Top Paste layer, how to reduce size for stencil

[djoshi]

Hi All

I am very new to this forum

I am in process of create a PCB using Altium. I also need to create the stencil file. If i am correct this is the "Top Paste" layer.

How do I reduce the size by 10%?

I am aware of the PasteMaskExpansion rule, but there i need specify an value such as -0.03.

Is there way to do it by percentage of the actual pad?

Thank You

Regards

DJ

[Pseudobyte]

you could script that in...but yes currently you would need to do the math yourself. Unfortunately the rule doesn't support % based reductions.

[ajb]

There are other tools that can do this as a post processing step, I think in the past I used Pentalogix Viewmate, but IIRC the free version doesn't support exporting back to gerber, so it's only useful if you're making the stencil yourself. 

FWIW, you can probably set all of the paste mask sizes in your library to whatever suits you, it's a bit of a pain, but once you know what works for a given package in your assembly process it shouldn't be something you have to mess with again.  If you choose to later on send the design to a CM, I would expect them to tweak the stencil to suit their workflow anyway and wouldn't stress about whether or not your paste mask works for anyone but you.

[free_electron]

stencil manufacturers can do that for you.
contraction is not normally handled at board level as it heavilty depends on the thickness of the stencil used.