Analysis of the Causes of the Pressure Pointer's Follow-up When Adjusting the Memory Pointer
The pressure gauge with memory means that the instrument has two pointers, one is the indicator needle of the pressure gauge, which is the active needle; the thermal resistance is the memory pointer, which is the driven needle. At the beginning, the two needles overlap at the zero position. When the meter is pressurized, the two needles run at the same time; when the pressure is relieved, the black pressure needle returns to the zero position, and the co-color memory needle stops, indicating the meter Maximum pressure at work. So this kind of instrument is called a memory gauge or a pressure gauge with memory needle.
When the user checked a batch of memory meters, it was found that the meter with a lot of digits, when the memory needle is rotated, the pressure pointer also moves, and when the meter is pressurized again, the pressure pointer appears to be stuck or skipped to different degrees. , The user is particularly dissatisfied and thinks that this batch of watches will be sent without inspection. However, the manufacturer believes that all instruments are inspected by stainless steel pressure gauges before they are transferred to packaging, storage, and delivery.
Since the delivered meters cannot meet the expected use requirements, the user has to return all the meters. When the manufacturer conducted an anatomical inspection of this batch of meters, it was found that the lower end of the connecting part of the memory needle was pressed against the needle library of the pressure gauge indicator needle to varying degrees. The stainless steel pressure gauge caused the two needles to interfere with each other. When the memory needle was rotated , Rubbing against the pressure needle, when pressurizing, the memory needle hinders the normal operation of the pressure gauge.
Because the instrument is inspected one by one before leaving the factory, this situation should have been discovered during the inspection, but why hasn't it been found out?
After analyzing the reasons, we found the following two points:
1. One of the problems lies in the design of the product. Since the product is modified on the basis of the original ordinary pressure gauge, most of them are borrowed needles, and there is not enough gap between the pressure gauge pointer and the memory pointer. , In this way, when the inner hole of the needle library is slightly smaller or the thimble is slightly higher, the two needles will interfere with each other.
2. The second problem arises in the finished product inspection procedure. According to the requirements, the finished product inspection should be the final inspection. Check the qualified form. Apart from the packaging, there should be no other work. Thermal resistance However, due to some reasons, this batch of meters is first checked for indication, then the glass and cover of the watch are placed, and then directly transferred to the packaging. In this way, the problems that should have been discovered in the finished product inspection are missed.
