On the basis of scrap metal recycling, the shredding process transforms a large variety of objects composed predominantly of steel in crunched scrap. The main equipment used in this process is called shredder: a device consisting of several hammers attached in a horizontal rotor. Due to high efforts involved in the transformation process, the maintenance is an essential aspect to ensure the continuity of the shredder operation. A non-efficient maintenance policy can have negative consequences for the shredder performance, whose failure can stop all downstream processes for which it provides the basic input (crunched scrap). In order to improve the performance of the steel production line, we are introducing an opportunistic inspection policy that makes use of the crushed scrap buffer level. The policy guides the execution of an inspection after a time T of continuous operation, when the system fails, when the buffer is full or empty, or when the opportunity criterion (operation time ≥ t AND buffer level ≥ h) is verified, whichever occurs first. At an inspection, the shredder is stopped, the hammers are inspected, and the failed and defective ones are replaced by new units. A discrete-event simulation model was developed and applied to the context of a real steel production line of a company. The optimal opportunistic inspection policy was obtained, and its performance was compared with that of the policy currently adopted by the company. The results showed the possibility of obtaining significant economic savings. A sensitivity analysis showed a cost reduction of around 95 %.

在废金属回收的基础上，粉碎过程将大量主要由钢组成的物体转化为碎屑。此过程中使用的主要设备称为碎纸机：一种由连接在水平转子中的多个锤子组成的设备。由于改造过程涉及大量工作，因此维护是确保碎纸机运行连续性的重要方面。非有效的维护策略会对碎纸机的性能产生负面影响，其故障可能会停止为其提供基本输入（碎屑）的所有下游流程。为了提高钢铁生产线的性能，我们正在引入利用破碎废料缓冲水平的机会主义检查政策。T连续操作，当系统出现故障时，当缓冲区已满或空时，或当机会标准（操作时间≥ t AND 缓冲区水平≥ h）被验证时，以先发生者为准。在检查时，粉碎机停止，检查锤子，用新单元更换失败和有缺陷的单元。开发了离散事件仿真模型，并将其应用于一家公司的真实钢铁生产线。得到了最优的机会主义检查策略，并与公司目前采用的策略进行了性能比较。结果表明有可能获得显着的经济节约。敏感性分析显示成本降低了约 95%。