This article discusses new developments in stencil laser and material technology and shows how these advancements, when combined, provide comparable and cost-effective alternatives to traditional electroformed stencils. The results are improved yields, cycle time reductions and significant cost savings.

Changes in the domestic printed circuit board assembly industry have resulted in a dominant shift to a high-mix, low-volume (HMLV) manufacturing environment resulting in a high frequency of line changeovers.

Although blade contact angle is a critical stencil printing parameter, screen printers have so far been unable to vary it ‘on-the-fly’, in software.

As the first process step in an SMT production line, solder paste printing is of key importance. 

This paper examines the construction of a notebook mainboard with more than 2000 components and no wave soldering required.

The consumer’s interest for smaller, lighter and higher performance electronics products has increased the use of ultra fine pitch packages, such as Flip Chips and Chip Scale Packages, in printed circuit board (PCB) assembly.

In order to better characterize the performance of wafer bumping stencils, a novel solder transfer ratio has been defined that relates the amount of solder paste volume transferred to a wafer to the actual stencil aperture volume.

In the early days of SMT assembly, step stencils were used to reduce the stencil thickness for 25 mil pitch leaded device apertures. However, as SMT requirements became more complex and, consequently, more demanding, so did the requirements for complex step stencils.