Advantages of CNC machine tools __ Screw thread milling machining
First, as a thread milling using CNC machining thread method, first in Europe, the United States became popular. With the development of China's CNC machine tools, China also gradually accepted and loved by the majority of customers. Thread milling is the use of three-axis CNC machining center linkage function and G02 or G03 spiral interpolation instructions to complete the thread milling work.
With the progress of the times, the NC and medium-sized industry in China machinery industry used more widely, some large parts of the thread, the thread turning and traditional Taps, Dies has been unable to meet production needs. In CNC milling machines or machining centers are widely used today, the use of three-axis machine tools for threading, changing the method of processing threads, and achieved good results.
Second, spiral milling bore
1. The range of processing large aperture blind holes or through holes, since the twist processing is too slow or not working, often choose the helical milling mode. And because of the way the selected tool without bottom edge, so more suitable for small depths of cut, high-speed and high-feed processing conditions.
Helical Milling hole is built under the knife spiral method based on processing methods, helical milling hole has a characteristic: Z axis milling spiral every week, a movement of the tool under the knife height.
Thread cutter selection
Select the three edge 16mm indexable cutter, tool speed S = 3000r / min, feed rate F = 2500mm / min.
This approach is quite distinctive spiral milling bore, its essence is to write a program under the knife height as the height of the helix compiled a subroutine, the subroutine calls the spiral through the loop, complete milling entire hole.
The method of machining hole cutter specifications and other factors are not, so the CNC milling machines and machining center applications is ideal.
5. Application examples and programming
Parts shown in Figure 1, to processing thread M36 × 1.5mm hole through the bottom hole. First, calculate the thread M36 × 1.5mm
The bottom hole diameter: Nominal diameter -1.0825 × P (pitch) = 36-1.0825 × 1.5 = 33.75mm. Confirm the rough parts of the processing of 80mm × 80mm × 30mm steel 45, the selected tool is a 16mm three-flute indexable milling cutter, cutter rotational speed S = 3000r / min, feed rate F = 2500mm / min. Import arc point A (Fig. 2), established in 0A segment cutter compensation, the arc export point B, in 0B segment cancel cutter compensation. Reference programming as follows (referred to herein by reference to verification procedures are used in the FANUC system). The main program is as follows. % (Program starting delimiter) O0001; (main name) T1; (Tool for the
16mm end mill) G80G40G69 (cancel the canned cycle, the tool radius compensation and rotation command) G90G54G00X0Y0M03S3000; (initialization) G43Z50.0 H01; (1 Tool length compensation) Z5.0; (Fast moving point positioning) G01Z0F50; (workers into) G41D01G01X-6.875Y10.0; (D01 = 8.0, build up the knife segment 0A) G03X-16.875Y0R10; (arc imported R10) M98P100L16; (subroutine call O100, 16 times the number of calls) G90G03X-6.875Y-10R10.0; (finishing contour one week) G40G01X0Y0; (cancel cutter compensation)
G0Z50.0; (exit) M05; (spindle stop) M30; (End of program and return to the program header)% (end of program) subroutine as follows. % (Program starting delimiter) O100; (subroutine) G91G03I16.875Z-2.0F2500; (prepared using incremental coordinates, every week, running the tool is moved downward 2mm in the Z-axis direction) M99; (return to the main)% (program terminator)
By the method of machining the bore spiral under the knife, but it can also be processed in accordance with this programming ideas cylindrical workpieces.
Third, thread milling method has the advantage.
1, due to the current thread cutter carbide manufacturing materials, processing line speeds of up to 80 ~ 200m / min, and high-speed steel cone processing line speed of only 10 ~ 30m / min, it is suitable for high-speed cutting thread cutter, surface finish threading also greatly improved. High hardness materials and high-temperature alloys, such as titanium, nickel-based alloy thread cutting has been a more difficult problem, mainly because of the high speed steel cone threaded processing these materials, the tool life is short, and the use of carbide thread milling knife for hard materials processing thread is the effect of ideal solutions. Machinable hardness HRC58 ~ 62. High temperature alloy materials processing thread, thread cutter also shows very excellent processing performance and long life than expected. For the same pitch, different diameter threaded hole, using the multi-tap processing tools required to complete, but if the use of thread milling, a tool it can use. In the tap wear, after processing thread size less than the tolerance you can not continue to use, can only be scrapped; and when the thread cutter wear, machining threaded hole size is less than tolerance, it can make the necessary adjustment tool radius compensation by CNC system, we can continue processed qualified size threads.
