Selection principle
The basic principle of determining the three elements: according to the cutting requirements, first determine the amount of back eating tool, then check the table to get the feed, and then calculate the main cutting speed through the formula through the table.
In many cases, empirical data can be used to determine the value of these three elements.
Choose a method
Practice has proved that the choice of reasonable cutting amount is related to various factors such as machine tools, tools, workpieces and processes. The method of reasonable selection of processing amount is as follows:
(1) When rough machining, it is mainly necessary to ensure high production efficiency, so a larger back eating tool quantity, a larger feed, and a cutting speed U should be selected at medium and low speed.
(2) When finishing, the main requirements of the size and surface accuracy of the parts are guaranteed, so a smaller back feed is selected, and a higher speed is selected for the cutting speed.
(3) When roughing, it is generally necessary to give full play to the potential of the machine tool and the cutting capacity of the tool. When CNC lathe factory semi-finishing and finishing, we should focus on how to ensure the processing quality, and on this basis, try to improve productivity. When choosing the amount of cutting, the CNC lathe factory should ensure that the tool can process a part or ensure that the durability of the tool is not less than one working shift, and the working time of at least half a working shift. The specific value of the CNC lathe factory should be selected according to the provisions in the machine tool manual, the durability of the tool and the practical experience.
The selection of the amount of back eating cutter: The selection of the amount of back eating tool should be determined according to the stiffness of the machine tool, fixture and workpiece, as well as the power of the machine tool. If the process system allows, choose the largest amount of back eating knives as much as possible. In addition to the allowance left for later operations, the rest of the roughing allowance is removed as much as possible at one time to minimize the number of passes.
Usually on medium-power machines, the back-eating amount for roughing is 8~10 mm (one side). CNC lathe factory semi-finishing back knife amount is 0.5 ~ 5 mm, finishing time back knife amount is 0 2 ~ 1.5 mm.
Determination of feed: When the quality requirements of the workpiece can be guaranteed, a higher feed rate can be selected to improve productivity. When CNC lathe factory cuts, turns deep holes or finishes turning, it is advisable to choose a lower feed speed. The feed speed should be adapted to the spindle speed and the amount of back eating knife. In roughing, the choice of feed is limited by the cutting force.