Cutting white polyester fabric with 1.7W 445nm

[Doucesti]

Hi great people of lpf

I've built my own cutting table to cut big squares of polyester fabrics for my start-up cie (fabrication and installation of thermally insulating shades). Dimensions are 48'' x 88''. It's almost redneck but is working like a charm!
See the pictures attached! The cutting surface is now coated with aluminium.

The problem that I have: My laser doesn't cut white fabrics! The light is almost all reflected. I'm thinking of using a chalk line prior to cutting but figured that you guys might have ideas to help me!
(I've searched the forums but can't find anything related)

Peace!

Edit: "Why a laser!?" -To prevent fraying of the plastic fabric!

 

[Cyparagon]

Lasers are light based of course. White reflects most visible light. It's a fundamental issue you can't avoid. You either have to use a lot of power, or color the fabric (or at least the cut-line).

Neat project either way.

 

[doubleone44]

Or you can use a laser which wavelength is absorbed well. (First thing that comes to mind is a CO2 laser, but I don't know if that would work)

 

[Doucesti]

You either have to use a lot of power, or color the fabric (or at least the cut-line).

Thanks! I was wondering what kind of coloring I could add. If I had a dark layer of fabric over the white one, it burns only the dark one.. :/

Or you can use a laser which wavelength is absorbed well. (First thing that comes to mind is a CO2 laser, but I don't know if that would work)

I should have tought of that before, no place for a CO2 laser module haha!

 

[Gabe]

What's preventing you from using a blade, or a hot wire even? Shapes too intricate?

 

[Doucesti]

What's preventing you from using a blade, or a hot wire even? Shapes too intricate?

The laser will seal the edges of the fabrics I cut, preventing fraying of the fabric normally given by cutting (permitting less sewing after).

Hot wire may work, but would need another system to mesure and square the whole cut. I'll think about it!

 

[Gabe]

The laser will seal the edges of the fabrics I cut, preventing fraying of the fabric normally given by cutting (permitting less sewing after).

Hot wire may work, but would need another system to mesure and square the whole cut. I'll think about it!

Ah, never bought of the fraying issue, smart. I feel like a hot wire would heave a nasty edge though, but I have no experience w/ polyester. A hot knife though?

 

[RedCowboy]

Wouldn't a 405nm work better, you would get a tighter rounder focus as well.

 

[Gabe]

Wouldn't a 405nm work better, you would get a tighter rounder focus as well.

Eh, it will cut coloured fabrics much better, but with the issue of white polyester... Better beam specs and sharper focus won't really help.

What's the deal with CO2 lasers and absorption? I never really understood that. Is white the colour its best absorbed by? Thanks.

 

[trussmonkey25]

A lot of seemingly clear materials to us are opaque to the 10200 nm wave length. A little 30/40 watt CO2 might do the trick.you could put a mirror* on the trolley instead of the whole laser. Check out some of the old gas laser threads for tips and ideas.
*This mirror should be one for co2 laser

 

[DashApple]

Nice Work , ^ 10600nm : P


You can get small 35cm ish long Co2 laser tubes , I have one that dose about 15W and it would be possible to mount vertically , but there's the hassle of the water cooling and added weight

 

[Trendkilla254]

I must say that I was reading this going "Why a laser". You should add that part about fraying into the OP. I could see this getting quite a bit of comments and attention and it could be easily missed. It is a wonderful idea. What if you added a system to "spray paint" a line with a fine spray nozzel from a air gun designed for detail graphics? It could be mounted to the same trolley system with minimal modifications. You might even be able to find a washable paint that would work.

 

[Pi R Squared]

I think a much more powerful blue laser could still do it. I have tested my 1.5W 445nm, and my 1913mW 450nm, and my 3W or so 445nm, I don't have any white polyester, just plastic, cardboard, paper, and wood painted white. The 1.5W burns most things real easy but not if its white, takes forever to make a burn mark on white plastic. The 1913mW 450 surprisingly does much better. The 3W will instantly burn or smoke anything white, I suspect though that it would take far too long to cut large pieces of polyester. I would try one of these: https://sites.google.com/site/dtrlpf/home/diodes/6w-nubm44-445nm-laser-diode
Run it at 4.5A with a G2 lens, I suspect that it will cut the white polyester, but no guarantee, it may again do it too slow, am sure you don't want it to take an hour or two. If anyone reading this has one of these in the neighborhood of 6.8W and some white polyester then please do a test.
I guess before spending the money though you should first try the line with black ink or paint, I wonder if this would work though, polyester is a type of plastic, you can't dye it like other fabric, it doesn't soak in, you can't even stain it by spilling something on it, it will wash out. I wonder if the ink or paint would burn away leaving the white underneath it? It's worth a try though, it might work.

Alan

 

[WizardG]

I built a 405 cutting head for my wife's cutting machine (google 'silver bullet') and the 405 seems to cut white fabrics fine at a reduced speed (800mm/min).

Two ideas:

1.) Fashion a jig to hold a pen such that the tip of the pen will land at the same spot the laser does. "Cut' the work peice twice; once with the pen to draw a black line, and again with the laser going over the same line.

2.) Polyester does not take most dyes well sooo.... go to Dharma trading company and get some yellow (absorbs blue light) dye. Soak the fabric to be cut and let it dry without rinsing. Cut the fabric with the laser then wash the dye out.

 

[Doucesti]

Hi everyone, thanks for your messages!
This community is pretty sharp, hehe.

I've tested normal pencil, permanent marker, non-permanent pen, everything works sorta good. I think that the ink or the matter that sits on top of the fabric becomes really hot and burns the polyester that it is touching.

I'll test the chalk line tomorrow, unfortunately it seems that red and black carpenter chalk line are permanent and blue isn't (please god let that blue be another wavelenght then 445 lol). Or maybe grind some colored black board chalk!

I think that dying the fabric would work but add a lot of fabrication steps (washing hot, rinsing, washing again)... Chalk lines would (I think) only require a humid sponge.

I did buy my 445nm laser component from DTR and he said to run it at 7 to 12 volts.
In my testing, I runned it from 5 to 8.4 volts with short wires.
I am running it, on my table, as recommended at 7volts, but since I have 50 feet of electrical cable, could I run it safely a little higher for extra burn speed?

 

[Pi R Squared]

I did buy my 445nm laser component from DTR and he said to run it at 7 to 12 volts.
In my testing, I runned it from 5 to 8.4 volts with short wires.
I am running it, on my table, as recommended at 7volts, but since I have 50 feet of electrical cable, could I run it safely a little higher for extra burn speed?

What diode is it?
An M140?
What driver are you using?
Did you buy it from DTR with a driver?
Or are you using a different driver?

If you bought it from DTR with a driver then it should be an X-drive set at 1.8A, I think the max voltage should be 9V. It won't make any difference if you bump it up to 9V, it is a constant current driver. That diode only needs 4.xV, the driver adjusts the voltage to keep the current constant.

Alan