In CNC machining, we often hear "turned parts". What does the turned part mean?
Turning parts, in a nutshell, are a kind of parts processed by CNC lathes on the lathe surface. It is through the rotation between the workpiece and the straight line between the tool or curve movement to change the shape and size of the blank to meet the requirements of the drawings.
Turning is one of the most common cutting methods. It is suitable for machining most workpieces and can achieve high precision. There are many types of turning parts, hard turning being best known for its high thermal stability and most widely used. Then let's take a closer look at the next hard turning.
Choosing a reasonably hard turning system can reduce or even eliminate the high cost and processing time, while achieving high accuracy and maximizing equipment utilization. Therefore, we must consider the following factors when choosing a reasonable turning piece:
1. Coolant. No coolant cutting has a cost advantage, but in continuous cutting, the coolant can improve the smoothness of the surface while prolonging the life of the tool, and the use of coolant is based on water. Takes away most of the heat during the cutting process, protects the machine and also avoids operator burns.
2, whitening layer. Also called heat-affected zone, in the cutting process, due to excessive heat transfer to the part, the whitening layer is often formed on the bearing steel, so the operator should randomly check to determine how many parts each blade can turn without forming Whitening layer.
3, machine tools. The stiffness of the machine tool largely determines the machining accuracy of hard cutting. In order to keep all parts as close as possible to the turret tool holder system, it is important to minimize hangs, tool extensions, and extension of parts and to eliminate strips and washers.
4, the thread. The use of a suitable blade is the key, and the best is a triangular blade. Properly increasing the number of passes and reducing the depth of cut, while using alternative side cuts, can control cutting forces and extend tool life.
5, the workpiece. The part that is best suited for hard turning has a small aspect ratio (L/D). Generally speaking, the L/D ratio of an unsupported workpiece is not greater than 4:1, and the L/D ratio of the supporting workpiece is not greater than 8:1. Although the slender parts have tailstock support, knife vibration may still occur due to excessive cutting pressure. In order to maximize the rigidity of hard turning systems, overhangs should be minimized. The tool extension must not be greater than 1.5 times the height of the tool holder.
6, bore hole. Cutting hardened materials requires large cutting pressures, so the torque and tangential forces to which the boring bars are subjected are often increased several times. With a positive rake angle (35° or 55°), a small tip radius blade can reduce cutting pressure. Increasing the cutting speed while reducing the depth of cut and the feed rate is also a way to reduce the cutting pressure.
7, process. Since most of the heat generated by hard turning is carried away by chips, inspection of the chips before and after processing can reveal whether the entire process is coordinated. In continuous cutting, the chips should be flaming yellow orange and flow out like a ribbon. If the chip is cooled after it is cooled by a pressure, the amount of heat removed by the chip is normal.