The plant maintenance department is responsible for making sure that all machines are running properly, such that workers are safe and that the plant can perform its function efficiently. The department makes periodic fixes and upgrades to all machines and equipment, and it might also perform janitorial and grounds services.
Manufacturing plants are typically very complex systems that rely on the efficient work of many different parts. The parts of the plant include all of the workers and staff, and the manufacturing machines themselves. While the administration of the company is typically responsible for maintaining the effectiveness of the workers, the machines themselves often need periodic repairs and changes for the plant to run effectively.
Most manufacturing plants have some sort of maintenance department to oversee the functionality of the machines and building itself. The department will make routine fixes to machines, making sure that they are safe and perform their function. Similarly, if a machine breaks down then it is up to the maintenance department to fix the machine in a timely manner. Along with the continual upkeep of the machines, the maintenance staff might also be responsible for the building's facilities, such as bathroom and kitchen repair and upkeep, and also grounds work.