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Laser Cutting Head

Posted by aka47 
VDX
Re: Laser Cutting Head
April 19, 2010 12:49AM
Update ...

... i've got a big (really gigantic eye popping smiley) charcoal absorber, so i can make some more 'stinky' laserworx grinning smiley

The next days i'm awaiting some samples of CerMark laser-marking paste some ceramic colours for colouring and marking tests ...


Viktor
VDX
Re: Laser Cutting Head
April 25, 2010 12:56PM
... atached two photos where i cutted black plastic foil with 1 Watt power at 500mm/min for testing the min-limits and with 2 Watts for a clean cut.

The carved tray in the first image is 0.25mm wide, the holes were melted at the start/end of lines and curves, where the moving speed was a bit slower.

The holes and through-cuts have a width of 0.28 to 0.3mm - for a thinner cut i need a much better optic and the material shouldn't be thermoplastic as this tend to melt around the laser spot and move away from the cut.

In this test i glued the foil on clear PMMA, so this could be used as a perfect photo-mask for PCB-making or such ...


Viktor
Attachments:
open | download - VD-1Watt.jpg (93.5 KB)
open | download - VD-2Watt.jpg (92.4 KB)
VDX
Re: Laser Cutting Head
April 26, 2010 11:38AM
... to compare i engraved the same material with the fiberlaser at 1Watt CW and a single focussing lens - so the spot was around 30 microns in diameter (with beamexpander the spot will be below 10 microns).

The trays have 2mm distance and measure between 40 and 80 microns in width.

I think the surrounding material melts and retracts, so the molten tray is much wider than the original laserspot - with the diode this could be the same.

So with CW-cutting you'll receive a melting area with a diameter of two times the laserspot.

With pulses and optimal balance between power and pulse-time this should reduce to nearly the original focus-diameter ...


Viktor
Attachments:
open | download - VDb-FL1Watt-2mm.jpg (97.8 KB)
VDX
Re: Laser Cutting Head
May 27, 2010 01:14PM
... update - designed a driver-PCB with 5xLM317 and a switching MOSFET.

Atached photos of the milled and populated PCB ...


Viktor
Attachments:
open | download - Platine-leer_kl.jpg (105.6 KB)
open | download - Platine-bestueckt_kl.jpg (137 KB)
VDX
Re: Laser Cutting Head
September 26, 2010 11:42AM
... update - haven't spent much time here, as i had some more urgent work to do eye rolling smiley

In the meantime i've got some different laserdiodes:
- 25Watts@808nm out of a fiber-bundle with 0.8mm diameter ...
- 1W@445nm ('real blue') in a 5.6mm-housing - today embedded in a cooler and current driver with 700mA ...
- 200mW@405nm (BluRay) - maybe interesting for etchant or chemical activation ...

For testing with SLS i've found and received two kg of lignin-powder from Tecnaro - as its dark brown and a natural thermoplast, this should be the ideal material for low-energy-SLS with the benefit of bio-degradability.


Viktor
Re: Laser Cutting Head
September 30, 2010 01:51AM
Hi,

i am bilding a laser cutter for my diploma.
I have a question.
Does anyone how to combine ir laser with a visible laser? (pilotlaser)
Which material (kind of mirror) is needed, and where to get it.

Thank you

Dean
VDX
Re: Laser Cutting Head
September 30, 2010 02:09AM
Hi Dean,

... you have seen the part "3.1. Embedding a Pilotlaser as guide or beam-indicator" in [objects.reprap.org] ?

Which IR-wavelength will you use?

808nm and 975nm can pass 'normal' transparent materials, so you can use a glass-window scewed by 45 degrees and align/adjust both beams as shown in the image.

Be aware of the 'splitted' IR-beam too - the reflected part should be caught (and cooled away) by black material ...


Viktor
VDX
Re: Laser Cutting Head
October 11, 2010 01:39AM
... did another test with cutting foil - the size of the tattoo is 10x8 cm:


The power was 2 Watts, spot diameter around 0.1mm (the thin lines are 0.08mm thick) ... and you can see the ugly residues of the glue, which wasn't evaporated, only slightly browned, so it stayed intact in the cutting groove.

As you can see in the previous images, when cutting the same foil on a plastic surface, the glue was completelly evaporated too ... but with a ceramic (cooling) tile as surface, the energy of 2Watts wasn't enough to remove the glue.

I think with 4 Watts this would be enough for the glue too - the fiberlaser won't have this issues even with only 1 Watt power, as the energy density is some decades higher, than with diode-lasers ...

Another interesting test could be using the blue (445nm) diodelaser with 0.5Watts power ... maybe i'll try this next time ...

