Laser Cutters

For the Full Spectrum Muse^, with a 45 Watt CO2 laser and 20x12" workarea:

Material	Speed	Power	Current	Passes	Notes These vector settings are just starting suggestions. Always test on a scrap first.
1/4" plywood	20	100	100	2	Lot's of popping, but faster / lower current causes very burnt edges. Try multiple passes? Note 1
1/8" / 3mm plywood	25	100	100	1
plywood etch	50	100	n/a	1
Luan door sheet	50	100	100	1
1/4" Acrylic, Clear	30	100	100	2	Colored materials are easier to cut. Try 1 pass at 80 and another at 25. Note 2
1/8" Acrylic, Clear	50	100	100	1	Colored materials are easier to cut. Note 2
PET (Polyethylene)					Nearly impossible to cut as it just melts back together instantly. The foams cut easily.
1/8" Corian / Avonite	10	100	100	2
Delrin	50	100	100
1/8" Leather	30	100	100
HDPE (Milk Bottles)		20	20	many	Melts / burns. Can catch fire easily. Keep power very very low and make multiple passes.
Mylar					?
Carbon Fiber	5	100	100	many	Must be UNcoated (coatings will emit noxios fumes). Very thin sheats might cut at low speed, high power.
Polycarbonate / Lexan					Burns, emits nasty yellow smoke with stringy black tar.
Cardboard	100	80	80	1	Note 1
Corrigated Cardboard	60	100	100	1	Note 1
Paper	100	10	10	1	Almost impossible to cut things out without the paper being blown out of position. You an use cardboard or cardstock over paper so that the weight holds the paper in place, and bump up the power accordingly. A sheet of glass might also work.
PolyStyrene / Poly Propylene Foams					DON'T USE! Catches fire at any setting and will melt hard flaming drips which are very difficult to clean off the bed.
PVC (Poly Vynil Chloride) / Vinyl, Records, Pleather, Artificial Leather					NEVER USE! Chlorine gas is emitted which will destroy the machine AND CAN KILL YOU!
ABS (Acrylonitrile Butadine Styrene)					NEVER USE! Catches fire, and emits hydrogen cyanide which will destroy the machine AND CAN KILL YOU!
Polyurethane					NEVER USE! Known respiratory toxin!
Fiberglass / Anything with Epoxy					NEVER USE! Emits toxic fumes and will damage the machine.
Anything with glue (including any of the above)					NEVER USE! The glue will vaporize, stick to the lenses, and cause them to heat and crack. There is no way to clean them off.
unknown					NEVER USE! MAY destroy the machine AND MAY KILL YOU!

"Power" Controls the frequency of laser pulses. "Current" controls the strength of each pulse, but is only active during vector cutting since the laser is modulated by the pixel darkness during raster operations.

Before cutting:

Switch on the power strip which also supplies power to the cooling pump and the air assist.
Ensure the water pump is running by squeezing the tube going from the bucket to the back of the laser. You should hear the sound of the pump change.
Check that everything is clear inside the unit
Power up the unit with the rocker switch in the back right.
Once the unit boots, press the button on the screen. It should slowly home.
Add your material, registering it in the upper left area on top of the cutting screen. Make sure it lays perfectly flat.
Loosen the lens mount on the cutting head and carefully slide it all the way up, then tighten, being very careful not to touch the mirror or lens.
Jog the cutting head over the material to the general area where you will work. Place the focus puck under the cutting head, on the material. Loosen the lens mount and allow the head to rest on the puck. Carefully tighten the mount, ensuring that it's not pressing the material down. Remove the puck.

After cutting, the fan will stay on. If you want to turn it if, it's under the gear icon on the front panel.

Open the lid, and do NOT move the material! Just hold it in place and try to remove a cutout or the outside edge. If it isn't fully cut, close the lid and run the job again, then decrease speed, increase power or passes the next time you that material.

Note 1: Woods and cardboard can catch fire. Always watch and have a fire extinguisher handy. Plywoods can vary because of the changes in the glue used to combine the layers. Individual testing is necessary. The gasses coming off the wood is often still combustible and will causes small explosions or "pops" which can blow up parts into the path of the cutting head.

Note 2: Setting the current to 10 will lightly mark the surface which will then allow you to verify the size and position without making super obvious marks on the part.

Note 3: On thicker materials, focus is critical to ensure a straight edge during the cut. Even with perfect focus, the edge will be slightly angled.

The web based RetinaEngrave 2.0 software has issues (which may or may not affect the Windows program version^ but it can not be used with the Muse):

An object with a width set to 10" in the software, actually cuts at 9.92" wide.
In the drawing section "Design View", units can not be edited by entering numbers. The number shown initially is inches, but if you change that number by dragging it up and down, the units change to hundredths of an inch. e.g. a box that is 10 (10") high will suddenly become 10 (0.1") high when you drag the units, and must be increased to 1000 (10.00") to regain the proper size. The only real way to use this feature is to make each thing a separate item and set the size in the main screen.
DXF files may not be imported. More than that, there is NO list of what formats ARE supported! So far PDF and SVG appear to work.
.re3 is the native file format in which projects are saved, and can be shared and re-opened.
.ai (Adobe Illustrator) doesn't appear to work
.bmp, .gif, .jpg, .jpeg, .png, .tif, .tiff, are bitmap formats, so only useful for etching
.pdf, .svg, .svgz are vector formats.
No file can be added except by drag and drop. E.g. there is no File / Open. The "Open File" icon opens an existing project saved internally. There is a File / Open in the "Design View" but it only accepts SVG, and it distorts the items. Update: in re3, you can only File / Import and not drag and drop.
Save projects locally: They will randomly disappear from the internal storage.
The Camera thing does not work at all under any circumstances that I can find.
The "trace outline" icon on the front panel never works. You must do it from the web interface. If your connection isn't fast (e.g. old PC or wifi) then the tracking of the laser position will lock up your browser.

Most of these issues have been fixed in version 3 of the software.

Engraving requires some space to either side of the picture for the head to reach the correct speed before turning on the laser. Otherwise, the burn would be greater at the edges. This means that you can NOT engrave all the way to the edge of the workable area. Decreasing the speed (and power to compensate) of the settings for engraving can help to decrease this, but it is still significant.

Silk Screens: By setting a light fill color, and an even lighter stroke color on thin lines around each fill, you can produce an SVG or other graphic which will "Half-Tone Dither" to burn tiny holes in a thin plastic or other durable material. This can then be used as a silk screen or stencil. Fills with a saturation of 25 or less and strokes (line color) of 20 or less seem to work well at 250x250 DPI, with Blur Filter Raius at 7, Edge Enhance Threshold at 30 and Intensity Correction at 0. PET plastic lids from candy containers work ok, but are a bit thick for the paint. Manila folders produce a very nice screen, but are not very durable.

Solder Paste Stencils: Lower speeds allow sharper, more accurate fine details. Using laser transparency film at a speed of 10 and a power and current of 25 produces a Printed Circuit Board stencil that is usable down to about 0805 or perhaps 0603. Rows of very fine pins will not reproduce, but can be cut out in blocks and the pins will automatically align during reflow if the solder mask is good.

Maintenance:

Use optical grade lens wipes to clean both sides of the beam combiner, all mirror surfaces, the focus lens, and the tube aperture. Optic surfaces may need to cleaned more often if cutting materials produce excessive residue (possibly daily).
Clean fallen debris from the catch tray of the machine. Less excess material will reduce fire risk, and provide for better exhausting.Alcohol wipes remove pitch residue from wood cutting.
Check the cooling water and replace if it starts getting slimy, or starts growing algae, or mold.

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