Introduction: Laser Etching Glass
This tutorial tracks my process of using various software programs and a laser etching machine, glass acid etch and glue with a base plate of LEDs to make the glass sculpture.
The sheets of 6mm float glass has been hand cut and laser etched twice (both sides) to preserve the resolution of the data. Below is a glass cutting video, showing the technique of hand cutting.
The final size of the glass work is 300mm w X 600mm h x 258mm d - weighing about 70kg
The sheets are glued together and footprint of LEDs below light the laser etching of the glass.
The scope of this tutorial is to address digitally handling data, using a laser cutter with glass, glass etching and gluing for an artistic application.
This project I used:
A 100w laser cutting machine
Below is a link to a very cheap laser cutter by darklylabs
https://darklylabs.com/emblaser2/
Float glass 6mm thick - see image above
Glass cleaning products, paper towels
3d scan data
software - Rhino & Illustrator (could be all done in Rhino) You could also use
http://www.123dapp.com/make to do slicing which is free :D
Netfabb - free version for cutting 3d files
Glue (various types depending on application)
Acid etch for glass
Gloves and safety equipment - eye protects and respiratory mask.
Strip LEDs 12v 5w power supply
Box board and card board sheet
A useful Instructables tutorial on laser cutting is
Step 1: Data
For all artwork that using some sort of CNC process you need to start with data. In this case I have scanned two figures, using the artec scanning system.
You may use scan data, download or model data for this project. Below are some links to download free data.
http://www.laserdesign.com/sample-files/
http://graphics.stanford.edu/data/3Dscanrep/
https://www.artec3d.com/3d-models
You may even want to model your own files, below is a link to Sketchup for modeling.
To prepare the data for slicing I used Netfabb to cut the data to smaller sections. For this I have used a hand and a head to work out this process.
Below is a link to Netfabb basic which is well suited for this task and free.
Step 2: Cutting Data
The images are of sections of data that I used for this experiment. I used smaller data sets to perfect the process before I move on to something larger.
The first section was a hand. You can see from the image I have sliced the data up, this was done using the contour function inside Rhino. You can pick any direction you like to contour your data, although remember it will be applied to a flat piece of glass. I scaled the data to the size to life size. I then cut the data at 3mm using the contour function.You could also perform this function with free software from aotudesk
The data is cut at 3mm so I can apply two layers of data to each 6mm sheet of glass, one either side.
If I only cut the data at 6mm I would lose a lot information - resulting in less resolution of final work
The boring part of this process is that each slice will need to be placed on it's own layer, which another reason to start with something smaller. It is also a good idea to change the colour of each layer so you have a visual reference later in the laying out the data slices.
Step 3: Data Layout for Laser Etching
The important aspect of the data layout is that you will be creating a digital jig to match a real world jig inside the laser cutter, the first image is of the digital gig. I made this in Illustrator.
This gig is simple, the first smaller square pushes the laser to the set position of the larger square - which I use to cut the cardboard. My reason for this was so I had material to hold the 6mm glass sheets in place and I could tape down the cardboard inside the laser cutter.
To etch both side of the glass every alternate layer is flopped to match up with the layer below.In Illustrator the function I used is the reflect tool.
The image above of the 2 head slices with the layer list, is the 3mm cut with is revered 3mm cut. These 2 cuts will be applied to each side of the 6mm glass sheet.
The gig inside the laser works on the fact that you can always home the laser to 0,0.
This function is called datum.
Every time you begin to etch a layer it will be best to home/datum the laser.
When importing the file into the laser you will only be etching the data that you sliced.
Inside laser cutting software you can set colours different for the etch data and the gig data which lets you only etch the sliced data but retain the gig spacing information to align the layers.
You can see that I also turned my data upside down because the top of the glass is hand cut and I needed a corner that would always be consistent to ensure all the layers align.
It's important to note when making the data jig, that this information will need to be present in each file for etching. This ensures that the laser has exact bounding box and start point to align each laser etch.
The gig inside the laser was cut from a thick cardboard and is simply corner edge that the glass can be slid into to stay square. I also used box board as a soft material below the glass to prevent any scratches.
You can see that the card is taped down inside the laser cutting machine so that it stays fixed for each etch.
Preparation of the data is key, vigorously reversing every other layer becomes critical. Numbering each file 1, 2, 3 etc is important and also applying labeling each side of glass that match the digital file numbers. This simple task will ensure you don't get mixed up later during the processes.
Step 4: Laser Set Up, Etching and Add Extra Lines of Data.
