The SMT chip processing workshop has environmental requirements for cleanliness, humidity and temperature, and it needs to work according to certain environmental requirements during processing. At the same time, we also need to pay attention to related matters. Next, Lexus will introduce the relevant content in detail.

1. Environmental requirements of SMT chip processing workshop

SMT production equipment is a high-precision mechatronics equipment. Equipment and process materials have certain requirements on environmental cleanliness, humidity and temperature. In order to ensure the normal operation of equipment, reduce environmental damage to components, and improve quality, the SMT workshop environment has the following requirements:

1. Power

Generally, single-phase AC 220 (220±10%, 0/60Hz) and three-phase AC 380 (380±10%, 50/60Hz) are required, and the power of the power supply is more than twice the power consumption.

2. Air source

According to equipment requirements, air source pressure can be configured. The factory air source can be used, or an oil-free compressed air machine can be configured separately. The general pressure is greater than 7kg/cm2. Clean and dry purified air is required, so degreasing, dusting and watering of the compressed air is necessary. The air duct adopts stainless steel or pressure-resistant plastic pipe.

3. Exhaust gas

Reflow and wave soldering equipment should be equipped with exhaust fans. For a full hot blast stove, the minimum flow rate for the exhaust pipe is 500 cubic feet per minute (14.15m3/min).

4. Temperature and humidity

The best ambient temperature of the production workshop is 23±3℃, generally 17~28℃, and the relative humidity is 45%~70%RH. According to the size of the workshop, set up appropriate temperature and humidity meter for regular monitoring, and provide temperature and humidity adjustment facilities.

5. Anti-static

Workers should wear anti-static clothes, shoes and anti-static wristbands before entering the workshop. The anti-static work area should be equipped with anti-static floors, anti-static table mats, anti-static packaging bags, turnover boxes, PCB racks, etc.

2. Precautions for SMT chip processing

1. Refrigeration of solder paste

I just bought the solder paste. If not used immediately, it needs to be refrigerated. The temperature should be between 5℃-10℃, not lower than 0℃.

2. Replace the products that are easily worn by the placement machine in time.

During the placement process, due to the aging of the placement machine equipment and the damage to the nozzle and feeder, it is easy to cause the placement machine to tilt, resulting in a large amount of material thrown, reducing production efficiency and increasing production costs. If the mounter cannot be installed, carefully check whether the suction nozzle is blocked or damaged, and whether the feeder is in good condition.

3. Measure the furnace temperature

The quality of PCB soldering is closely related to the reasonable setting of reflow soldering process parameters. Generally speaking, in order to continuously improve the temperature curve and set the temperature curve suitable for welding products, it is necessary to test the furnace temperature twice a day, at least once a day. For productivity and cost savings, don't miss this link.