[bgirit]

I just read a thread that engraving quality on an 80+ W laser can be poor. I assume this is because there might not be as great power control compared to lower power lasers? I expect this might be an issue with the chinese lasers. Does anyone who is not a chinese distributor have any experience with this? I plan to get an 80 or 100 W laser to cut up to 1/2" acrylic but I also plan on engraving paper or very thin plastic. Any suggestions?

Thanks

[MacGyver]

While I can't yet speak from experience, I would imagine using a PWM output control rather than simply twisting a power knob is the key here. The typical Chinese laser is controlled by way of the current through the tube... as current is decreased, power control becomes less stable. By running the tube at 100% power but rapidly turning it on/off (i.e., PWM), the "average" output power is decreased, thereby allowing a higher level of control over the etch depth. By stabilizing the output power, beam width is also stabilized, thereby preserving image detail.

Or so the theory should be...

[SkipW]

I have an 80w from wklaser and it engraves just as well as it cuts. The power control is software regulated, not with a knob. It uses LaserCut5 to run it, which isn't a bad program once you get used to it.

Here's a little box I made yesterday out of 5/32" cherry. I used a little too much power for cutting out the pieces I think, but it's not really as dark as it looks in the pic, and no residue comes off on your fingers. I'm going to power it down a little on the next one. I was surprised how easy the wood cut. Used air assist also. Sorry for the crappy picture.

I should add also that the box drawing was made for 1/4" material and I was too lazy to scale it down for 5/32", so the finger joints overhang a little. I kind of like that effect though.

So yes, an 80w can cut and engrave. I don't know how it would do on a portrait like some do on marble or glass, but I didn't buy it for that anyhow. I may have to try that sometime.

[zoltan]

Hi,

Do you share the dxf of this box? i would like to try it.

Thank you.

Zoltan

[SkipW]

I got it from the Epilog site on their sample club pages.

Sample Club

Lots of neat stuff there. They call the box a music box and it's toward the bottom of the page. It's in .cdr format. If you need a .dxf I can maybe convert it.

[zoltan]

Thank you very much. I got it.

Best regards,

Zoltan

[MonoNeuron]

I think the issue is that it is too powerful and engraves too deeply. I use 5-10 watts ( from my 35 watt laser ) for glass and anymore blasts the glass away in fragments and if you run your finger over it after you will cut yourself on the shards. I clean it up with steel wool after and this helps. I am still experimenting with different materials and having a fun time trying different things but I would love a 80-100 watt laser for cutting.........so much faster. ULSinc use 2 x 30 watt tubes in their 60 watt machine and stop one of them when engraving but use both of them when cutting.

[SkipW]

I think the issue is that it is too powerful and engraves too deeply. I use 5-10 watts ( from my 35 watt laser ) for glass and anymore blasts the glass away in fragments and if you run your finger over it after you will cut yourself on the shards. I clean it up with steel wool after and this helps. I am still experimenting with different materials and having a fun time trying different things but I would love a 80-100 watt laser for cutting.........so much faster. ULSinc use 2 x 30 watt tubes in their 60 watt machine and stop one of them when engraving but use both of them when cutting.

Hi Mono,

Maybe all Chinese 80w machines aren't created equal, but with mine I can set the power through the software so low that I can engrave manila folder paper without completely burning through it. The power is adjustable from zero to 100% in LC5 .

I've been etching glass ornaments with it lately. It does a great job but as you say, you have to buff it a little after etching to remove the jiggers. I use a scotch-brite pad, which works good for me. Do you ever color fill the etchings? I'd like to try that but I don't know what would work the best. I might try masking the ornament then etch it, then lightly spray paint it. Any advice?

[MonoNeuron]

Hey Skip,
The only stuff I have used so far has been " Rub 'n Buff " from Amaco at about $8 AUD for a 15ml tube (which is a lot as it goes a long way. I think there is about 8 colours in their range and it is made up of waxes and fine metal powders and I think they look great. Other people use acrylic paints which also look great, so they say. Head on over to "Sawmill Creek" where you will find a veritable cornucopia of people who have been in the trade for millennia and are willing to give away ALL their secrets for lasering.
I hope you find something worthwhile to use.
Rich.
http://www.sawmillcreek.org/

Have fun. He he he. More hours of reading.

