As shown below, this product is used at the dock to detect the draught of the ship according to the water fluctuations. Smaller freighters need 4-6 units roughly, others need more. This PCBA has tended to mature in mass production.
But recently we communicated with our customers and they found a problem. When they tested the products, they found that 8 of them were short-circuited in 500 units. The customer analyzed all the possibilities and also let our technical cooperation help to discuss whether it is possible of our product problems.
8 PCBA Products Problem
After the video conference with customer, we found that the customer placed the product directly in the metal tube, which causes the solder joint of the plug connects to the metal tube directly, maybe the short circuit is coming from here. The customer is very confused, he thinks that the product has been coated with the glue, and it is already insulated. When he asked this question, we found the crux.
The glue for coting has another name “Three anti-paints”, as the name suggests, only prevent 3 kinds: waterproof, moisture-proof and anti-corrosion. The three anti-paints are not insulated, and the solder joints of the inserts are particularly sharp as shown in the figure below, so that the contact with any hard things will knock off the top painting, no matter how thick the glue is.
After the customer understands the reason, immediately rectify the product and add an insulating mat to the contact part to prevent short circuits.
The accident was mainly caused by the designer’s design of the PCBA three-coating step, and did not discuss the assembled performance with the entire project team. Short circuit occurs when test the actual finished PCBA product. Although the customer is very grateful to us for helping to find out the problem, we are also very embarrassed. This also gives our company a wake-up call, if we knew the product usage environment in advance, we will inform the customer in advance about what may happen, then perhaps avoid this problem.
Later we discussed why these 8 blocks will have a short circuit. First of all, these 8 products are already test articles in one and a half years ago. It has no problem to put the normal product for so long, and this product is also glued. But why this only happens on these 8 products?
Analyze the Possible Reason
Our company sent technicians to the customer shop to find the answer. When he saw the warehouse where the customer stored the goods, he pointed out many possibilities:
1. The PCBA is stored in theentire environmentthat does not conform to the specifications, not dry and without ventilation environment.
2. The storage temperature and humidity is not met required for electronic products .
3. The product is exposed to the outside without any dustproof measures.
4. There is no anti-static measures for all working equipment in the workshop.
5. Workers are in direct contact with the product without gloves when they come into contact with the product.
Therefore, it is very likely that the quality of these 8 products cannot be guaranteed, because the storage environment does not meet the standards. And the product has been placed for more than 1 year.
Our company has proposed the following rectification plans:
1. The annual consumption is not very large. It is indeed necessary to place orders for two years in advance at the beginning of the year. This is not conducive to the control of product quality. Therefore, customers can give us the annual plan, we will produce in batches according to the plan, reduce the customer’s inventory, and also avoid the impact on product quality such as improper storage.
2. The environment in customers store products is not ideal, so our company will customize the packaging box according to the customer’s products. This way, customers can use it when they receive the product. Each box is sealed, dustproof and anti-static, which greatly maintains the stability of the product.
After we raised these issues, our customers also deeply understood the professionalism of our company. They also very grateful for the valuable comments we have made.