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Laser Settings 80W

IMPORTANT NOTE The laser RFID access control system has been changed as of January 20, 2019!
Please watch the following video to learn about the new access control system!

January 22, 2019: RATT can currently only detect that you've homed the laser once you've badged in and it's telling you to home it.  If you power up the laser and home it before you badge in, RATT won't realize the laser has been homed and will still require you to do so when you badge in.  Until I can make some changes and test them, the sure-fire way to do things is to follow these steps:

  1. Power on laser
  2. Badge into RATT with your RFID
  3. RATT will tell you to home the gantry - press XY-0
  4. Proceed with your cutting/engraving
  5. Log out (optional, RATT also detects shutting off laser power as a logout)
  6. Home laser
  7. Power off laser
  8. Clean up!

NOTE: if you log out (or are timed out due to inactivity), but don't shut the laser off, it will not need to be re-homed when you log in again.  Basically just pay attention to what the display says when you log in, if you need to home it, it will say so, otherwise you'll be ready to go.  This is covered in the video above.


Settings

Change if you find in appropriate (keep in mind these are with a clean lens, dirty lens = requires more power, make sure the lens is clean first before changing these)

Here are some examples using the rotary attachment on a glass bottle.  Scan gap was set to 0.055 for all of these (level recommended by Rabbit).  We decided that (for this particular type of glass), a speed of 350 with a power of 18 looked best.  Higher power levels increase the "fuzziness" of the graphic.

Scan Gap = 25.4/DPI, so DPI = 25.4/Scan Gap.  Theoretical limit is 1000DPI, or 0.0254

Speed: 350, Power: 15,_2 Passes
Speed: 350, Power: 18, Sample 1
Speed: 350, Power: 18, Sample 2
Speed: 350, Power: 20
Speed: 400, Power: 20

More on what you can and cannot cut

Rotary attachment:
Rotary: 0.01823829
Linear:  Y same as X

Post work:
From wikipedia: Pulsed lasercutting acrylic introduces a high internal stresses along the cut edge, which when exposed to solvents produces undesirable "stress-crazing" at the cut edge and several millimetres deep.  Annealing the PMMA sheet/parts is therefore an obligatory post-processing step when intending to chemically bond lasercut parts together. This involves heating the parts in an air circulating oven from room temperature up to 90 degrees C (at a rate of no more than 18 degrees per hour) down to room temperature (at a rate of no more than 12 degrees per hour). Temperature should be maintained as follows: One hour for 3mm thickness, two hours for up to 6mm thickness, four hours for up to 12mm thickness, and six hours for up to 20mm thickness. A rapid annealing cycle is reliable for thin sheets and involves placing them in a pre-heated oven to 80 degrees C for one hour, then removing parts from oven and allowing to cool to room temperature. .
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