Items from other CNC worlds brought to K40? Lens turret, air flow controller?

As of right now, I’m certain that nobody has these capabilities supported in laser software. However, I’ve noticed some of the newer machines simply having a focus lens kind of hanging mid-air via a bracket, with air assist be via some complicated curved tube.

Additionally, I watched some other K40 videos with regards to flame-polished edges, etc.

This got me thinking: Would putting a lens turret under the last mirror be worthwhile? You could get a multitude of focal distances under there (maybe it’s only worth putting 2 or 3), and then use your short-focal distance for engraving, and swap over to a long focal distance for cutting the piece out. Obviously this would all have to be paired with a stepper-adjusted table and likely a Z-probe.

Additionally, even when you’re “not using” air assist, depending on the air assist style (talking about the conical types here) - you may want to leave the air running at a smaller flow rate, but still running. Then on a different piece of the part you may want an increased flow (verses simply on/off).

Is there a good solution currently for digitally controlling an air flow valve?


Some very interesting ideas. An automatic lens changer would definitely be of interest.

As far as an air controller goes, not sure I’ve seen anyone implement an digitally controlled air mass flow controller other than an on/off solenoid. Higher air flow is good for cutting but requires the close in narrow tube delivery to really get any benefit to enhance the cutting. For the under lens conical types the air flow rate isn’t critical as the opening is too big and and the amount of air that gets down into a cut isn’t sufficient to make a difference. But that being said, a mass flow controller could be useful with the right delivery setup.

The lens changer is an intersting idea, but not sure how you would implement it in software, unless it is a gcode based machine. Don’t see a way that it would be possible with a DSP controller. But a head with easy to use manual turret would be nice, sort of like what is on a microscope.


I like the mindset approach of bringing experience from other type machines into one like this.
This is another great advantage to have several communities in the same Maker’s place.

Now at our scale is it worth it ? It’s definitely something here for production, a lens turret will need to come with height ajustment (moving head or bed).

A third way to use laser power is heating (nor cutting nor engraving), a lens for that would be amazing.
My point would be better explain with this old video :
Welding or Forming


@StephaneBUISSON WOW! That Forming YouTube video is one of the best arguments I’ve seen for getting a motorized and g-code controlled z-axis bed!


Perhaps some kind of iris mechanism could be used to modify air flow rate. Or maybe jus a baffle that rotates to block the flow? That should be pretty simple. EDIT: or maybe vary the power going to the air pump?