Skills of CNC Turning Process
Four standard thread can be done by CNC turning,No matter what kind of thread turning, we must maintain a strict relationship between movement lathe spindle and tool,That is a turn per spindle, the tool should be moved away from a lead evenly. The following analysis by the common thread, a better understanding of the common threads in order to better processing common thread.
1.Common thread size analysis
Calculation of the required size common thread processing mainly includes the following two aspects.
<1.1> Consider the amount of expansion tooth type of threading, thread machining diameter of the workpiece before the D / D-0.1P, namely large-diameter minus 0.1 thread pitch.
<1.2> Thread cutting feed rate
Thread cutting feed rate can refer to the thread bottom diameter, that thread cutter infeed final position. Thread Trail are: large diameter minus two times higher teeth; tooth height = 0.54P, thread cutting feed rate should continue to decrease, the amount of feed based on specific tools and working materials selection.
2.Loading knife of Common thread cutter
When turning installed too high or too low, then the feed to a certain depth, after turning the flank against the workpiece, increasing friction, even the workpiece benders, resulting in eating knife phenomenon,Tools should adjust the height of its axis tool tip and workpiece contour.In the roughing and semi-precise turning process,Tip position higher than the center of the workpiece about 1% D.
Workpiece clamping should labor solid, tailstock can be used, so as to increase the rigidity of the workpiece.
3.Common thread programming process
In the current CNC turning, there are three processing methods of thread cutting.
<3.1> G32 Straight cutting method, since the work simultaneously on both sides of the blade, the cutting force is large, and difficult to discharge cut, so when cutting, the two cutting edges subject to wear. When a large pitch thread cutting, the cutting depth is large, the blade wear faster, resulting in pitch diameter errors; however its high precision machining of tooth shape, it is generally used for small-pitch thread processing.
<3.2> G92 Straight cutting method simplifies the programming, compared with G32 instruction improves efficiency.
<3.3> G76 Angular cutting method, since the unilateral edge, machining blade easy to damage and wear, so that the thread surface machining is not straight, sharp knife changes caused by poor tooth shape accuracy. But because of its unilateral edge work, tool load is small, chip easily, and cutting depth of regressive. Therefore, this processing method is generally applicable to large pitch thread processing.
When machining high precision thread, can be twice the processing is completed, both first with the G76 machining methods roughing, then finishing with a G32 working method. But pay attention to the starting point of the tool must be accurate.
