Computer-Switchable Air/Nitrogen Atmosphere Option

Nitrogen Atmosphere Usage

The need for the use of a nitrogen-enriched atmosphere depends on many factors. However, below are some of the more common applications associated with its use;

• Bare-copper PWB soldering (to maintain an appropriate coating thickness over the copper).
• BGA soldering (to decrease voiding in specific types of packages).
• Flip chip soldering (to reduce oxidation of balls and promote wetting).
• BGA/Chip Scale Package balling (to reduce oxidation).

Assuming appropriate system baffles, to a large extent the total "open" area at each end of the oven, and, the "needed" level of residual oxygen for the process will dictate nitrogen consumption. Since all forced convection ovens obey the same laws of fluid flow, nitrogen performance should be similar when the same total open area (e.g., conveyor width and baffle settings) are used at each end of the oven.

Although ALL Conceptronic systems OPERATE CONTINUOUSLY AT THEIR MAXIMUM CONVECTION LEVEL, many other forced convection ovens have such high turbulence levels at each end of the oven that baffling efforts are partially defeated. To compensate for this, they reduce blower speeds for comparable nitrogen performance data. And, with a reduction in blower speed there is a significant reduction in the convective heat transfer coefficient. Thus, the infrared component of heat transfer increases. Beware of this during the evaluation phase!

Conceptronic’s Computer-Switchable Air/Nitrogen Atmosphere Option

Conceptronic’s Computer-Switchable Air/Nitrogen option allows you to activate and de-activate the flow of nitrogen into the oven through the control software. In fact, the atmosphere mode chosen is stored in each profile "recipe" just like heater temperature and conveyor speed. Thus, when a "nitrogen" product is to be processed, you only need to choose the recipe and nitrogen flow will be turned "on" automatically. An additional benefit is that you DON’T NEED compressed air for operation air mode operation to maintain the same heating profile!

And, unlike many competitive suppliers, we include everything you need when you purchase the option. The only exception relates to oxygen analyzers, atmosphere stabilizer hoods or Genesisä cooling. We don’t "play games" with you by "sub-optioning" features that you really need to operate effectively!

In fact, the full-array of features we include with our Computer-Switchable Air/Nitrogen Option are as follows:

• Proprietary blower shaft seals and specialized process chamber gasketing.
• A computerized valve for automatic mode switching between air and nitrogen atmospheres.
• Storage of atmosphere mode selection within individual oven profile "recipes".
• Self-adjusting horizontal baffles for low nitrogen consumption at various opening widths.
• Adjustable vertical baffles at each end of the oven for oxygen contamination control.
• A forced convective ECU cooling module (REQUIRES NO CHILLED WATER/ETHYLENE GLYCOL FLUIDS).
• A 30-inch/76.2 cm cooling section extension for reduced product exiting temperatures.
• Process-level gas sample lines located throughout the interior of the heating chamber.
• A lockable cabinet (with clear view port) for flow meters and sample port connections.
• A nitrogen safety shutoff system (that engages when bonnet is raised or when power is lost).
• Operation at continuous maximum blower speeds (maximum convective efficiency) when in nitrogen or air atmospheres.

High Performance Atmosphere Stabilizer Option.

This option applies to the "Computer-Switchable, Air/Nitrogen" option with standard ECU cooling. It includes two, specially engineered flow hoods with adapter ducts (and is retrofittable).

This option offers the following enhancements when using no-clean fluxes in nitrogen mode:

• Reduces total required nitrogen consumption and oxygen levels at conveyor widths over 12-inches/30.5 cm.
• Improves oxygen level stability when the oven is loaded and when the tunnel opening varies.
• Removes aerosol and aromatic no-clean flux constituents that may be emitted from the oven.

NOTE: Atmosphere stabilizers are included with all Genesisä cooling modules.