Speed

[Julian Ashcroft]

As part of my business I laser engrave a lot of leather, most of the engraving is no more than 34mm in diameter. Different finished leather requires different speed and power settings, but most I run at 65% power and 400mm a second, any faster than this doesn’t make a difference as it’s such a small area. The time it takes to engrave an item 34mm in diameter is around a minute. This is on a Chinese 60w machine.

I was wondering what sort of time I would get running the same file on a machine such as a Trotec, would there be a significant time saving? I have heard this Austrian machine is much faster at engraving than a Chinese laser.

[Kev Williams]

For such a small area, you should experiment with slower speeds, the X-axis turnaround/overrun at 200mm/s is much less than 400mm/s; this overrun is built in to compensate for the laser head speed to reduce shock, but across 1-1/4", the machine can never reach 400mm/s, but the overrun is the same at 1-1/4" as it is running 10". If you cut the speed in half, I'm betting you'll find it runs much faster :) - be sure to adjust power....

but this speed goes out the window if you run multiples of the same color layer horizontally, so run different colors ACROSS, same colors DOWN...

A Trotec would shine running several at once across, at least until the speed overtakes the power.

Another thing I've found with leather, is it's usually pretty forgiving as to Y axis res, aka 'gap'... Not sure what you're running at, but I get good results at .08 to .1mm gap (250-300dpi), and that only helps speed things up too...

[Mike Null]

The Trotec would probably cut a little time from the engraving but I agree with Kevin, engrave a lot of them and your time saving would be significant. If you send your file to Trotec they will test it for you and give you the results.

[Steve Utick]

Have you ever experimented with any leather on your fiber laser? I've done quite a bit of leatherette and a couple of leather things on our Fiber, and it turns out nicely and is fairly fast as well. Might do some experimenting and see what the results are like.

[Julian Ashcroft]

Thanks for the replies. I have experimented a lot over the years with speed and power and I do find running a single woggle at 400mm rather than 200mm a second will cut around 10 seconds off the time. Most of the leather I use has a coating on it and some is harder to get through than others and so require a slower speed to acheive a smilar result. I have the gap or line spacing set at 0.10mm which works well.

I use jigs to hold my pieces, a lot are one offs, but some are multiples. I will have a look at doing a jig that can hold a few pieces in a line, which might speed things up a tad.

[Kev Williams]

I stand mostly corrected :) -- in that the machine won't reach 400mm/s in 30mm-- yeah, it will ;) -- I ran some 'air' tests, 30mm square, first at 400, took 57 seconds- second at 200, and instead of faster it was ridiculously slower, I didn't ever bother to time it- third pass I ran at 500, that took 58 seconds, 1 second LONGER at the higher speed, so basically the exact same results as yours! The part I got right, it the extra overrun at the higher speed did come into play, actually slowing the machine down... ERGO, when you're able to do multiples, you'll likely shave some time running them sideways at a faster speed, say 700mm/s, which should still give decent results in leather, provided your 60w is enough, which it should be. You might even get away with 800 with leather, but I've found 700 is about the limit before detail starts to noticeably suffer...

Note-- even if your machine is set up with a 500mm/s max speed, it should be capable of 1000mm/s, you just need to get into the factory parameters and raise the default max speed... :)

(here's where I changed mine)
386737

[Wojciech Szul]

I was wondering what sort of time I would get running the same file on a machine such as a Trotec, would there be a significant time saving?
I was trying to do REAL speed test on different machines, unfortunately there was no response from high-end brand users :(
The biggest problem with Chinese machines are:
- steppers (or semi-steppers with loop) and not REAL servo [as this fitted in Thunderlaser]
- bulky, heavy head [is this rocket science to make stiff and LIGHT holder for 3mirror and lens?~?]

I do my own test of real achievable speed on my (Chinese) machine and it "go lower in higher entered number" - so for speed as 5-10-20mm/s speed is real, but at numbers as 400/700/1000 goes way lower. Say lower by 1/3. Some small part of test you can see here (from ~8:20) https://youtu.be/dLtXHDDMkKE?list=PLKqvqV6FhMtWv-wab69zSEvSEPDgJN4cz&t=500
I know my English is rough, so if you feel confused switch off-audio ;)

[Kev Williams]

For what it's worth--

My 14 year old Gravograph LS900 is an 80 inch per second machine, and it uses steppers, not servo's.... It runs at any speed with less than 2mm of over-run beyond the left/right edges of the work being engraved, and will engrave 24.012" (609.9mm) worth of the 24.016" (610mm) actual working area at full speed....

using the spiral Boy Scout motto above as reference, I drew a 33mm circle, engraved it at 200dpi (.127mm gap), at 50% speed which with my 40w power would need to be that slow- and it took exactly 30 seconds-
I then ran 4 across at once, and it took 1:03-- that right there is a 300% production increase over 1 part per minute! So to be fair to 'detail' I upped the res to 300 (.085mm gap) and the time increased to 1:34, which is still still a 265% production increase--

AGAIN, this is factoring in my 40w power, with 60 or 80 watts on tap, my machine could easily cut the 1:34 time in half! And a faster/higher power machine could likely knock out 10 of these stacked across the X axis in about a minute-- a 10:1 factor over current production...!

SO- this begs the question: how many of these things can you move out the door on a consistent basis? From just my sample testing and best-guess estimating of 'stronger' machines than mine, you can see that you can easily buy a machine that will nearly exactly fit your needs! :D