#27 - I like the S graphic there, shows a hint of 3D but is clever at the same time.
The conjoined "gg" in #25 #26 #27 #28 is somehow not quite right, but interesting. I don't like the dual colour in #28, it splits the word unnecessarily. #28 and #29 - don't like the arrow graphic.
It would be interesting to somehow mix the "S" graphics in #1 and #4, keeping in mind that each layer in 3D printing is usually slightly different from the last.
#44 #45 #46 I really like that logo shape! Although the green bit in #46 looks unnecessary. Is there any way to incorporate the theme of "layers" into these designs?
#41 This font doesn't look as good as the other ones you (and others) have been using.