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Leo Voisine

Leo Voisine

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East Freeetown, Massachusetts
I will be asking this same question on the RDWorks forum

One thing I have noticed on laser cutting my thin - solid hardwood is that it breaks EXTREMELY easily.

The laser beam cuts with a draft angle, and depending on the style of lense used and the focal distance, the draft angle can change. At least that is how I see it.

I am using a 38.1 mm lense which has a very short focal length to it. A 63.5 mm lense has a much longer focal length, which MAY make less of a draft angle.

Now, I am cutting solid hardwood at .150 - .165 thick with a TINY cross section due to the size of the text. The laser cuts ON the line and I see no option to change that. The result is that the text gets thinner at the top with a fine cut through line at the bottom. Additionally, the grain of the solid wood it very weak depending on the direction of grain at those narrow cross section. Thusly - really weak sections.

I think trying a longer focal length lense

I think plywood will be a better choice over solid thin wood because of alternating grain directions.

I may be able to stain 1/8 baltic birch before laser cutting.
This brings me back to finding thin plywood.

What are your thoughts
 
I'm not sure what you mean by draft angle? Maybe a picture?

That being said, you might want to do a 'ramp' test in order to find the sweet spot, height wise for cutting.

Also, are you using air assist on the cutting?

I'm wondering if you are having issues with the thin wood, maybe covering it with a mask sheet before cutting would help to keep the wood together until you glue it on the sign, and then remove the mask.
 
Brent Dowell said:
I'm not sure what you mean by draft angle? Maybe a picture?

That being said, you might want to do a 'ramp' test in order to find the sweet spot, height wise for cutting.

Also, are you using air assist on the cutting?

I'm wondering if you are having issues with the thin wood, maybe covering it with a mask sheet before cutting would help to keep the wood together until you glue it on the sign, and then remove the mask.
Click to expand...

I do use air assist

The draft is where the laser cuts a wider swath at the top of the wood and narrower at bottom of cut. Based on the things from Russ's videos this is due to the angle of the beam as it converges to a focal point.

I do know where the sweet spot is

A mask sheet will not help, as the text width in places is .01 - .015 wide.
I would never be able to remove the mask.

I will try to get pics later.
 
Leo Voisine said:
I do use air assist

The draft is where the laser cuts a wider swath at the top of the wood and narrower at bottom of cut. Based on the things from Russ's videos this is due to the angle of the beam as it converges to a focal point.

I do know where the sweet spot is

A mask sheet will not help, as the text width in places is .01 - .015 wide.
I would never be able to remove the mask.

I will try to get pics later.
Click to expand...

Since you're working with very thin solid wood (not ply) it's going to be brittle. One solution might be to glue a piece of veneer (it's generally about 1/32 ~ 1/40" thick) cross-grain on the back of the wood.

I don't do lasers, so I'm guessing you might have to adjust your laser position to account for the added thickness, but other than that, you're still just burning wood. Leave the veneer on when gluing the finished cutting to your sign.
 
Leo Voisine said:
the text width in places is .01 - .015 wide.
Click to expand...

Inches or millimeters, that's some frog hair fine details, lol.

Would help to see an image of what you're trying to cut. I leaning towards Jims idea of making your own ply to cut to 'firm' it up.
 
Can you compensate for the laser cutting on the line by bumping the text size up a point, and adjust the sharp intersections in the text with a radius?
 
Not sure what software you are using, but lightburn lets you specify a 'kerf offset' that will shift the cut inward or outward a bit on closed shapes. I think it's primary use is for cutting inlay shapes and that sort of thing.

Maybe your software has a similar function?

kerf offset.PNG
 
Brent Dowell said:
Inches or millimeters, that's some frog hair fine details, lol.

Would help to see an image of what you're trying to cut. I leaning towards Jims idea of making your own ply to cut to 'firm' it up.
Click to expand...

Inches,

I agree with the veneer thing also. The cross grain I believe is what is needed. I've been think this since I started talking about this plywood.

Maybe I will end up simply just staying on the 1/8 baltic birch and staining sheets before cutting.
 
Leo Voisine said:
The laser cuts ON the line and I see no option to change that. The result is that the text gets thinner at the top with a fine cut through line at the bottom.
Click to expand...
Option: If I was doing this in Adobe Illustrator, stroke the vector/path and convert the stroke to path. You need the laser to cut on in the center of the kerf. If not, you are distorting the typeface.


Ted Calver said:
Can you compensate for the laser cutting on the line by bumping the text size up a point, and adjust the sharp intersections in the text with a radius?
Click to expand...

This doesn't resolve the problem of distorted type.
 
Brent Dowell said:
Not sure what software you are using, but lightburn lets you specify a 'kerf offset' that will shift the cut inward or outward a bit on closed shapes. I think it's primary use is for cutting inlay shapes and that sort of thing.

Maybe your software has a similar function?

View attachment 106938
Click to expand...

I am using RDWorks - which is sortof a predecessor to lightburn. It may be time to think about lightburn. That ONE option is a BIG help.
 
Ed Thomas said:
Option: If I was doing this in Adobe Illustrator, stroke the vector/path and convert the stroke to path. You need the laser to cut on in the center of the kerf. If not, you are distorting the typeface.




This doesn't resolve the problem of distorted type.
Click to expand...

I use Vectric Aspire to do almost all of my design work.

This was my first run through with the really fine text. I have a few things yet to try. I really like the kerf offset in lightburn. I will be looking at RDWorks for that offset. Being a Chinese program that may be a little difficult to find
 
I have to say for doing laser based stuff, I really like lightburn.

The developer of it is pretty responsive and it seems like they are pushing up updates to the software on a regular basis, constantly improving it.
 
I purchased Lightburn over the weekend. I remember even before it was launched from the RDWorks forum we had the trial version. I don't know why I didn't just purchase it from the start when it became available.

Anyway, Now I have it. I was OK with RDWorks, it really is nearly the same, but is a chinese maker. The English is much better in Lightburn.

I also like programming in in/minute, RDworks is in/sec. That if fine for some, but I have been programming in/min for 30 years and in just fits in my head better.

I tried a Baltic Birch sample at a few settings and landed on 30 IPM @ 50% power with a .030 kerf offset to get a clean cut on the BB. Then I put in a piece of Walnut thinwood and was able to get the same result and the Walnut does not break so easily.

Seems like a problem solved. Soooo - ONWARD, we shall go!!
 
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