The purpose of the research on double-start threads on CNC lathes is to solve processing problems and improve processing methods. By combining existing CNC processing equipment, optimizing processing procedures and processes, and using CNC lathes and processing procedures, double-start thread parts can be processed, which can not only meet the requirements of dimensional accuracy, but also optimize the processing time quota.
Characteristics of double-start threads
There are many types of threads. According to the shape of the spiral line, they can be divided into cylindrical threads and conical threads. According to different uses, they can be divided into connecting threads and transmission threads. According to the characteristics of the tooth type, they can be divided into triangular threads, rectangular threads, trapezoidal threads, serrated threads, etc. According to the direction of the spiral line, they can be divided into right-handed threads and left-handed threads. According to the number of spiral lines, they can be divided into single spiral threads and multi-spiral threads.
Among various mechanical products, parts with threads are widely used, especially transmission threads, which are widely used in the manufacturing industry.
One of them is to play the role of transmission. For example, the long wire on the ordinary lathe and the wire of the medium and small slides are also transmitted through the trapezoidal thread between the two wires to realize the movement of the workbench and the tool holder.
Secondly, it plays the role of connecting steel structures. In steel frame structures, trapezoidal threads are used to connect steel columns and steel beams to achieve stable structural support.
At the same time, in the installation process of some large mechanical equipment, trapezoidal threads are also used to fix the connection between the equipment and the base.
Thirdly, it plays the role of transmitting power. For example, the original rotational motion is changed into a linear motion form, and it is driven by manpower through the screw pair. In the maintenance of railway vehicles, the support of construction projects, and the lifting of general heavy objects, the screw and nut sleeve are used as lifting parts.
Key points for double-head thread processing
(1) Before running the thread cycle program, it is necessary to ensure that the parts and tools are clamped and stable on the CNC lathe, and ensure that the workpiece or tool will not loosen or fall during the processing, because the second clamping is not allowed before the thread processing is completed, otherwise the thread will be messy.
(2) Before processing, the spindle speed of the lathe must be normal. The spindle speed of the CNC lathe must not be changed during the processing, and the spindle speed of the CNC lathe multiplier cannot be adjusted at will. Otherwise, the thread will be messy.
(3) Since the thread dimensions have high precision requirements, the metric micrometer should be correctly selected for measurement to ensure the precision of the thread dimensions.
(4) G78 is the most commonly used thread cycle instruction for CNC lathe processing double-start threads. The difference between G76 and G78 is that G76 is a single-side feed method, while G78 is a left-right feed method. Therefore, G78 is more suitable for the processing of multi-start threads and trapezoidal threads such as lead screws and worms. Therefore, G78 is more commonly used in the CNC processing of multi-start threads.
(5) In CNC processing, CNC lathe processing of double-start threads has advantages over ordinary lathe processing. Ordinary lathe processing accuracy is not easy to guarantee, and there are many error factors. CNC lathe processing not only reduces the fatigue strength of workers, but also greatly reduces errors and improves the product quality and production efficiency of double-start threads.
