laser_cutter [Saskatoon Techworks]

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==== Large Laser Cutter ====
Note: We have two laser cutters now.  This page is for the big one!

==== Material Settings ====
Please consider the following settings as guidelines only, it's always a good idea to do a test cut first.

=== Through Cuts ===
^ Material  ^ Thickness  ^ Power  ^ Speed  ^ Notes ^
| Plywood   | 1/8"       | 35%   |<del>40mm/s</del> 30-35mm/s  | Use masking to prevent charring |
| Plywood   | 1/4"       | 100%   |<del>15mm/s</del> 10-15mm/s  | |
| MDF   | 1/8"       | 35%   | 40mm/s  | |
| MDF   | 1/4"       | 100%   | 5mm/s  | |
| Hardboard | 1/8" | 100% | 40mm/s | |
| PET-G | 1/8"       | 100%   | 1 pass at first 25mm/s then 50mm/s*  | |
| PET-G | .020"       | 100%   | 75mm/s   | |
| Acrylic | 1/8" - 3mm | 100% | 20mm/s  | |
| ABS | 1/8" - 3mm | 75% | 20mm/s  | |
| Felt | 1/16" | 10% | 20mm/s  | Use backing board |
| Styrene | 0.30" | 100% | 20mm/s  |  |
| Acetate Film (Transparencies)| |10-15%|50mm/s|
| Paper/Heavy Paper | -- | 5% | 50mm/s|
| Bristol Board | -- | 20% | 50mm/s|
| Compact Disc | -- | 15% | 25mm/s|

* Make sure the first pass cuts through or there will be too much smoke. The second pass is necessary because the plastic melts itself back together during the first pass.
=== Preventing scorch marks on through cuts ===
The honeycomb bed has a lot of soot deposited on it from organic materials being cut (mostly plywood and MDF).  You'll notice that when you do through cuts, the back of your material is sometimes scorched.  This is caused by a combination of laser reflection (from the metal honeycomb) and old soot deposits being reheated and redeposited on the back of your work.  You can avoid (or at least minimize) scorching by using the minimum amount of power required to cut through your work, so that little to no laser energy gets through to be reflected back or to heat old soot.  This can be fiddly to get exactly right, and even slightly overshooting will result in either work not being cut through all the way, or soot on the back.  A better approach is to lift the work up above the bed somehow, so that it's not resting on the honeycomb.  There are several 1/2" x 3/4" pieces of aluminum angle sitting on top of the machine to accomplish this.  The limitation is that lifting your material up takes away from potential thickness - the 1/2" aluminum will limit you to 1/4" material.

=== Masking your work with paper transfer tape ===

Sometimes you can't easily raise your work.  You might be dealing with warped stock which is difficult to both raise and pull flat (see below), or cutting tightly-spaced parts that risk falling "under" future cut lines when they come loose from the stock.  In these cases, masking the back of your work is a good idea.  Regular or painters masking tape can work, but is tedious to apply in narrow strips and can release harmful fumes when cut through.  A better option is to use paper transfer tape from a sign making supply shop.  The material is just paper, which is safe to cut.  These tapes come in rolls up to 24 inches wide and 100 feet long.  Most supply shops can slice the rolls into narrower dimensions for free if you ask.  Crossman Graphic Supply (now TG Graphics) is a good Saskatoon source for this.  They currently (March 2015) have discounted rolls of low-tack transfer tape available - this tape is becoming useless for vinyl signmakers, because most vinyl has more powerful adhesive on it, making the tape not usable for transfers.  But low-tack is exactly what you want for laser masking, because it won't wreck your work when peeling it off, and there's minimal adhesive to burn through and cause smoke.

=== Holding down thin, warped material ===
If you've ever cut 1/8" plywood, you'll know that warped stock is pretty much inescapable, and it can be difficult to lay your piece down flat on the bed.  Even a couple mm of variation can take the laser from being perfectly focused to being a total mess.  There are some heavy white metal bars laying on top of the machine. These work to a degree, but get in the way of the laser head sometimes, depending on the cut you're doing and how much warp you're trying to flatten.

An excellent alternative is to use rare earth/neodymium magnets directly on top of your material.  A 1" magnet with 30lbs of pull (sorry for lack of metric) will easily flatten out a region of think plywood or curved cardstock, etc.  The advantage is that the laser head will pass right over it, unlike the bars, so you can set them right in the middle of your sheet, instead of just on the edges.  Make sure you put them in an area that isn't going to be cut - measure from your origin on both the cutter bed and your SmartCarve drawing to where you plan to drop a magnet, just to be sure you aren't on top of a cut line

=== Etching ===
^ Material  ^ Power  ^ Speed  ^
| Plywood   | 5% - 10% | 100mm/s to 200mm/s  |
| Acrylic  |5% - 10% | 100mm/s to 500mm/s  |
| Leather  |5% - 15% | 200mm/s to 500mm/s |
| Stainless Steel | 100% | 25mm/s to 50mm/s |

=== Transparencies ===
^ Method  ^ Power  ^ Speed ^ Notes ^
| Raster | 1% | 40mm/s | [[smtstencil|Detailed SMT Stencil Instructions]]|
laser_cutter.1503695314.txt.gz · Last modified: 2017/08/25 21:08 by swalde
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