Desiccant Dry Cabinets – Just Released..

Safe And efficient PCB drying achieved with no damage to higher temperatures utilizing extremely low humidity drying out enclosures to produce an atmosphere containing less than .05g/m3 water vapor.

Guidelines for the appropriate stocking and dampness protection of Dry Storage Cabinets may be found in IPC standards (IPC-J-STD-033C). Because there were no published specifications for storage and dampness safety for published circuit panels till 2010, (IPC 1601) these were typically overlooked. But with the proper stocking manage and the use of expert drying techniques, substantial advantages may be gained: Coated published panels will remain solderable to get a considerably longer some time and damage throughout reflow because of dampness may be eliminated.

The ‘IPC-1601 printed table handling and storage guidelines’ states that “ If process regulates are ineffective, and printed boards have soaked up extreme moisture, baking is easily the most practical treatment.” It is going onto condition, “However, baking not just raises price and period time, it can also degrade solderability in the published board which demands additional dealing with and boosts the likelihood of dealing with damage or contamination. Generally, both printed board fabricator and the user ought to strive to steer clear of cooking by exercising effective handling, packaging, storage space, and procedure controls…”

The record also states “Baking is not really suitable for OSP films, because it deteriorates the OSP finish. If cooking is deemed necessary, the usage of the lowest possible temperature and dwell time is suggested being a place to start.”

Natural solderability preservative (OSP) films are among the top surface complete options in guide totally free soldering simply because they offer an attractive blend of solderability, ease of processing and affordable. In comparison to alternatives, nevertheless, they are usually by far the most prone to oxidation. The cause for this is based on the 100 % pure copper surface safeguarded only through the OSP coating layer. Below normal climatic problems within a manufacturing process, after only a few minutes there will be a splitting up of a water film on the surface area (3-5 atom layers). This then begins a diffusion procedure which results in a vapour stress equilibrium with the OSP coat.

Baking also speeds up solid diffusion between metals, and raises intermetallic development. This may lead to a “weak knee” or other solderability issues if the intermetallic coating gets to the top and oxidizes.

The packaging quality of PCBs as obtained from your producers can in addition have a substantial impact. Normally a simple foil handbag or perhaps an ESD handbag is used rather than a Moisture Buffer Bag (MBB). With your packaging coated panels will likely arrive getting already absorbed moisture, and if stored like this they are useless after a short time. Adsorption procedure Dry Storage Cabinets For Optics can be used for the careful drying of such and other moisture delicate gadgets.

In addition to extending safe storage space time, defects and damage (shown previously mentioned), such as popcorning and delamination during reflow may be prevented with appropriate handling and storage.

Safe and effective PCB drying can be accomplished with no damage to higher temperatures using ultra low humidity drying out enclosures that produce an environment that contains lower than .05g/m3 water vapour. This creates a ‘moisture vacuum’ that produces the previously soaked up dampness from the PCBs while safeguarding against oxidation and inter-metal growth. These enclosures are also ideal for secure storage of PCBs for limitless times, for each IPC/JEDEC specifications. Additional oxidation is stopped by the removing of the electrolytic water molecules. Since these storage techniques could work at space heat, boards do not need to be removed until ready for handling. Low heat heat may be used to speed up the drying time. (See reference conditions for drying out listed below).

Dried out and kept in this manner the OSP coated printed board is ideally safeguarded and can be used more than long periods of time with steady wetting qualities.

Dry storage space is also necessary for a much less essential coating; e.g. at first the wettability of the covering of the hot air tin-coated printed board is preferable to of OSP coated printed boards. Right here an oxide movie forms on top under the influence of moisture influence which may also limit good wetting and solderability. This problem can also be averted with the aid of a dried out cabinet, allowing the preservation of any constant wettability for any much longer time period.

The suggested drying times were decided as outlined by IPC-STANDARD JSTD 033C for drying of components. Because variation according to MSL-Level through the PCB-producers is not but included in the regular, measures were carried out on test panels. These showed, that this MSL-Degree 3 of components is comparable with all the actions of Moisture Control Cabinets.

Exceptions are for PCB’s with numerous surface levels and copper division inside, the thickness which must be multiplied by a aspect 2 beforehand. Because these levels could have a strong effect on the rate of dehumidification, these specifications should be searched on as recommendations. As a result of complexity of influences, an exact judgement is anmtvj feasible having a PCB-particular dehumidification check.