The three main reasons machine tool sumps need to be cleaned are unwarranted tool wear and/or poor part finish, poor or no coolant flow to the tool, and stench or skin irritation
Poor or no coolant flow, unwarranted tool wear, and poor part finish can be caused by excessive solid particulate in the sump. The solid contaminants not only add to bacteria and fungi issues but may stop production without notice if the machine tool pump stalls or a tool becomes worn or chipped too soon. Excessive solids in the sump reduces the coolant volume which in turn increases the coolant temperature and reduce its effectiveness.
The Monday morning stench and/or skin irritation is caused by bacteria and fungi. When a sump gets this bad it requires the entire machine to be cleaned. This includes the sump, the pump, coolant lines, conveyors, etc. It will also require the coolant to be discarded. Proper coolant concentration and pH controls will help keep these bugs at bay. Periodic cleaning of the sump will remove their food source; tramp oil and solid contaminates and help extend the coolants life.