2. Similarly, in order to obtain high-precision screw holes, with thread milling cutter radius adjustment method, than the production of high-precision tap much easier. For small diameter threaded processing, particularly high hardness materials and high temperature materials processing thread, tap sometimes broken, plug screw holes, and even scrapped parts; with thread cutter, because the tool diameter is smaller than the hole machining, also break even not clog screw holes, very easy to remove without cause parts scrap;
3, the use of thread milling, and tap compared to significantly reduce cutting force, when this large diameter threaded processing, is particularly important because it solves the machine load is too large to drive taps normal processing problem.Machine clip thread cutter blade had come out ten years ago, it is also recognized that the processing M20 above the threaded hole in the processing center, using thread cutter compared with a tap, can significantly reduce processing costs.
4, in recent years, solid carbide thread milling cutter design and production technology matures, we developed a range of products size range. Our solution providers Israel VARGUS (Vargas) in recent years developed thread cutter products from the world famous carbide thread cutter thread cutter trends can be seen, the overall development of carbide thread milling knife Millipro series covers M1.6 × 0.35 to M4; Helicool series covers M5 ~ M19; MITM multi-blade, high-efficiency machine clip thread cutter series covers M19 ~ M60 size ranges; Shellmill series of multi-bit installation disc milling formula thread cutter covers the large diameter threaded processing M60 ~ M300 even larger. To help users use thread cutter solutions, making it easier to use, convenient, Vargas also developed TMGen software system, and has been in the culture, it can help users automatic tool selection and automatic preparation of the corresponding thread milling CNC program . Because it is easily broken when a blind hole, difficult chip removal, the use of tap processing: For small diameter threaded processing applications, an aviation companies need to process 50 M1.6 × 0.35 threaded blind holes in a piece of aluminum, customer problems are ; since the tapping of the final steps, such as scrap parts, on the part of the process takes a lot of time all the losses. Finally, customers choose processed M1.6 × 0.35 screw thread cutter, the linear velocity Vc = 25m / min, speed S = 4900r / min (machine limit), the amount of feed per revolution fz = 0.05mm / r, the actual processing time 4 seconds / thread with a tool to complete all 50 of the workpiece.
5, a blade manufacturer, since the blade hardness is generally HRC44, for small-diameter blade clamping screw holes, using high-speed steel cone difficult machining, tool life is short, easy to break, the M4 × 0.7 threading, customers choose solid carbide thread milling, Vc = 60m / min, Fz = 0.03mm / r, the processing time is 11 seconds / thread, tool life up to 832 threads, thread finish is very good.
6, for the medium-diameter threaded processing, the aluminum parts to be processed in an enterprise, there are M12 × 0.5, M6 × 0.5, M7 × 0.5 three different sizes of the same pitch threaded holes, previously required the use of three taps to completeprocessing. Now convert thread cutter, cutting conditions: Vc = 100m / min, S = 8000r / min, fz = 0.04mm / r, a thread processing time was 4 seconds, three seconds, three seconds, a tool can be processed 9000 thread, after the completion of the entire batch of parts, the tool has not been damaged.
7, in a large power generation, metallurgy and processing industry equipment, pumps, valves processing industry, thread cutter to solve the problem of large diameter threaded processing, a high efficiency, low cost ideal processing tool. If a valve parts processing enterprises, the need for processing 2 "× 11BSP-30 thread, material is steel, and want to improve the processing efficiency. By selecting multiple flutes, multi-blade machine clip thread cutter, using Vc = 80m / min, S = 850r / min, cutting parameters fz = 0.07mm / r, to achieve the processing time 2min / thread, blade life 620, effectively improve the processing efficiency of large diameter threads.
8, thread cutter as an advanced tool of rapid development in recent years, is more and more widely accepted by businesses, and exhibit excellent processing performance, as companies reduce thread processing costs, improve efficiency, solve problems thread processing a powerful weapon