The main purpose of PCB baking is to dehumidify and dehumidify, and to remove the moisture contained in the PCB or absorbed from the outside world, because some materials used in the PCB itself are easy to form water molecules. The next group (dry cabinet at 45☌/ View more.Do you know “why the PCB must be baked before SMT can pass through the reflow oven after the expiration date exceeds the shelf life”? The comparison shows that the nitrogen cabinet, the vacuum cabinet and the climate chamber at 40☌/7% RH demonstrate only a slight drop in the drying curves and are therefore rather suitable for storage (keeping to the dwell period), and that the nitrogen cabinet is the favourite for this. Different drying methods using QFP100 as an example Trocknung im Trockenschrank 60☌ >1°r.F.įig.: 1. RH Lagerung im Stickstoffschrank Drying in dry Trocknung im cabinet Trockenschrank 45° >1°r.F. Storage inimclimate test chamber 40☌/7% Lagerung Klimaschrank 40☌/7% r.F. Amongst other things, it should be pointed out that tempering at high temperatures > 125☌ / 1°r.F. Apart from the dependency on the thickness of the plastic surrounding the chip, the recovery time under production conditions is above all determined by the humidity class. The range extends from low to high temperatures. The IPC/JEDEC J-STD-033B.1 standard (“Handling, packaging, despatch and deployment of moisture/reflow-sensitive components for surface mounting” ) provides a series of alternatives for baking/drying components. Standards and recommendations for baking components The industry provides novel dry cabinets which are suitable for rapid drying at relative humidities below one percent. The following investigates whether gentle drying at 45☌ or 60☌ and at low relative humidity achieves the same result as baking at high temperatures. Corrosion and the formation of intermetallic phases of the metallic surfaces are also to be expected. If this is applied, the result is often de-lamination and distortion of the circuit boards. The cardinal problem is the high temperature which is recommended for baking. Information from the ZVEI should also be regarded critically. Circuit board manufacturers are extremely hesitant at providing instructions on drying their circuit boards. It is therefore essential that the circuit board be dried before these soldering processes. When it is rapidly heated as, for example, in soldering technology temperature processes, it is a wellknown fact that the water will evaporate abruptly, leading to destruction. Like most integrated components enclosed in plastic, it absorbs water. The following aims lie behind the investigations described: The circuit board is an integrated structure made of metal and plastic.

Introduction – printed circuit boards as moisture-sensitive components

Ipc standard for pcb baking