Benbox Laser Machines/CO2 Lasers/3D Printers

General Category => Projects => Topic started by: Administrator on January 07, 2017, 05:24:50 PM

Title: Text engraving on 3/8 thick clear acrylic
Post by: Administrator on January 07, 2017, 05:24:50 PM
It's still a work in progress, but I wanted to share early proof of concept testing!

I wanted to see if my 1.6 watt laser could engrave Text on 3/8 thick clear acrylic such that I could insert the acrylic plate into a white LED base and light up the text. I'm interested in making award plaques using 6x6 inch acrylic 3/8 thick. The LED strips are 3/8 inches thick.

I'm attaching my first test results. It's just test data to validate if the laser burning will light up at all by the LED white lights...and the answer is Yes indeed it certainly does...!!!

Software used was BCL.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: wild.bill on January 07, 2017, 05:50:13 PM
Don't know if you tried the method of etching glass, by putting some copy paper on top and wetting it down? I have used this on glass and had to de-focus the laser a little. It heats the surface rather than letting the light just go through.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: Administrator on January 07, 2017, 06:18:54 PM
BCL doesn't do graphics engraving yet...it's on the to do list however...right now I'm just laser burning text onto this acrylic...BCL does beautiful text surface burning.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: wild.bill on January 07, 2017, 06:32:21 PM
The image was very small which could make it look like a graphic imabe, but it was from a vector file.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: nottingham82 on January 07, 2017, 06:59:37 PM
nice work bill and ralph both good results.  I had given up on glass.  Maybe i'll give it another go with a defocus.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: Zax on January 08, 2017, 05:06:22 AM
Both impressive results with a 445nm laser.

For the acrylic edge lighting, this is a pretty standard technique for signs and you can buy cheap bases to insert the panel.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: jtice on January 08, 2017, 07:28:51 AM
Very cool, this is something I have been wanting to do.
I did a quick test on some plexi, but my laser burned the table under the plexi and did nothing to the plexi. haha
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: Administrator on January 08, 2017, 09:00:41 AM
Very cool, this is something I have been wanting to do.
I did a quick test on some plexi, but my laser burned the table under the plexi and did nothing to the plexi. haha

Correct! That is what happens if you try to laser burn on the clear acrylic...the beam passes right through it and burns on your waste board!

However, there is a trick: leave the sticky protective paper on the acrylic and laser on that. Then you'll be able to burn onto the surface of the acrylic!
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: ggallant571 on January 08, 2017, 09:44:09 AM
Is the paper on the bottom or top?
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: Administrator on January 08, 2017, 09:46:29 AM
Is the paper on the bottom or top?

It's on both sides. Take your pick.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: ggallant571 on January 08, 2017, 10:31:05 AM
When you etch do you remove any backing paper?
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: Administrator on January 08, 2017, 10:55:33 AM
When you etch do you remove any backing paper?

No, laser burn right onto the paper (on the top)...then peel it away when finished...the paper is enough of a barrier to stop the beam from reaching the 'bottom' side of the acrylic and it just burns on the upper surface.

I wasn't sure how or if it would work but it did.

The other 'secret', if you want to call it that, is that the side you're burning on, becomes the back side of the plate when places into the LED light base. This means you have to mirror your text (BCL has this feature) when burning it in order to have it light up nicely when displayed. In other words, when sitting in the display, the burning is one the 'back side' of the acrylic.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: wild.bill on January 08, 2017, 11:00:26 AM
What you are describing is basically the same thing I was saying. When there is no backing paper (like with glass) you can put printer paper down and use that the same way. By spraying the paper with water will make it stick to the surface flat.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: Colka on January 08, 2017, 11:22:47 AM
I have also heard you can use masking tape over the area you wish to etch haven't tried it myself yet. it also supposed to help to stop the charring effect on the edges when cutting wood. still untested though myself
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: wild.bill on January 08, 2017, 11:28:11 AM
Just make sure its wide tape, you don't want a seam or overlap where the laser is cutting because it will become visible.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: Administrator on January 08, 2017, 12:04:51 PM
I have also heard you can use masking tape over the area you wish to etch haven't tried it myself yet. it also supposed to help to stop the charring effect on the edges when cutting wood. still untested though myself

I tested with wide painters blue tape and wide regular tan masking tape...the blue did not work as well as the regular tan masking tape.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: Administrator on January 08, 2017, 12:06:00 PM
What you are describing is basically the same thing I was saying. When there is no backing paper (like with glass) you can put printer paper down and use that the same way. By spraying the paper with water will make it stick to the surface flat.

Now I see what you mean...I will have to test this...thanks...
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: nottingham82 on January 08, 2017, 12:22:29 PM
I tape all my wood projects.  Yes overlaps do make visible lines since it doesnt cut quite the same  on the overlap area.  If you dont overlap it creates worse lines. 

I dunno why but I agree with ralph.  Tan is my favorite.  Blue works too. 

