Hi John,

Kapton and Mylar are films of choice when making inexpensive SMT stencils that are cut via Laser, Kapton being much more expensive and durable. I have an IR laser diode and am told the film must be a dark as possible... I want to experiment with colored acrylic sheet at the same thickness once I am successful with Kapton and Mylar...

To your point about burning... this is why the laser needs to be pulsed. The link that Fred27 posted in this thread explains the issue of cutting very well and shows pics of various pulse rates, etc. Such a control would "dial-in" the correct setting for making the best cut, and would scale this setting with the travel/speed of the table - all for uniformity.

Everyone's input has been quite good, and I appreciate everyone's response to my questions!

-charlie

Thanks Charlie,
I realize that I should have clarified my post by saying I think a laser diode will cause the melting and shrinking, due to its low power and slower ipm.

Hope I'm wrong - won't be a first for me.

John

I don't have much $ invested; enjoying the theory, design and problem solving at this point. I have a couple of lenses that will allow me to focus the laser - so, we'll see... if not, then I'll do some engraving with it! 

We'll see....

-charlie