The goal of SMT production is a zero-defect process in which flawed materials never get to the customer; however,
in the ideal scenario,zero-defect production would mean that no flawed products ever come off the production line.
The typical SMT production line,which integrates inspection as a defect-containment method,operates with less
efficiency and effectiveness than is possible with modern technology,making the zero-defect proposition difficult to
achieve. The effort to increase product quality with inspection stations integrated into the product line can have two
results: no appreciable increase in quality metrics; and/or a loss of production line efficiency due to bottlenecks,
caused by choosing the wrong inspection system. In order to achieve increased quality,product yield,and line
efficiency,one must employ the right inspection system in the right way for process development and improvement,
not just defect containment.
What is the right system? Electronics packages are becoming increasingly smaller and more densely populated.
With this comes the need for high-intensity,nondestructive inspection that is both thorough and fast. X-ray
inspection is the only method of nondestructive testing that can provide high-level detection of the most-common
production defects: solder short,solder open,insufficient solder and reliability,and missing parts. Furthermore,only
offline X-ray inspection systems have the speed,imaging capabilities,and flexibility to create a zero-defect process.
What is “the right way?” In order to make quality a value-added part of the process at every level,the design of the
production line must reflect this goal. Inspection is not merely for post-production. A closed-loop production
process sets goals to achieve quality at all stages: setting process limits,measuring the process,controlling the
process,decreasing defect rate,and increasing first-pass yield.
This paper will analyze the typical SMT production process in terms of line setup,the role of inspection,the level of
quality achieved,and flaws in the process. We will also suggest an “ideal” SMT production line with regard to line
setup,the right inspection system to meet those goals,and the anticipated benefits towards achieving a zero-defect
result.