Does the cone height matter?

Community Laser Talk
1

Hi, second topic for the day: I recently bought an aged CO2 laser that came with no useful info and I am trying to get up to speed on it’s set-up etc. (I’m not new to lasering per se, just CO2 - I also have an Elegoo Phecda 20w diode laser so do have some basic knowledge). Anyway, here’s the topic. I’ve needed to remove the focusing lens for cleaning and noticed that the height of the cone / lens holder (the knurled assembly in the photo) could be set within a range of maybe 30mm - 40mm within the body. It came with the top of the knurling set at about 5mm from the body. I fully realise the lens itself needs to be at a particular distance from the workpiece and I can set this by raising or lowering the table. What I wanted to know is whether the distance between the lens and the final mirror matters? In other words, is the position of the lens holder important? And if so, how do I determine the correct distance?

Many thanks in advance for reading and, hopefully, any advice.

BW

Kevin

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2

Because the beam is pretty nearly collimated all the way from the tube to the lens, a few millimeters either way don’t matter.

You could use it as a focus block adjustment:

  • Raise the nozzle all the way
  • Set the platform + material to a convenient height
  • Put a focus block under the nozzle
  • Lower the nozzle to sit atop the block

From then on, the focus block is your BFF.

1 Like
3

Thanks, that’s very helpful.