Aperture Area Ratio, and Determining Stencil Thickness

Includes information regarding protoyping, technical questions, company news, and input about our products.


Aperture Area Ratio, and Determining Stencil Thickness

    by Al Secchi » Mon May 14, 2012 9:30 am

When ordering a stencil it is important to request the appropriate stencil thickness to insure proper paste release from the stencil. The aspect ratio for rectangular apertures should be 1.5, and an area ratio of 0.66. It is best to evaluate the smallest apertures on the stencil to determine the proper stencil thickness.

You can use the following formulas to select an appropriate stencil thickness:

Aspect Ratio = Aperture Width (W) / Stencil Thickness (T) [should be 1,5]

Area Ratio = Area of Pad (LxW) / Area of Aperture Walls (2 x (LxW) x T) [should be 0.66]

(diagram attached)
Attachments
Stencil Thickness & Aspect Ratio.jpg
Stencil Thickness & Aspect Ratio.jpg (85.49 KiB) Viewed 24685 times
Al Secchi
Sunstone Circuits
13626 S. Freeman Road
Mulino, OR 97042
Phone: 800-228-8198
Fax: 503-829-6657
Al Secchi
 
Posts: 5
Joined: Wed Jul 13, 2011 12:00 am

Re: Aperture Area Ratio, and Determining Stencil Thickness

    by meli117 » Tue Dec 03, 2013 11:36 pm

When ordering a stencil it is important to request the appropriate stencil thickness to insure proper paste release from the stencil. The aspect ratio for rectangular apertures should be 1.5, and an area ratio of 0.66. It is best to evaluate the smallest apertures on the stencil to determine the proper stencil thickness.

You can use the following formulas to select an appropriate stencil thickness:

Aspect Ratio = Aperture Width (W) / Stencil Thickness (T) [should be 1,5]

Area Ratio = Area of Pad (LxW) / Area of Aperture Walls (2 x (LxW) x T) [should be 0.66]

(diagram attached)
Hello,

thanks , this was really helpful, but do these formulas go in any circumstances ? There are no exceptions ?

thanks
meli117
 
Posts: 1
Joined: Tue Dec 03, 2013 11:34 pm

Re: Aperture Area Ratio, and Determining Stencil Thickness

    by Sal Hernandez » Mon Dec 09, 2013 6:56 am

This is a general formula for stencil thickness. Is there a particular exception you would like to discuss?
Regards,

Sal Hernandez
Software Support Engineer I
Sunstone Circuits
13626 S. Freeman Road
Mulino, OR 97042
Phone: 503-829-9108 x226
Fax: 503-829-5482
Sal Hernandez
 
Posts: 381
Joined: Wed Jul 06, 2011 12:00 am

Re: Aperture Area Ratio, and Determining Stencil Thickness

    by nevertalk00 » Sun Apr 19, 2015 10:47 pm

Have your board fab house plug the via and then plate copper over it. They can plug with metal or a thermally and electrically conductive epoxy before the final plating steps."
What’s up
nevertalk00
 
Posts: 1
Joined: Sun Apr 19, 2015 10:20 pm




Return to “Products and Services”

Who is online

Users browsing this forum: No registered users and 3 guests

cron