Edited 1 time(s). Last edit at 10/11/2010 01:42AM by VDX.

Viktor
Re: Laser Cutting Head
November 28, 2010 03:20PM
I bought a 1W 808nm diode laser + housing with plastic lenses + protection goggles.

I hope to have all of it in 2 weeks and so I will start making my tests. My target is to cut paper and if possible, etch PCB.


---
New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]
VDX
Re: Laser Cutting Head
November 29, 2010 01:58AM
Hi Casainho,

have you tested your diode with white paper?

With the 975nm i have trouble to burn white paper even with 5Watts, but better results with 0.5Watts at 445nm (blue).

Coloured or dark paper is no problem, so it's a matter of absorption (material colour) and energy density (focus diameter).

---
For updating my (really slow eye rolling smiley) progress: - i'm actually finishing two 'comercial' 5Watt-modules and will post some images later.

When ready with the IR-modules and the old lathe i've bought from ebay, i'll make some tests with the blue 1W-laser burning/engraving different materials.

Then i can give better estimates what's possible with the specific diodes and wavelengths ...


Viktor
Re: Laser Cutting Head
November 29, 2010 02:15AM
VDX Wrote:
-------------------------------------------------------
> Hi Casainho,
>
> have you tested your diode with white paper?

I don't have my diode and other parts yet. I just bought them from Ebay.

At Makerbot, there are already results reported: [wiki.makerbot.com]


> With the 975nm i have trouble to burn white paper
> even with 5Watts, but better results with 0.5Watts
> at 445nm (blue).
>
> Coloured or dark paper is no problem, so it's a
> matter of absorption (material colour) and energy
> density (focus diameter).
>
> ---
> For updating my (really slow eye rolling smiley) progress: - i'm
> actually finishing two 'comercial' 5Watt-modules
> and will post some images later.
>
> When ready with the IR-modules and the old lathe
> i've bought from ebay, i'll make some tests with
> the blue 1W-laser burning/engraving different
> materials.
>
> Then i can give better estimates what's possible
> with the specific diodes and wavelengths ...

I went for 808nm because seems the best price/wattage available.


---
New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]
VDX
Re: Laser Cutting Head
November 29, 2010 03:47AM
Hi Casainho,

... the samples at makerbot are made with a 445nm-blue-diode, which has nearly half the wavelength as the 808nm and is mostly focussing the direct diode-output and not through a fibre - so the energy-density in the spot is higher than when focussing after a fiber ... i think, 1Watt @445nm in a spot of 0.5mm could be roughly comparable in its effect on paper to 3Watts @808nm or 4Watts @975nm focussed on a spot of 0.1mm ... but this is more gut-feeling than real experience ...

I'll recommend the 1W-445nm-diodes for low-power-laserworks ... they can be found for around 30€ (mostly salvaged from Casio-beamers), are really good (much too good maybe) visible ... and for goggles you can try with UV/blue-shielding PC-windows (bright orange in colour) commonly used for housings around photolithography and etching systems.

I have some samples of UV-shielding plates, so i'll try next days if they are usable for 445nm ...


Viktor
Re: Laser Cutting Head
November 29, 2010 08:49AM
VDX Wrote:
-------------------------------------------------------
> Hi Casainho,
>
> ... the samples at makerbot are made with a
> 445nm-blue-diode, which has nearly half the
> wavelength as the 808nm and is mostly focussing
> the direct diode-output and not through a fibre -
> so the energy-density in the spot is higher than
> when focussing after a fiber ... i think, 1Watt
> @445nm in a spot of 0.5mm could be roughly
> comparable in its effect on paper to 3Watts
> @808nm or 4Watts @975nm focussed on a spot of
> 0.1mm ... but this is more gut-feeling than real
> experience ...
>
> I'll recommend the 1W-445nm-diodes for
> low-power-laserworks ... they can be found for
> around 30€ (mostly salvaged from Casio-beamers),
> are really good (much too good maybe) visible ...
> and for goggles you can try with UV/blue-shielding
> PC-windows (bright orange in colour) commonly used
> for housings around photolithography and etching
> systems.
>
> I have some samples of UV-shielding plates, so
> i'll try next days if they are usable for 445nm
> ...

So, I should went for 445nm... and the cheaper I can found on Ebay are $60 (including shipping to Portugal): [cgi.ebay.com]

So, for now I will test the 808nm. I am looking for PCB laser etching and mylar stencil cut.

Do you know if with this [cgi.ebay.com] housing with plastic lenses I can get near to 0.1mm burning point/lines? higher, lower?


