The successful realization of Industry 4.0 depends much on how coherently the cyber and physical realms are conjoined in cyber-physical systems. In the context of the fourth industrial revolution, research efforts have mostly been channeled toward the cyber domain, whereas the physical domain has received significantly lesser consideration. A physical domain generally comprises material shaping equipment, work material, tools, working medium, sensors, automation technology, and connectivity mechanisms. The article provides a comprehensive review of the published literature to establish the states of readiness of the two most important manufacturing technologies: subtractive and additive and their sustainable merger from the perspective of Industry 4.0. Rich potentials in the four characteristics at the process level: speed, sustainability, agility, and customer centricity and three at the system level: connectivity, data collection, and automation are required for a manufacturing system (physical domain) to be Industry 4.0 compatible. The review establishes that the subtractive manufacturing domain is nearly compatible regarding speed and agility but needs improvements in respect of sustainability and customer centricity. Additive manufacturing, on the other hand, appears strong on agility and customer-centricity fronts but needs amelioration regarding production speed and sustainability. In respect of the system level characteristics, both technologies seem to be compatible regarding automation, whereas significant improvements are required in connectivity and data sensing and collection. For the sake of raising compatibility levels of the manufacturing systems, subtractive-additive amalgamation is scrutinized. The amalgamation, especially in a done-in-one configuration, has, reportedly, succeeded to retain the favorable traits of the two manufacturing technologies, thus, bringing the merger much closer to the Industry 4.0 requirements. Proper process planning and optimal work distribution between the subtractive and additive modes are critical for operating an amalgamated system at high levels of the key characteristics.

工业4.0的成功实现很大程度上取决于网络和物理领域在网络物理系统中的结合程度。在第四次工业革命的背景下，研究工作主要集中在网络领域，而物理领域的考虑则少得多。物理领域通常包括材料成型设备，工作材料，工具，工作介质，传感器，自动化技术和连接机制。本文对出版的文献进行了全面的回顾，以从工业4.0的角度确定两种最重要的制造技术：减法和加法及其可持续合并的准备状态。在流程级别的四个特征中具有丰富的潜力：速度，可持续性，敏捷性，和以客户为中心，以及在系统级别上的三个：连接系统，数据收集和自动化是制造系统（物理域）与Industry 4.0兼容所必需的。审查确定，减法制造领域在速度和敏捷性方面几乎兼容，但在可持续性和以客户为中心方面需要改进。另一方面，增材制造在敏捷性和以客户为中心的方面显得很强大，但在生产速度和可持续性方面需要改善。在系统级别的特性方面，两种技术在自动化方面似乎都是兼容的，而在连接以及数据感测和收集方面则需要进行重大改进。为了提高制造系统的兼容性水平，仔细检查减法加法合并。据报道，合并，尤其是在多合一配置中，合并成功地保留了两种制造技术的良好特性，因此使合并更加接近工业4.0的要求。正确的工艺计划以及减法和加法模式之间的最佳工作分配对于在关键特性的高水平下操作合并系统至关重要。