Some gears and testing for laser-ablating and -marking ...

Hi Adam,

the last parts were made with a 20 Watt pulsed fiber-laser, not with the 85W-CW-laser.

The results in steel are comparable with the CW- and pulsed lasers -- with other, more shiny/reflective materials the pulsed laser will be much more effective!

The CW-lasers were "random" parts, I've got in exchange of some of my old gears and private developments, so it's mostly counted/paid in time and ideas, not money.

The pulsed fiber-laser and galvoscanner in the showed setup was sourced and built in my day-job, so a totally different game -- this is my money-making job ... but I'll get it for my private use, when the next "updated" version will be functional ;)

We plan to sell the complete marking system with software, equipped with this pulsed 20W laser, for around 15 thousand Euros ...

Viktor

... I'm searching for different "give-aways" for the next exhibition in Juny - could be this ;)

Attachment 52071


Viktor

... made them smaller (20mm instead of 35mm) for higher mechanical stability/stiffness and lower material effort.

Here a video, lasering the smaller parts - https://vimeo.com/216584306


... and the results:

Attachment 52078 Attachment 52077 Attachment 52076


Viktor

I realize this was an old project but what are you using for the pulsed fiber laser?
How are you pulsing it?

Quote:

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Originally Posted by VDX

We plan to sell the complete marking system with software, equipped with this pulsed 20W laser, for around 15 thousand Euros ...

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That will compete very favorably with the units I've seen from Trotech. And based on your pictures, you've got them beat in terms of resolution. :)

Adam

Quote:

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Originally Posted by gn3481

I realize this was an old project but what are you using for the pulsed fiber laser?
How are you pulsing it?

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... with the CNC-mill, I'm using to move the CW-laser-heads or older pulse-laser-head, it's the same way as with the PZT-drive pastedispensers or lasermodules - setting the "pulses per mm"-value in the software parameters and let the hardware (when synced with the X/Y-Clock-pulses) or software (calculating variable PWM for acc-/decceleration) handle the pulsing.

With the XY-galvoscanner it's simply a frequency I'm setting in the parameters - e.g. "cutting" with 100mm/s feedrate and 2kHz pulsing ... or "engraving" with 2m/s and 50kHz pulsing ...

Viktor

Hi Adam,

Quote:

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Originally Posted by buffo

That will compete very favorably with the units I've seen from Trotech. And based on your pictures, you've got them beat in terms of resolution. :)

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... are you referring to the fiber-laser systems, or the CO2-lasers from Trotec?

With the CO2-lasers they'll have much bigger spot sizes, so not really comparable to the fiber-lasers.

My tests were made with spot sizes of roughly 40 microns (without beam-expander and with 7mm entry beam diameter), but 30 microns are common with this types of laser-markers too ...

Viktor

... here some samples of "micro-machining" - did tests with varying hatch-densities and repeated engraving in brass and a multi-layer ceramic part ...

First the tests in brass - with 30microns hatch-spacing and 10x ablating it will "engrave" 0,3mm deep:

Attachment 52099 Attachment 52098


... in ceramic it's a bit more effective - same parameters and 10x engraving will remove 0,6mm:

Attachment 52097 Attachment 52096

Attachment 52095 Attachment 52094 Attachment 52100


Viktor

Quote:

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Originally Posted by VDX

are you referring to the fiber-laser systems, or the CO2-lasers from Trotec?

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Both! :) My wife operates a Trotech at work that has both a CO2 and a YAG laser. Most of what they do is marking, not cutting, but even so I've seen the results and the level of detail you're getting is superior to the best I've seen from the unit she runs - even when using the YAG.

Makes sense though. You're moving a tiny mirror with precision optical feedback. The Trotech is moving a huge, heavy (by comparison) carriage with optics, a fiber head, a fan, and so on... Plus the carriage has to move over a very large travel distance while maintaining positional accuracy. And finally, there is a limit to how precise you can get with a stepper motor and it's nowhere near the precision of a modern galvo.

Like I said: you guys are definitely onto something here, and at that price point you can be very competitive. Hope it goes well for you!

Adam

Hi Adam,

thanks for the thumbs-up!

Yes, there's a big difference in resolution and positioning accuracy between belt-driven systems and galvo-scanners, but it's too related to the targeted working dimensions -- so more a compromise between marking speed and accuracy.

But on the other hand - I'm working since maybe 30 years with different setups - my first DIY-CO2-lasercutter/engraver was driven with steel-wires and steppers too, with up to 200mm/s moving speed ... and for high accuracy I have used different gantry-style machines with steppers or servos.

My actual gantry is a modified prototype from Isel, driven with servo-motors and encoders with a positioning accuracy of 2,5 microns, so potentially even more accurate than the galvo-scanner.

The main difference is the positioning speed - when engraving, then max. 80mm/s reliable with the gantry, more than 5m/s with the galvos ... and the galvos can fast move to the next coordinate with up to 50m/s! (but need then some microseconds to decay/swing off).

The main drawback with the galvos is the limited marking area - 110x100mm with my actual setup ... but could be resolved by an aditional linear XY-positioner with bigger moving range - the software can divide the marking area in "tiles" and use both positioning methodes to mark much bigger areas ...

Viktor