---
New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]
VDX
Re: Laser Cutting Head
November 29, 2010 01:24PM
Hi Casainho,

this is a common collimator head, so could be good enough for 0.1mm focus.

In most cases glass lenses are better than plastic, so if possible, use glass.

If you cover the PCB's with black paint, there souldn't be a difference in absorption, so try best with dark or coloured materials.

And here is a photo of my last 5Watt-module: - actually emitting 1Watt on a fluorescence-plate ...

Edited 1 time(s). Last edit at 11/29/2010 01:25PM by VDX.

Viktor
Re: Laser Cutting Head
November 29, 2010 02:53PM
VDX Wrote:
-------------------------------------------------------
> Hi Casainho,
>
> this is a common collimator head, so could be good
> enough for 0.1mm focus.

Ok, nice to know. I will try to measure it when I test it. I would love to 50um or 10um... but maybe I don't need for my application.


> In most cases glass lenses are better than
> plastic, so if possible, use glass.

The price... the price...


> If you cover the PCB's with black paint, there
> souldn't be a difference in absorption, so try
> best with dark or coloured materials.
>
> And here is a photo of my last 5Watt-module: -
> actually emitting 1Watt on a fluorescence-plate

So, my target application is for be able to prototype electronics, for 0.5mm pitch. Etching PCB using the black paint and laser, and laser cut mylar stencils for applying solder past to PCB.
I wish I could do this with cheap (under $50) diodes/hardware.

And what are your targets?

So, I will need about 1.3A @ >2V. If I want full power all the time, how many LM317 should I use If I do not want to use cooling and running from 5V or 3.3V of PC power supply?

Is there any typical circuit using some step-down IC which is relative cheap? maybe something we can control linear and not using steps like using LM317 in parallel?


---
New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]
VDX
Re: Laser Cutting Head
November 30, 2010 12:22AM
Hi Casainho,

... my targets are mainly cutting thin plastic foils and melting/sintering powders to solid tracks.

For my needs i have some stronger and finer lasers, so don't need the diodes really - but with the cheap laserdiodes i can develop DIY-lasermodules, so others can start with laserworks too ...

I'm started with the LM317 as current regulators because they are highly reliable and the PCB is totally simple.

For higher powers (for 25Watt-diodes or multi-5Watt-arrays) and less heat-dissipation i'll design another PS with MOSFETS, but this can take a while ...

When powering a single LM317 sitting on the cooler in the photo with 6Volts@1Ampere continuous, i measured 86°C at the chip and 55°C at the cooler ... better use 3x LM317 with 1/3 PWM (e.g. pulse-ratios = 10ms ON, 20ms OFF), so they'll stay much cooler ...


Viktor
Re: Laser Cutting Head
November 30, 2010 01:48AM
VDX Wrote:
-------------------------------------------------------
> Hi Casainho,
>
> ... my targets are mainly cutting thin plastic
> foils and melting/sintering powders to solid
> tracks.
>
> For my needs i have some stronger and finer
> lasers, so don't need the diodes really - but with
> the cheap laserdiodes i can develop
> DIY-lasermodules, so others can start with
> laserworks too ...

Ok. As I said, I am looking for laser etching PCBs and cut mylar stencils - I need that for me and I sure RepRap community would love to have such technology. If I success, I plan to develop and maybe later sell a module for controlling the laser, for my electronics: HBox_RepRap_Electronics


---
New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]
VDX
Re: Laser Cutting Head
December 25, 2010 12:04AM
Update:

... i've sold my first housed 5W-module - it's similar to the one in the last linked image with switches connected to the LM317-jumpers, so i can select max. oputput easy from 1Watt to 5Watt in 1W-steps.

The power (6 to 8 Volts @ 6 Amps) is connected to the 4mm-jacks, PWM signal is connected to the BNC-terminal.



Now i'm awaiting some 9W- and 20W-diodes and testing with some 7.5Amps regulators and IRF1404-MOSFETS for drivers up to 35Amps. the 9W and 20W-diodes needs 'only' 10 resp. 20Amps, but there is the 25Watts@808nm-diode too that needs 35Amps eye popping smiley


Viktor
Re: Laser Cutting Head
December 25, 2010 12:11AM
VDX, tell reprap-dev about them? (I'm trying to jumpstart laser discussion there.) grinning smiley


-Sebastien, RepRap.org library gnome.

Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything! grinning smiley
Re: Laser Cutting Head
December 25, 2010 02:08AM
VDX Wrote:
-------------------------------------------------------
> Update:
>
> ... i've sold my first housed 5W-module - it's
> similar to the one in the last linked image with
> switches connected to the LM317-jumpers, so i can
> select max. oputput easy from 1Watt to 5Watt in
> 1W-steps.

