Rounded corners milling process of research and application
Peripheral milling is made by milling cutter with circular week to movement of a cylindrical surface milling technology, in recent years, because of the machining center and cutting tool manufacturing technology progress, promote the development of the milling process and a wide range of applications.
At present, the use of the circumference of the milling principle, has been widely used in () slot inside hole milling, milling, milling thread, chamfering, milling ring end face and the milling sink hole and a variety of different processing tasks (figure 1).
Owing to the peripheral milling process is characterized by a high machining efficiency, with other processing technology using range and composite etc, make the circumference of the milling process in industrial production, especially in the automotive industry to obtain the more and more applications.
Figure 1: peripheral milling process is used for a variety of processing tasks
To achieve the circular week to movement of the cutter is the precondition of peripheral milling conditions, on the CNC machining center, as well as by X axis and Y axis of the circular arc interpolation to realize the cutter circular week for sports, but can be by X axis and Y axis and Z axis helical interpolation to realize the milling spiral feed movement, and through the CNC program to achieve a variety of peripheral milling process. At present, with high precision nc system driven by linear motor dynamic machining center can not only reduce the circumference of the milling time, and improve the peripheral milling machining precision, which can be through peripheral milling machining instead of boring and by drilling and milling thread instead of the traditional tapping.
Application of peripheral milling process of milling hole, basically can be used two ways and two types of cutting tools. One is used on the cylindrical blade grinding helical blade circumference of the milling cutter or arranged on the cylindrical blade tangential multiple indexable insert the circumference of the milling cutter, this kind of tool is generally used in shallow hole processing, milling hole, spindle milling around the Z axis for circular week to exercise. Another is to use a round diamond blade or rectangular blade multifunctional vertical milling cutter, such tools can be used for processing is not more than five times the diameter deep hole, hole milling, vertical milling cutter for the spiral feed movement, the processing center of the X axis and Y axis and Z axis linkage (that is, three axis helical interpolation motion).
Use the first method when milling hole, hole machining of cylindrical degree mainly depends on the geometry precision of milling cutter manufacturing. For precision machining hole shape, whether it is what a kind of tool for milling hole, mainly depends on the interpolation precision of numerical control system. And processing the surface roughness of the hole and the precision of the cutting tool and cutting parameters related to the selected.
Figure 2 is a multifunctional vertical milling cutter in milling hole sketch. When milling hole, end mill around the Z axis of rotation screw feed movement, work in a travel needed for milling of the size of the hole. Processing, for example, the hole diameter of 285 mm, 160 mm diameter can be used in the vertical milling cutter, without a need for knife through a work schedule the processing tasks can be completed. Than the traditional boring process can save five reaming process, which greatly simplifies the processing technological process, and can save 73% of the processing time.
Peripheral milling process, both for rough machining and finish machining can be realized, for the blind hole can also milling flat bottom hole, the ladder hole or cone hole, and can also be in the bottom of the hole bottom on the circumference of the circumferential surface milling.
Milling holes always adopt milling cutter, the boring cutter and usually adopt the single blade, compared to the boring process of milling holes can be used to a larger quantity of turning, and milling hole has the very high machining efficiency, and even in the intermittent milling hole also won't produce a shaking of the milling cutter.
At present, driven by linear motor in high speed machining center, the application of peripheral milling process to 40 m/min the feed speed of processing of automobile engine gearbox SUNTHAI bearing hole, hole roundness can be up to 6 microns. Due to such good machining precision, it can completely removed from subsequent finishing process.
Using the peripheral milling principle for milling screw hole and screw thread of drilling and milling, thread of drilling and milling process can not only simplify the production process, and can greatly shorten the processing time.
Application principle of peripheral milling machining threaded hole, either in the pre-process of tap milling thread, can also be in the absence of advance work out tap a threaded hole drilling and milling on solid materials.
Milling can often be with screw hole drilling, chamfering and economic screw hole convex face associated processes such as composition, which is some functions will be associated with threaded holes on the surface of the processing and focus on a tool, using a threaded composite cutting tools for integrated processing of drilling and milling, this not only can reduce the amount of cutting tool, and greatly shorten the processing time. At present, the thread of drilling and milling process has been widely used in engine gear case, clutch shell and cylinder head and other parts of fastening screw hole processing, for example, USES the thread of drilling and milling cutter machining cylinder head on the M6 screw hole depth of 14.1 mm, the spindle speed 20000 r/min, under the condition of feeding of 700 mm/min, a screw hole machining time just 1.2 seconds. In a cylinder head on the flexible production line of high speed machining center, using such a thread compound of drilling and milling cutter, in more than one processing 120 M6 screw hole on cylinder head is less than 3 minutes.