[SkipW]

Hi Rich,

Yep, I'm a creeker too. It's like a laser encyclopedia, that's for sure. I've seen posts telling of poor results from the rub-n-buff. Maybe it's all in how you apply it though. You seem to like it. I guess I'll order a tube and give it a go.

Thanks and g'day.

Skip

[MonoNeuron]

I don't like the Blue, antique white or red.
I DO like the gold and the silver. They seem to stand out a bit more so if I was to suggest one for you to try then it would be the gold. It dries pretty quickly and seeing as though it's made from carnuba waxes etc then I think it would be pretty good in a bathroom where the water and mist would be repelled.
Just put a small dab on your finger tip (size of a match head) and rub it in until it starts to dry then buff off the rest with a soft cloth. The small amount should cover about 1 1/2" square
maybe you will like it and maybe you won't. All a matter of taste I think and I wish I had some samples for you to look at.
I think I will go and do an MC Escher onto a mirror in a minute and see what happens.
Rich.

[SkipW]

I don't like the Blue, antique white or red.
I DO like the gold and the silver. They seem to stand out a bit more so if I was to suggest one for you to try then it would be the gold. It dries pretty quickly and seeing as though it's made from carnuba waxes etc then I think it would be pretty good in a bathroom where the water and mist would be repelled.
Just put a small dab on your finger tip (size of a match head) and rub it in until it starts to dry then buff off the rest with a soft cloth. The small amount should cover about 1 1/2" square
maybe you will like it and maybe you won't. All a matter of taste I think and I wish I had some samples for you to look at.
I think I will go and do an MC Escher onto a mirror in a minute and see what happens.
Rich.

MC Escher is an incredible artist. Please post a picture if you get good results.

[MonoNeuron]

I just engraved a couple of pics of an Escher drawing on white cardboard and a glass mirror 300x300mm. I can cheerfully say the rubNbuff doesn't do much for the front side of the mirror. I have used the stuff on the backside of a pane of glass and it really brings out the detail but on the front it is pretty crappy.
In the glass photo I took if I had a piece of black card in front of the mirror it wouldn't reflect everything and would make the picture stand out (I will take another photo in a min to demonstrate) but it doesn't do anything for the finished product in real life.
Conclusion....... Don't use Rub N Buff on mirror surfaces. :-)
Rich

[MonoNeuron]

so here we are again....
It looks so much better with a black reflector so the mirrors would be good in a black room. Not too many of them around, me thinks.
rich.

[MonoNeuron]

Grrrr. The picture had a missing file extension and didn't upload. I usually save the 3 meg picture to my Desktop then email myself a copy and select "make all my pictures smaller" option and they are shrunk and mailed then all I have to do is save the attachments to the desktop then pick them when I upload. Easier to do than type. Saves opening a program and going through the motions of resizing and not knowing if it is right or not.
Rich.
I think the secret is not to have too much detail in the picture and use large blocks of colour (Black and white) instead of fine details.

[SkipW]

How about doing a mirror image on the back of the mirror and spraying it with black paint? I haven't tried that myself but I've read of others doing that.

The ones you did look pretty good though but I see what you mean about the rub-n-buff.

Thanks for the pics !!!

[MonoNeuron]

You may as well use a piece of float glass if you are going to do that so as not to waste a mirror. (I am tight)
I would have thought the backing wouldn't allow the laser to cut as the inside is very reflective but maybe the backing absorbs the laser really well.
Aren't you up past your bedtime?

[SkipW]

Hmmm, interesting point.

Nope, it's 9:00 PM here, just getting coffee'd up... miles to go before I sleep.

[MonoNeuron]

I'll have a go at engraving a title "MC ESCHER" on the back down one side and see how it goes. Interesting stuff.
(I should be doing some work but this is more exciting)

Did we just Hijack this thread. ????? :-)

[MonoNeuron]

The outcome was a lot better than I first had thought it would be. I started off with 10% power and 10 ipm but it didn't burn through the coating then I went with 15%, 25%, 40%, 80% but there is still a bit of silvering left so I would engrave at the full 30 watts or do 2 passes if using a lower wattage laser.
So we have 100% power and 100% speedn at 10 ipm. If it was slowed down then it may cut a little better maybe at 5-7 ipm.
The outcome says it all with the black background. Now I know why some people use wet newspaper when engraving as it would leave a finer bit of detail.
This is getting good.