I would like to report to you the following quality issues we have experienced with the most recent A189 batches made in your China plant.
1. Using the batches made in Thailand as a bench mark, the first few batches that came from your China plant were virtually the same.
2. However, after a few batches, we started to see very large variation of measured focal length values within each box.
3. With some recent batches we’ve received, we noticed that the spread has increased toward the lower end. We’ve seen around 8-10 lenses out of each box (132/box) with extremely low focal length values, making the lenses not usable by our process.
4. For the focal length numbers, we can only measure the relative numbers. With the Thailand and first few China batches, the relative focal length ranged 73-92 mm. However, the later batches from China ranged from 70-110 mm. The more recent batches ranged from 50-110 mm.
Could you please check with the factory on why there is such a large variation of focal length value within a box? Why the range of focal length has increased? How do you control your process to ensure that focal length variation is within range?
This is a serious matter. Your immediate attention is highly appreciated.