would take around 150 watts using a 4" lens to get thru 1" of wood or plex 'reasonably'. But the cut itself should be as good as a 40w cut thru 1/4"... I guess ;)

[Doug Fisher]

Thanks for the reply, Kev. In order to compare apples to apples, since your 25 would get through 1/4" plex "slowly", do you remember at about what speed your 40w and 80w require to go through 1/4"? Since your 40w would go through 3/8" plex at 4-5mm, do you remember what speed you would use for the same 3/8" plex with your 80w? I just thought I would ask in case you knew the actual numbers because they would make interesting apples to apples comparisons.

Thanks.

[Dave Sheldrake]

it follows the inverse square law on a DC tube pretty much for a given speed and focal length, remember RF are different, the beam profiles and beam quality are a lot better.

A 35 watt RF will perform about the same as a 60 Watt DC tube

An 80 watt DC will cut 3mm acrylic at 26 to 28mm per second, a 150 watt will give the same results at around 35 to 38mm per second.

Unless you are cutting a lot of sheet anything over 80 - 100 watts is pointless.

Upgrading from 40 - 60 is pointless

40 - 80 is worth it,

80 to 100 is pointless

80 to 150 is worth it

Consider doubling DC tube power usually runs about 4x the price for replacement tubes as well as the big increase in PSU price

There are a hell of a lot of contributing factors as well that make for the lower efficiency as you move up in power and/or material thickness

[Kev Williams]

Thanks for the reply, Kev. In order to compare apples to apples, since your 25 would get through 1/4" plex "slowly", do you remember at about what speed your 40w and 80w require to go through 1/4"? Since your 40w would go through 3/8" plex at 4-5mm, do you remember what speed you would use for the same 3/8" plex with your 80w? I just thought I would ask in case you knew the actual numbers because they would make interesting apples to apples comparisons.

Thanks.

Video (pardon the quality) of my Triumph cutting 1/4" plex at 26mA and 17 mm/sec...

https://www.youtube.com/watch?v=9mKTg__OMPo

Haven't done a time-run with the 40w Synrad yet, but pretty much 1/2 to 2/3 the speed the Triumph did--

Bottom line: Even with 80 watts, it's not blazingly fast... ;)

[Doug Fisher]

Thanks for posting but your video is marked private.

[Kev Williams]

Not sure when I made it private, but it should work now!