banner
During PCB assembly ,SMD packaging bags operation after opening

191 Published by FASTPCBA 8月 01,2019

During PCB assembly ,SMD packaging bags operation after opening

The previous section describes how PCB manufacturers’ stores and uses surface PCB assembly components. This section continues to talk about SMT process requirements. After the SMD bag is opened, it should be taken as soon as possible. The environment of the production site should be: room temperature below 30 ° C, relative humidity less than 60%; production time limit: QFP is 10h, other (SOP, SOJ, PLCC) is 48h (some are 72h).

pcb assembly

All PCB assembly plastic packaging SMDs , when the temperature is found to be 30% or more after opening or the SMD after unsealing is not completed within the specified time, and when the SMD is stored over time, it must be carried out driving wet to dry before the pcb assembly mounting. The drying method is divided into a low temperature drying method and a high temperature drying method.

 

The low temperature box temperature in the PCB assembly low temperature drying method is (40±2) °C, the applicable relative humidity is less than 5%, the drying time is 192h; the oven temperature in the high temperature drying method is (125±5) °C, the drying time is 5-8h.

 

In PCB assembly, SMD (SOP, SOJ, PLCC, QFP, etc.) in plastic tube packaging, the packaging tube is not resistant to high temperature, can not be directly placed in the oven for baking, should be placed in a metal tube or metal plate to be baked .

 

QFP’s packaging plastic trays are not resistant to high temperatures. High temperature resistance can be directly put into the oven for baking; if it is not resistant to high temperature, it can not be directly baked in the oven to prevent accidents. It should be placed in a metal plate for baking. Preventing damage to the pins during transfer to avoid damage to their coplanarity.

 

The remaining SMD preservation method

1.Equipped with special low temperature and low humidity storage box. The SMD that is temporarily unused after the opening is stored in the box together with the feeder, but the cost of the large dedicated low-temperature and low-humidity storage box is high.

2.Usingthe original intact packaging bag. As long as the bag is not damaged and the desiccant is good, the unused SMD can be repacked into the bag and then sealed with tape.

PCB manufacturer reflow soldering machine heating system

PCB manufacturer reflow soldering machine heating system   The full hot air and infrared hea...

Do you like ? 227

Read more
Types and advantages of flexible pcb circuit board

Types and advantages of flexible pcb circuit board The PCBA board is the finished product after t...

Do you like ? 323

Read more
What are the SMT process

What are the  SMT process Everyone knows that the electronic products we use in our lives are ass...

Do you like ? 986

Read more
What is the difference between PCB and PCBA

What is the difference between PCB and PCBA What is a PCB PCB = printed circuit board; PCB is an ...

Do you like ? 864

Read more