That day, the manager's face went pale with dread, because the customer's complaint concerned goods already shipped overseas.
I still remember an incident a few years ago when a customer called, extremely aggressive, saying they had received a batch of goods with several defective items that were not only unusable but also jammed their machinery. The key issue was that the batch number they provided couldn't be found in our system! I was completely dumbfounded at the time, repeatedly confirming with the production line, and everyone was adamant, saying, "Our production batch numbers are all clear, how could they not be found?" After much investigation, we finally discovered that a new engineer had randomly entered a batch number into the system, turning that batch of goods into "orphans" that were untraceable after leaving the factory. The manager's face went pale with dread, because that batch of goods had already been shipped overseas—how could they be recalled?
So the key question is, do your batch numbers have a "household registration booklet"?
To put it simply, this is a traceability system design problem, specifically concerning batch number management. Many people think, isn't it just assigning a number to a product? What's so difficult about that? But if you think carefully, when a defective product appears, can you immediately find out on which day, which machine, using which batch of raw materials, through which processes, and by which operator this defective item was produced? If you say, "Hmm... I probably know," then congratulations, your traceability system is likely only 30% effective.
In other words, a batch number is not just a number; it's a "household registration booklet." You must ensure that every product, from incoming material to outgoing shipment, carries its batch number like an identity card number. When a customer complains that DPMO has soared to 6210, or worse, the CPK report shows only 1.08, you must be able to narrow down the scope and pinpoint the problem in the shortest possible time, rather than searching for a needle in a haystack.
How to do it in practice? Make your batch numbers "meaningful."
At the very least, your batch number design must contain sufficient information. I would recommend including at least:
- Production Date: YYMMDD, e.g., 240520.
- Production Batch: The sequence number of the batch produced on that day, e.g., 01, 02.
- Machine Information: Which machine produced it, e.g., A01, B05.
So, a complete batch number might look like this: 240520A0101. This is just the simplest form. If you need more detailed traceability, such as adding raw material batch numbers or operator IDs, then layer that information on top.
More importantly, these batch numbers must "span" the entire production process. From incoming material, production, testing, packaging, to final shipment, this batch number must be used for recording. Data from each station must be linked to this batch number. For example, a batch of raw material with part number 123456 is assigned batch number RM-240519-001 upon arrival. When this raw material is fed into production machine A01 and combined with products assigned batch number 240520A0101, the system must record, "Products with batch number 240520A0101 used raw material RM-240519-001." This way, when you discover a problem with the finished product, you can directly trace it back to specific raw materials.
The most common pitfalls: Human error and the "good enough" mentality.
To be honest, the biggest pitfall I've encountered is "human error." The most common is what I mentioned earlier: operators randomly entering batch numbers into the system, leading to incorrect information. Or, changing materials but forgetting to update the batch number record; changing machines but still using the old machine's batch number. These small "good enough" mentalities accumulate into a major disaster.
Frankly, many times we design systems perfectly, but implementation is compromised due to busyness, fatigue, or unfamiliarity with the process. Another common issue is "batch number overlap." For example, different product lines use similar batch number rules, and when checked in the database, two completely different products are found to have the same batch number—that's truly beyond tears.
Therefore, in addition to system design, training and regular audits are indispensable. You need to ensure that every participant understands the importance of batch numbers and knows how to operate correctly.
One thing you can do today
Open your traceability system and randomly check 5 batch numbers to see if you can fully trace them back to the incoming material.