Description
ALPHA Step – Step Stencils
ALPHA Step Multi-level, Step Stencil Technology offers the SMT engineer significant flexibility in achieving the right solder paste volume deposit for devices with markedly diverse paste requirement. They can provide additional paste height in selected areas of the PCB (step-up stencils) or reduced height deposits in other areas (step down stencils). Design “keep out area1” rules must be adhered to when incorporating step areas into a stencil.
Where a board has raised areas that would hamper the ability of the stencil to perform to its optimum, contact side relief cavities can be incorporated in the PCB side of the stencil to overcome the problem. (Step relief cavity stencils).
Alpha stencils can be ordered through the Alpha on line stencil management system ‘i-Stencil’, this system cuts out the middle-man and allows you stencil to be ordered directly into the factory manufacturing system to ensure that it is processed immediately. Next-day or in certain cases, same-day, delivery is possible with the i-Stencil interface and the order can be tracked from receipt to delivery. i-Stencil also stores all the history and any design guidelines that are customer specific.
Step-up areas
Used to increase the volume and height of the solder deposit. Useful for ‘pin in paste’ and large format devices with co planarity consistency problems.
Step-down areas
Used to reduce the volume and height of the paste deposit (or possibly increase the volume depending on aperture area ratio and transfer efficiency). Useful to improve Deposit Volume Repeatability in fine line and micro package attachment.
“Stepless” steps
Ramped step-up areas, produced by the electroforming process, to increase paste deposits in selected areas of the stencil for large components or large features such as antenna’s or shieldings. Formed on the PCB side of the stencil to provide a smooth print surface for enclosed printheads etc while minimizing smearing.
Step-relief cavities
Used to overcome board surface irregularities such as raised pads, vias, legends such as bar codes and edge clamping issues. These features also afford relief for paste print deposits in two step stencil printing processes… where the use of a thin stencil is followed up by a thicker stencil in order to achieve multi-height deposits without the need for “keep out areas1“.
In order to print successfully, apertures must be designed to be a minimum distance from the step edge. This distance is dependent on the step dimensions and is known as known as a “keep out area”.
Alpha stencils can be ordered through the Alpha on line stencil management system ‘I-Stencil’, this system cuts out the middle-man and allows you stencil to be ordered directly into the factory manufacturing system to ensure that it is processed immediately. Next-day or in certain cases, same-day, delivery is possible with the i-Stencil interface and the order can be tracked from receipt to delivery. i-Stencil also stores all the history and any design guidelines that are customer specific.
For further information, please contact us.
