Is there a recommended list of upgrades to do to a K40 laser cutter?

Lasers
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1

Is there a recommended list of upgrades to do to a K40 laser cutter? Winter is Coming and I’ll have some time on my hands to finally do the upgrades to mine…

2

In order of preference: smoothie, air assist, exhaust, lense, mirrors, Z table

3

Do you have recommended links for each of these updates?

4

Couple of link in this collection https://plus.google.com/collection/EndMTB