Lubrication Systems and Cooling Devices
All of the device tools has two diverse systems, one for refrigeration and one more for lubrication. The lubrication system itself tends, in general, quite intricate and involves a combination of different procedures, as we shall see.
The cooling system is autonomous of the previous and focuses primarily on the cooling of the cutting tool or tools. It has a blocked circuit circulation of liquid refrigerant recovery comprising tray,
reservoir, rigid pipes, hoses, flow regulators and pump. The cutting fluid also serves as a lubricant to Minimize friction in the machining process.
Lubricating System
The lathe lubrication system is designed to ensure a specified amount of lubricant, appropriate for each element, among the different mechanical parts that are formed. Various of the essential elements that need to oil are guides to the bench or tree bearings and bearings and shafts.
The procedure used for lubrication and lubricant selection depends on the explicit characteristics of the organ or mechanism, in particular the relative speed of work, the highest heat specified and the position in the whole instrument. Consequently, while the gearbox is ordinarily lubricated by partial immersion in an oil bath and splash, the lubrication bearings are located, either through an secondary duct bearing lubricant, either through what is called "self-lubricating" which requires a special assembly.
The localized lubrication of bearings and axle bearings requires a circuit design that incorporates a gear pump, besides the canals and pipes needed. Other elements, such as guides and ball screws are lubricated carts manually using a dispenser or oil.
Cooling System
Investigations developed in the late nineteenth century (Taylor and others) showed that the cooling and lubrication of the tool improves cutting conditions. Evidently, in a machining operation, which produces metal removal under precise cutting conditions (depth in passing, cutting speed, feed rate) a process of plastic deformation is showed previous to fissure, which generates a lot of warm up, equivalent to the deformation work. However, the heat intensification at the tip of the tool can turn into unusable in a few seconds of work. However, this circumstances involves a unsustainable cost in frequent replacement of tools with a lousy quality finish of the machined surfaces, and it is needed a guaranteed amount of refrigerant which must be supplied continuously and whose course is directly dependent on the conditions of the cutting process and supplies of the tool and the workpiece.
Not so obvious is that lubrication is beneficial to the cutting process. Indeed, in the initiation as in the progression of the cut, the tool must overcome a quantity of internal resistance in the material to be machined by consuming some power. In addition, contact and the existence of relative action among two materials of diverse rigidity are inherent to the process. It is clear that the action of a lubricant film will reduce friction and, consequently, the deformation work and the overall power necessary. The presence of the lubricant will get also lessen the tool wear (edges and angles of cut) and lengthen its life. It is eminent that friction reduction represents a decrease of the Heat reached during the cutting process, thereby improving the efficiency of the cutting fluid as a coolant.
To prevent loss of fluid in the circuit, the lathes are built with a movable protective cabs, preventing at the same time that chip projections touch the operator of the machine.