PCB Stencils Frequently Asked Questions (FAQs)
Q:Why would I need a PCB stencil?
A: The PCB stencil thickness is determined by the smallest component land pattern. Stencils replace hand soldering of surface mount devices, and the inconsistencies created by hand soldering.
Q: How do I choose my stencil thickness?
A: The stencil thickness is determined by the smallest component land pattern. If you are not sure, our design staff can choose the optimum thickness based on the data you supply.
Q: What are home base apertures and why would I need them?
A: Home base apertures are used to control solder balling and tomb-stoning of chip components.
Q: What are Trapezoidal Apertures and why would I need them?
A: Trapezoidal Apertures are created by distorting the beam on the laser, creating a draft in the aperture wall. Trapezoidal Apertures are effective if you plan on a long dwell time between printing of solder paste and placement of components. The taper in the aperture wall causes the paste to sit on top of itself, rather than sliding out the sides.
Q: What are fiducials? Do I need them on my PCB stencil?
A: Fiducials are alignment marks. If your screen printer is equipped with a vision system, fiducials half cut in the stencil to allow for the printer to automatically align the board with the stencil. If you are manually aligning the stencil with the board, you could either full cut the fiducials or just use the surface mount pads.
Find out more about stencils.
Circuit Board Assembly & Manufacturing Capabilities, and Inspection Guidelines.