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Single Frequency PPR
Single frequency (“square waveform”) pulse reverse rectifiers have been used for 20+ years in the printed circuit board industry to improve plating speed and throwing power. BTA has typical single frequency PPR rectifiers able to meet the needs of simpler pulse reverse plating applications.
• IGBT Technology• Operation is current or voltage mode
• Fast polarity switching
• Modular design
• Water or air cooled configurations
• Low operating costs due to high efficiency and power factor
• Flexible local control user interface for setting all pulse parameters
• Computer interface for automatic control and batch programming
Multi Frequency WST
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, BTA developed its Wave Switching Technology (WST) complex waveform, multi-frequency pulse rectifier, 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 rectifiers, allowing users to program in “rests” within the forward and/or reverse 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 tofive (5) pulse/pulse reverse waveforms each second.
• The WST multi-frequency waveform eliminates the need for “batching” cycles and the ongoing demand for process engineering assistance.
• 95% of all WST users require only 1 or 2 waveforms for ALL products 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 or refurbished WST systems are available.
• WST Makes pulse plating SIMPLE!!!