Laser Cutter Maintenance - April 19th, 2016

Phew, big night with the laser cutter. @lukeo, @dbynoe, @newton.jason, and I were present.

New Chiller
@newton.jason built a new chiller for the cutter about 6 weeks ago but we haven’t had time to install it… until now!

BEHOLD

The chiller is now a compressor based chiller which is set to 15 degrees celcius. Given that the laser dissipates an estimated 800W and the new chiller has a cooling capability of about 1800W, we should have a very constant temperature laser. This should greatly improve the consistency of your cuts and should keep the laser running well as we move into summer.

We will be making some more upgrades to it in the near future, including, but not limited to:

  • A water pump failure protection circuit
  • Intake/Outflow temperature logging to stats.vanhack.ca
  • Water flow measurement to stats.vanhack.ca

The measurements should allow us to derive the thermal power dissipated by the laser tube.

Y-axis troubles
There was some reports of the laser cutter producing terrible results when engraving with y-swing at 300 mm/s. This was reproduced by trying to cut a square. Note that below the first mark on the left is the attempt to engrave a rectange similar to other rectanges.
<img src=“/uploads/default/original/2X/a/a0af1f63ef09980e91550043a740ba02ea6cc7f0.jpg” width=“674” height=“500”
The issue was diagnosed by checking if there was ‘play’ in the axes. The x-axis showed minimal amount, but the y-axis had about a mm or two. This was tracked down to a loose set screw on the y-axis rod that runs at the back of the cutter (parallel and near the tube). I wish I could have taken photos but my phone died half way through. These were tightened and it seemed to resolve the issue.

I noticed that the cutter still made a pretty horrible noise when doing y-swing at 300mm/s. This was due to the max acceleration setting being set really high and caused the machine to jar. I have reduced this to cause the controller to slow down the gantry in a more smooth matter. This should help keep these set screws in place.

Alignment

After all the y-axis work, I found out that I knocked the laser out of alignment horribly. Therefore @dbynoe and I recalibrated the optics and tried to align things again as best as possible.

Power measurement
We did a quick power measurement with the optical power monitor. It read 84W after the first two mirrors and with the chiller installed. I am not yet sure how consistent this device is - but it is certainly encouraging.

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great work guys - thanks.