**How to Choose a PCBA Assembly Manufacturer? The Introduction is as follows:**
1. **How is the machine condition (pick-and-place and reflow oven)?**
What is the accuracy of the old versus new machines? How much data can be processed internally? Are the machines from Chinese or Japanese manufacturers? These parameters are crucial because they directly impact productivity and output. If the machines lack precision, they may not be able to handle the latest, smallest component packaging technologies, such as SMD layouts.
Some older machines may not be well-maintained and used in production. For instance, defects in the equipment could reduce production speed. If the placement machine is inaccurate or prone to frequent breakdowns, production will inevitably slow down. Continuous PCB production can’t be guaranteed under such conditions.
I have experienced situations where frequent machine failures resulted in production delays because we could not push back work schedules. I’ve also encountered situations where certain PCB components were treated like idolized objects. For example, when purchasing second-hand equipment, the placement accuracy of parts often suffers, with components being misaligned in the X/Y positions. Operators must then reposition the parts manually, which increases production time and causes delays. Replacing a single component manually on a batch of just 10,000 PCBs can lead to significant delays.
**2. What quality inspections did they complete?**
As we know, quality control is crucial when considering production operations in China. PCB assembly services are available, but not all suppliers are familiar with or consistently apply the full range of 2-3 key quality control processes.
*Visual Inspection:* The first step is visual verification, which is the most common method for operators to identify any abnormal component configurations. This is a critical part of PCB production that every factory should implement.
*AOI Vision Machine:* Next, automated optical inspection (AOI) is used to enhance the speed and reliability of visual quality control. This process typically involves using cameras to compare the correct component placement and positioning on the PCB, often by evaluating image contrast.
*Functional Testing:* Functional testing checks the operational performance of the PCB. This is typically powered by the circuit’s power supply, with input signals generated, followed by observation and analysis of the PCB’s output.
**3. How many production lines do they have?**
When quick delivery of a PCBA prototype is necessary, it’s crucial to ensure fast production. Suppliers that can manage multiple orders and run several production lines in parallel offer an advantage by accelerating the process. Choose a PCBA partner that can operate multiple production lines simultaneously to handle orders more efficiently. Having a junction box is also essential.
**4. Do they have standard passive component inventory?**
Typically, a PCB will stock common components such as resistors, capacitors, diodes, transistors, and inductors. Maintaining this inventory can help streamline production and avoid delays. Suppliers should accept small orders and support mass production, especially during the R&D phase, where small PCBA prototypes may be required. This is similar to producing small-scale versions of the final product, which may carry some inherent risks of instability.
You can collaborate with two different PCB suppliers—one for prototyping and another for mass production—but this approach may compromise process consistency. It’s generally best to have a continuous product development phase that transitions smoothly into manufacturing. Ensure your supplier can manage both small and large production runs to guarantee future production consistency.
**6. How do they use solder paste?**
Is the solder paste printer manual or automatic? Since human error tends to be more frequent than machine error, using an automatic solder paste printer is the preferred method for higher precision and efficiency.
**7. The position of unqualified workers’ hands:**
Sometimes, a component may be too difficult for a placement machine to handle (e.g., if the component has a unique shape that the suction head cannot grasp, or it is not compatible with the board or tray). In such cases, the operator must manually place the component and perform reflow soldering. It’s critical to ensure that these operators are properly trained, as they need to have the skills to handle small parts with precision. For especially tiny components, the right skills and tools (such as microscopes) are necessary to ensure accurate placement.
**8. Do they separate lead and lead-free production lines?**
If a supplier uses lead-based solder for certain market segments (typically because it’s less expensive), they must ensure that it does not mix with lead-free solder lines. Contamination can result from physical contact or even lead-containing dust. To avoid this, some PCB manufacturers maintain physical barriers, such as walls or netted partitions, to keep the lead and lead-free production lines separated.
**9. What is their defect rate?**
How many defective PCBs will be produced per 100 units after rework? The yield rate is a key factor that affects delivery time. Many suppliers claim that their defect rates are under 1%, but the actual performance may vary. Understanding the cost implications of rework and defects is essential to assess overall production efficiency.
**10. How do they store materials?**
The air in China can be very humid and hot, so when components or PCBs are released from storage, they are often vacuum-sealed with silica gel packs to prevent moisture absorption. This is done to prevent oxidation, which could damage the components over time.
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