Technical Article: “A Laser in your Studio” by Ross Kowalski

Digital fabrication techniques are increasingly becoming a part of educational and individuals’ studio practices.  Although it can be daunting to incorporate new technologies into our established ways of working, Ross has written an article that is both easily accessible for those just getting started as well as tremendously exciting and inspirational for those with years of experience.  I hope this article is the beginning of a longer series of articles by others applying various technologies in exciting and inventive ways—please get in touch and share your discoveries with all of us! — James Thurman, Technical Article Editor

“A Laser in your Studio” by Ross Kowalski
Incorporating desktop laser technology into your jewelry and metalsmithing tool chest.

Over the last few years, many relatively inexpensive imported desktop lasers have become available through eBay and other sources. Having purchased one for my program [Norwell High School], we have found it to be a fantastic tool for creating roll printing patterns. This article describes the selection, setup, safety, and use of laser technology for indirect patterning of metal in our shop.

Selection of a laser was difficult because of so many options on the market. After a lot of looking and comparing, I ended up choosing a model from a company out of Vegas called Full Spectrum.  At the time, I could not have known less about lasers. As I think back, about all I knew was that lasers cut things.  I originally looked at the units available from eBay starting around $1000 (with several hundred dollars for shipping), you could get a laser for USD 1500. “Can’t afford NOT to have a laser for that kind of money,” I thought. The first consideration I had for a machine was that it could do vector cutting (think: cutting out shapes in acrylic) and raster etching (think: making pixel images on black granite). A big second consideration was that the laser be easy for students to use. Many lasers in this price point are kind of rustic using obsolete hardware interfaces and have crazy impossibly quirky and unstable control software. The last consideration was good customer support because I had no idea what I was doing.

The product I settled on was not as cheap as the lowest end units from eBay, but what sold me was that they developed an interface card that allowed output to the laser directly from the print menu of ANY program and was USB capable. Through a grant from the Norwell Education Foundation (our local educational non-profit), I purchased a desktop 40W Hobby laser for something like $2400 shipped. Several weeks later we had a laser in a box sitting on my desk. So, off we went.

Setting up the laser was straightforward but there are some things unique to this technology that you will need to know about. I will be referring specifically to the needs of our laser. You will need the following items, whether they come as part of a kit or are acquired separately:

• a covered 5 gal bucket with distilled water and pump (to cool the laser tube)
• a small air pump like a fish tank air pump (to blow smoke out of the beam)
• an assist fan and vent to the outside
• fire extinguisher
• fire safe trash can

Safety is important. After your laser is set up, you are probably going to want to throw a piece of Lexan in there and make a forming die for your hydraulic press…. Don’t. Read all the safety material that comes with your laser, and read up to inform yourself of any hazards associated with the tool or material you intend to cut. There are lots of ways to start fires and lots of ways to slowly poison yourself. Be cautious.

• BEAM SAFETY.  The laser beam is outside the range of human sight and invisible so make sure the enclosure has no light leaks. Don’t try cutting a mirrored or chromed surface. This can reflect the beam to places you don’t want it going, which is dangerous to you and the laser.
• HAVE A FIRE EXTINGUISHER HANDY.  I use a CO2 unit because a water or dry chemical unit would also destroy the laser.
• BABYSIT THE CUT.  You don’t have to stand over the machine while it is working, but don’t leave the room while cutting flammable materials.
• FOCUS THE BEAM. You are going to have to focus the beam. If it is focused, there is a very small very hot point that will vaporize wood, paper, etc. If you forget to focus, the same light goes over a bigger area of the material heating it, and if you are not lucky, igniting it. The laser must be focused each time you cut.
• FUME SAFETY means knowing what you are cutting. I am not going to provide a list, but there is a lot of material online about which materials are better or worse to cut. I will explain a bit about why some things are OK and others not. Back to the Lexan. You can’t cut it because any chlorinated or fluorinated plastics can release chlorine and fluorine when cut, which are toxic to you and corrosive to the delicate mirrors that control the beam in your laser. Materials with dyes and colored inks need special caution because the chemicals can be altered by the heat of the laser and make corrosive fumes.  Some OK things: acrylic sheet, wood, white paper, glass and stone (for etching), true vegetable tanned leather, and white card stock. Some things you should definitely research before cutting include: specialty papers, anodized aluminum, plywood, unknown plastics, dyed products, painted products, and rubbers.

Using a laser. The laser basically allows two ways of working with materials: vector mode (where a continuous beam is used to cut out shapes) and raster mode (where images are etched into the surface of a material). We use both methods with metal. There are more things one can do, but vector cutting and raster etching are likely to be your first steps into laser fabrication. Specifically, I am going to explain our use of the laser to create a paper texture plate for use in a rolling mill, and a raster cut image in acrylic plastic.

