With the continuous development of the market economy, improving product quality has become one of the key factors in determining success or failure in market competition. This is especially true for the bearing industry, where global trade and the integration with the WTO have intensified competitive pressure. The production of bearing rollers is a complex process that involves multiple stages and requires precise control to ensure high-quality output. During the forming process, various factors can affect the final quality of the roller. For instance, cold heading machines often produce defective or substandard roller blanks, which can lead to waste and reduced efficiency. To address these issues, manufacturers are continuously seeking more effective and cost-efficient methods to produce high-quality rollers.
For example, when using a Z31-25 cold heading machine to form bearing rollers, problems such as under-pressure, stack damage, pitting, and deformation may occur. Although the roller appears acceptable at the time of stamping, it may later develop a curved shape due to elastic recovery. Upon investigation, we found that the raw materials may not always meet ideal standards, which affects the straightness and overall quality of the final product. To solve this, a more rigorous alignment system is needed to ensure the best possible straightness of the raw material before processing.
**1. Process Analysis**
In the production of bearing rollers, many quality issues arise during the stamping and forming process. One common problem is the squeezing and deformation of the roller after compression. These defects can significantly impact the performance and reliability of the final product.
(1) **Under-Pressure**: As shown in Figure 1, the thickness and length of the roller vary significantly. This irregularity affects the quality of the finished product. Additionally, bending in the raw material can hinder the feeding process, leading to uneven pressure distribution and further quality issues.
(2) **Deformation After Compression**: Even if the roller looks good after stamping, it may later bend due to residual stresses. Initially, a one-way straightening device was used, but it failed to fully resolve the issue. Further research revealed that unidirectionally bent materials could be corrected, but bidirectionally bent materials were more challenging. This led to the development of a two-way straightening device, which proved more effective in addressing the problem.
**2. One-Way Straightening Device Principle**
This device is placed before the cold heading machine to align and stabilize the raw material. It helps correct minor bends and improves the feeding process. By adjusting the handwheel, the moving plate drives the D4 and D5 wheels to move back and forth, effectively straightening the material. However, overuse can cause counteraction, so careful adjustment is necessary. This device works well on smaller machines like the Z31-13, where the smaller diameter of the roller reduces the risk of bending.
**3. Bidirectional Straightening Device and Its Principle**
For larger machines like the Z31-25, where the roller is thicker and more prone to multi-directional bending, a one-way straightening device is insufficient. To address this, a two-way straightening device was designed. It builds upon the one-way model by adding an additional set of wheels at a 90-degree angle, allowing for more comprehensive correction. However, early versions caused feeding difficulties and insufficient feed length. To improve performance, bearings were added to each wheel to enhance rotation, and reinforcing ribs were introduced to increase structural strength while reducing weight. After testing, the results were highly satisfactory.
**4. Effect of the Two-Way Straightening Device**
We tested the device on the Z31-25 cold heading machine. The table below shows the improvement in compression conditions before and after installation:
[Image: A comparison chart showing improved performance]
From the data, it's clear that the two-way straightening device significantly improves the quality of the raw material, reduces defects, and enhances production efficiency. It is recommended for widespread use to achieve better economic benefits. Similar devices are already in use in both domestic and international industries, proving their effectiveness.
**5. Conclusion**
The original one-way straightening device was not sufficient for bidirectional correction. To overcome this, we developed and implemented a two-way straightening device. This innovation has proven invaluable in the cold forming process, reducing waste, minimizing material deformation, and greatly improving the overall quality of the roller. Its application has significant implications for production efficiency and cost savings.
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Yangzhou Donglun Industrial Equipment Co., Ltd , https://www.dltubemill.com