It smells... :( nothing too toxic though data sheets say its just paper and adhesive

I have not tried it on acrylic since acrylic seems to engrave so nicely without it. Although some acrylics dont engrave at all.  maybe it will help there

Removing tape - use a credit card
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: treinbert on January 09, 2017, 01:25:58 AM
I also tape my acrylic projects. It came out even more crispy, than without.

I also use the paper versie, tan.

I may try the paper adhesive used for vinyl cutting posters. As it is thinner and available in very low adhesive, so easy to remove afterwards.

Regards,
Bert
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: Administrator on January 10, 2017, 04:45:54 PM
OK I was finally able to do some testing using wild.bill's suggestion:

I placed an 8.5x11 inch piece of paper, about the thickness of a 3x5 index card, down onto my mesh screen work area.

I did a re-focus on this paper surface.

Next, I slid my 6x6 inch 3/8 inch thick clear acrylic plate into my lower left work area 'pocket'.

I did some laser burn tests.

I'm happy to report that the burn tests were a great success...!!! The advantages of this technique are:

1. I don't have to mirror my Text since the surface burns are taking place on the 'bottom' of the plate as it lays in my laser machine work area.

2. No tape, no sticky paper, nothing of any kind needed on the bottom surface of the acrylic.

This was a great idea wild.bill...all one has to do is just lay down some white, thick paper and then the acrylic and start laser burning the text!!
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: ggallant571 on January 10, 2017, 06:19:10 PM
Please post this technique some place safe. Easy for us less skilled/artistic/talented nerds to find.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: HaniC on January 10, 2017, 08:04:05 PM
OK I was finally able to do some testing using wild.bill's suggestion:

I placed an 8.5x11 inch piece of paper, about the thickness of a 3x5 index card, down onto my mesh screen work area.

I did a re-focus on this paper surface.

Next, I slid my 6x6 inch 3/8 inch thick clear acrylic plate into my lower left work area 'pocket'.

I did some laser burn tests.

I'm happy to report that the burn tests were a great success...!!! The advantages of this technique are:

1. I don't have to mirror my Text since the surface burns are taking place on the 'bottom' of the plate as it lays in my laser machine work area.

2. No tape, no sticky paper, nothing of any kind needed on the bottom surface of the acrylic.

This was a great idea wild.bill...all one has to do is just lay down some white, thick paper and then the acrylic and start laser burning the text!!

Any pictures you can share?
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: Administrator on January 10, 2017, 08:27:07 PM
Please post this technique some place safe. Easy for us less skilled/artistic/talented nerds to find.

I plan to make a video on this process. Two parts. In Part I, I will show all the steps on how I create the .dxf file, the award sample Text, all from within BCL, no outside CAD program needed.

Part II, I will show the acrylic actually being laser burned on the laser machine using my video camera.

I'm attaching a photo of my prototype acrylic plate...the red arrow is pointing to the test burn using the technique of white paper down, then the acrylic plate on top of that...in other words, showing the results of the burn on the bottom!!

It's just beautiful...so easy to see...!!! BTW that was with a 1.6w laser diode...!!!

Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: HaniC on January 10, 2017, 09:05:54 PM
That's a beautiful effect. I wonder if an engraved picture would work with this technique. A nice greyscale or dithered photo would look great when lit up and serve as a nice gift.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: Administrator on January 10, 2017, 09:19:04 PM
That's on my BCL radar...my co-developer Paul and I are going to be adding the capability for BCL to pull a graphics image into a CAD drawing, something like a .jpg file of a logo or anything really, and then load that dxf file into BCL and be able to mix graphics and Text. I don't have a time line for this, but it's on our to do list.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: nottingham82 on January 10, 2017, 09:30:52 PM
what speed did you try
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: Administrator on January 10, 2017, 10:09:55 PM
I tried many speeds but what worked best on the acrylic from my 1.6w laser beam was a speed of 100mm/min at full power.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: wild.bill on January 11, 2017, 07:07:18 AM
I tried about 20 different methods yesterday (lots of failures and some just OK) and I am back to the method that you used. The only difference is that I am using a black craft paper because it works much better than the copy paper that I was using a few day's ago. Also the easiest to use - just put the paper down, focus, put the plastic on top and cut away.

I am using the 2.0W TTL laser and I also ended up at 100mm/min to 110mm/min for the speed. By far this is where I was getting the sharpest images. Any slower and it starts to over melt the edges and burns the paper enough that it starts to be work to get the paper off.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: bansil on February 14, 2017, 05:56:14 AM
I have some 6" medium tack transfer tape I use for vinyl graphics/stickers.
Will this work? I may try some it comes in lots of different widths
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: wild.bill on February 14, 2017, 07:49:49 AM
I have some 6" medium tack transfer tape I use for vinyl graphics/stickers.
Will this work? I may try some it comes in lots of different widths
I don't have that material so I have never tried it, but give it a try and show us how it works.
Title: Re: Text engraving on 3/8 thick clear acrylic
Post by: nottingham82 on February 14, 2017, 08:19:09 AM
it works as a good cover for wood to prevent smoke burn.  Should work ok for acrylic too.