Vector cutting textured plates for roll printing is a great way to start using the laser in your work and one of the first things we tried with it at the studio.  Turns out good quality file folders work about as well as anything for this so I’ll describe the process for making a star pattern texture roll printing plate from a file folder and printing it onto a sheet of metal. Making a star field texture plate and rolling it into the sample plate in the picture on the left took less than 20 minutes total. The process can be divided into four steps:

Step 1. Original vector line art is created using Inkscape. We use Inkscape because it is free, easy to use and available for Mac, Linux, and PC. At our studio, we color code lines: those to be cut through red, those to be etched blue, and those to ignore as black.

Step 2.  We “print” to the laser printer driver which generates a laser ready cut file. This is the main reason we went with this particular laser. A student generates some art, sends what they see on the printer and Bob’s your uncle.

Step 3.  The file is opened in the laser control program (Retina Engrave in our case) and the laser set to make one cut pass at about 2 watts of power. The patterns can be cut through the card stock for a deep impression in the metal or just partially cut through for a more subtle effect. For the star pattern plate, the cut is made through the card stock.

   

Step 4.  The pattern is roll printed into the metal using a rolling mill. As you can see in the picture, we simply place the pattern on the metal and run it through. The roll printing itself is pretty straight forward and quite well-documented in other sources.

Vector cut paper leaves a rough texture where it is pressed into the metal, but clear polyester transparency film cuts cleanly and leaves a smooth surface on the metal. We have had to sand it to keep it from sliding around on the metal surface in the rolling mill. For example, if a student wanted a poem in the author’s own handwriting imprinted into a piece of metal, it can be done in less than an hour, and because it is reproducible, if mistakes are made with the roll printing or any later steps, another patterned plate can be recut in minutes. There is a list at the end of the article of some techniques and materials we have tried and/or are currently experimenting with. While vector cut patterns are our go-to technique for roll printing patterns, low relief raster cut images can be roll printed with great success as well.

Raster cutting images with the laser works like a dot matrix printer. The laser moves back and forth over the area where the image is going to be etched and pulses on and off to create the image into the material line by line. Unlike vector work where the laser only moves where there are lines, this process is very slow because the laser scans completely over the whole image.

   

Step 1.  Raster etching requires processing the image to be suitable for the laser. Using a photo editing program, the image is converted to Grayscale or black and white. The image is then set to 500 dpi and the output size you need.  If the image is black and white, we convert it to 1 bit color depth which assures that only black or white can be rendered. If the image is grayscale, we leave it at 16 bit. The image is saved as an uncompressed TIFF file so it can be directly loaded into the laser control program.

Step 2.  The TIFF file is directly loaded into the control program and if necessary, dithered to create a halftone using an option in the control program itself. If the image is pure black and white like the one shown, dithering is unnecessary.

We have been using 500 dpi with good success for most etching, though 1000 dpi is available in the software if one needed to make an extremely detailed cut. Shown is the level of detail on a 1.5” etched sample tile cut with two passes of 2 watts power. The cut is about .015in deep.  This is about as deep as you can go with acrylic for roll printing.

Step 3. The etched images created with this technique can be rolled into metal to create a low relief copy of what was etched into the acrylic. The example shown was rolled into 28 gauge copper. It would have looked better as a dithered halftone print in thicker metal, but this is enough for you to see how the process works. The acrylic printing plates only survive the single print, but they are so effortless to make their short duty cycle really doesn’t matter. With a little fiddling, the resulting images can be made quite photographic.

My goal here was to demystify laser technology a little and give you some ideas as to how it could fit into your own creative efforts. It has become a very productive part of our studio and one we could not easily give up at this point.

While I only mentioned the indirect processes we use related to roll printing, lasers are primarily used to cut out various design elements in different materials and create surface treatments on those elements. The material pool for directly cut design elements is limited, but because you are cutting with light you can easily cut materials far too fine to cut with conventional means. Think of the thinnest tissue imaginable, then imagine any design cut through it. The fact that there is absolutely no stress on the material while cutting is amazing!

But that’s not all!  Because the laser we have was inexpensive and robust, we experiment freely with it. On the plus side, I can speak from experience regarding the “merits” of cutting, fusing, and etching porcelain, acorns, potato chips, graphite, soap, carrots, lacquer, silk, spun bond polyester, seashell, LED lights, latex, enamel, etc.  For the students running the experimentation and me, it is educational and fun learning about the performance envelope of the tool. That experimentation so far has resulted in many useful techniques and workflows, including its use for cutting patterned material for roll printing.

Some current directions we are exploring include: directly vector cutting linear designs into enamel, sintering underglaze onto glass substrates, directly vitrifying bone dry ceramic, creating resists for salt water etching, sintering black sand and some serious Shrinky Dink work.

Laser Cut Roll Printing Stencils handout

---

SNAG would like to take this opportunity to recognize our Corporate Members for their support: Facèré Jewelry Art Gallery, Halstead, Jewelers Mutual Insurance Company, and Tim Roark Imports.

TIM ROARK IMPORTS