CNC processing parts
1、 Tap CNC processing method:
It is the most common processing method to use the tap to process the threaded hole in tap processing, which is mainly applicable to the threaded hole with smaller diameter (D<30) and low requirements on the accuracy of the hole position.
In the 1980s, the flexible tapping method was adopted for threaded holes, that is, the flexible tapping chuck was used to hold the tap. The tapping chuck can be used for axial compensation to compensate the feed error caused by the asynchronous axial feed of the machine tool and the spindle speed to ensure the correct pitch. The flexible tapping chuck has complex structure, high cost, easy damage and low processing efficiency. In recent years, the performance of CNC machining centers has gradually improved, and the rigid tapping function has become the basic configuration of CNC machining centers.
Therefore, rigid tapping has become the main method of thread machining. In other words, a rigid spring chuck is used to hold the tap, and the feed of the spindle is consistent with the spindle speed controlled by the machine tool.
Compared with the flexible tapping chuck, the spring chuck is simple in structure, cheap in price and widely used. In addition to holding the tap, it can also hold the end mill, drill and other tools, which can reduce the cost of the tool. At the same time, rigid tapping can be used to conduct high-speed cutting, improve the use efficiency of the machining center, and reduce the manufacturing cost.
The programming of tap processing is relatively simple. Now the tapping subprogram is generally fixed in the machining center, and it is only necessary to assign each parameter. However, it should be noted that the meaning of some parameters is different due to different NC systems and different subroutine formats.
For example, SIEMEN840C control system, its programming format is: G84 X_ Y_ R2_ R3_ R4_ R5_ R6_ R7_ R8_ R9_ R10_ R13_。 During programming, only these 12 parameters need to be assigned.
2、 Thread milling CNC processing:
Thread milling is a milling method that uses thread milling cutter, three-axis linkage of machining center, namely X and Y axis arc interpolation, and Z axis linear feed to process threads.
Thread milling is mainly used for machining large hole threads and threaded holes of difficult to machine materials. It has the following characteristics:
(1) Fast processing speed, high efficiency and high processing precision. The cutting tool is generally made of cemented carbide, with fast cutting speed. The manufacturing precision of the cutter is high, so the milling thread precision is high.
(2) Milling tools are widely used. As long as the pitch is the same, whether the thread is left or right, a tool can be used to reduce the cost of the tool.
(3) The milling process is easy to remove chips and cool down. Compared with the tap, the cutting condition is good. It is especially suitable for the thread processing of difficult to machine materials such as aluminum, copper, stainless steel, and especially suitable for the thread processing of large parts and components and parts of valuable materials. It can ensure the quality of thread processing and the safety of workpieces.
(4) Because there is no tool front guide, it is suitable for machining blind holes with short thread bottom holes and holes without undercut.
3、 CNC processing method of snap fastener:
Large threaded holes can sometimes be found on box type parts. In the absence of taps and thread milling cutters, a method similar to lathe thread picking can be used. Install a thread turning tool on the boring tool bar to bore the thread. Precautions for Buckling Method
(1) After the spindle is started, there should be a delay time to ensure that the spindle reaches the rated speed.
(2) When retracting the tool, if it is a hand ground thread tool, because the tool cannot be grinded symmetrically, reverse retracting cannot be used. The spindle must be oriented, the tool moves radially, and then retracts.
(3) The cutter bar must be manufactured accurately, especially the position of the cutter groove must be consistent. In case of inconsistency, multiple tool bars cannot be used for machining. Otherwise, it will cause disorderly deduction.
(4) Even if it is a very thin buckle, it cannot be picked with one knife, otherwise it will cause tooth loss and poor surface roughness. At least two knives should be used.
(5) The processing efficiency is low, and it is only applicable to single small batch, special pitch thread and no corresponding cutter.