Laser Cutter

From Shrimp Maker Wiki
Jump to: navigation, search

Different Machines

Universal Laser Systems 60 watt

This is a new laser for the TSMP and SJ locations. A few notes that are key to its operation, and different than the Epilog.

  • By default it will recognize three colors, Red, Blue, Black. Items that are Red and .001pt will cut; Blue and .001pt will vector etch; Black will raster no matter what.
  • I was told that any other color will show up on the preview of the output but the laser will ignore it. However, my own tests show that a solid shape with a gradient of red will raster the gradient.
  • Be sure the document is RGB not CMYK. The three operative colors must be pure (except for rastering).
  • Make sure "Auto Z" is enabled, otherwise the table will not move to the correct height.
  • Small etch areas take longer on the ULS because it always sweeps through a larger area than the Epilog.
  • We're told that the ULS will make correct round cuts (Epilog circles were never quite round).

Settings

Baltic Birch 3mm plywood

  • Meterial Type: Natural / Wood / Very Hard Wood / General Very Hard Wood.
  • Cutting: Intensity Vector Cutting -50%; this is the setting that would vector cut through.
  • Vector Etch: Intensity Vector Engraving +50%; vector etching looked good. Vector Performance Settings seemed to make the vector etching sharper in Qualty vs Throughput mode, but it was hard to tell.
  • Raster Etch: Raster etching also looked good - more experimenation needed.

Cast Acrylic

  • Material Type: Plastic / Acrylic / Cast Acrylic / Cell Cast Acrylic Standard Engraving
  • Cutting: Intensity Vector Cutting +25%
  • Vector Etch: Default is fine. I could not see a difference in my test of Quality vs Throughput modes. I tried Cell Cast Acrylic Deep Engraving and the vector etch was significantly deeper.

Techniques

Wood Staining

Use Minwax Water Based Wood Stain to color the wood before cutting. Available everywhere, including Ace Hardware stores. They add tint just like they would with a paint. I ignore the colors in the samples on the shelf. I asked to see the colors in the tint machine, there are about a dozen. For my red, I use the red tint straight, no other colors. The stuff works great. I brush it on with a foam brush, then wipe it with a cotton rag.

Cut for Vacuum_Forming

I cut a 3 inch medallion positive to use in laser forming. I cut it out of 6mm Baltic Birch plywood. I set the 3d Stamp mode in the driver to Shoulder 45, Widening 0. This gave great relief. On the 120w laser I used 400 DPI, speed 40, power 90, Stucki, bottom up. I did two passes.

Fitting Parts to a Sheet

SVGNest

Sometimes you have a lot of irregular shapes you want to cut. Maximizing the use of a piece of material can be tough. The demo on this site is pretty cool: http://svgnest.com/   It's open souce, source found here: https://github.com/Jack000/SVGnest

I haven't tried SVGNest yet, but the sample images on his page are impressive.

Sudo 3D

This web site shows a technique to create nice 3D chess pieces. He cuts the front profile then a bounding box. Then he rotates the piece 90 degrees to cut the other profiles. The results are very interesting. http://imgur.com/a/Rt8kz   Thanks to Bruce for finding this.

Materials

Baltic Birch Plywood

It comes in 5x5 foot sheets 3mm (1/8th inch) for about $18. I have them cut the boards into 24 inch strips so that they fit in my car. I then cut the strips into 24x18 panels at TechShop. The price per panel is about $2.50. It also comes in 6mm sheets. These prices are from 2014 at the now defunct Southern Lumber. We've found a supplier on the web: Ocooch Hardwoods

I've found that the glue in this plywood makes it harder to cut than plain wood. There are also some hidden hard spots in the plywood. I have to cut at a slower speed or else I'll have some places that do not cut through.
  • Settings for 3mm
    45watt: speed 8, power 90, frequency 500. If the laser is really clean then speed can go up to 12.
  • Settings for 6mm
Another source for Birch Ply is Mayan Hardwoods In Paso Robles. http://www.mayanhardwood.com/   Mayan carries a full line of hardwood plywood and regular hardwood lumber by the board foot. They do not have a cutting service for sheets of plywood. They do have a chop saw to cut board down.

They have the Baltic Birch in 5' X 5' sheets in both 1/8" (3 mm) and 1/4" (6 mm).
They also have Birch Plywood in 4' X 8' sheets. The 5 X 5 sheets are a much better quality than the 4 X 8 sheets.

They offer contractor prices
  • Birch 1/8" 5 X 5 sheets for $17.77
  • Birch 1/4" 5 X 5 sheets for $21.45
Mayan also has Oak 1/8"; and 1/4" plywood in 4' X 8' sheets.

Worbla

Feels like plastic, but is laser cutter friendly. One side is sticky. You can heat it with a heat gun and form it like clay. Works great to make costume parts. An internet search for warbla will show a plethora of cool examples.

Worbla activates at 90 C.  I dipped in almost boiling water and was able to easily work it by hand. This is great stuff.

You can buy it at CosPlay Supplies.

You can also make your own Worbla

Supplies

LaserBits

http://www.laserbits.com/
I have not purchased from this company yet. Full line of engraving supplies.  They have Color fills and seals. Engrave a piece of acrylic and then use this stuff to fill the engraving with a different color.
http://www.laserbits.com/laser-supplies/laserbits-pro-color-fill-sealer.html

Marking metal and glass

Thermark

You spray this product onto a metal or glass surface, laser it, then wash off the part that was not hit with the laser. I saw this used at TSMP on metal and the result was very good. The woman using it recommended it. I got a 6oz bottle of the spray on Thermark Laser Marking Material LMM14 Black from the manufacturers web site [url]thermark.com[/url] for $62 plus $11 shipping UPS. Not cheap.

My settings: 60W laser, 600 DPI, Stucki, speed 5, power 90.  Anything with less heat left the image susceptible to scratching off.

Dry Moly Lube

(From Evil Mad Scientist web site) A can of "CRC Dry Moly Lube" sells for about $10. Clean your metal with isopropyl alcohol. Spray lube on your metal, let dry. Do this three times. They etched with 20-30% speed (laser power unspecified) which showed a big difference. Clean off the excess lube with alcohol. They say the finished image seems tough. I haven't tried this yet.

Sawmill Creek also has a riff on this technique. He used "Sprayon LU200", 2 coats from 4 inches high. 600 DPI, 3% speed and 100% power, air assist and two passes. He cleaned it by spraying with Krud Kutter and letting it sit for a few minutes.

And... one commentator says that Cermark is so easy to use (one coat, water clean up) and fast to laser that the cost of the good stuff is not significant.

</div></div>