Is it true that "nothing has changed"?
When there is a problem with production, the most common phrase said by production staff is "I haven't changed anything, why is today's production abnormal?" Is it true that "nothing has changed"? 
There are many factors in production. To make sure that nothing has changed, we must first make sure that each link has detailed and quantified process parameters, and secondly, make sure that the operators operate completely according to the parameters.
Formulating detailed and quantified process parameters is not a simple task. The parameters we can pay attention to are often not comprehensive. For example, when setting the parameters of the hot air oven, we only set the quantified temperature parameters, but not the quantified air volume parameters and the relative humidity of the air. In fact, the three major factors that affect the drying speed, temperature, air flow, and relative humidity of the air, each of which will affect the drying efficiency. When the temperature remains unchanged, but the air volume and air humidity change, the effect is different, and at this time, the operator often says "nothing has changed". Therefore, we should not easily say "nothing has changed". If we want to have stable production, we must spend a lot of time and energy to improve our process parameter table and strictly implement it in production operations so that every influencing factor can be effectively controlled. Jim He