The laser I used was a 100w laser, though you might be able to use a laser cutter as low as 40w. Glass is actually easy to etch and not much power will be needed.
I should note that if there is more lead is in the glass (which means the glass is clear) it will be harder to etch. Some people add detergent to the surface before etching if the glass is very clear. I did not need to do this - though you may need to experiment with your settings.
My setting for the cut function were 80 speed 25% power going down to 15% on the corners. I chose the cut setting because of the speed of the cutting setting process rather than using the straight etch function. If you have lots of time you can use either - though the cut setting will always be faster.
To improve the visual impact of the etch line I selected all the line work layers inside Illustrator and copied the lines again either side of the original line but only .2mm away in each direction. This is the offset path function inside Illustrator.
Step 5: Appling Acid Etch the Glass
Warning!!! Acid etch for glass is a dangerous
http://www.armourproducts.com/ecom-catshow/Armour_...
I used armour etch for glass to etch inside the laser etched line work. This is actually a simple process of painting on the acid etch inside the line and leaving it more than 5 min, longer will not effect the final result.
Check the link below which is a video on the use of the product. I should note that they don't use as much safety equipment as I would use.
My approach was to be neat and not go over the line but not to be concerned about if it was consistent after that. In fact inconsistency looks better in my option, the main issue is making the acid line thicker inside and spread it so when the glass sheets are assembled the you don't have sections that are see through from the layer above or below.
This is important as the painted acid etch really helps add body to the final result.
Rubber gloves, safety glasses and respiratory equipment should be worn and the work done in a well ventilated area.
Wash off all the applied glass etch very well and dry the glass, preparing it for gluing.
Step 6: Asesembling and Gluing Glass
These process should be done in a very clean environment because dust can be trapped between your layers.
Before I started this process I layered all the sheets of glass on top each other so I was certain I had the layers in the right order and that it worked. At this stage you might find out that you need to redo a couple of sheets. I had to redo a couple of sheets of glass.
To help I put a little square of masking tape on each sheet which help figure me sort of which sheet was out and needed to be re done.
The gluing process will change a little depending on the glue you wish to use and the final application. The real issue with gluing is choosing a glue that does not yellow over time!
Check with your local supplier and application approach. Below are links to standard glass glue. The important part of the process is to minimize bubbles.
http://www.glass-etching-kits.com/uv_glass_glue_or...
http://fewproducts.com/product.sc?productId=83&cat...
Before you attempt your final gluing, test gluing and get a feel for the process.
The key to gluing is about loading the glue on the layers and how it flows - all glues are different.
A rule of thumb is to use more - sacrificing glue this ensures you can keep bubbles to a minimum as you squeeze out glue from the edges.
When squeeze out glue, remember too much pressure as this can cause a crazing of the glue in between the glass. The key is consistent firm pressure only.
Step 7: Samples
Here are some images are of the samples I made. I did not outline doing the foot you can see, but it was between doing the hand and the head and helped me to understand to refine the process more. The hand was the first part I made and has a couple of mistakes. The head was more challenging with many more layers and larger and heavier. The light below is a simple footprint of LEDs.
Step 8: LED Lighting
The LED footprint works best is they go perpendicular to the glass sheets. The reason being the LED strip won't always be in line with the glass and this will create a dark sheet. While perpendicular has more chance of emitting into each piece of glass and one LED will light most of the glass.
The next step will be to be able to control these LEDs. There are many good Instructables on making LEDs matrix which you can apply - see the links below.
My next version will be controllable as I want to be able to add a movement and colour to the LEDs.
https://www.instructables.com/id/LED-Arduino-Matrix...
https://www.instructables.com/id/Large-8x8-LED-Matr...
https://www.instructables.com/id/LED-matrix-on-a-bu...
The main thing to consider is to ensure when the glass block is placed on top of your LEDs that it doesn't crush them by the weight.
Step 9: Enjoy
Final glued glass sample siting on LEDs. Enjoy :D
Step 10: Another Sample - More Laser and No Acid Etch
Just added another test sample.
In this sample I cut the data up at .5mm and etched each 6mm layers of glass with 12 layers of data. 12 layers at .5mm = 6mm of glass. This test is different to the first test, as I only etched one side. This makes the registration of the data easier and speeds up time of flipping the glass. Although I'm now using much more data than before, therefore the laser etch time is more.
I have now also laser etched both full life size figures into 2 x 86 panels of glass @ 2350mm x 900 x 6mm. When I have these assembled I'll re-post.
