preliminary pressure meaning in English

初压
预压力

It advances that the non - lapping envelope region is a major fact of generating roundness errors and inquires into the effects of ball roundness with non - lapping envelope region , preliminary pressure error and lap tool wear
根据四研具体对球面研磨的包络原理，提出了未包络研磨区是产生残存圆度误差的主要因素，并探讨了未包络研磨区、四研具初始压力误差、研具磨损不均匀性产生的原因和对研磨残存圆度误差的影响及解决措施。