I am looking for a cheap laser that be able to cut paper, etch black paint, just like this one: [wiki.makerbot.com]

I bought from Ebay a 1W 808nm diode but it seems to be fake and have just 100mW :-(

Do you have a solution for that wattages and prices?

I am developing my electronics and I would love to provide and sell a complete solution (mechanics, electronics, firmware and software), please contact me.


---
New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]
VDX
Re: Laser Cutting Head
December 25, 2010 02:11PM
Hi Casainho,

for paper i'll recommend a 445nm-diode with 1Watt power - i've got one for 30 Euros and you'll find them in ebay too.

They are 'bright-blue', so really good visbible and the wavelength is much better absorbed by organic material, so you'll be able to cut with 1 Watt blue directly focussed from the diode maybe even better than with 3Watt IR through the fiber.

The driver is a single LM317 used similar to my sheet in the Wiki - maybe with a 2.2 Ohm resistor for an current around 0.57 Amps, so not in the max.-range ...

@Sebastien - we can discuss this there, but i'll prefer better giving tips and infos for DIY than selling laser-modules all over the world.

Selling of 'burning lasers' is a critical/dangerous theme, so i'll concentrate on building and selling lasers and modules to friends and local users, where i have a good communication ... it's pretty dangerous, giving them away to people without proper knowledge in laser safety and use confused smiley


Viktor
Re: Laser Cutting Head
December 25, 2010 02:26PM
VDX Wrote:
-------------------------------------------------------
> Hi Casainho,
>
> for paper i'll recommend a 445nm-diode with 1Watt
> power - i've got one for 30 Euros and you'll find
> them in ebay too.

You know, I bought on Ebay my diode laser and it do not work...


> They are 'bright-blue', so really good visbible
> and the wavelength is much better absorbed by
> organic material, so you'll be able to cut with 1
> Watt blue directly focussed from the diode maybe
> even better than with 3Watt IR through the fiber.
>
> The driver is a single LM317 used similar to my
> sheet in the Wiki - maybe with a 2.2 Ohm resistor
> for an current around 0.57 Amps, so not in the
> max.-range ...

I don't have problems with electronics, but I have difficult to find laser + lenses + knowledge/safety.


> Selling of 'burning lasers' is a
> critical/dangerous theme, so i'll concentrate on
> building and selling lasers and modules to friends
> and local users, where i have a good communication
> ... it's pretty dangerous, giving them away to
> people without proper knowledge in laser safety
> and use confused smiley

I would love to have a complete solution, including goggles for safety.

I would love to bring for RepRap the possibility to prototype current electronics of 0.5mm pitch, just like here: [blog.arcol.hu]


---
New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]
VDX
Re: Laser Cutting Head
December 25, 2010 03:17PM
Hi Casainho,

... ebay is like a lottery - i've bought several parts on ebay too ... all functional and sometimes much cheaper too - but you have to find trustable sellers ...

I'm activating a business modell with the GRRF, but this is work in progress, so can take a while ... there is some other work too, what's more urgent eye rolling smiley

Actually i'm working on more efficient drivers and will receive two collimators for the 445nm-diodes in the next days, but i have only one of the blue diodes here, so not ready for selling.

With the 5Watt IR-diodes it's different - i've assembled one more driver and several of the 5Watt-diodes are ready too, but i'm waiting on feedback from the last users ... one of them fried his PWM-opto by exceeding the specified max. voltage, the other is only starting with his tests, so this can take a while too eye rolling smiley


Viktor
Re: Laser Cutting Head
December 25, 2010 03:20PM
VDX Wrote:
-------------------------------------------------------
> Hi Casainho,
>
> ... ebay is like a lottery - i've bought several
> parts on ebay too ... all functional and sometimes
> much cheaper too - but you have to find trustable
> sellers ...

Do you know/have experience of some trust online shop?


---
New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]
VDX
Re: Laser Cutting Head
December 25, 2010 03:31PM
casainho Wrote:
> Do you know/have experience of some trust online shop?

... not really - for unknown seller i'm checking for counts and ratings and sometimes the content/design of the offers.

Most business laser-related is performed with users of specific (sometimes closed) forums, where we communicate in the posts and sometimes crosslinking to ebay auctions that are interesting or digged out occasionally.

I've bought my blue laser and a 200mW BluRay-diode in a laser-forum, but sometimes other users start auctions with blue diodes salvaged from casio beamers, so this aren't shops but rare occasions ...

