1. 纠正性维护(CM)：
CM 是一种维护任务或操作，通常在设备故障后执行。它只是将故障或损坏的资产恢复到其正常工作状态的所有活动。它本质上是反应性的。每当任何资产出现故障时，都会对其进行更换、修理或恢复其可操作性。
2. 预防性维护(PM)：
PM 是一种维护任务或操作，通常在设备故障之前执行。它被简单地视为所有维护资产并防止其发生故障或崩溃的活动。它本质上是预防性的。
CM 和 PM 的区别：
| Corrective Maintenance | Preventive Maintenance |
|---|---|
| CM is performed after asset failure or after anything goes wrong. | PM is performed before asset failure or before anything goes wrong. |
| It is less complex and simple process because it does not involve any planning to prevent asset from failure. | It is more complex as compared to CM because t involves planning to prevent assets from failure. |
| It can be more expensive than PM as some equipment failure causes greater damage to system. | It can be expensive but it prevents assets from failure. |
| It can affect overall system as some assets failure can cause greater loss in production. | It prevents loss in production by reducing chances of failure occurrence. |
| CM leads to expensive repairs along with unscheduled repairs. | PM mainly aims to avoid expensive repairs and corrective actions. |
| It is performed at random intervals as it is only performed when a failure occurs. | It is performed at regular intervals as asset maintenance is important and should be checked regularly to avoid any failure occurrence. |
| CM generally increases need for assets preventive actions. | PM generally decreases need for corrective actions. |
| CM overall decreases lifecycle of assets. | PM overall increases life cycle of assets. |
| This process results in loss of production, loss of product quality, loss of time. | This process leads to increase in production, increase in product quality, no loss of production time. |
| It is not better for safety of employees and working environment as it increases risk of injury. | It is better for safety of employees and working environment as it reduces risk of injury. |
| Downtime of assets is more in CM. | Downtime of assets is less in PM. |
| It requires a greater number of employees or technicians to perform CM. | It requires a smaller number of employees or technicians to perform PM. |
| It increases workload for technicians. | It decreases workload for technicians. |