The importance of manual welding line in PCBA processing

PCBA processing manual welding advantages

When small batch PCBA processing is involved; Welding by hand is fast and economical. When small batch operations are involved, in particular through-hole components (impregnated wire) work well with manual assembly. PCBA first pieces also benefit from hand soldering because you treat small batch runs as unusual component placement.

Automatic optical inspection (X-ray, 3DAOI, Online AOI) cannot properly examine some parts and requires manual intervention to verify placement and check for any welding problems. For surface mounted connectors, you may need to manually check again. Sometimes during the reflux process, you may encounter a widget that needs to be cleaned manually. Manual processes are also effective when you are looking for repairs and rework of existing PCbas.

Therefore, both methods have their advantages. There can be no one-size-fits-all solution. So, while you will use automated assembly to increase speed, consistency, and reduce cost, there are more and more cases where manual intervention is required. You will need to work with a PCBA manufacturer who has the necessary SMT automatic assembly equipment and a skilled manual welding team. Therefore, you can use the correct method according to your custom requirements. Next-generation equipment with industry best practices and experienced manpower can play an important role in producing high quality PCbas.

2. Why should PCBA be preheated before processing?

The importance of temperature distribution in mass-produced PCBA machining and welding environments is widely understood. Slow heating and preheating phases help activate flux, prevent thermal shock, and improve solder joint quality during SMT placement. However, when it comes to rework, prototyping, or PCBA first piece proofing projects, it's easy to forget the importance of the warm-up phase, which can lead to damage to the equipment, even if the equipment isn't broken. So, for such an important step, why is it often forgotten in the actual operation of SMT factories? What are the consequences of omitting this stage?

What is the preheating before PCBA welding?

When technicians and practitioners hear the words "temperature curve" or "temperature curve", they think of smt reflow soldering. Along the huge length of the weld zone, it is easy to see the four main temperature control zones, which will eventually produce a perfect weld spot, hopefully. Carefully control and improve each stage through the experience of technicians and trial and error. Each stage plays a role in improving solder joint quality and reducing defects. But other industrial welders may not have such fine temperature control. But what they have in common is the warm-up phase.

Flux combustion in selective wave soldering

The function of the preheating stage is to steadily increase the temperature of the entire assembly from room temperature to the holding temperature below the melting point of the solder paste, i.e., about 150℃. Adjust temperature changes to maintain a constant slope of a few degrees per second. The warm-up phase is followed by the soaking phase, which will maintain the temperature over a period of time to ensure that the board heats evenly. Then there is the reflux stage, where the solder joint is formed. During the preheating and soaking phases, the volatile solvent in the solder paste is burned off and the flux is activated.

kingford's actual operation proves that preheating before welding is very important.

kingford PCBA processing capability

1. Maximum board card: 310mm*410mm(SMT);

2. Maximum plate thickness: 3mm;

3. Minimum plate thickness: 0.5mm;

4. Minimum Chip parts: 0201 package or parts above 0.6mm*0.3mm;

5. Maximum weight of mounted parts: 150g;

6. Maximum parts height: 25mm;

7. Maximum parts size: 150mm*150mm;

8. Minimum spacing of pin parts: 0.3mm;

9. Minimum ball parts (BGA) spacing: 0.3mm;

10. Minimum ball parts (BGA) ball diameter: 0.3mm;

11. Maximum parts mounting accuracy (100QFP) : 25um@IPC;

12. Patch capacity: 3-4 million points/day.

PCBA machining manual welding

Why kingford?

1. Strength assurance

▪ SMT workshop: We have imported SMT machines and a variety of optical testing equipment, capable of producing 4 million pieces per day. Every process is equipped with QC personnel who can keep a close eye on product quality.

▪ DIP production line: There are two wave welding machines. Among them, there are more than ten old employees who have worked for more than three years. Skilled workers can weld all kinds of insert materials.

2. Quality assurance, high cost-effective

▪ High-end equipment can mount precision heterosexual parts, BGA, QFN, 0201 materials. Proofing can be machine paste, also can be hand pendulum.

▪ Samples and large and small batches can be produced. Proofing starting price 800 yuan, batch starting price 0.008 yuan/point, no start-up fee.

3. Rich experience in SMT and welding of electronic products, stable delivery time

▪ Has served thousands of home appliance subsidiaries, involving various kinds of automotive equipment and industrial control motherboard SMT SMT processing services. Products are often exported to Europe and the United States, the quality of new and old customers affirmed.

▪ On time delivery, usually within 3-5 days after the board is assembled, small batch expedited can also be shipped on the same day.

4. Strong maintenance ability and perfect after-sales service

▪ Experienced maintenance engineers are able to repair defective products caused by various welding problems and ensure the connectivity rate of each circuit board.

▪ 24-hour customer service staff will be ready to respond and resolve your order as soon as possible.