The BTU Lab is equipped with a 75-watt Universal Laser Systems PLS 6.75 laser cutter. This is a high-performance laser capable of cutting through a variety of materials at various thicknesses. It is an impressive piece of machinery.

You can sign up for laser cutter time by selecting open time slots with a laser master on the BTU laser calendar. (See sticker on the laser cutter for the URL.)

Laser Cutter Quick Facts

Bed size 18×32″
Max material thickness (soft limit) 0.25″
Common materials Wood, paper, cardboard, acrylic
Colors RGB Red (vector cut),
RGB Blue (vector etch),
Black/Grayscale (raster)

When the laser is running, someone must be watching it at all times!

Choosing Your Material

Your material and its individual properties and thickness can influence your design, so it’s best to decide on a material before you get too far into the designing process. The laser cutter can cut through a variety of things and etch even more, although it’s best not to bring in material over 0.25″ thick. The most tried and true materials are paper, cardboard, wood, and acrylic. You can see a full list of materials on this page.

The laser absolutely cannot cut vinyl (use our vinyl cutter for that), lexan, polycarbonate, PVC, or other materials with chlorides in them. They produce poisonous chlorine gas when burned, and our filtration system isn’t equipped to handle that.

You’re welcome to bring in your own material, but laser masters may have to run a burn test (especially on unidentified plastics) just to ensure that we don’t burn anything toxic. Alternatively, we stock wood, acrylic, and cardboard at the lab, but it’s first come first serve and may only be scraps. The laser bed is 18″x32″, and all material must be cut to size. A laser master can usually help you cut your material if you don’t bring it pre-cut, but that will take up some of the time you booked, so be sure you plan accordingly!

If you have material you need to cut over several days, we do allow you to store materials in the lab as long as you label it with your name, date, and email. Any material left for two weeks is free to use so that we don’t run out of storage space. If you have somewhere else to put your material, please do, because our space is limited!

Making Your File

You can use a variety of different programs in order to make files that the laser cutter understands, including:

  • Rhino

  • Adobe Illustrator
  • Inkscape – Inkscape is a professional vector graphics editor for Windows, Mac OS X and Linux. ” Free!
  • Corel Draw
  • http://www.makercase.com/ – Web-based application for designing laser-cut project cases
  • And any other program that works with vectors

Save your file as a .pdf and store it on a removable USB drive. This is the easiest way to load your file on onto the Windows computer that runs the laser cutter.  Be sure to remember to take your USB drive with you when you leave.

The laser splits each file into two separate kinds of cuts – vectors and rasters. Vectors are lines which can either go all the way through (cut) or only part way (etch), and have a consistent line width and depth. Rasters can only etch, not cut, but can have a variety of depths which can make the illusion of pictures with gradients. Rasters take much longer than vectors in most cases.

Vectors must have a very thin line width, but the exact units and values can vary. Below are some default values that work with the laser.

  • To make a vector cut:
    • The line must be #FF0000 (RGB red)
    • Set the line width to hairline (Rhino), 0.01 pt (Illustrator), or 0.001 in (Inkscape)
  • To make a vector etch:
    • The line must be #0000FF (RGB blue)
    • Set the line width to hairline (Rhino), 0.01 pt (Illustrator), or 0.001 in (Inkscape)
  • To make a raster etch:
    • Can be any colors, but will be converted to grayscale by the laser cutter
    • Darker colors make a deeper etch, lighter colors make a shallower etch
    • Can be any image – vector designs, photos, artwork, etc.

Resources:

Tips:

  • Text is faster and usually more readable as a raster rather than a vector.
  • The laser cutter rasters side-to-side, row-by-row, so rasters that are taller than they are wide tend to etch faster.
  • The laser burns away some of the material, and the harder the material is to cut, the more is burned away. This usually isn’t a problem with paper or wood, but acrylic cutouts tend to shrink a millimeter or two.
  • Cheaper wood doesn’t always cut all the way through, but you can cut it out with an x-acto knife. If this is a concern, ask the laser master if they can up the power of the cut a little bit.

Booking a Slot

Once your file’s ready, you can book an appointment with a laser master! You can find the link to do so on the laser cutter itself. We ask that if you have to cancel, do so 12 hours in advance, and please don’t sign up for a slot less than 12 hours in advance unless you’ve spoken to the laser master directly. If an emergency comes up, please be sure to email the laser master and let them know you can’t make it.

There’s no surefire way to calculate how long a cut will take, but there are a few ways to ballpark it. Full vector cuts go relatively fast, usually capping at 20-30 minutes, with simpler cuts taking as short as a minute and more complex cuts taking longer. Raster etches can take anywhere from a few minutes to an hour depending on size. Cardboard and paper cuts are incredibly fast, wood is slower, and acrylic is the slowest.

When you arrive at your appointment, try to have your file and material picked out. However, most laser masters are happy to help you troubleshoot if you’re having trouble with your file. Just keep in mind that when your time slot is over, the laser master will have to move on to the next appointment, or may have other obligations.

Making the Cut

Finally, when the cut starts running, it is your responsibility to watch the laser cutter and make sure it doesn’t catch on fire. If it does, press the big red pause button on the front of the laser, and go find your laser master immediately. Please take this seriously – 30 seconds on the other side of the room could be 30 seconds of laser-destroying flames! (Note: while watching for fire is a must, avoid staring directly towards the beam for long periods, as this can hurt your eyes.)

After your job is complete, check to make sure everything went as planned before fully removing your material—in some cases, a second pass may be required to completely cut through and it’s best if the material isn’t moved so the job can stay aligned properly.

When your cut is completed, remove your job and clean up any remaining material in the laser bed. (You may find the shop-vac helpful for picking up small pieces left behind.) Also, make sure to let the laser master know as soon your cut is finished- they’ll need to make sure that the air assist and ventilation system are properly shut off. Congrats! You’ve successfully shot lasers through something!

(Does this all excite you greatly? Read more about becoming a LASERMASTER.)