Apart from all types of Printed Circuit Boards (PCBs) such as Prototype PCB), Standard PCB, Aluminum PCB, HDI PCB, Flexible PCB, Flex-Rigid PCB, High-Frequency PCB, Thick copper PCB, High-Tg PCB and Halogen-Free PCB, Plus Circuit also specializes in manufacturing solder paste stencils in order to meet Surface Mount Technology (SMT) requirements.
Stencils, also called SMT stencils, play a key role in transferring accurate amount of solder paste to correct positions on bare circuit boards ready for assembly. In other words, stencils can fast and efficiently ensure the most accurate solder paste amount and optimal electrical connection. With solder stencils, it is possible to use metal squeegee blades to apply solder paste easily over the openings on PCBs and make stencil to be well aligned with the surface of the advanced circuit board.
According to SMT stencil manufacturing technologies, we provide two types of stencils: laser-cut stencils and chemical-etch stencils.
The openings are lasered on 100% stainless steel. Generally speaking, this kind of stencil can be produced with high quality and a high degree of precision within a short time.
• Advantages: high accuracy; barely influenced by objective elements; trapezoid opening beneficial for demoulding; suitable for accurate cutting; reasonable price;
• Disadvantages: relative low manufacturing speed.
The openings are etched into the metal using acid. Usually this kind of stencil offers better protection on material temper and hardness.
• Advantages: one-time formation; relatively high manufacturing speed; low cost;
• Disadvantages: tending to form sand clock shape or large openings; numerous manufacturing stages and accumulating errors; unsuitable for fine pitch stencils; bad for environmental protection.
The size of stencils is determined by the size of PCBs. Size of framed stencils conforms to the following simple calculation:
Width = width of PCB + 100mm
Length = length of PCB + 100mm
Size of frameless stencils conforms to the following simple calculation:
Width = width of PCB + 200mm
Length = length of PCB + 200mm
For example, if the size of a PCB is 50*50mm, then the size of its frameless stencil should be around 150*150mm and the size of its framed stencil should be around 250*250 mm.