If moisture is absorbed from the environment by surface-mounted components, and then the components are exposed to high temperatures, as in solder reflow ovens (by convection, infrared, IR/convection, vapour phase, hot air rework tools, etc), then the absorbed moisture will expand rapidly, causing internal device stress. The resulting stress can cause internal or external cracking, delamination, and internal corrosion in the components.
Mekko offers a range of drying cabinets that are equipped with active desiccant rotor drying units, which continuously regenerate the desiccant. This means that only the cabinet and electricity is required, eliminating the requirement for any extra consumables or services to operate the unit.
All models are equipped with a desiccant rotor drying unit. This unit is installed inside the cabinet to keep the internal humidity at less than 5%RH. The operator can select continuous operation, or automatic control by an RH meter. Valuable components are protected from micro-cracking and delamination by using active desiccant, rather than baking.
Principle of operation
The drying unit is built into the base of the cabinet. The powerful absorbing desiccant rotor system incorporating Mekko's 'MTX-flow' technology, whereby the desiccant rotor rotates in two separate streams of air. One sector has air flowing through it within the cabinet (moisture absorb), while a smaller sector uses an external heated air flow to regenerate the desiccant (moisture release). As the disk rotates, fresh, dry desiccant is always presented to the process air flow.
Much research was done on the air flow. This unique air flow system optimises the drying and regenerating ability with minimal air leakage into the cabinet.
Cabinets
The cabinets are free-standing and self-controlled, and do not require nitrogen or compressed air. They comply with IPC/JEDEC J-STD-033, which details recommendations for handling, packing, shipping and use of moisture/reflow sensitive surface mount devices. The RH meter and digital thermo-meter are included in the cabinet, viewable through door. Mains electrical supply is 230 V a.c., 1 kW max. (ave. power is approx. 100 W). They are electrostatic safe and conform to ESD standard EN 61340-5-1.
| Tel: | +27 11 726 6758 |
| Email: | [email protected] |
| www: | www.eispty.co.za |
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