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50 SMT Magazine • January 2015 Editor's Note: SMT Magazine welcomes new columnist Robert Voigt, who will help folks ana- lyze and select SMT equipment for the PCB busi- ness, beginning with stencil printers. Future col- umns will walk potential buyers through the en- tire cycle of assembly equipment, including new technologies. What is a stencil printer? The first step in a paste, place, and reflow assembly operation is the stencil printer, which can be manual, semi-automatic, or automatic. This machine dispenses solder paste which, using a squeegee, is forced over the openings in a stencil onto a printed circuit board. Production volume The first question to answer is: What pro- duction range are you dealing with? Knowing this will help you to decide what level of auto- mation you'll need. • Up to 150 boards/day indicates a manual system, and will likely run about $2,000– $5,000 for a decent new machine • Up to 500 boards/day is in the semi- automatic range, and will command in the range of $8,000–$14,000 • More than 500 boards/day is in the fully automatic range, and can cost $30,000 or more, depending on the bells and whistles that come with it Manual Systems Here, speed is typically not a big issue. Fine pitch and accuracy are the most important fac- tors. Accuracy is determined by how securely aligned the circuit board is in the machine. There are four dimensions to consider for the control method: X, Y, Z and Θ. Once the board is aligned in the machine, paste is applied using a squeegee. While there are typically a couple of options on all systems, by robert voigt DDM NoVASTAR SMT QuICK TIPS How to Select a Stencil Printer Column