When milling the hole by the first method, the cylindricity of the machined hole depends mainly on the geometric accuracy of the milling cutter. Regarding the shape accuracy of the machined hole, no matter which tool is used for the hole milling, it is mainly determined by the interpolation accuracy of the numerical control system. The surface roughness of the machined hole is related to the accuracy of the tool and the selected cutting parameters. A drill-and-thread complex tool can be used to machine tapped holes with the same pitch and different diameters, as well as milling left- or right-handed threads and through-hole or non-through-holes. Since the cutting of the thread produces short chips, the chip jam does not occur. Also, since the drilling and milling threads are completed in one working stroke, the thread bottom hole is precisely concentric with the thread and the precise thread depth is ensured. Previous Next Led Underwater Light,Waterproof Underwater Light,Uv Casing Led Light,Custom Led Underwater Light Guangzhou Qshine Pool Lights Manufacture Co., Ltd , https://www.qshinepoollight.com
Figure 2 is a schematic view of a milling hole using a multi-function end mill. When milling the hole, the rotating end mill makes a spiral feed motion around the Z axis, and the hole of the required size is milled in one working stroke. For example, to machine a hole with a diameter of 285 mm, a 160 mm diameter end mill can be used to complete the machining task with one working stroke without changing the tool. This saves five reaming operations compared to the traditional boring process, which greatly simplifies the machining process and saves up to 73% of machining time.
The circumferential milling process can be used for both roughing and finishing. For non-through holes, flat bottom holes, stepped holes or tapered holes can be milled, and circumferential milling of the circumferential surface can also be performed on the bottom surface of the bottom of the hole.
Milling holes are always achieved with multi-blade milling cutters. Compared with the boring process, which usually uses a single-edged boring tool, the milling hole can use a larger amount of back-feeding, so the milling hole has high processing efficiency. And the milling cutter does not vibrate even when the intersecting holes are intermittently milled.
At present, in the high-speed machining center driven by a linear motor, when the circumferential milling process is applied to the bearing housing hole of the automobile engine gearbox at a feed speed of 40 m/min, the hole roundness can reach 6 μm. Due to such good machining accuracy, this eliminates the need for subsequent finishing operations.
Milling tapping and drilling and milling threads can be performed using the circumferential milling principle. The drilling and milling thread process not only simplifies the production process, but also greatly reduces the machining time.
When the threaded hole is machined by the principle of circumferential milling, the thread can be milled on the pre-machined threaded bottom hole, or the threaded hole can be drilled and drilled on a solid material without pre-machining the threaded bottom hole.
Milling screw holes can often be combined with the associated processes of drilling, chamfering, and boring boss end faces, that is, the machining of some functional surfaces associated with the threaded holes is concentrated on a tool, using a drill Milling threaded composite tools for comprehensive machining, which not only reduces the number of tools, but also greatly reduces machining time. At present, this drilling and milling threading process has been widely applied to the machining of screw holes for parts such as engine gearbox, clutch housing and cylinder head. For example, drilling and milling thread cutters are used to machine M6 tapped holes with a depth of 14.1 mm on the cylinder head. In the case of a spindle speed of 20000r/min and a feed rate of 700mm/min, the machining time of one screw hole is only 1.2 seconds. In such a high-speed machining center of a cylinder head flexible production line, it is less than 3 minutes to process 120 M6 tap holes on a plurality of cylinder heads using such a drill-and-mill thread compound tool.
Jel Precision Tooling uses a drill-and-thread complex tool to machine the screw holes in the gearbox fastening holes. The gearbox body is made of aluminum alloy castings. The cutting edge of the composite tool is welded polycrystalline diamond with a spindle speed of 20000r/min. When machining, the drilling and milling thread compound tool is carried out in sequence: drilling 22.5mm thread bottom hole - circumferential milling M24X1.5 screw hole - removing the burr at the screwing point - the reverse 锪 outer diameter is 24.5mm and the opening angle is 90 Chamfer of ° - Threaded boss with 锪 36 mm outer diameter - 1X45° inside and outside chamfer on threaded boss and tapped hole. Since all functional surfaces are machined by a single tool on a single machine, this not only eliminates many related tools and tool change processes, but also improves machining accuracy and machining time (only 4 for the entire machining process) Second), which greatly increases production efficiency. 
Figure 2: Milling holes with an end mill
Research and application of fillet milling technology (2)