Units Of Measure


Not sure if there’s ever been an official request, so…

Speed = 100 - 1000 what per what? Gits per gimboid?

“Precision” Power = 1 - Full? Or is it 0 - Full? The slider shows 0, but it appears impossible to achieve it and it would server no purpose anyway. So it should start at 1. But, again, 1 what? Micropew?

It’s difficult to speak intelligently about things without units of measure.
My son asked me “What’s the difference between 100% and ‘Full Power’?” I said “Ah! Great question. First of all it’s not percent. If it was it could only go from 0-100. But this goes from 1-Full.” “So if it’s not percent, what is it?” I said “Another great question. And it’s one that nobody seems to know the answer to.”



It isn’t percent, as 1-100 is identical between Basic and Pro, but Full is the full 40/45 watts, apparently. What the rest of the range is set on, don’t know.


Right. That’s what I said. :slight_smile:


It would be nice, but as one to jump on glowforge being below par on many things I will give them a pass on this one.

Even a epilog laser doesn’t have units in its settings. In fact the speed scale isnt linear on them either so 50 speed is not half of 100 speed. So annoying, but not unprecedented.

edit: said power but it’s actually speed that isnt linear


Speed is defined as some distance moved in some time. GF speed is not that, so they redefined another English word. cf Shipped, Soon, etc.


All the more reason why we need to know the units/scale. If not, one would easily presume that 50 powerses is half of 100 powerses.


oh for sure, I don’t like it because I am a hard numbers person. But I was just saying that I can’t really condemn glowforge for this since it is industry standard


:grinning:Hi Tom :grinning:

This topic has been raked over a few times. :grinning: When the change was made this point was made pointedly by a few folks. There was no response from the powers that be.

This might be one of those dead horse issues. :grinning:

If I find a bit of time, I’ll do the search.




Definitely not condemning. It only makes sense.

Is it?! I’ve never owned a laser before now. Do they all measure speed at 100-1000 thingies per whatsits?

Might be. I don’t recall it ever being officially requested (in a Support capacity). So I thought it was worth opening an official ticket about it.


When / if I get mine I will attempt to measure the power delivered and check the scale.


Harsh edit. (I watched it happen. :slight_smile: )


Well I miss remembered slightly, it is speed that isn’t linear and power that is linear. But still, this is from the manual of a full professional machine

"Because there are many factors that influence the time it takes to engrave or cut a
given image, the Speed settings were designed to be reference numbers only. The
Speed setting scale of 1% to 100% is not linear – i.e. 100% speed will not be twice as
fast as 50% speed. This non-linear scale is very useful in compensating for the
different factors that affect engraving time, but using speed to predict a jobs
engraving time is not practical.
The Power settings are linear – i.e. 50% power is half as much as 100% power. "

The manual is a great read and explains alot of the “magic” and theory of laser cutting


Thanks for that! I see they made it even more confusing by calling it “percents.” I get what they’re saying. But… I mean… This stuff is measurable! I’m not a physics genius. But I know there are some working at Glowforge. And certainly some here in this forum. Am I crazy in thinking that this should be calculable?


I agree and think that everything should also be able to be shown as real units should the user choose so. I’m not a fan of made-up measurements


my assumption is that while 50% is not half of 100% speed wise, the scale is designed so that if you keep the same power and just change the speed you will get a mark that is that much percentage lighter (50% in this example). This makes the machine easier to use that if it was straight numbers and you had to remember “this cuts all the way through the material but I want a mark 75% of the way through it… but that doesn’t mean I dial my speed back by 25%, it means I dial it back buy 20 ips”


I would be interested in the interpretations of both scales. I have learned, from experience, that 500 speed is not twice the engrave time of 1000 speed. It’s about half again.If it is some kind of logarithmic scale, I’m just going to give up on figuring now and pull numbers out of the air. (I don’t think it is, just saying.)


I understand what they’re saying on speed. 3D printers allow you to specify the speed in mm/min in the gcode (ui’s usually show mm/s), but it is only the goal speed. The motion system has to compute the actual speed based on acceleration and other factors. For people in the know, it makes perfect sense, but I’m not sure it is worth it in the general case because it leads to all kinds of confusion and disappointment when people form the expectation that doubling it will cut the time in half.

Or they get into boast arguments about how fast they can tell their machine to go when it is just ignored by their firmware. That is kinda funny to watch though.


That explanation of percentage of outcome actually explains a lot and helps quite a bit. It does require a slightly different way of thinking, though.


For sure, but it also requires less expertise. And if you watch marketting for laser there is a heavy emphasis on “anyone can do it!”.

Having dug into industrial machines while waiting for my glowforge there are many weird things that show the laser industry is actually a bit stagnent when it comes to the software. Take Epilog for example; they are only bettered by one company in the industry for laser cutters and they just run everything off a fancy priter driver. Think you can have you artwork up on a digital bed and see even a cross hair to see where the head is in relation to it? Additional software. Save settings from a print? Same additional software. Want to know how long a print will take? Nope


I get what you’re saying. And that’s totally fair. But that “goal speed” can be measured in some unit. And that’s the important part. Kind of like setting a min framerate for video playback… It’s a goal. It may get hit, it may not. But it’s measured in FPS… a real unit of measure.