The issue of the number of passes

Ethan

Categories:

Laser

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02-28

I’m only just getting started with LB, and I doubt this is actually a LB issue, but the number of passes does not seem to work like I would have expected.

I have some experience with lasers and optics going back years.

My expectation was that if I can get a 1mm deep cut on pass #1, I should get a bit less than 1mm again on pass 2. However that does not seem to be the case, more like 0.5mm or less.

I’m using the Snapmaker 40W blue laser, which has a fairly long beam “waist” (the part where the beam diameter is minimum) so I don’t think focus is the issue.

Why would the second pass be more like 0.5mm or less?

Christian

03-01

You have to consider any “waste” material in the cut (i.e. ash. etc.) and any changes in reflectivity over the cut area versus the native surface. Material properties can change when exposed to heat and this can influence the laser’s progress.

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Gilbert

03-03

Depending on the settings, the laser creates much charring in the cut path. On the next run, it has to remove the charring before it hits new material. If you have a good air assist, this effect should be minimized, but is still there.

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