MULTI-FREQUENCY WST RECTIFIERS
Substantial research confirms that a single and unique pulse frequency is required to plate a particular hole diameter in a panel of a particular thickness with 100% throwing power. Since most, if not all panels have multiple hole sizes and/or various size blind vias, it is necessary to have multiple frequencies of pulses to plate each feature size with 100% throwing power. When using a single frequency pulse rectifier a “batch program is commonly used where the plating frequency is changed a number of times during the plating cycle. With this approach, a single frequency is used for some minutes, and then changed to another frequency. This method of batch programming is a way to “average” the plating on the board’s various features; however, once non-uniform plating has begun, it cannot be corrected later in the plating process.
Furthermore, as the aspect ratios increase, the single frequency on a conventional pulse rectifier must also increase to obtain 100% throwing power, however, for very high aspect ratios there is a point beyond which classic PPR waveforms alone are inadequate, and do not achieve 100% throwing power. To overcome the limitations of these single frequency pulse rectifiers, American CRS's Wave Switching Technology (WST) complex waveform, multi-frequency pulse rectifier was developed, which is specifically designed for advanced technology, multi-featured, high value-added printed circuit boards.
|• WST combines the benefits of both pulse and pulse reverse
allowing users to program in “rests” within the forward
pulses. This drastically improves the throwing
power on very high
aspect ratio applicatons.
• WST allows the user to run a multi-frequency waveform with up to
(5) pulse/pulse reverse waveforms each second.
• The WST multi-frequency waveform eliminates the need for “batching”
cycles and the ongoing demand for process
• 95% of all WST users require only 1 or 2 waveforms for ALL
in their factory.
• WST eliminates the worries about cable inductance common with
single-frequency, square waveform PPR rectifiers and, therefore,
the need for costly coaxial cable.
• New and refurbished WST systems are available.
• WST Makes pulse plating SIMPLE!!!