Thread Rolling Machine Selection Guide

New & Used Thread Rolling Machine For Sale, Thread Rolling Machine Selection Guide

Thread rolling machines create threads by moving and flowing metal into the thread shape. Thread rolling machines are used to produce screws, bolts and studs. Thread rolling is a cold forming operation used to form external threads in a blank.

Symmetrical threads are easier to manufacture and are used for general purpose fasteners. The most common thread form has a symmetrical V-shaped profile. The most common thread forms are uniform or metric threads. Other types of symmetrical threads include Whitworth and trapezoidal threads.

Thread rolling machines work much faster than tapping or threading. In addition, thread rolling produces fine surfaces, high productivity, low material costs, and no chips. Thread rolling machines produce threads and screws with higher strength in terms of tensile, shear and fatigue resistance. Thread rolling machines are more cost-effective than cutting threads due to long die life, minimal tool maintenance requirements, and high productivity.

Among them, the cylindrical die thread rolling machine is the most common.

So how to choose a right thread rolling machine?

The engineers of YTMTOOLS told us that the main factors affecting the accuracy of rolling workpieces are machine stability, die accuracy, blank selection, and machine debugging.

Regarding the stability of the machine, there are two important factors: 

First, the transmission system.

1. The stability of the transmission method.

At present, there are two transmission modes, worm gear transmission and gearbox transmission. The worm gear box is a single-speed transmission, with a high transmission ratio and easy deceleration. It was fine at the beginning, but the worm will be damaged in long-term operation, and the gap will be large, which will affect the accuracy. The gear box is a multi-speed drive, and the force is stable, and it is not easy to produce gaps. Therefore, the gearbox transmission is more stable, the service life is longer, and the long-term stable accuracy is maintained, but the price will be higher. A good thread rolling machine is usually driven by a gearbox.

2. The connection between the gearbox and the roller seat is connected by a transmission shaft, and the transmission must be smooth and free of gaps.

The key is that the universal joint has high precision and small spline clearance. Therefore, the selection of the drive shaft is very important. A good drive shaft enables the gearbox to drive to the roller seat without jumping and is stable, so that the roller seat can ensure the accuracy of the rollers. In general, when choosing a thread rolling machine, be sure to pay attention to the quality of the drive shaft.

3. The roller seat needs high precision, and the left and right brackets are parallel to each other and at the same level.

Accuracy can also be tested by the circular motion of the spindle. As shown in the table below, the test has five parts. Within the same rolling pressure range, TOBEST's spindle accuracy tolerances are higher than market standards.

Second, the feeding system.

1. The stability of the feeding system.

Both feeding and returning are hydraulically controlled, running smoothly and positioning accurately, which ensures the rolling accuracy of the workpiece. The integrated hydraulic system has more stable feeding and less noise. The split hydraulic system is prone to shaking and losing stability.

2. Stability of hydraulic oil cooling system.

The oil is cool at first, and the machine gets hot after running for a while. The liquid volume will expand, affecting the feed accuracy. According to the principle of thermal expansion, shrinkage, too high or too cold oil temperature will affect the accuracy of the feeding position. For example, in cold regions, the machine needs to be warmed up before threading. Therefore, a machine with a hydraulic oil cooling system is much better. It can keep the oil temperature between 19℃~20℃.

3. The slide rail is stable without any looseness.

Dovetail type, T type, linear guide slider. The stability of the slider determines the stability of the feed. Linear guide carriages are typically used on light lathes. The traditional thread rolling machine is a heavy-duty cold extrusion machine, so it's not suitable to use linear guide rails. The T-slides are easy to machine and service, and are advanced or retracted by means of two screw-locked plates. The dovetail slides advance and retreat as a unit. T-shaped slide rails are prone to large gaps, which affect the long-term running accuracy, while dovetail slides are subject to large forces, high stability and high precision. Therefore, the dovetail slide has higher stability than the T slide.

In addition to the influence of the drive system and the feeding system, the coolant of the cooling system also affects the accuracy of the workpiece. Coolant can promote oil circulation and maintain a certain oil temperature.

The iron powder produced by the workpiece can be filtered out, so as not to damage the roller and affect the machining accuracy. There are still many factors that affect the accuracy of rolling stock.

If you have more questions about purchasing a thread rolling machine, please feel free to contact us!

Email: ytmtools@gmail.com