A comercial source for 9Watt-IR-diodes with 808nm for around 350 Euros is lumics: [www.lumics.com]


Viktor
Re: Laser Cutting Head
December 25, 2010 03:37PM
VDX Wrote:
-------------------------------------------------------
> casainho Wrote:
> > Do you know/have experience of some trust online
> shop?
>
> ... not really - for unknown seller i'm checking
> for counts and ratings and sometimes the
> content/design of the offers.
>
> Most business laser-related is performed with
> users of specific (sometimes closed) forums, where
> we communicate in the posts and sometimes
> crosslinking to ebay auctions that are interesting
> or digged out occasionally.
>
> I've bought my blue laser and a 200mW BluRay-diode
> in a laser-forum, but sometimes other users start
> auctions with blue diodes salvaged from casio
> beamers, so this aren't shops but rare occasions
> ...

ok.


> A comercial source for 9Watt-IR-diodes with 808nm
> for around 350 Euros is lumics:
> [www.lumics.com]
> eets_Lumics_Products/Multimode/TO_package/LU09xxT0
> 90.pdf

Well, I guess that's a very high price that almost no one would buy it for paper and PCB etch.

Who knows if maybe 500mW or 300mW laser is ok, and so relative cheap? -- if my 300mW red laser can melt black tape, maybe a 300mW blue laser would "burn" black paint on PCB?


---
New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]
VDX
Re: Laser Cutting Head
December 26, 2010 01:35PM
... try to find a blue diodelaser with 1Watt@445nm - they'll be sold occasionally around 40 Euros.

Then you can have the complete wiring schemes or a driver with focussing lens from me ...


Viktor
Re: Laser Cutting Head
December 27, 2010 05:04PM
VDX Wrote:
-------------------------------------------------------
> ... try to find a blue diodelaser with 1Watt@445nm
> - they'll be sold occasionally around 40 Euros.

Right now I just bought from another seller a 500mW 808nm diode, for 11€. It's from Europe and he seems to be very well rated. I decided to invest a bit more on 808nm because I have goggles for it and also I want to compare that "500mW" diode with that one of "1000mW"...

> Then you can have the complete wiring schemes or a
> driver with focussing lens from me ...

Isn't easy for me to understand what you can provide me. I don't know how such lenses work. Are they needed? will they work with the diode I will get?

If you have one 445nm-diode with 1Watt power, could you please take some pictures and record a video, showing what it can do/cut? -- I want to understand/have guaranties before buy.

-------------------------------------------
I was contacted by Peter who is working on OpenSource Laser Cutter driver project. There is already a lot of information on that wiki page for start making a laser cutter/engraver, using RepRap GCode commands :-)

Peter contacted me because of my RepRap electronics ARM board -- Peter want to use the same electronics/ARM/firmware :-)

If there is anyone interested on working for a laser cutter/engraver, please look at that project.


---
New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]
VDX
Re: Laser Cutting Head
December 28, 2010 02:18PM
Hi Casainho,

... i'll reactivate the 445nm-diode with the prototype-head and take some photos the next days.

I'm awaiting some collimators and lenses with AR-coatings for blue and red, this will be better to compare.

For 808nm (or even 975nm) in the 'low-power' range below 10Watts you can use any optical lenses you have at hand - the reflection of some percents isn't critical and the lenses work as normal.

For the 5Watt-diodes with 975nm i use old 15mm-lenses with focal distance of maybe 30-40mm without any AR-coating, i found in my basement, so not perfect, but it's working ... with proper lenses this can only run better winking smiley


Viktor
VDX
Re: Laser Cutting Head
December 30, 2010 12:31PM
... atached some images of the 445nm-prototype - its running with 1Amp CW, so around 1Watt output power, but not optimal focussing, so the energy density (or cutting efficiency) could be dramatically enhanced with better optics (i'm awaiting some in the next week)

I'ts extreme bright and overpowering the camera, so i'll have to reduce the sensitivity or apply the orange coloured UV-filters in the last image to reduce the blue brightness ...

I tested burning balsa (what's nearly impossible with 3Watts IR!) - the big spot on the right was burned nearly 5 seconds, the smaller in the middle around 2 seconds and the smallest on the left maybe 0.5 seconds.

With better optics the burned trace will be smaller and the cutting speed could be much higher than with the actual lenses ...


Viktor
Attachments:
open | download - 445nm von Vorne_kl.jpg (95.9 KB)
open | download - 445nm brennt Balsaholz_kl.jpg (44.2 KB)
open | download - 445nm - 1s 2s 5s_kl.jpg (91.9 KB)
open | download - UV-Filter_kl.jpg (112.6 KB)
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