How to improve the qualification rate of short cylindrical roller bearings

**How to Improve the Qualification Rate of Short Cylindrical Roller Bearings** Home > Bearing Knowledge > How to Improve the Qualification Rate of Short Cylindrical Roller Bearings Source: China Bearing Network | Time: 2014-02-05 --- Short cylindrical roller bearings are known for their high rotational precision, accurate fit, and ability to handle primary radial loads. They are commonly used in large precision machine tools and finishing equipment. Recently, these bearings have become a key product for Luo Axis Groupâ€™s large-scale bearing business unit, contributing significantly to its production valueâ€”accounting for about one-third of the total output. However, due to outdated production processes and methods, the qualification rate of these bearings was only around 60%, which led to excessive waste in data, time, and resources, ultimately affecting the unitâ€™s economic performance. To address this issue, the company focused on optimizing the production process of the "32672" type short cylindrical roller bearing, which has the highest annual output. This model was chosen as a pilot for process improvement, with the goal of applying the same techniques to other bearing types and achieving greater economic benefits. ### Current Production Issues 1. The inner and outer rings of the "32672" bearing are made from Gcr15simn steel, which is difficult to control during heat treatment and quenching. This often leads to deformation and elliptical shapes, making it hard to perform grinding after quenching, resulting in over-scaling of the raceways. 2. Due to uneven residual stress caused by non-uniform quenching, the raceway surface becomes unstable after grinding, making it difficult to meet process requirements. 3. The aging of the machine tool equipment leads to low spindle rotation accuracy, causing significant surface irregularities after rough grinding, which then results in excessive differences after final grinding. 4. Inconsistent skills among workers further contribute to over-grinding of the raceways, affecting the installation clearance of the entire bearing and leading to instability during operation. These issues resulted in a low qualification rate of just 60%, along with unnecessary costs in labor, processing, and materials. ### Improvement Plan and Methods To tackle these challenges, the company implemented several process improvements: 1. **Heat Treatment Optimization**: By collaborating closely with the heat treatment plant, they managed to control deformation more effectively. Adjustments were made based on the heat treatment shortening data provided, ensuring sufficient grinding allowance after quenching. 2. **Additional Tempering Process**: A new tempering step was introduced to eliminate residual stresses and stabilize the raceway scale after final grinding. 3. **Machine Tool Upgrade**: The old machine tools were overhauled to improve spindle accuracy and control feed rates, thereby enhancing the surface finish of the raceways and preventing over-grinding. 4. **Process Layout Adjustment**: Based on production scheduling, the layout was optimized to focus on the inner ring, where deformation had the greatest impact. When over-grinding occurred, adjustments such as undercutting the housing or modifying the middle diameter of the retainer hole were made to ensure proper fit. 5. **Standardization of Raceway Dimensions**: Tighter control was applied to the raceway dimensions, ensuring that the size variation between batches remained minimal. This helped improve the matching qualification rate significantly. After implementing these improvements, the qualification rate of the "32672" short cylindrical roller bearing increased from 60% to over 96%. This not only reduced the repair rate but also saved a significant amount of labor and material costs, greatly improving overall production efficiency. --- **Related Bearing Knowledge** Understanding the authenticity of NSK bearings involves recognizing features like smooth timing protection. For large motor bearings, proper housing design plays a crucial role in ensuring smooth operation. Additionally, FAG bearing information can help users make informed decisions when selecting high-speed bearings. --- This article is linked to http:// Please indicate the bearing network at http:// Previous: The Difference Between Ball Bearings and Roller Bearings Next: The Characteristics of Sliding Bearings
Fish Scale
Fish Scale,Scales Fish,Digital Fish Scale,Fish Weight Scale
Jiangyin Suofei Electronic Technology Co.,Ltd. , https://www.suofeiscales.com