What/How are stencil frames used?

[alank2]

So far I've done a couple of pcbs with a flat kapton stencil.  I've got a metal one coming from elecrow to try next.  For these flat ones I just use some masking tape to stick them to a metal work surface I use.  What is the deal with the framed stencils?  How would one use them differently?  What is their purpose?

[8086]

They're used in machines that apply paste to the boards automatically. Not much use for manual pasting.

[janekm]

There are also "plain" aluminium frames that the metal stencil is stretched onto. This keeps the stencil flat to the PCB, and is convenient for manual paste application too. Those are the standard in China (and remarkably cheap) but awkward to ship outside China.

[alank2]

Thanks for the explanations.