The primary purpose of using SMT stencils is to facilitate placing of a component onto aboard after a coat of solder paste is applied on it. Power stencils help a great deal in cutting down labor costs and lead time by reducing the manual placement of components and are hence considered a boon for mass production of the same PCB.SMT stencils come in two different formats – framed and frameless. Although the framed stencils are more suited for high volume print circuit boards the frameless foils being easily replaceable are preferable for a high mix environment where various PCBs are being manufactured on the very same line. The frameless ones have an added advantage that they need not be permanently glued onto the frame.
The frameless systems are somewhat expensive but the lower replacement costs for the foils and less storage space required in their case make them a worthwhile purchase.
Handling Data :
PCB POWER MARKET introduced framed stencils for the SMT ,semiconductor and solar industries. The fine grade polished SS technology ensures relatively no burrs on the hole walls and a mirror like finish that helps paste flow evenly on the surface. We guarantee an aperture size accuracy of +-5um and positioning accuracy of +- 10um. For boards with fine pitch components we recommend also combining F3 Nano Coating for better throughput.
Frameless SMT Stencils also referred to as foils are laser cut solder paste stencils designed to work with stencil tensioning systems known as reusable stencil frames. This type of stencil does not need to be permanently glued in a frame. Frameless stencils are significantly less expensive than framed stencils and provide money-saving storage while still delivering superior quality and performance.
Framed/Frameless SMT Stencils Specs :
|Opening precision||±5µm Within ±5µm [Stencil thickness 50µm, round hole|
|With Frame Stencils : Available Sizes(mm)||737 X 737, 584 X 584, 559 X 559, 508 X 508, 650 X 550|
|Opening precision||4, 5, 6, 7, 8|
|Pitch dimensional precision||+2Oµm Within ±20µm [per pitch 2 0 mm]|
|Min hole diameter||F120µm [for stencil thickness 100mm]|