|A high First Pass Yield demands highly accurate and repeatable placement and assembly. |
The economic instability and currency fluctuations of the last months should give pause to equipment manufacturers. Even before the events of October, an increasing number of them had been deciding to keep production local, close to their customers. The West is beginning to see that any continuing loss of manufacturing industries to low-wage countries could be unwise.
Improvements in automation techniques, particularly in pick-and-place machines, have altered the financial equation. Board and component handling has to be automated, and the best machines run virtually unattended. Operators now have a much higher level function, which demands skilled personnel.
However, the specialized workforce needed for high-tech manufacturing is in many places just not available. And in countries like China where the expertise is available, wages are rising. Transportion costs are also rising — driven largely by the rising cost of energy — and there are hidden costs (and logistics problems) in locating production away from end customers. Companies are increasingly finding that they must keep a production base in the West, closer to their end markets.
For product manufacturers, the key measure is the price per output, which is closely related to First Pass Yield (FPY). That is in turn determined by the Defects per Million (DPM) figures of the pick-and-place machines used in production. Machines from different manufacturers have widely different figures, with between 50 and 75 defects per million being common for sequential pick-and-place machines that dominate the industry.
The more recent parallel placement technique used by Assembleon can have a DPM figure of less than 10 — some 40 DPM below the figures from other types of machines — a figure that brings with it major savings. In high-wage areas like Europe, it can reduce costs by EUR800,000/line/year. Even in eastern European countries, where labor costs are still relatively low, Assembleon has saved customers more than EUR300,000/line/year.
The high cost of field recalls, the loss of reputation, and the growing need to meet legal and safety regulations are making product quality and production reliability top priority. As the complexity of electronics systems rises, the probability of failure rises with it. Achieving zero-defect production is therefore a necessity, particularly with expensive end products, since the cost of non-quality rises with the value of the end product.
And there's another element in the equation; this is possibly the last generation of electronic equipment that can be reworked. Hardware has become so incredibly miniaturized with vanishingly small terminations, spacings and indeed components are making connections almost impossible to see, let alone repair. It is already only just barely possible, and very expensive to rework a defective assembly. So, too, is the high cost of retrieving costly components from scrap.
The cost of reject boards that are fully populated with expensive components is high enough, but a low First Pass Yield means that a whole department is kept busy testing for and tracing faults, and then trying to repair defective assemblies. Add to this each succeeding generation of smaller and smaller components. The latest 01005 components, for example, are almost too small to see. With low First Pass Yields, a large proportion of the valuable output will be just so much scrap.
These unnecessary costs must be reduced at their source — by avoiding placement defects to begin with. That means increasing First Pass Yield, which in turn means improving the accuracy and repeatability of the assembly processes. And that primarily depends on the process capability of the pick-and-place machine and the equipment (particularly the screen printer) that surrounds it. First-pass yields of above 99.8 percent for parallel pick-and-place can save more than 50,000 phones a year from scrap or rework. That means that placement equipment must automate the entire placement process, particularly by placing very difficult connectors and other mechanical parts. And machines may have to place a trillion components over their lifetime, with a reliability factor that's so high, the quality of the assembled product has to be as good (or better) at the end of the assembly equipment's life. Manufacturers should therefore study the lifetime performance of any pick-and-place equipment they consider.
Contact: Assembleon America, Inc., 5110 McGinnis Ferry Rd., Alpharetta, GA 30005 800-474-4547 or 770-751-4420 fax: 770-751-4450 Assembleon Netherlands B.V., De Run 1110, 5503 La Veldhoven, The Netherlands +31 40 27 23000 fax: +31 40 27 23200