Three methods for machining threads on CNC machining centers

The benefits of using CNC machining centers to process workpieces are well understood, and there is still a mysterious veil surrounding the operation and programming of CNC machining centers. Today, Chenghui editor will share with you the machining method of threads. There are three ways to use CNC machining: thread milling, tap machining, and thread picking machining
1, Thread milling method
Thread milling is the use of thread milling tools for processing large hole threads, as well as for processing threaded holes in materials that are difficult to machine. It has the following characteristics:
1. The cutting tools are generally made of hard alloy materials, with fast speed, high precision in milling threads, and high processing efficiency;
2. With the same pitch, both left-hand and right-hand threads can use a single tool, reducing the cost of the tool;
3. Thread milling method is particularly suitable for thread processing of difficult to machine materials such as stainless steel and copper, which is easy to remove chips and cool, ensuring the quality and safety of processing;
4. Without tool front guidance, it is more convenient to process blind holes with shorter threaded bottom holes or holes without tool withdrawal slots.
The cutting tools for thread milling are divided into two types: machine clamp type hard alloy blade milling cutters and integral hard alloy milling cutters. Machine clamp type cutting tools can process holes with thread depth less than the length of the blade, as well as holes with thread depth greater than the length of the blade; The integral hard alloy milling cutter is used to process holes with thread depth less than the tool length;
Precautions for CNC programming of thread milling: to avoid tool damage or machining errors.
1. After machining the threaded bottom hole, use a drill bit to machine small diameter holes, and use boring to machine larger holes to ensure the accuracy of the threaded bottom hole;
2. The tool generally adopts a 1/2 circle arc trajectory for cutting in and out to ensure the shape of the thread, and the tool radius compensation value should be entered at this time.
2, CNC machining center tap machining method
Suitable for threaded holes with small diameters or low precision requirements for hole positions. In general, the diameter of the threaded bottom hole drill bit should be selected close to the upper limit of the diameter tolerance of the threaded bottom hole, which can reduce the machining allowance of the tap, reduce the load of the tap, and also improve the service life of the tap.
Everyone should choose a suitable tap according to the material being processed, relative to milling cutters and boring cutters;
Very sensitive to the processed material; Taps are divided into through hole taps and blind hole taps. The front end of the through hole tap has a long guide, which is the front chip. When processing blind holes, the depth of the thread cannot be guaranteed, while the front end of the blind hole has a short guide, which is the back chip. Therefore, it is important to pay attention to the difference between the two; When using a flexible tapping chuck, it is important to ensure that the diameter of the tap handle and the width of the four sides are the same as the tapping chuck; The diameter of the handle of the rigid tapping tap should be the same as the diameter of the spring jacket.
The programming of the tap machining method is relatively simple, all in fixed modes, and adding parameter values is sufficient. It should be noted that different CNC systems have different formats for subroutines, so the representative meanings of parameter values are different.
3, Picking buckle processing method
The pick buckle machining method is suitable for machining large threaded holes on box type parts, or when there is no tap or thread milling cutter, this method is used to install a thread turning tool on the boring bar for thread boring. There are several precautions for implementing the pick buckle processing method:
1. There should be a delay time when starting the spindle to ensure that it reaches the rated speed;
2. The grinding of hand ground thread cutting tools cannot be symmetrical, and reverse retraction cannot be used. Instead, the main spindle should be used to orient the tool to move radially and then retract it;
3. The tool holder must be precise and consistent with the position of the tool slot, otherwise multiple tool holders cannot be used for processing, resulting in disorderly locking;
4. When picking buckles, be careful not to cut them all at once, even for very thin buckles, otherwise it will cause tooth loss and poor surface roughness. Multiple cuts should be used for picking buckles;
5. The pick buckle machining method is only applicable to single piece, small batch, special pitch threads, and situations without corresponding cutting tools, resulting in low machining efficiency.
The CNC machining center buckle machining method is only a temporary emergency method. It is recommended that everyone use the thread machining method to machine tools, in order to effectively improve the efficiency and quality of thread machining, reduce machining costs, and improve the efficiency of using the machining center.