I’d go with a large format (3 or 4 feet by 5 feet) 130W machine.
The higher power allows for faster throughput. The larger format allows for more items to be done in one run with fewer material changes - putting stock in, removing completed items, placing & lining up more material. The larger the number of items you do, the more the impact of “feeding the machine” times.
Absolutely. There is nothing wrong with farming out work. It is very much how things are done these days. For laser work, I’d look to services like Pokino for the first big batch and then get on the spreadsheet to figure out if I need to continue to farm it out or will that $20K laser be paid for in a year and be making me more.
Real world, I 3d print a part that becomes a major component. Not the cheapest way but it is on demand. If someone wanted 500 units I’d be looking for an injection molding service.
This is what I have been wondering - if any increases in speed would come from actual machine speed or from reducing the overhead in activity between runs (laser down time). At a certain point, this is going to max out, right?
If I am engraving something that can run at 50% power at 450mm/sec (for argument’s sake) on a 60w machine, I can’t buy a machine that is going to do it at 900mm/sec, though it might be able to do 500mm/sec at a lower power. I could pick up more time on cutting material.
My point is that I am likely to get as much an increase in efficiency by reducing transitions as I am from getting more power, right? The flip side is that I have yet to see a huge bed and a moderately powered laser - they seem to increase correspondingly.
You want to reduce two things:
because both of those contribute to total time. Only spreadsheet and experience will tell you which is your bottleneck for which jobs.
You’re right about the general correspondence between power and size, which is for multiple reasons. Without more power, some of the jobs you can try to do with the bigger machine will take forever. And on the expense side, it’s already going to be ridiculously pricey to make a bigger but still-accurate motion system, so why not go with the bigger tube as well. (And of course, going the other way, with CO2 lasers, tube length and hence power scales with the long dimension of the box, so more power means bigger by default. With diode lasers that equation isn’t true, but we’re still an optics breakthrough or two from making that meaningful.)
Most machines have higher speed capacities than their power can utilize. For instance, 1000mm/sec is pretty common but you’ll not get much engraving done at that speed from a 40 or 60 watt machine - it’s just not enough delivered power. So in your example, if you could get decent results engraving at 50% power/450mm/sec on a 60 W machine, then a 130W machine should indeed allow you to do it at 900mm/sec.
true in most cases. But I would rather have the capability than not. It can allow you to do things with certain materials that you might not be able to otherwise, like taking a very thin top layer off of cardstock, or engraving thin EVA foam, both of which require very low power to speed ratios.
True, but the original question was whether the extra power and speed actually paid off in increased throughput.
Scoring paper for folding is a good use case for 40/60W machines and the higher end of their speed ranges.
For Tim’s question, he could get both reduced material handling time and increased speed of engrave/cuts with a bigger machine.
All for the hypothetical volume machine to supplement our GFs question.
I guess my point was it really depends on what youre trying to make with it. If you make greeting cards might need something with really high speed. if youre making deep engraved signs its not as much of an issue.
Back to the power cord derailment… I want one like this, but for big boy power levels…
I almost got one of those, but sleeping wouldnt be happening for me haha. I do have extension cords in my shop that have a light at the end so I can know its plugged in or find it in the dark
It’s not (as far as I understand) that important for the GF, but for some other machines it can be: that number of millimeters per second is a top speed. How much of your zapping gets done at that speed is seriously dependent on the shape and size of your design. So for example with a 1x1" engrave you are never going to reach that speed before the head has to turn around and try to zoom the other way. Which may affect your power levels depending on how the laser calculates that.
(Speaking of which @dan if someone is doing multiples of something involving an engrave, is there a way to gang them in the UI to minimize head acceleration/deceleration, or do you have to put them all in one image-to-be-zapped?)
Thanks. I was largely ignorant about larger machines, hence my question. My assumption was that bed size and power increased, but axial movement remained somewhat the same. This could be because those are the two most quoted specs for machines. Thanks for the info.
I think I understand your question, that is if it is the same one I had. I was excited by this:
Correct. Pathing is critical. It depends on how the software treats the individual copies of the base item - as part of a single whole or one of many. And then for vectors, what’s the order of the paths. Really complicated if you want it to be 
nano one does it great but once you’re used to your machine’s software, you can adjust for it at least to some extent.
Do laser heads travel the same speed when firing as when not? I mean if I set the speed at 300mm/sec, and am engraving a big letter “U”, the laser head is going to travel that speed when engraving and for the blank space in between, correct? Do more sophisticated lasers move faster when not firing?
for a raster engrave, yes. I dont know if larger lasers have some sort of gap detection and will accelerate faster to clear those gaps more quickly, but i know the lasers Ive used dont. They just go across at the same speed.
I will have probably a 5 foot run to my window. when I get the forge set up in the basement. I probably will make a double wallled tube with foam between the two.
This applies to all CNC like machines. When tool is not active (or if Z is raised) these moves are called ‘rapids’ (aka G0 X-100) these are limited by the controller itself.
Tool engagement moves (tool is active) these are dictated by the feedrate. i.e. G1 X-100 F3000 (feedrate is 3000mm/sec in this case)
The thing that determines if that feedrate can be hit is the acceleration / deceleration values. This is used to tune the machine so where if there is a short move (or aggressive) instead of the gantry going from 0mm/sec to lets say 3000mm/sec it gradually get to that speed. But this depends on the distance specified.
For example. If you told it to go from 0 to 3000mm/sec is a distance of 3ft- There is more than enough space and time to gradually get to that speed then ramp down. That same move in a distance of 3in- it would not hit the max feedrate specified.
In the case of the glowforge. The head assembly is pretty hefty. (a lot going on in there) so they need to tune it where the weight and inertia does not affect the performance of the machine. Tuning that value keeps vibrations and swaying under control. And this also dictates if a high speed move can be done (if at all possible)
Those red power cords were supposed to be “don’t trip on me” cords for expensive lab equipment, but it looks like they somehow found their way out of the lab and into your homes. My loss is your gain 
so youre the one with good taste in power cords eh… =)