What is CNC machining boring? CNC machining boring means expanding or refining the original hole on the workpiece. The CNC machined boring feature is to correct the eccentricity of the lower hole and obtain the precise hole position, achieving high-precision roundness, cylindricity and surface finish. Therefore, boring is often used in the final process.
Compared with other mechanical processing, CNC machining boring is a difficult process. It only needs to adjust a blade (or blade seat) to process micron-sized holes such as H7 and H6.
What are the characteristics of CNC machining boring machining?
1, tool rotation
Different from CNC machining and lathe machining, the machining center can not control the tool tip in the process of machining because of the tool rotation. It is also not possible to change the machining diameter just by adjusting the numerical control button like a CNC lathe. This has become a big obstacle to fully automated processing. It is precisely because the machining center does not have automatic processing of diameter adjustment function (except U-axis function), the file must have a fine-tuning mechanism or automatic compensation function. .
In addition, since the outflow direction of the chip is constantly changing during the boring of the machining center, the cooling of the blade tip, the workpiece, and the discharge of the chip are more difficult than when the lathe is being processed. Especially when the blind hole rough machining of steel is performed by a vertical machining center, this problem has not been completely solved yet.
2, bullet knife
The most common and most troublesome problem in boring machining is the spatula. The following are the main reasons for the occurrence of a spatula on a machining center:
1 The rigidity of the tool system: including the rigidity of the shank, boring bar, boring head, and intermediate connecting part. Because of the cantilever machining, especially the machining of small holes, deep holes, and hard workpieces, the rigidity of the tool is particularly important.
2 Dynamic balance of the tool system: With respect to the rotational axis of the tool system, the tool itself has an unbalanced mass, which causes flutter to occur due to unbalanced centrifugal forces during rotation. In particular, the tool's dynamic balance during high-speed machining has a great influence.
3 The fixed rigidity of the workpiece itself or the workpiece: For example, some small and thin parts cannot be fixed with a reasonable fixture due to their own insufficient rigidity or due to the shape of the workpiece.
4 Blade tip shape: The cutting force generated by the blade's rake angle, flight angle, nose radius, and chip flutes shape is also different.