1. PR: 预生产（Pilot Run）2. PP: 试产（Pilot Production）3. MP: 批量生产（Mass Production）4. MR: 没有在常见的产工备料缩写中找到与"MR"对应的准确含义。可能需要更多的上下文来确定其具体意义。
1. PR: Pre-production Run 2. PP: Pre-production Production 3. MP: Mass Production 4. MR: The abbreviation "MR" is not commonly associated with production and material preparation. Additional context is needed to determine its specific meaning in this context.
MP mass production 正式批量生产