The effective monitoring of the multi-stage process in the modern manufacturing and service processes is crucial in maintaining and improving the final output quality. The essential of the multi-stage process monitoring is to be able to give a signal at each single stage in order to avoid the delay in detecting assignable causes in the process. A multi-stage process is separated to a series of the single-stage processes, and each single-stage process is treated as a profile structure, whose quality is considered as the process output with inputs from the previous stage and the current stage. The EWMA chart is implemented to the profile process using the orthogonal design input. The true process output is often measured with errors because the complexity of the multi-stage process makes the true quality difficult to measure. The harmfulness of measurement errors in the multi-stage process is also investigated.

在现代制造和服务流程中，有效监控多阶段流程对于维持和改善最终输出质量至关重要。多阶段过程监视的本质是能够在每个单个阶段发出信号，以避免在过程中发现可分配原因的延迟。一个多阶段过程被分为一系列的单阶段过程，并且每个单阶段过程被视为一个概要文件结构，其质量被视为具有前一阶段和当前阶段的输入的过程输出。使用正交设计输入将EWMA图表用于轮廓过程。由于多阶段过程的复杂性使真实质量难以测量，因此真实过程的输出经常会出现误差。