New user question on the use of 100% power?

I just got my GF basic and I’m in love with how well it works. I had previously been using a diode laser and you obviously can’t even compare the speed difference.

My question: I remember reading about the cheap 40w china lasers owners forums that using 100% power for cutting exponentially decreased the lifespan of the laser. Is that not the case with the Glowforge?

In trying to find cut settings for non-proof grade material, I keep seeing people using 100% power in their cutting and just wanted to make sure that if I did the same, I wasn’t taking considerable time off my tube’s lifespan unnecessarily if slightly less power and slightly longer cuts would work and do less damage.

Related, I used to make fridge magnets as gifts from jumbo popsicle sticks. Anyone have a settings guess on cutting/engraving 1mm thick popsicle sticks?

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Very much discussed before.

As for settings, those guys are pretty basic wood. Are you pro or basic GF?

I’d probably start at about 260/full pro and go from there.


True on both fronts.

One of the issues with the Chinese “40W” lasers is that usually represents the maximum power output of the tube. To get that you actually have to overdrive the tube. Combine that with the inability to actually measure the output in real time and the lack of calibration on the power controls and it’s easy to burn out a tube. My K40 actually has a 32W tube for example.

Sometimes you’ll see the tube marked as 40/50 or 100/120 which gives you running rated power & maximum output when overdriven. So my K40’s tube should be marked 32/40 but the machine’s seller says it’s a 40W. Not entirely untrue but somewhat deceptive.

Running a tube at maximum or “100%” power will reduce the lifespan of the tube vs even 95%. So some lasers allow you to set governors to prevent running them too hot. The K40s generally don’t have this feature and you have to be careful not to dial up the power too much.

GF takes this into account and “Full” power is the full normal operating power - you can’t overdrive the tube and it’s something less than 100% power per Dan last year. We shouldn’t see any reduction in lifespan by running at Full power. The 0-100 scale is used to provide settings compatibility between the Basic and the higher power (45W) Pro.

There is some misperception that Full = 100% and 100 is therefore really 99%. In reality it’s some other value but that means Full on the Basic = 40W safe maximum and Full on the Pro = 45W safe maximum which means the difference between 100 & Full on a Pro is a larger power jump than between 100 & Full on a Basic.

In practice you don’t need to worry about how many watts of power (or %) you’re using - just keep track of the ordinal settings and let GF take care of translating it into delivered power.


Thank you for an awesome and comprehensive answer to my question! It really put me at ease about playing around with settings on my own.


Thank you so much! I’ve got a basic but I’ll still try and setup a file to test it at speed increments of 20 from that 260 range and see what works.

NP. There are a bunch of us K40 owners here. It’s a gateway drug to lasers & CNC :slight_smile:

You’re now officially warned…as you get skilled at using your GF you’re going to be tempted by a CNC router because then you can use the same files but do 2.5D or more carving…and then there’s the metal ones (including the CNC plasma one I just bought in to :smile:) It’s really hard to spend a lot of time here without finding a hundred other things you could use.


Just to chime in - this is a great answer.

1-100 gives you precision power mode, which is much more stable - helpful for delicate cuts and scores. Full power is more than 100, but much less than your tube is capable of, so it can be used without reducing your expected tube life at all.